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52 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
Linus Torvalds
|
a9dce6679d |
pidfd patches for v5.1-rc1
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Merge tag 'pidfd-v5.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux
Pull pidfd system call from Christian Brauner:
"This introduces the ability to use file descriptors from /proc/<pid>/
as stable handles on struct pid. Even if a pid is recycled the handle
will not change. For a start these fds can be used to send signals to
the processes they refer to.
With the ability to use /proc/<pid> fds as stable handles on struct
pid we can fix a long-standing issue where after a process has exited
its pid can be reused by another process. If a caller sends a signal
to a reused pid it will end up signaling the wrong process.
With this patchset we enable a variety of use cases. One obvious
example is that we can now safely delegate an important part of
process management - sending signals - to processes other than the
parent of a given process by sending file descriptors around via scm
rights and not fearing that the given process will have been recycled
in the meantime. It also allows for easy testing whether a given
process is still alive or not by sending signal 0 to a pidfd which is
quite handy.
There has been some interest in this feature e.g. from systems
management (systemd, glibc) and container managers. I have requested
and gotten comments from glibc to make sure that this syscall is
suitable for their needs as well. In the future I expect it to take on
most other pid-based signal syscalls. But such features are left for
the future once they are needed.
This has been sitting in linux-next for quite a while and has not
caused any issues. It comes with selftests which verify basic
functionality and also test that a recycled pid cannot be signaled via
a pidfd.
Jon has written about a prior version of this patchset. It should
cover the basic functionality since not a lot has changed since then:
https://lwn.net/Articles/773459/
The commit message for the syscall itself is extensively documenting
the syscall, including it's functionality and extensibility"
* tag 'pidfd-v5.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux:
selftests: add tests for pidfd_send_signal()
signal: add pidfd_send_signal() syscall
|
||
|
Linus Torvalds
|
38e7571c07 |
io_uring-2019-03-06
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Merge tag 'io_uring-2019-03-06' of git://git.kernel.dk/linux-block
Pull io_uring IO interface from Jens Axboe:
"Second attempt at adding the io_uring interface.
Since the first one, we've added basic unit testing of the three
system calls, that resides in liburing like the other unit tests that
we have so far. It'll take a while to get full coverage of it, but
we're working towards it. I've also added two basic test programs to
tools/io_uring. One uses the raw interface and has support for all the
various features that io_uring supports outside of standard IO, like
fixed files, fixed IO buffers, and polled IO. The other uses the
liburing API, and is a simplified version of cp(1).
This adds support for a new IO interface, io_uring.
io_uring allows an application to communicate with the kernel through
two rings, the submission queue (SQ) and completion queue (CQ) ring.
This allows for very efficient handling of IOs, see the v5 posting for
some basic numbers:
https://lore.kernel.org/linux-block/20190116175003.17880-1-axboe@kernel.dk/
Outside of just efficiency, the interface is also flexible and
extendable, and allows for future use cases like the upcoming NVMe
key-value store API, networked IO, and so on. It also supports async
buffered IO, something that we've always failed to support in the
kernel.
Outside of basic IO features, it supports async polled IO as well.
This particular feature has already been tested at Facebook months ago
for flash storage boxes, with 25-33% improvements. It makes polled IO
actually useful for real world use cases, where even basic flash sees
a nice win in terms of efficiency, latency, and performance. These
boxes were IOPS bound before, now they are not.
This series adds three new system calls. One for setting up an
io_uring instance (io_uring_setup(2)), one for submitting/completing
IO (io_uring_enter(2)), and one for aux functions like registrating
file sets, buffers, etc (io_uring_register(2)). Through the help of
Arnd, I've coordinated the syscall numbers so merge on that front
should be painless.
Jon did a writeup of the interface a while back, which (except for
minor details that have been tweaked) is still accurate. Find that
here:
https://lwn.net/Articles/776703/
Huge thanks to Al Viro for helping getting the reference cycle code
correct, and to Jann Horn for his extensive reviews focused on both
security and bugs in general.
There's a userspace library that provides basic functionality for
applications that don't need or want to care about how to fiddle with
the rings directly. It has helpers to allow applications to easily set
up an io_uring instance, and submit/complete IO through it without
knowing about the intricacies of the rings. It also includes man pages
(thanks to Jeff Moyer), and will continue to grow support helper
functions and features as time progresses. Find it here:
git://git.kernel.dk/liburing
Fio has full support for the raw interface, both in the form of an IO
engine (io_uring), but also with a small test application (t/io_uring)
that can exercise and benchmark the interface"
* tag 'io_uring-2019-03-06' of git://git.kernel.dk/linux-block:
io_uring: add a few test tools
io_uring: allow workqueue item to handle multiple buffered requests
io_uring: add support for IORING_OP_POLL
io_uring: add io_kiocb ref count
io_uring: add submission polling
io_uring: add file set registration
net: split out functions related to registering inflight socket files
io_uring: add support for pre-mapped user IO buffers
block: implement bio helper to add iter bvec pages to bio
io_uring: batch io_kiocb allocation
io_uring: use fget/fput_many() for file references
fs: add fget_many() and fput_many()
io_uring: support for IO polling
io_uring: add fsync support
Add io_uring IO interface
|
||
|
Christian Brauner
|
3eb39f4793
|
signal: add pidfd_send_signal() syscall
The kill() syscall operates on process identifiers (pid). After a process
has exited its pid can be reused by another process. If a caller sends a
signal to a reused pid it will end up signaling the wrong process. This
issue has often surfaced and there has been a push to address this problem [1].
This patch uses file descriptors (fd) from proc/<pid> as stable handles on
struct pid. Even if a pid is recycled the handle will not change. The fd
can be used to send signals to the process it refers to.
Thus, the new syscall pidfd_send_signal() is introduced to solve this
problem. Instead of pids it operates on process fds (pidfd).
/* prototype and argument /*
long pidfd_send_signal(int pidfd, int sig, siginfo_t *info, unsigned int flags);
/* syscall number 424 */
The syscall number was chosen to be 424 to align with Arnd's rework in his
y2038 to minimize merge conflicts (cf. [25]).
In addition to the pidfd and signal argument it takes an additional
siginfo_t and flags argument. If the siginfo_t argument is NULL then
pidfd_send_signal() is equivalent to kill(<positive-pid>, <signal>). If it
is not NULL pidfd_send_signal() is equivalent to rt_sigqueueinfo().
The flags argument is added to allow for future extensions of this syscall.
It currently needs to be passed as 0. Failing to do so will cause EINVAL.
/* pidfd_send_signal() replaces multiple pid-based syscalls */
The pidfd_send_signal() syscall currently takes on the job of
rt_sigqueueinfo(2) and parts of the functionality of kill(2), Namely, when a
positive pid is passed to kill(2). It will however be possible to also
replace tgkill(2) and rt_tgsigqueueinfo(2) if this syscall is extended.
/* sending signals to threads (tid) and process groups (pgid) */
Specifically, the pidfd_send_signal() syscall does currently not operate on
process groups or threads. This is left for future extensions.
In order to extend the syscall to allow sending signal to threads and
process groups appropriately named flags (e.g. PIDFD_TYPE_PGID, and
PIDFD_TYPE_TID) should be added. This implies that the flags argument will
determine what is signaled and not the file descriptor itself. Put in other
words, grouping in this api is a property of the flags argument not a
property of the file descriptor (cf. [13]). Clarification for this has been
requested by Eric (cf. [19]).
When appropriate extensions through the flags argument are added then
pidfd_send_signal() can additionally replace the part of kill(2) which
operates on process groups as well as the tgkill(2) and
rt_tgsigqueueinfo(2) syscalls.
How such an extension could be implemented has been very roughly sketched
in [14], [15], and [16]. However, this should not be taken as a commitment
to a particular implementation. There might be better ways to do it.
Right now this is intentionally left out to keep this patchset as simple as
possible (cf. [4]).
/* naming */
The syscall had various names throughout iterations of this patchset:
- procfd_signal()
- procfd_send_signal()
- taskfd_send_signal()
In the last round of reviews it was pointed out that given that if the
flags argument decides the scope of the signal instead of different types
of fds it might make sense to either settle for "procfd_" or "pidfd_" as
prefix. The community was willing to accept either (cf. [17] and [18]).
Given that one developer expressed strong preference for the "pidfd_"
prefix (cf. [13]) and with other developers less opinionated about the name
we should settle for "pidfd_" to avoid further bikeshedding.
The "_send_signal" suffix was chosen to reflect the fact that the syscall
takes on the job of multiple syscalls. It is therefore intentional that the
name is not reminiscent of neither kill(2) nor rt_sigqueueinfo(2). Not the
fomer because it might imply that pidfd_send_signal() is a replacement for
kill(2), and not the latter because it is a hassle to remember the correct
spelling - especially for non-native speakers - and because it is not
descriptive enough of what the syscall actually does. The name
"pidfd_send_signal" makes it very clear that its job is to send signals.
/* zombies */
Zombies can be signaled just as any other process. No special error will be
reported since a zombie state is an unreliable state (cf. [3]). However,
this can be added as an extension through the @flags argument if the need
ever arises.
/* cross-namespace signals */
The patch currently enforces that the signaler and signalee either are in
the same pid namespace or that the signaler's pid namespace is an ancestor
of the signalee's pid namespace. This is done for the sake of simplicity
and because it is unclear to what values certain members of struct
siginfo_t would need to be set to (cf. [5], [6]).
/* compat syscalls */
It became clear that we would like to avoid adding compat syscalls
(cf. [7]). The compat syscall handling is now done in kernel/signal.c
itself by adding __copy_siginfo_from_user_generic() which lets us avoid
compat syscalls (cf. [8]). It should be noted that the addition of
__copy_siginfo_from_user_any() is caused by a bug in the original
implementation of rt_sigqueueinfo(2) (cf. 12).
With upcoming rework for syscall handling things might improve
significantly (cf. [11]) and __copy_siginfo_from_user_any() will not gain
any additional callers.
/* testing */
This patch was tested on x64 and x86.
/* userspace usage */
An asciinema recording for the basic functionality can be found under [9].
With this patch a process can be killed via:
#define _GNU_SOURCE
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <unistd.h>
static inline int do_pidfd_send_signal(int pidfd, int sig, siginfo_t *info,
unsigned int flags)
{
#ifdef __NR_pidfd_send_signal
return syscall(__NR_pidfd_send_signal, pidfd, sig, info, flags);
#else
return -ENOSYS;
#endif
}
int main(int argc, char *argv[])
{
int fd, ret, saved_errno, sig;
if (argc < 3)
exit(EXIT_FAILURE);
fd = open(argv[1], O_DIRECTORY | O_CLOEXEC);
if (fd < 0) {
printf("%s - Failed to open \"%s\"\n", strerror(errno), argv[1]);
exit(EXIT_FAILURE);
}
sig = atoi(argv[2]);
printf("Sending signal %d to process %s\n", sig, argv[1]);
ret = do_pidfd_send_signal(fd, sig, NULL, 0);
saved_errno = errno;
close(fd);
errno = saved_errno;
if (ret < 0) {
printf("%s - Failed to send signal %d to process %s\n",
strerror(errno), sig, argv[1]);
exit(EXIT_FAILURE);
}
exit(EXIT_SUCCESS);
}
/* Q&A
* Given that it seems the same questions get asked again by people who are
* late to the party it makes sense to add a Q&A section to the commit
* message so it's hopefully easier to avoid duplicate threads.
*
* For the sake of progress please consider these arguments settled unless
* there is a new point that desperately needs to be addressed. Please make
* sure to check the links to the threads in this commit message whether
* this has not already been covered.
*/
Q-01: (Florian Weimer [20], Andrew Morton [21])
What happens when the target process has exited?
A-01: Sending the signal will fail with ESRCH (cf. [22]).
Q-02: (Andrew Morton [21])
Is the task_struct pinned by the fd?
A-02: No. A reference to struct pid is kept. struct pid - as far as I
understand - was created exactly for the reason to not require to
pin struct task_struct (cf. [22]).
Q-03: (Andrew Morton [21])
Does the entire procfs directory remain visible? Just one entry
within it?
A-03: The same thing that happens right now when you hold a file descriptor
to /proc/<pid> open (cf. [22]).
Q-04: (Andrew Morton [21])
Does the pid remain reserved?
A-04: No. This patchset guarantees a stable handle not that pids are not
recycled (cf. [22]).
Q-05: (Andrew Morton [21])
Do attempts to signal that fd return errors?
A-05: See {Q,A}-01.
Q-06: (Andrew Morton [22])
Is there a cleaner way of obtaining the fd? Another syscall perhaps.
A-06: Userspace can already trivially retrieve file descriptors from procfs
so this is something that we will need to support anyway. Hence,
there's no immediate need to add another syscalls just to make
pidfd_send_signal() not dependent on the presence of procfs. However,
adding a syscalls to get such file descriptors is planned for a
future patchset (cf. [22]).
Q-07: (Andrew Morton [21] and others)
This fd-for-a-process sounds like a handy thing and people may well
think up other uses for it in the future, probably unrelated to
signals. Are the code and the interface designed to permit such
future applications?
A-07: Yes (cf. [22]).
Q-08: (Andrew Morton [21] and others)
Now I think about it, why a new syscall? This thing is looking
rather like an ioctl?
A-08: This has been extensively discussed. It was agreed that a syscall is
preferred for a variety or reasons. Here are just a few taken from
prior threads. Syscalls are safer than ioctl()s especially when
signaling to fds. Processes are a core kernel concept so a syscall
seems more appropriate. The layout of the syscall with its four
arguments would require the addition of a custom struct for the
ioctl() thereby causing at least the same amount or even more
complexity for userspace than a simple syscall. The new syscall will
replace multiple other pid-based syscalls (see description above).
The file-descriptors-for-processes concept introduced with this
syscall will be extended with other syscalls in the future. See also
[22], [23] and various other threads already linked in here.
Q-09: (Florian Weimer [24])
What happens if you use the new interface with an O_PATH descriptor?
A-09:
pidfds opened as O_PATH fds cannot be used to send signals to a
process (cf. [2]). Signaling processes through pidfds is the
equivalent of writing to a file. Thus, this is not an operation that
operates "purely at the file descriptor level" as required by the
open(2) manpage. See also [4].
/* References */
[1]: https://lore.kernel.org/lkml/20181029221037.87724-1-dancol@google.com/
[2]: https://lore.kernel.org/lkml/874lbtjvtd.fsf@oldenburg2.str.redhat.com/
[3]: https://lore.kernel.org/lkml/20181204132604.aspfupwjgjx6fhva@brauner.io/
[4]: https://lore.kernel.org/lkml/20181203180224.fkvw4kajtbvru2ku@brauner.io/
[5]: https://lore.kernel.org/lkml/20181121213946.GA10795@mail.hallyn.com/
[6]: https://lore.kernel.org/lkml/20181120103111.etlqp7zop34v6nv4@brauner.io/
[7]: https://lore.kernel.org/lkml/36323361-90BD-41AF-AB5B-EE0D7BA02C21@amacapital.net/
[8]: https://lore.kernel.org/lkml/87tvjxp8pc.fsf@xmission.com/
[9]: https://asciinema.org/a/IQjuCHew6bnq1cr78yuMv16cy
[11]: https://lore.kernel.org/lkml/F53D6D38-3521-4C20-9034-5AF447DF62FF@amacapital.net/
[12]: https://lore.kernel.org/lkml/87zhtjn8ck.fsf@xmission.com/
[13]: https://lore.kernel.org/lkml/871s6u9z6u.fsf@xmission.com/
[14]: https://lore.kernel.org/lkml/20181206231742.xxi4ghn24z4h2qki@brauner.io/
[15]: https://lore.kernel.org/lkml/20181207003124.GA11160@mail.hallyn.com/
[16]: https://lore.kernel.org/lkml/20181207015423.4miorx43l3qhppfz@brauner.io/
[17]: https://lore.kernel.org/lkml/CAGXu5jL8PciZAXvOvCeCU3wKUEB_dU-O3q0tDw4uB_ojMvDEew@mail.gmail.com/
[18]: https://lore.kernel.org/lkml/20181206222746.GB9224@mail.hallyn.com/
[19]: https://lore.kernel.org/lkml/20181208054059.19813-1-christian@brauner.io/
[20]: https://lore.kernel.org/lkml/8736rebl9s.fsf@oldenburg.str.redhat.com/
[21]: https://lore.kernel.org/lkml/20181228152012.dbf0508c2508138efc5f2bbe@linux-foundation.org/
[22]: https://lore.kernel.org/lkml/20181228233725.722tdfgijxcssg76@brauner.io/
[23]: https://lwn.net/Articles/773459/
[24]: https://lore.kernel.org/lkml/8736rebl9s.fsf@oldenburg.str.redhat.com/
[25]: https://lore.kernel.org/lkml/CAK8P3a0ej9NcJM8wXNPbcGUyOUZYX+VLoDFdbenW3s3114oQZw@mail.gmail.com/
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Jann Horn <jannh@google.com>
Cc: Andy Lutomirsky <luto@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Florian Weimer <fweimer@redhat.com>
Signed-off-by: Christian Brauner <christian@brauner.io>
Reviewed-by: Tycho Andersen <tycho@tycho.ws>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Serge Hallyn <serge@hallyn.com>
Acked-by: Aleksa Sarai <cyphar@cyphar.com>
|
||
|
Jens Axboe
|
edafccee56 |
io_uring: add support for pre-mapped user IO buffers
If we have fixed user buffers, we can map them into the kernel when we setup the io_uring. That avoids the need to do get_user_pages() for each and every IO. To utilize this feature, the application must call io_uring_register() after having setup an io_uring instance, passing in IORING_REGISTER_BUFFERS as the opcode. The argument must be a pointer to an iovec array, and the nr_args should contain how many iovecs the application wishes to map. If successful, these buffers are now mapped into the kernel, eligible for IO. To use these fixed buffers, the application must use the IORING_OP_READ_FIXED and IORING_OP_WRITE_FIXED opcodes, and then set sqe->index to the desired buffer index. sqe->addr..sqe->addr+seq->len must point to somewhere inside the indexed buffer. The application may register buffers throughout the lifetime of the io_uring instance. It can call io_uring_register() with IORING_UNREGISTER_BUFFERS as the opcode to unregister the current set of buffers, and then register a new set. The application need not unregister buffers explicitly before shutting down the io_uring instance. It's perfectly valid to setup a larger buffer, and then sometimes only use parts of it for an IO. As long as the range is within the originally mapped region, it will work just fine. For now, buffers must not be file backed. If file backed buffers are passed in, the registration will fail with -1/EOPNOTSUPP. This restriction may be relaxed in the future. RLIMIT_MEMLOCK is used to check how much memory we can pin. A somewhat arbitrary 1G per buffer size is also imposed. Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> |
||
|
Jens Axboe
|
2b188cc1bb |
Add io_uring IO interface
The submission queue (SQ) and completion queue (CQ) rings are shared between the application and the kernel. This eliminates the need to copy data back and forth to submit and complete IO. IO submissions use the io_uring_sqe data structure, and completions are generated in the form of io_uring_cqe data structures. The SQ ring is an index into the io_uring_sqe array, which makes it possible to submit a batch of IOs without them being contiguous in the ring. The CQ ring is always contiguous, as completion events are inherently unordered, and hence any io_uring_cqe entry can point back to an arbitrary submission. Two new system calls are added for this: io_uring_setup(entries, params) Sets up an io_uring instance for doing async IO. On success, returns a file descriptor that the application can mmap to gain access to the SQ ring, CQ ring, and io_uring_sqes. io_uring_enter(fd, to_submit, min_complete, flags, sigset, sigsetsize) Initiates IO against the rings mapped to this fd, or waits for them to complete, or both. The behavior is controlled by the parameters passed in. If 'to_submit' is non-zero, then we'll try and submit new IO. If IORING_ENTER_GETEVENTS is set, the kernel will wait for 'min_complete' events, if they aren't already available. It's valid to set IORING_ENTER_GETEVENTS and 'min_complete' == 0 at the same time, this allows the kernel to return already completed events without waiting for them. This is useful only for polling, as for IRQ driven IO, the application can just check the CQ ring without entering the kernel. With this setup, it's possible to do async IO with a single system call. Future developments will enable polled IO with this interface, and polled submission as well. The latter will enable an application to do IO without doing ANY system calls at all. For IRQ driven IO, an application only needs to enter the kernel for completions if it wants to wait for them to occur. Each io_uring is backed by a workqueue, to support buffered async IO as well. We will only punt to an async context if the command would need to wait for IO on the device side. Any data that can be accessed directly in the page cache is done inline. This avoids the slowness issue of usual threadpools, since cached data is accessed as quickly as a sync interface. Sample application: http://git.kernel.dk/cgit/fio/plain/t/io_uring.c Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> |
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|
Arnd Bergmann
|
48166e6ea4 |
y2038: add 64-bit time_t syscalls to all 32-bit architectures
This adds 21 new system calls on each ABI that has 32-bit time_t today. All of these have the exact same semantics as their existing counterparts, and the new ones all have macro names that end in 'time64' for clarification. This gets us to the point of being able to safely use a C library that has 64-bit time_t in user space. There are still a couple of loose ends to tie up in various areas of the code, but this is the big one, and should be entirely uncontroversial at this point. In particular, there are four system calls (getitimer, setitimer, waitid, and getrusage) that don't have a 64-bit counterpart yet, but these can all be safely implemented in the C library by wrapping around the existing system calls because the 32-bit time_t they pass only counts elapsed time, not time since the epoch. They will be dealt with later. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Acked-by: Catalin Marinas <catalin.marinas@arm.com> |
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|
Arnd Bergmann
|
d33c577ccc |
y2038: rename old time and utime syscalls
The time, stime, utime, utimes, and futimesat system calls are only used on older architectures, and we do not provide y2038 safe variants of them, as they are replaced by clock_gettime64, clock_settime64, and utimensat_time64. However, for consistency it seems better to have the 32-bit architectures that still use them call the "time32" entry points (leaving the traditional handlers for the 64-bit architectures), like we do for system calls that now require two versions. Note: We used to always define __ARCH_WANT_SYS_TIME and __ARCH_WANT_SYS_UTIME and only set __ARCH_WANT_COMPAT_SYS_TIME and __ARCH_WANT_SYS_UTIME32 for compat mode on 64-bit kernels. Now this is reversed: only 64-bit architectures set __ARCH_WANT_SYS_TIME/UTIME, while we need __ARCH_WANT_SYS_TIME32/UTIME32 for 32-bit architectures and compat mode. The resulting asm/unistd.h changes look a bit counterintuitive. This is only a cleanup patch and it should not change any behavior. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> |
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|
Arnd Bergmann
|
00bf25d693 |
y2038: use time32 syscall names on 32-bit
This is the big flip, where all 32-bit architectures set COMPAT_32BIT_TIME and use the _time32 system calls from the former compat layer instead of the system calls that take __kernel_timespec and similar arguments. The temporary redirects for __kernel_timespec, __kernel_itimerspec and __kernel_timex can get removed with this. It would be easy to split this commit by architecture, but with the new generated system call tables, it's easy enough to do it all at once, which makes it a little easier to check that the changes are the same in each table. Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Arnd Bergmann <arnd@arndb.de> |
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|
Arnd Bergmann
|
8dabe7245b |
y2038: syscalls: rename y2038 compat syscalls
A lot of system calls that pass a time_t somewhere have an implementation using a COMPAT_SYSCALL_DEFINEx() on 64-bit architectures, and have been reworked so that this implementation can now be used on 32-bit architectures as well. The missing step is to redefine them using the regular SYSCALL_DEFINEx() to get them out of the compat namespace and make it possible to build them on 32-bit architectures. Any system call that ends in 'time' gets a '32' suffix on its name for that version, while the others get a '_time32' suffix, to distinguish them from the normal version, which takes a 64-bit time argument in the future. In this step, only 64-bit architectures are changed, doing this rename first lets us avoid touching the 32-bit architectures twice. Acked-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> |
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|
Arnd Bergmann
|
7948450d45 |
x86/x32: use time64 versions of sigtimedwait and recvmmsg
x32 has always followed the time64 calling conventions of these syscalls, which required a special hack in compat_get_timespec aka get_old_timespec32 to continue working. Since we now have the time64 syscalls, use those explicitly. Signed-off-by: Arnd Bergmann <arnd@arndb.de> |
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|
Arnd Bergmann
|
0d6040d468 |
arch: add split IPC system calls where needed
The IPC system call handling is highly inconsistent across architectures, some use sys_ipc, some use separate calls, and some use both. We also have some architectures that require passing IPC_64 in the flags, and others that set it implicitly. For the addition of a y2038 safe semtimedop() system call, I chose to only support the separate entry points, but that requires first supporting the regular ones with their own syscall numbers. The IPC_64 is now implied by the new semctl/shmctl/msgctl system calls even on the architectures that require passing it with the ipc() multiplexer. I'm not adding the new semtimedop() or semop() on 32-bit architectures, those will get implemented using the new semtimedop_time64() version that gets added along with the other time64 calls. Three 64-bit architectures (powerpc, s390 and sparc) get semtimedop(). Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> |
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|
Mathieu Desnoyers
|
05c17cedf8 |
x86: Wire up restartable sequence system call
Wire up the rseq system call on x86 32/64. This provides an ABI improving the speed of a user-space getcpu operation on x86 by removing the need to perform a function call, "lsl" instruction, or system call on the fast path, as well as improving the speed of user-space operations on per-cpu data. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Joel Fernandes <joelaf@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Watson <davejwatson@fb.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: "H . Peter Anvin" <hpa@zytor.com> Cc: Chris Lameter <cl@linux.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Andrew Hunter <ahh@google.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: "Paul E . McKenney" <paulmck@linux.vnet.ibm.com> Cc: Paul Turner <pjt@google.com> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Ben Maurer <bmaurer@fb.com> Cc: linux-api@vger.kernel.org Cc: Andy Lutomirski <luto@amacapital.net> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lkml.kernel.org/r/20180602124408.8430-8-mathieu.desnoyers@efficios.com |
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|
Christoph Hellwig
|
7a074e96de |
aio: implement io_pgetevents
This is the io_getevents equivalent of ppoll/pselect and allows to properly mix signals and aio completions (especially with IOCB_CMD_POLL) and atomically executes the following sequence: sigset_t origmask; pthread_sigmask(SIG_SETMASK, &sigmask, &origmask); ret = io_getevents(ctx, min_nr, nr, events, timeout); pthread_sigmask(SIG_SETMASK, &origmask, NULL); Note that unlike many other signal related calls we do not pass a sigmask size, as that would get us to 7 arguments, which aren't easily supported by the syscall infrastructure. It seems a lot less painful to just add a new syscall variant in the unlikely case we're going to increase the sigset size. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> |
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|
Dominik Brodowski
|
d5a00528b5 |
syscalls/core, syscalls/x86: Rename struct pt_regs-based sys_*() to __x64_sys_*()
This rename allows us to have a coherent syscall stub naming convention on
64-bit x86 (0xffffffff prefix removed):
810f0af0 t kernel_waitid # common (32/64) kernel helper
<inline> __do_sys_waitid # inlined helper doing actual work
810f0be0 t __se_sys_waitid # C func calling inlined helper
<inline> __do_compat_sys_waitid # inlined helper doing actual work
810f0d80 t __se_compat_sys_waitid # compat C func calling inlined helper
810f2080 T __x64_sys_waitid # x64 64-bit-ptregs -> C stub
810f20b0 T __ia32_sys_waitid # ia32 32-bit-ptregs -> C stub[*]
810f2470 T __ia32_compat_sys_waitid # ia32 32-bit-ptregs -> compat C stub
810f2490 T __x32_compat_sys_waitid # x32 64-bit-ptregs -> compat C stub
[*] This stub is unused, as the syscall table links
__ia32_compat_sys_waitid instead of __ia32_sys_waitid as we need
a compat variant here.
Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20180409105145.5364-4-linux@dominikbrodowski.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
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|
Dominik Brodowski
|
5ac9efa3c5 |
syscalls/core, syscalls/x86: Clean up compat syscall stub naming convention
Tidy the naming convention for compat syscall subs. Hints which describe
the purpose of the stub go in front and receive a double underscore to
denote that they are generated on-the-fly by the COMPAT_SYSCALL_DEFINEx()
macro.
For the generic case, this means:
t kernel_waitid # common C function (see kernel/exit.c)
__do_compat_sys_waitid # inlined helper doing the actual work
# (takes original parameters as declared)
T __se_compat_sys_waitid # sign-extending C function calling inlined
# helper (takes parameters of type long,
# casts them to unsigned long and then to
# the declared type)
T compat_sys_waitid # alias to __se_compat_sys_waitid()
# (taking parameters as declared), to
# be included in syscall table
For x86, the naming is as follows:
t kernel_waitid # common C function (see kernel/exit.c)
__do_compat_sys_waitid # inlined helper doing the actual work
# (takes original parameters as declared)
t __se_compat_sys_waitid # sign-extending C function calling inlined
# helper (takes parameters of type long,
# casts them to unsigned long and then to
# the declared type)
T __ia32_compat_sys_waitid # IA32_EMULATION 32-bit-ptregs -> C stub,
# calls __se_compat_sys_waitid(); to be
# included in syscall table
T __x32_compat_sys_waitid # x32 64-bit-ptregs -> C stub, calls
# __se_compat_sys_waitid(); to be included
# in syscall table
If only one of IA32_EMULATION and x32 is enabled, __se_compat_sys_waitid()
may be inlined into the stub __{ia32,x32}_compat_sys_waitid().
Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20180409105145.5364-3-linux@dominikbrodowski.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
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|
Dominik Brodowski
|
e145242ea0 |
syscalls/core, syscalls/x86: Clean up syscall stub naming convention
Tidy the naming convention for compat syscall subs. Hints which describe the purpose of the stub go in front and receive a double underscore to denote that they are generated on-the-fly by the SYSCALL_DEFINEx() macro. For the generic case, this means (0xffffffff prefix removed): 810f08d0 t kernel_waitid # common C function (see kernel/exit.c) <inline> __do_sys_waitid # inlined helper doing the actual work # (takes original parameters as declared) 810f1aa0 T __se_sys_waitid # sign-extending C function calling inlined # helper (takes parameters of type long; # casts them to the declared type) 810f1aa0 T sys_waitid # alias to __se_sys_waitid() (taking # parameters as declared), to be included # in syscall table For x86, the naming is as follows: 810efc70 t kernel_waitid # common C function (see kernel/exit.c) <inline> __do_sys_waitid # inlined helper doing the actual work # (takes original parameters as declared) 810efd60 t __se_sys_waitid # sign-extending C function calling inlined # helper (takes parameters of type long; # casts them to the declared type) 810f1140 T __ia32_sys_waitid # IA32_EMULATION 32-bit-ptregs -> C stub, # calls __se_sys_waitid(); to be included # in syscall table 810f1110 T sys_waitid # x86 64-bit-ptregs -> C stub, calls # __se_sys_waitid(); to be included in # syscall table For x86, sys_waitid() will be re-named to __x64_sys_waitid in a follow-up patch. Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20180409105145.5364-2-linux@dominikbrodowski.net Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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|
Dominik Brodowski
|
ebeb8c82ff |
syscalls/x86: Use 'struct pt_regs' based syscall calling for IA32_EMULATION and x32
Extend ARCH_HAS_SYSCALL_WRAPPER for i386 emulation and for x32 on 64-bit
x86.
For x32, all we need to do is to create an additional stub for each
compat syscall which decodes the parameters in x86-64 ordering, e.g.:
asmlinkage long __compat_sys_x32_xyzzy(struct pt_regs *regs)
{
return c_SyS_xyzzy(regs->di, regs->si, regs->dx);
}
For i386 emulation, we need to teach compat_sys_*() to take struct
pt_regs as its only argument, e.g.:
asmlinkage long __compat_sys_ia32_xyzzy(struct pt_regs *regs)
{
return c_SyS_xyzzy(regs->bx, regs->cx, regs->dx);
}
In addition, we need to create additional stubs for common syscalls
(that is, for syscalls which have the same parameters on 32-bit and
64-bit), e.g.:
asmlinkage long __sys_ia32_xyzzy(struct pt_regs *regs)
{
return c_sys_xyzzy(regs->bx, regs->cx, regs->dx);
}
This approach avoids leaking random user-provided register content down
the call chain.
This patch is based on an original proof-of-concept
| From: Linus Torvalds <torvalds@linux-foundation.org>
| Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
and was split up and heavily modified by me, in particular to base it on
ARCH_HAS_SYSCALL_WRAPPER.
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20180405095307.3730-6-linux@dominikbrodowski.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
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|
Dominik Brodowski
|
ab0d1e85bf |
fs/quota: use COMPAT_SYSCALL_DEFINE for sys32_quotactl()
While sys32_quotactl() is only needed on x86, it can use the recommended COMPAT_SYSCALL_DEFINEx() machinery for its setup. Acked-by: Jan Kara <jack@suse.cz> Cc: Christoph Hellwig <hch@infradead.org> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> |
||
|
Dominik Brodowski
|
b51d3cdf44 |
x86: remove compat_sys_x86_waitpid()
compat_sys_x86_waitpid() is not needed, as it takes the same parameters (int, *int, int) as the native syscall. Suggested-by: Al Viro <viro@ZenIV.linux.org.uk> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jiri Slaby <jslaby@suse.com> Cc: x86@kernel.org Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> |
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|
Dominik Brodowski
|
af52201d99 |
x86/entry: Do not special-case clone(2) in compat entry
With the CPU renaming registers on its own, and all the overhead of the syscall entry/exit, it is doubtful whether the compiled output of mov %r8, %rax mov %rcx, %r8 mov %rax, %rcx jmpq sys_clone is measurably slower than the hand-crafted version of xchg %r8, %rcx So get rid of this special case. Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: luto@amacapital.net Cc: viro@zeniv.linux.org.uk Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
|
Dominik Brodowski
|
4ddb45db30 |
x86/syscalls: Use COMPAT_SYSCALL_DEFINEx() macros for x86-only compat syscalls
While at it, convert declarations of type "unsigned" to "unsigned int". Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: luto@amacapital.net Cc: viro@zeniv.linux.org.uk Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
|
Dominik Brodowski
|
b411991e0c |
x86/syscalls/32: Simplify $entry == $compat entries
If the compat entry point is equivalent to the native entry point, it does not need to be specified explicitly. Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: luto@amacapital.net Cc: viro@zeniv.linux.org.uk Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
|
Ingo Molnar
|
67caadc611 |
Merge branch 'x86/build' into x86/asm, to fix up conflicts
Conflicts: arch/x86/entry/syscalls/Makefile Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
|
Greg Kroah-Hartman
|
b24413180f |
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
||
|
Masahiro Yamada
|
af8e947079 |
x86/build: Beautify build log of syscall headers
This makes the build log look nicer. Before: SYSTBL arch/x86/entry/syscalls/../../include/generated/asm/syscalls_32.h SYSHDR arch/x86/entry/syscalls/../../include/generated/asm/unistd_32_ia32.h SYSHDR arch/x86/entry/syscalls/../../include/generated/asm/unistd_64_x32.h SYSTBL arch/x86/entry/syscalls/../../include/generated/asm/syscalls_64.h SYSHDR arch/x86/entry/syscalls/../../include/generated/uapi/asm/unistd_32.h SYSHDR arch/x86/entry/syscalls/../../include/generated/uapi/asm/unistd_64.h SYSHDR arch/x86/entry/syscalls/../../include/generated/uapi/asm/unistd_x32.h After: SYSTBL arch/x86/include/generated/asm/syscalls_32.h SYSHDR arch/x86/include/generated/asm/unistd_32_ia32.h SYSHDR arch/x86/include/generated/asm/unistd_64_x32.h SYSTBL arch/x86/include/generated/asm/syscalls_64.h SYSHDR arch/x86/include/generated/uapi/asm/unistd_32.h SYSHDR arch/x86/include/generated/uapi/asm/unistd_64.h SYSHDR arch/x86/include/generated/uapi/asm/unistd_x32.h Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: linux-kbuild@vger.kernel.org Link: http://lkml.kernel.org/r/1509077470-2735-1-git-send-email-yamada.masahiro@socionext.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
|
Linus Torvalds
|
204f144c9f |
Merge branch 'work.compat' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull fs/compat.c cleanups from Al Viro: "More moving of compat syscalls from fs/compat.c to fs/*.c where the native counterparts live. And death to compat_sys_getdents64() - the only architecture that used to need it was ia64, and _that_ has lost biarch support quite a few years ago" * 'work.compat' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: fs/compat.c: trim unused includes move compat_rw_copy_check_uvector() over to fs/read_write.c fhandle: move compat syscalls from compat.c open: move compat syscalls from compat.c stat: move compat syscalls from compat.c fcntl: move compat syscalls from compat.c readdir: move compat syscalls from compat.c statfs: move compat syscalls from compat.c utimes: move compat syscalls from compat.c move compat select-related syscalls to fs/select.c Remove compat_sys_getdents64() |
||
|
Al Viro
|
2611dc1939 |
Remove compat_sys_getdents64()
Unlike normal compat syscall variants, it is needed only for biarch architectures that have different alignement requirements for u64 in 32bit and 64bit ABI *and* have __put_user() that won't handle a store of 64bit value at 32bit-aligned address. We used to have one such (ia64), but its biarch support has been gone since 2010 (after being broken in 2008, which went unnoticed since nobody had been using it). It had escaped removal at the same time only because back in 2004 a patch that switched several syscalls on amd64 from private wrappers to generic compat ones had switched to use of compat_sys_getdents64(), which hadn't needed (or used) a compat wrapper on amd64. Let's bury it - it's at least 7 years overdue. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> |
||
|
Kyle Huey
|
79170fda31 |
x86/syscalls/32: Wire up arch_prctl on x86-32
Hook up arch_prctl to call do_arch_prctl() on x86-32, and in 32 bit compat mode on x86-64. This allows to have arch_prctls that are not specific to 64 bits. On UML, simply stub out this syscall. Signed-off-by: Kyle Huey <khuey@kylehuey.com> Cc: Grzegorz Andrejczuk <grzegorz.andrejczuk@intel.com> Cc: kvm@vger.kernel.org Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: linux-kselftest@vger.kernel.org Cc: Nadav Amit <nadav.amit@gmail.com> Cc: Robert O'Callahan <robert@ocallahan.org> Cc: Richard Weinberger <richard@nod.at> Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: Andy Lutomirski <luto@kernel.org> Cc: Len Brown <len.brown@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: user-mode-linux-devel@lists.sourceforge.net Cc: Jeff Dike <jdike@addtoit.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: user-mode-linux-user@lists.sourceforge.net Cc: David Matlack <dmatlack@google.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Dmitry Safonov <dsafonov@virtuozzo.com> Cc: linux-fsdevel@vger.kernel.org Cc: Paolo Bonzini <pbonzini@redhat.com> Link: http://lkml.kernel.org/r/20170320081628.18952-7-khuey@kylehuey.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de> |
||
|
David Howells
|
a528d35e8b |
statx: Add a system call to make enhanced file info available
Add a system call to make extended file information available, including
file creation and some attribute flags where available through the
underlying filesystem.
The getattr inode operation is altered to take two additional arguments: a
u32 request_mask and an unsigned int flags that indicate the
synchronisation mode. This change is propagated to the vfs_getattr*()
function.
Functions like vfs_stat() are now inline wrappers around new functions
vfs_statx() and vfs_statx_fd() to reduce stack usage.
========
OVERVIEW
========
The idea was initially proposed as a set of xattrs that could be retrieved
with getxattr(), but the general preference proved to be for a new syscall
with an extended stat structure.
A number of requests were gathered for features to be included. The
following have been included:
(1) Make the fields a consistent size on all arches and make them large.
(2) Spare space, request flags and information flags are provided for
future expansion.
(3) Better support for the y2038 problem [Arnd Bergmann] (tv_sec is an
__s64).
(4) Creation time: The SMB protocol carries the creation time, which could
be exported by Samba, which will in turn help CIFS make use of
FS-Cache as that can be used for coherency data (stx_btime).
This is also specified in NFSv4 as a recommended attribute and could
be exported by NFSD [Steve French].
(5) Lightweight stat: Ask for just those details of interest, and allow a
netfs (such as NFS) to approximate anything not of interest, possibly
without going to the server [Trond Myklebust, Ulrich Drepper, Andreas
Dilger] (AT_STATX_DONT_SYNC).
(6) Heavyweight stat: Force a netfs to go to the server, even if it thinks
its cached attributes are up to date [Trond Myklebust]
(AT_STATX_FORCE_SYNC).
And the following have been left out for future extension:
(7) Data version number: Could be used by userspace NFS servers [Aneesh
Kumar].
Can also be used to modify fill_post_wcc() in NFSD which retrieves
i_version directly, but has just called vfs_getattr(). It could get
it from the kstat struct if it used vfs_xgetattr() instead.
(There's disagreement on the exact semantics of a single field, since
not all filesystems do this the same way).
(8) BSD stat compatibility: Including more fields from the BSD stat such
as creation time (st_btime) and inode generation number (st_gen)
[Jeremy Allison, Bernd Schubert].
(9) Inode generation number: Useful for FUSE and userspace NFS servers
[Bernd Schubert].
(This was asked for but later deemed unnecessary with the
open-by-handle capability available and caused disagreement as to
whether it's a security hole or not).
(10) Extra coherency data may be useful in making backups [Andreas Dilger].
(No particular data were offered, but things like last backup
timestamp, the data version number and the DOS archive bit would come
into this category).
(11) Allow the filesystem to indicate what it can/cannot provide: A
filesystem can now say it doesn't support a standard stat feature if
that isn't available, so if, for instance, inode numbers or UIDs don't
exist or are fabricated locally...
(This requires a separate system call - I have an fsinfo() call idea
for this).
(12) Store a 16-byte volume ID in the superblock that can be returned in
struct xstat [Steve French].
(Deferred to fsinfo).
(13) Include granularity fields in the time data to indicate the
granularity of each of the times (NFSv4 time_delta) [Steve French].
(Deferred to fsinfo).
(14) FS_IOC_GETFLAGS value. These could be translated to BSD's st_flags.
Note that the Linux IOC flags are a mess and filesystems such as Ext4
define flags that aren't in linux/fs.h, so translation in the kernel
may be a necessity (or, possibly, we provide the filesystem type too).
(Some attributes are made available in stx_attributes, but the general
feeling was that the IOC flags were to ext[234]-specific and shouldn't
be exposed through statx this way).
(15) Mask of features available on file (eg: ACLs, seclabel) [Brad Boyer,
Michael Kerrisk].
(Deferred, probably to fsinfo. Finding out if there's an ACL or
seclabal might require extra filesystem operations).
(16) Femtosecond-resolution timestamps [Dave Chinner].
(A __reserved field has been left in the statx_timestamp struct for
this - if there proves to be a need).
(17) A set multiple attributes syscall to go with this.
===============
NEW SYSTEM CALL
===============
The new system call is:
int ret = statx(int dfd,
const char *filename,
unsigned int flags,
unsigned int mask,
struct statx *buffer);
The dfd, filename and flags parameters indicate the file to query, in a
similar way to fstatat(). There is no equivalent of lstat() as that can be
emulated with statx() by passing AT_SYMLINK_NOFOLLOW in flags. There is
also no equivalent of fstat() as that can be emulated by passing a NULL
filename to statx() with the fd of interest in dfd.
Whether or not statx() synchronises the attributes with the backing store
can be controlled by OR'ing a value into the flags argument (this typically
only affects network filesystems):
(1) AT_STATX_SYNC_AS_STAT tells statx() to behave as stat() does in this
respect.
(2) AT_STATX_FORCE_SYNC will require a network filesystem to synchronise
its attributes with the server - which might require data writeback to
occur to get the timestamps correct.
(3) AT_STATX_DONT_SYNC will suppress synchronisation with the server in a
network filesystem. The resulting values should be considered
approximate.
mask is a bitmask indicating the fields in struct statx that are of
interest to the caller. The user should set this to STATX_BASIC_STATS to
get the basic set returned by stat(). It should be noted that asking for
more information may entail extra I/O operations.
buffer points to the destination for the data. This must be 256 bytes in
size.
======================
MAIN ATTRIBUTES RECORD
======================
The following structures are defined in which to return the main attribute
set:
struct statx_timestamp {
__s64 tv_sec;
__s32 tv_nsec;
__s32 __reserved;
};
struct statx {
__u32 stx_mask;
__u32 stx_blksize;
__u64 stx_attributes;
__u32 stx_nlink;
__u32 stx_uid;
__u32 stx_gid;
__u16 stx_mode;
__u16 __spare0[1];
__u64 stx_ino;
__u64 stx_size;
__u64 stx_blocks;
__u64 __spare1[1];
struct statx_timestamp stx_atime;
struct statx_timestamp stx_btime;
struct statx_timestamp stx_ctime;
struct statx_timestamp stx_mtime;
__u32 stx_rdev_major;
__u32 stx_rdev_minor;
__u32 stx_dev_major;
__u32 stx_dev_minor;
__u64 __spare2[14];
};
The defined bits in request_mask and stx_mask are:
STATX_TYPE Want/got stx_mode & S_IFMT
STATX_MODE Want/got stx_mode & ~S_IFMT
STATX_NLINK Want/got stx_nlink
STATX_UID Want/got stx_uid
STATX_GID Want/got stx_gid
STATX_ATIME Want/got stx_atime{,_ns}
STATX_MTIME Want/got stx_mtime{,_ns}
STATX_CTIME Want/got stx_ctime{,_ns}
STATX_INO Want/got stx_ino
STATX_SIZE Want/got stx_size
STATX_BLOCKS Want/got stx_blocks
STATX_BASIC_STATS [The stuff in the normal stat struct]
STATX_BTIME Want/got stx_btime{,_ns}
STATX_ALL [All currently available stuff]
stx_btime is the file creation time, stx_mask is a bitmask indicating the
data provided and __spares*[] are where as-yet undefined fields can be
placed.
Time fields are structures with separate seconds and nanoseconds fields
plus a reserved field in case we want to add even finer resolution. Note
that times will be negative if before 1970; in such a case, the nanosecond
fields will also be negative if not zero.
The bits defined in the stx_attributes field convey information about a
file, how it is accessed, where it is and what it does. The following
attributes map to FS_*_FL flags and are the same numerical value:
STATX_ATTR_COMPRESSED File is compressed by the fs
STATX_ATTR_IMMUTABLE File is marked immutable
STATX_ATTR_APPEND File is append-only
STATX_ATTR_NODUMP File is not to be dumped
STATX_ATTR_ENCRYPTED File requires key to decrypt in fs
Within the kernel, the supported flags are listed by:
KSTAT_ATTR_FS_IOC_FLAGS
[Are any other IOC flags of sufficient general interest to be exposed
through this interface?]
New flags include:
STATX_ATTR_AUTOMOUNT Object is an automount trigger
These are for the use of GUI tools that might want to mark files specially,
depending on what they are.
Fields in struct statx come in a number of classes:
(0) stx_dev_*, stx_blksize.
These are local system information and are always available.
(1) stx_mode, stx_nlinks, stx_uid, stx_gid, stx_[amc]time, stx_ino,
stx_size, stx_blocks.
These will be returned whether the caller asks for them or not. The
corresponding bits in stx_mask will be set to indicate whether they
actually have valid values.
If the caller didn't ask for them, then they may be approximated. For
example, NFS won't waste any time updating them from the server,
unless as a byproduct of updating something requested.
If the values don't actually exist for the underlying object (such as
UID or GID on a DOS file), then the bit won't be set in the stx_mask,
even if the caller asked for the value. In such a case, the returned
value will be a fabrication.
Note that there are instances where the type might not be valid, for
instance Windows reparse points.
(2) stx_rdev_*.
This will be set only if stx_mode indicates we're looking at a
blockdev or a chardev, otherwise will be 0.
(3) stx_btime.
Similar to (1), except this will be set to 0 if it doesn't exist.
=======
TESTING
=======
The following test program can be used to test the statx system call:
samples/statx/test-statx.c
Just compile and run, passing it paths to the files you want to examine.
The file is built automatically if CONFIG_SAMPLES is enabled.
Here's some example output. Firstly, an NFS directory that crosses to
another FSID. Note that the AUTOMOUNT attribute is set because transiting
this directory will cause d_automount to be invoked by the VFS.
[root@andromeda ~]# /tmp/test-statx -A /warthog/data
statx(/warthog/data) = 0
results=7ff
Size: 4096 Blocks: 8 IO Block: 1048576 directory
Device: 00:26 Inode: 1703937 Links: 125
Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041
Access: 2016-11-24 09:02:12.219699527+0000
Modify: 2016-11-17 10:44:36.225653653+0000
Change: 2016-11-17 10:44:36.225653653+0000
Attributes: 0000000000001000 (-------- -------- -------- -------- -------- -------- ---m---- --------)
Secondly, the result of automounting on that directory.
[root@andromeda ~]# /tmp/test-statx /warthog/data
statx(/warthog/data) = 0
results=7ff
Size: 4096 Blocks: 8 IO Block: 1048576 directory
Device: 00:27 Inode: 2 Links: 125
Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041
Access: 2016-11-24 09:02:12.219699527+0000
Modify: 2016-11-17 10:44:36.225653653+0000
Change: 2016-11-17 10:44:36.225653653+0000
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
||
|
Dave Hansen
|
eac0ca77e4 |
x86, pkeys: remove cruft from never-merged syscalls
pkey_set() and pkey_get() were syscalls present in older versions
of the protection keys patches. The syscall number definitions
were inadvertently left in place. This patch removes them.
I did a git grep and verified that these are the last places in
the tree that these appear, save for the protection_keys.c tests
and Documentation. Those spots talk about functions called
pkey_get/set() which are wrappers for the direct PKRU
instructions, not the syscalls.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: mgorman@techsingularity.net
Cc: arnd@arndb.de
Cc: linux-api@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: luto@kernel.org
Cc: akpm@linux-foundation.org
Fixes:
|
||
|
Linus Torvalds
|
93c26d7dc0 |
Merge branch 'mm-pkeys-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull protection keys syscall interface from Thomas Gleixner: "This is the final step of Protection Keys support which adds the syscalls so user space can actually allocate keys and protect memory areas with them. Details and usage examples can be found in the documentation. The mm side of this has been acked by Mel" * 'mm-pkeys-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/pkeys: Update documentation x86/mm/pkeys: Do not skip PKRU register if debug registers are not used x86/pkeys: Fix pkeys build breakage for some non-x86 arches x86/pkeys: Add self-tests x86/pkeys: Allow configuration of init_pkru x86/pkeys: Default to a restrictive init PKRU pkeys: Add details of system call use to Documentation/ generic syscalls: Wire up memory protection keys syscalls x86: Wire up protection keys system calls x86/pkeys: Allocation/free syscalls x86/pkeys: Make mprotect_key() mask off additional vm_flags mm: Implement new pkey_mprotect() system call x86/pkeys: Add fault handling for PF_PK page fault bit |
||
|
sylvain.bertrand@gmail.com
|
2df0e78b44 |
x86/syscalls: Remove bash-isms in syscall table generator
Signed-off-by: Sylvain BERTRAND <sylvain.bertrand@gmail.com> Link: http://lkml.kernel.org/r/20160929162234.GA29592@freedom Signed-off-by: Thomas Gleixner <tglx@linutronix.de> |
||
|
Dave Hansen
|
f9afc6197e |
x86: Wire up protection keys system calls
This is all that we need to get the new system calls themselves working on x86. Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Cc: linux-arch@vger.kernel.org Cc: Dave Hansen <dave@sr71.net> Cc: mgorman@techsingularity.net Cc: arnd@arndb.de Cc: linux-api@vger.kernel.org Cc: linux-mm@kvack.org Cc: luto@kernel.org Cc: akpm@linux-foundation.org Cc: torvalds@linux-foundation.org Link: http://lkml.kernel.org/r/20160729163017.E3C06FD2@viggo.jf.intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de> |
||
|
David Howells
|
f7d665627e |
x86/syscalls/64: Add compat_sys_keyctl for 32-bit userspace
x86_64 needs to use compat_sys_keyctl for 32-bit userspace rather than calling sys_keyctl(). The latter will work in a lot of cases, thereby hiding the issue. Reported-by: Stephan Mueller <smueller@chronox.de> Tested-by: Stephan Mueller <smueller@chronox.de> Signed-off-by: David Howells <dhowells@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: keyrings@vger.kernel.org Cc: linux-security-module@vger.kernel.org Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/146961615805.14395.5581949237156769439.stgit@warthog.procyon.org.uk Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
|
H.J. Lu
|
3ebfd81f7f |
x86/syscalls: Add compat_sys_preadv64v2/compat_sys_pwritev64v2
Don't use the same syscall numbers for 2 different syscalls: 534 x32 preadv compat_sys_preadv64 535 x32 pwritev compat_sys_pwritev64 534 x32 preadv2 compat_sys_preadv2 535 x32 pwritev2 compat_sys_pwritev2 Add compat_sys_preadv64v2() and compat_sys_pwritev64v2() so that 64-bit offset is passed in one 64-bit register on x32, similar to compat_sys_preadv64() and compat_sys_pwritev64(). Signed-off-by: H.J. Lu <hjl.tools@gmail.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/CAMe9rOovCMf-RQfx_n1U_Tu_DX1BYkjtFr%3DQ4-_PFVSj9BCzUA@mail.gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Christoph Hellwig
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482dd2ef12 |
x86/syscalls: Wire up compat readv2/writev2 syscalls
Reported-by: David Smith <dsmith@redhat.com> Tested-by: David Smith <dsmith@redhat.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20160407204359.GA3720@lst.de Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Linus Torvalds
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3c2de27d79 |
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs updates from Al Viro:
- Preparations of parallel lookups (the remaining main obstacle is the
need to move security_d_instantiate(); once that becomes safe, the
rest will be a matter of rather short series local to fs/*.c
- preadv2/pwritev2 series from Christoph
- assorted fixes
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (32 commits)
splice: handle zero nr_pages in splice_to_pipe()
vfs: show_vfsstat: do not ignore errors from show_devname method
dcache.c: new helper: __d_add()
don't bother with __d_instantiate(dentry, NULL)
untangle fsnotify_d_instantiate() a bit
uninline d_add()
replace d_add_unique() with saner primitive
quota: use lookup_one_len_unlocked()
cifs_get_root(): use lookup_one_len_unlocked()
nfs_lookup: don't bother with d_instantiate(dentry, NULL)
kill dentry_unhash()
ceph_fill_trace(): don't bother with d_instantiate(dn, NULL)
autofs4: don't bother with d_instantiate(dentry, NULL) in ->lookup()
configfs: move d_rehash() into configfs_create() for regular files
ceph: don't bother with d_rehash() in splice_dentry()
namei: teach lookup_slow() to skip revalidate
namei: massage lookup_slow() to be usable by lookup_one_len_unlocked()
lookup_one_len_unlocked(): use lookup_dcache()
namei: simplify invalidation logics in lookup_dcache()
namei: change calling conventions for lookup_{fast,slow} and follow_managed()
...
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Christoph Hellwig
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4babf2c5ef |
x86: wire up preadv2 and pwritev2
Signed-off-by: Milosz Tanski <milosz@adfin.com> [hch: rebased due to newly added syscalls] Reviewed-by: Stephen Bates <stephen.bates@pmcs.com> Tested-by: Stephen Bates <stephen.bates@pmcs.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> |
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Andy Lutomirski
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bb56968a37 |
x86/syscalls/64: Mark sys_iopl() as using ptregs
sys_iopl() both reads and writes pt_regs->flags. Mark it as using ptregs. This isn't strictly necessary, as pt_regs->flags is available even in the fast path, but this is very lightweight now that we have syscall qualifiers and it could avoid some pain down the road. Reported-and-tested-by: Borislav Petkov <bp@suse.de> Signed-off-by: Andy Lutomirski <luto@kernel.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/3de0ca692fa8bf414c5e3d7afe3e6195d1a10e1f.1454261517.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Andy Lutomirski
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46eabf06c0 |
x86/entry/64: Call all native slow-path syscalls with full pt-regs
This removes all of the remaining asm syscall stubs except for stub_ptregs_64. Entries in the main syscall table are now all callable from C. The resulting asm is every bit as ridiculous as it looks. The next few patches will clean it up. This patch is here to let reviewers rest their brains and for bisection. Signed-off-by: Andy Lutomirski <luto@kernel.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/a6b3801be0d505d50aefabda02d3b93efbfc9c73.1454022279.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Andy Lutomirski
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302f5b260c |
x86/entry/64: Always run ptregs-using syscalls on the slow path
64-bit syscalls currently have an optimization in which they are called with partial pt_regs. A small handful require full pt_regs. In the 32-bit and compat cases, I cleaned this up by forcing full pt_regs for all syscalls. The performance hit doesn't really matter as the affected system calls are fundamentally heavy and this is the 32-bit compat case. I want to clean up the 64-bit case as well, but I don't want to hurt fast path performance. To do that, I want to force the syscalls that use pt_regs onto the slow path. This will enable us to make slow path syscalls be real ABI-compliant C functions. Use the new syscall entry qualification machinery for this. 'stub_clone' is now 'stub_clone/ptregs'. The next patch will eliminate the stubs, and we'll just have 'sys_clone/ptregs'. As of this patch, two-phase entry tracing is no longer used. It has served its purpose (namely a huge speedup on some workloads prior to more general opportunistic SYSRET support), and once the dust settles I'll send patches to back it out. The implementation is heavily based on a patch from Brian Gerst: http://lkml.kernel.org/g/1449666173-15366-1-git-send-email-brgerst@gmail.com Originally-From: Brian Gerst <brgerst@gmail.com> Signed-off-by: Andy Lutomirski <luto@kernel.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Frédéric Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/b9beda88460bcefec6e7d792bd44eca9b760b0c4.1454022279.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Andy Lutomirski
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cfcbadb49d |
x86/syscalls: Add syscall entry qualifiers
This will let us specify something like 'sys_xyz/foo' instead of 'sys_xyz' in the syscall table, where the 'foo' qualifier conveys some extra information to the C code. The intent is to allow things like sys_execve/ptregs to indicate that sys_execve() touches pt_regs. Signed-off-by: Andy Lutomirski <luto@kernel.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/2de06e33dce62556b3ec662006fcb295504e296e.1454022279.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Andy Lutomirski
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3e65654e3d |
x86/syscalls: Move compat syscall entry handling into syscalltbl.sh
Rather than duplicating the compat entry handling in all consumers of syscalls_BITS.h, handle it directly in syscalltbl.sh. Now we generate entries in syscalls_32.h like: __SYSCALL_I386(5, sys_open) __SYSCALL_I386(5, compat_sys_open) and all of its consumers implicitly get the right entry point. Signed-off-by: Andy Lutomirski <luto@kernel.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/b7c2b501dc0e6e43050e916b95807c3e2e16e9bb.1454022279.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Andy Lutomirski
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32324ce15e |
x86/syscalls: Remove __SYSCALL_COMMON and __SYSCALL_X32
The common/64/x32 distinction has no effect other than determining which kernels actually support the syscall. Move the logic into syscalltbl.sh. Signed-off-by: Andy Lutomirski <luto@kernel.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/58d4a95f40e43b894f93288b4a3633963d0ee22e.1454022279.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Andy Lutomirski
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fba324744b |
x86/syscalls: Refactor syscalltbl.sh
This splits out the code to emit a syscall line. Signed-off-by: Andy Lutomirski <luto@kernel.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1bfcbba991f5cfaa9291ff950a593daa972a205f.1454022279.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Zach Brown
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cb4c4e8091 |
x86: add sys_copy_file_range to syscall tables
Add sys_copy_file_range to the x86 syscall tables. Signed-off-by: Zach Brown <zab@redhat.com> [Anna Schumaker: Update syscall number in syscall_32.tbl] Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> |
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Eric B Munson
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a8ca5d0ecb |
mm: mlock: add new mlock system call
With the refactored mlock code, introduce a new system call for mlock. The new call will allow the user to specify what lock states are being added. mlock2 is trivial at the moment, but a follow on patch will add a new mlock state making it useful. Signed-off-by: Eric B Munson <emunson@akamai.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Guenter Roeck <linux@roeck-us.net> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Shuah Khan <shuahkh@osg.samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Andy Lutomirski
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8169aff611 |
x86/entry/64/compat: Set up full pt_regs for all compat syscalls
This is conceptually simpler. More importantly, it eliminates the PTREGSCALL and execve stubs, which were not compatible with the C ABI. This means that C code can call through the compat syscall table. The execve stubs are a bit subtle. They did two things: they cleared some registers and they forced slow-path return. Neither is necessary any more: elf_common_init clears the extra registers and start_thread calls force_iret(). Signed-off-by: Andy Lutomirski <luto@kernel.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/f95b7f7dfaacf88a8cae85bb06226cae53769287.1444091584.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Mathieu Desnoyers
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5b25b13ab0 |
sys_membarrier(): system-wide memory barrier (generic, x86)
Here is an implementation of a new system call, sys_membarrier(), which executes a memory barrier on all threads running on the system. It is implemented by calling synchronize_sched(). It can be used to distribute the cost of user-space memory barriers asymmetrically by transforming pairs of memory barriers into pairs consisting of sys_membarrier() and a compiler barrier. For synchronization primitives that distinguish between read-side and write-side (e.g. userspace RCU [1], rwlocks), the read-side can be accelerated significantly by moving the bulk of the memory barrier overhead to the write-side. The existing applications of which I am aware that would be improved by this system call are as follows: * Through Userspace RCU library (http://urcu.so) - DNS server (Knot DNS) https://www.knot-dns.cz/ - Network sniffer (http://netsniff-ng.org/) - Distributed object storage (https://sheepdog.github.io/sheepdog/) - User-space tracing (http://lttng.org) - Network storage system (https://www.gluster.org/) - Virtual routers (https://events.linuxfoundation.org/sites/events/files/slides/DPDK_RCU_0MQ.pdf) - Financial software (https://lkml.org/lkml/2015/3/23/189) Those projects use RCU in userspace to increase read-side speed and scalability compared to locking. Especially in the case of RCU used by libraries, sys_membarrier can speed up the read-side by moving the bulk of the memory barrier cost to synchronize_rcu(). * Direct users of sys_membarrier - core dotnet garbage collector (https://github.com/dotnet/coreclr/issues/198) Microsoft core dotnet GC developers are planning to use the mprotect() side-effect of issuing memory barriers through IPIs as a way to implement Windows FlushProcessWriteBuffers() on Linux. They are referring to sys_membarrier in their github thread, specifically stating that sys_membarrier() is what they are looking for. To explain the benefit of this scheme, let's introduce two example threads: Thread A (non-frequent, e.g. executing liburcu synchronize_rcu()) Thread B (frequent, e.g. executing liburcu rcu_read_lock()/rcu_read_unlock()) In a scheme where all smp_mb() in thread A are ordering memory accesses with respect to smp_mb() present in Thread B, we can change each smp_mb() within Thread A into calls to sys_membarrier() and each smp_mb() within Thread B into compiler barriers "barrier()". Before the change, we had, for each smp_mb() pairs: Thread A Thread B previous mem accesses previous mem accesses smp_mb() smp_mb() following mem accesses following mem accesses After the change, these pairs become: Thread A Thread B prev mem accesses prev mem accesses sys_membarrier() barrier() follow mem accesses follow mem accesses As we can see, there are two possible scenarios: either Thread B memory accesses do not happen concurrently with Thread A accesses (1), or they do (2). 1) Non-concurrent Thread A vs Thread B accesses: Thread A Thread B prev mem accesses sys_membarrier() follow mem accesses prev mem accesses barrier() follow mem accesses In this case, thread B accesses will be weakly ordered. This is OK, because at that point, thread A is not particularly interested in ordering them with respect to its own accesses. 2) Concurrent Thread A vs Thread B accesses Thread A Thread B prev mem accesses prev mem accesses sys_membarrier() barrier() follow mem accesses follow mem accesses In this case, thread B accesses, which are ensured to be in program order thanks to the compiler barrier, will be "upgraded" to full smp_mb() by synchronize_sched(). * Benchmarks On Intel Xeon E5405 (8 cores) (one thread is calling sys_membarrier, the other 7 threads are busy looping) 1000 non-expedited sys_membarrier calls in 33s =3D 33 milliseconds/call. * User-space user of this system call: Userspace RCU library Both the signal-based and the sys_membarrier userspace RCU schemes permit us to remove the memory barrier from the userspace RCU rcu_read_lock() and rcu_read_unlock() primitives, thus significantly accelerating them. These memory barriers are replaced by compiler barriers on the read-side, and all matching memory barriers on the write-side are turned into an invocation of a memory barrier on all active threads in the process. By letting the kernel perform this synchronization rather than dumbly sending a signal to every process threads (as we currently do), we diminish the number of unnecessary wake ups and only issue the memory barriers on active threads. Non-running threads do not need to execute such barrier anyway, because these are implied by the scheduler context switches. Results in liburcu: Operations in 10s, 6 readers, 2 writers: memory barriers in reader: 1701557485 reads, 2202847 writes signal-based scheme: 9830061167 reads, 6700 writes sys_membarrier: 9952759104 reads, 425 writes sys_membarrier (dyn. check): 7970328887 reads, 425 writes The dynamic sys_membarrier availability check adds some overhead to the read-side compared to the signal-based scheme, but besides that, sys_membarrier slightly outperforms the signal-based scheme. However, this non-expedited sys_membarrier implementation has a much slower grace period than signal and memory barrier schemes. Besides diminishing the number of wake-ups, one major advantage of the membarrier system call over the signal-based scheme is that it does not need to reserve a signal. This plays much more nicely with libraries, and with processes injected into for tracing purposes, for which we cannot expect that signals will be unused by the application. An expedited version of this system call can be added later on to speed up the grace period. Its implementation will likely depend on reading the cpu_curr()->mm without holding each CPU's rq lock. This patch adds the system call to x86 and to asm-generic. [1] http://urcu.so membarrier(2) man page: MEMBARRIER(2) Linux Programmer's Manual MEMBARRIER(2) NAME membarrier - issue memory barriers on a set of threads SYNOPSIS #include <linux/membarrier.h> int membarrier(int cmd, int flags); DESCRIPTION The cmd argument is one of the following: MEMBARRIER_CMD_QUERY Query the set of supported commands. It returns a bitmask of supported commands. MEMBARRIER_CMD_SHARED Execute a memory barrier on all threads running on the system. Upon return from system call, the caller thread is ensured that all running threads have passed through a state where all memory accesses to user-space addresses match program order between entry to and return from the system call (non-running threads are de facto in such a state). This covers threads from all pro=E2=80=90 cesses running on the system. This command returns 0. The flags argument needs to be 0. For future extensions. All memory accesses performed in program order from each targeted thread is guaranteed to be ordered with respect to sys_membarrier(). If we use the semantic "barrier()" to represent a compiler barrier forcing memory accesses to be performed in program order across the barrier, and smp_mb() to represent explicit memory barriers forcing full memory ordering across the barrier, we have the following ordering table for each pair of barrier(), sys_membarrier() and smp_mb(): The pair ordering is detailed as (O: ordered, X: not ordered): barrier() smp_mb() sys_membarrier() barrier() X X O smp_mb() X O O sys_membarrier() O O O RETURN VALUE On success, these system calls return zero. On error, -1 is returned, and errno is set appropriately. For a given command, with flags argument set to 0, this system call is guaranteed to always return the same value until reboot. ERRORS ENOSYS System call is not implemented. EINVAL Invalid arguments. Linux 2015-04-15 MEMBARRIER(2) Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Nicholas Miell <nmiell@comcast.net> Cc: Ingo Molnar <mingo@redhat.com> Cc: Alan Cox <gnomes@lxorguk.ukuu.org.uk> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Stephen Hemminger <stephen@networkplumber.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: David Howells <dhowells@redhat.com> Cc: Pranith Kumar <bobby.prani@gmail.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Shuah Khan <shuahkh@osg.samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Andrea Arcangeli
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1380fca084 |
userfaultfd: activate syscall
This activates the userfaultfd syscall. [sfr@canb.auug.org.au: activate syscall fix] [akpm@linux-foundation.org: don't enable userfaultfd on powerpc] Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Pavel Emelyanov <xemul@parallels.com> Cc: Sanidhya Kashyap <sanidhya.gatech@gmail.com> Cc: zhang.zhanghailiang@huawei.com Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Andres Lagar-Cavilla <andreslc@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Hugh Dickins <hughd@google.com> Cc: Peter Feiner <pfeiner@google.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: "Huangpeng (Peter)" <peter.huangpeng@huawei.com> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |