Commit Graph

244 Commits

Author SHA1 Message Date
Thomas Garnier
bf29ed1567 syscalls: Use CHECK_DATA_CORRUPTION for addr_limit_user_check
Use CHECK_DATA_CORRUPTION instead of BUG_ON to provide more flexibility
on address limit failures. By default, send a SIGKILL signal to kill the
current process preventing exploitation of a bad address limit.

Make the TIF_FSCHECK flag optional so ARM can use this function.

Signed-off-by: Thomas Garnier <thgarnie@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Pratyush Anand <panand@redhat.com>
Cc: Dave Martin <Dave.Martin@arm.com>
Cc: Will Drewry <wad@chromium.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: David Howells <dhowells@redhat.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-api@vger.kernel.org
Cc: Yonghong Song <yhs@fb.com>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1504798247-48833-2-git-send-email-keescook@chromium.org
2017-09-17 19:45:32 +02:00
Yonghong Song
609320c8a2 perf/bpf: fix a clang compilation issue
clang does not support variable length array for structure member.
It has the following error during compilation:

kernel/trace/trace_syscalls.c:568:17: error: fields must have a constant size:
'variable length array in structure' extension will never be supported
                unsigned long args[sys_data->nb_args];
                              ^

The fix is to use a fixed array length instead.

Reported-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-09-11 14:28:45 -07:00
Linus Torvalds
aae3dbb477 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next
Pull networking updates from David Miller:

 1) Support ipv6 checksum offload in sunvnet driver, from Shannon
    Nelson.

 2) Move to RB-tree instead of custom AVL code in inetpeer, from Eric
    Dumazet.

 3) Allow generic XDP to work on virtual devices, from John Fastabend.

 4) Add bpf device maps and XDP_REDIRECT, which can be used to build
    arbitrary switching frameworks using XDP. From John Fastabend.

 5) Remove UFO offloads from the tree, gave us little other than bugs.

 6) Remove the IPSEC flow cache, from Florian Westphal.

 7) Support ipv6 route offload in mlxsw driver.

 8) Support VF representors in bnxt_en, from Sathya Perla.

 9) Add support for forward error correction modes to ethtool, from
    Vidya Sagar Ravipati.

10) Add time filter for packet scheduler action dumping, from Jamal Hadi
    Salim.

11) Extend the zerocopy sendmsg() used by virtio and tap to regular
    sockets via MSG_ZEROCOPY. From Willem de Bruijn.

12) Significantly rework value tracking in the BPF verifier, from Edward
    Cree.

13) Add new jump instructions to eBPF, from Daniel Borkmann.

14) Rework rtnetlink plumbing so that operations can be run without
    taking the RTNL semaphore. From Florian Westphal.

15) Support XDP in tap driver, from Jason Wang.

16) Add 32-bit eBPF JIT for ARM, from Shubham Bansal.

17) Add Huawei hinic ethernet driver.

18) Allow to report MD5 keys in TCP inet_diag dumps, from Ivan
    Delalande.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1780 commits)
  i40e: point wb_desc at the nvm_wb_desc during i40e_read_nvm_aq
  i40e: avoid NVM acquire deadlock during NVM update
  drivers: net: xgene: Remove return statement from void function
  drivers: net: xgene: Configure tx/rx delay for ACPI
  drivers: net: xgene: Read tx/rx delay for ACPI
  rocker: fix kcalloc parameter order
  rds: Fix non-atomic operation on shared flag variable
  net: sched: don't use GFP_KERNEL under spin lock
  vhost_net: correctly check tx avail during rx busy polling
  net: mdio-mux: add mdio_mux parameter to mdio_mux_init()
  rxrpc: Make service connection lookup always check for retry
  net: stmmac: Delete dead code for MDIO registration
  gianfar: Fix Tx flow control deactivation
  cxgb4: Ignore MPS_TX_INT_CAUSE[Bubble] for T6
  cxgb4: Fix pause frame count in t4_get_port_stats
  cxgb4: fix memory leak
  tun: rename generic_xdp to skb_xdp
  tun: reserve extra headroom only when XDP is set
  net: dsa: bcm_sf2: Configure IMP port TC2QOS mapping
  net: dsa: bcm_sf2: Advertise number of egress queues
  ...
2017-09-06 14:45:08 -07:00
Linus Torvalds
6c51e67b64 Merge branch 'x86-syscall-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull syscall updates from Ingo Molnar:
 "Improve the security of set_fs(): we now check the address limit on a
  number of key platforms (x86, arm, arm64) before returning to
  user-space - without adding overhead to the typical system call fast
  path"

* 'x86-syscall-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  arm64/syscalls: Check address limit on user-mode return
  arm/syscalls: Check address limit on user-mode return
  x86/syscalls: Check address limit on user-mode return
2017-09-04 11:18:17 -07:00
Christoph Hellwig
ddef7ed2b5 annotate RWF_... flags
[AV: added missing annotations in syscalls.h/compat.h]

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-08-31 17:32:38 -04:00
Al Viro
4f59c71852 teach SYSCALL_DEFINE/COMPAT_SYSCALL_DEFINE to handle __bitwise arguments
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-08-31 17:32:37 -04:00
Yonghong Song
cf5f5cea27 bpf: add support for sys_enter_* and sys_exit_* tracepoints
Currently, bpf programs cannot be attached to sys_enter_* and sys_exit_*
style tracepoints. The iovisor/bcc issue #748
(https://github.com/iovisor/bcc/issues/748) documents this issue.
For example, if you try to attach a bpf program to tracepoints
syscalls/sys_enter_newfstat, you will get the following error:
   # ./tools/trace.py t:syscalls:sys_enter_newfstat
   Ioctl(PERF_EVENT_IOC_SET_BPF): Invalid argument
   Failed to attach BPF to tracepoint

The main reason is that syscalls/sys_enter_* and syscalls/sys_exit_*
tracepoints are treated differently from other tracepoints and there
is no bpf hook to it.

This patch adds bpf support for these syscalls tracepoints by
  . permitting bpf attachment in ioctl PERF_EVENT_IOC_SET_BPF
  . calling bpf programs in perf_syscall_enter and perf_syscall_exit

The legality of bpf program ctx access is also checked.
Function trace_event_get_offsets returns correct max offset for each
specific syscall tracepoint, which is compared against the maximum offset
access in bpf program.

Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-08-07 14:09:48 -07:00
Thomas Garnier
5ea0727b16 x86/syscalls: Check address limit on user-mode return
Ensure the address limit is a user-mode segment before returning to
user-mode. Otherwise a process can corrupt kernel-mode memory and elevate
privileges [1].

The set_fs function sets the TIF_SETFS flag to force a slow path on
return. In the slow path, the address limit is checked to be USER_DS if
needed.

The addr_limit_user_check function is added as a cross-architecture
function to check the address limit.

[1] https://bugs.chromium.org/p/project-zero/issues/detail?id=990

Signed-off-by: Thomas Garnier <thgarnie@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: kernel-hardening@lists.openwall.com
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Pratyush Anand <panand@redhat.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Will Drewry <wad@chromium.org>
Cc: linux-api@vger.kernel.org
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Link: http://lkml.kernel.org/r/20170615011203.144108-1-thgarnie@google.com
2017-07-08 14:05:32 +02:00
Al Viro
613763a1f0 take compat_sys_old_getrlimit() to native syscall
... and sanitize the ifdefs in there

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-05-27 15:38:06 -04:00
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>
2017-03-02 20:51:15 -05:00
Dave Hansen
71757904ef generic syscalls: kill cruft from removed pkey syscalls
pkey_set() and pkey_get() were syscalls present in older versions
of the protection keys patches.  They were fully excised from the
x86 code, but some cruft was left in the generic syscall code.  The
C++ comments were intended to help to make it more glaring to me to
fix them before actually submitting them.  That technique worked,
but later than I would have liked.

I test-compiled this for arm64.

Fixes: a60f7b69d9 ("generic syscalls: Wire up memory protection keys syscalls")
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86@kernel.org
Cc: linux-arch@vger.kernel.org
Cc: mgorman@techsingularity.net
Cc: linux-api@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: luto@kernel.org
Cc: akpm@linux-foundation.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-17 09:50:56 -07:00
Dave Hansen
a60f7b69d9 generic syscalls: Wire up memory protection keys syscalls
These new syscalls are implemented as generic code, so enable them for
architectures like arm64 which use the generic syscall table.

According to Arnd:

  Even if the support is x86 specific for the forseeable future, it may be
  good to reserve the number just in case.  The other architecture specific
  syscall lists are usually left to the individual arch maintainers, most a
  lot of the newer architectures share this table.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Cc: linux-arch@vger.kernel.org
Cc: Dave Hansen <dave@sr71.net>
Cc: mgorman@techsingularity.net
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/20160729163018.505A6875@viggo.jf.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-09-09 13:02:27 +02:00
René Nyffenegger
2eeed7e98d include/linux/syscalls.h: use pid_t instead of int
In include/linux/syscalls.h, the four functions sys_kill, sys_tgkill,
sys_tkill and sys_rt_sigqueueinfo are declared with "int pid" and "int
tgid".

However, in kernel/signal.c, the corresponding definitions use the more
appropriate "pid_t" (which is a typedef'd int).

This patch changes "int" to "pid_t" in the declarations of sys_kill,
sys_tgkill, sys_tkill and sys_rt_sigqueueinfo in <linux/syscalls.h> in
order to harmonize the function declarations with their respective
definitions.

Link: http://lkml.kernel.org/r/57302FDA.7020205@renenyffenegger.ch
Signed-off-by: René Nyffenegger <mail@renenyffenegger.ch>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
Cc: Zach Brown <zab@redhat.com>
Cc: Milosz Tanski <milosz@adfin.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-20 17:58:30 -07:00
Milosz Tanski
f17d8b3545 vfs: vfs: Define new syscalls preadv2,pwritev2
New syscalls that take an flag argument.   No flags are added yet in this
patch.

Signed-off-by: Milosz Tanski <milosz@adfin.com>
[hch: rebased on top of my kiocb changes]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Stephen Bates <stephen.bates@pmcs.com>
Tested-by: Stephen Bates <stephen.bates@pmcs.com>
Acked-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-03-04 12:20:10 -05:00
Zach Brown
29732938a6 vfs: add copy_file_range syscall and vfs helper
Add a copy_file_range() system call for offloading copies between
regular files.

This gives an interface to underlying layers of the storage stack which
can copy without reading and writing all the data.  There are a few
candidates that should support copy offloading in the nearer term:

- btrfs shares extent references with its clone ioctl
- NFS has patches to add a COPY command which copies on the server
- SCSI has a family of XCOPY commands which copy in the device

This system call avoids the complexity of also accelerating the creation
of the destination file by operating on an existing destination file
descriptor, not a path.

Currently the high level vfs entry point limits copy offloading to files
on the same mount and super (and not in the same file).  This can be
relaxed if we get implementations which can copy between file systems
safely.

Signed-off-by: Zach Brown <zab@redhat.com>
[Anna Schumaker: Change -EINVAL to -EBADF during file verification,
                 Change flags parameter from int to unsigned int,
                 Add function to include/linux/syscalls.h,
                 Check copy len after file open mode,
                 Don't forbid ranges inside the same file,
                 Use rw_verify_area() to veriy ranges,
                 Use file_out rather than file_in,
                 Add COPY_FR_REFLINK flag]
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>
2015-12-01 14:00:53 -05:00
Arnd Bergmann
fbc416ff86 arm64: fix building without CONFIG_UID16
As reported by Michal Simek, building an ARM64 kernel with CONFIG_UID16
disabled currently fails because the system call table still needs to
reference the individual function entry points that are provided by
kernel/sys_ni.c in this case, and the declarations are hidden inside
of #ifdef CONFIG_UID16:

arch/arm64/include/asm/unistd32.h:57:8: error: 'sys_lchown16' undeclared here (not in a function)
 __SYSCALL(__NR_lchown, sys_lchown16)

I believe this problem only exists on ARM64, because older architectures
tend to not need declarations when their system call table is built
in assembly code, while newer architectures tend to not need UID16
support. ARM64 only uses these system calls for compatibility with
32-bit ARM binaries.

This changes the CONFIG_UID16 check into CONFIG_HAVE_UID16, which is
set unconditionally on ARM64 with CONFIG_COMPAT, so we see the
declarations whenever we need them, but otherwise the behavior is
unchanged.

Fixes: af1839eb4b ("Kconfig: clean up the long arch list for the UID16 config option")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: stable@vger.kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2015-11-25 15:49:13 +00:00
Eric B Munson
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>
2015-11-05 19:34:48 -08:00
Mathieu Desnoyers
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>
2015-09-11 15:21:34 -07:00
Andrea Arcangeli
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>
2015-09-04 16:54:41 -07:00
Linus Torvalds
e382608254 This patch series contains several clean ups and even a new trace clock
"monitonic raw". Also some enhancements to make the ring buffer even
 faster. But the biggest and most noticeable change is the renaming of
 the ftrace* files, structures and variables that have to deal with
 trace events.
 
 Over the years I've had several developers tell me about their confusion
 with what ftrace is compared to events. Technically, "ftrace" is the
 infrastructure to do the function hooks, which include tracing and also
 helps with live kernel patching. But the trace events are a separate
 entity altogether, and the files that affect the trace events should
 not be named "ftrace". These include:
 
   include/trace/ftrace.h	->	include/trace/trace_events.h
   include/linux/ftrace_event.h	->	include/linux/trace_events.h
 
 Also, functions that are specific for trace events have also been renamed:
 
   ftrace_print_*()		->	trace_print_*()
   (un)register_ftrace_event()	->	(un)register_trace_event()
   ftrace_event_name()		->	trace_event_name()
   ftrace_trigger_soft_disabled()->	trace_trigger_soft_disabled()
   ftrace_define_fields_##call() ->	trace_define_fields_##call()
   ftrace_get_offsets_##call()	->	trace_get_offsets_##call()
 
 Structures have been renamed:
 
   ftrace_event_file		->	trace_event_file
   ftrace_event_{call,class}	->	trace_event_{call,class}
   ftrace_event_buffer		->	trace_event_buffer
   ftrace_subsystem_dir		->	trace_subsystem_dir
   ftrace_event_raw_##call	->	trace_event_raw_##call
   ftrace_event_data_offset_##call->	trace_event_data_offset_##call
   ftrace_event_type_funcs_##call ->	trace_event_type_funcs_##call
 
 And a few various variables and flags have also been updated.
 
 This has been sitting in linux-next for some time, and I have not heard
 a single complaint about this rename breaking anything. Mostly because
 these functions, variables and structures are mostly internal to the
 tracing system and are seldom (if ever) used by anything external to that.
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Merge tag 'trace-v4.2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing updates from Steven Rostedt:
 "This patch series contains several clean ups and even a new trace
  clock "monitonic raw".  Also some enhancements to make the ring buffer
  even faster.  But the biggest and most noticeable change is the
  renaming of the ftrace* files, structures and variables that have to
  deal with trace events.

  Over the years I've had several developers tell me about their
  confusion with what ftrace is compared to events.  Technically,
  "ftrace" is the infrastructure to do the function hooks, which include
  tracing and also helps with live kernel patching.  But the trace
  events are a separate entity altogether, and the files that affect the
  trace events should not be named "ftrace".  These include:

    include/trace/ftrace.h         ->    include/trace/trace_events.h
    include/linux/ftrace_event.h   ->    include/linux/trace_events.h

  Also, functions that are specific for trace events have also been renamed:

    ftrace_print_*()               ->    trace_print_*()
    (un)register_ftrace_event()    ->    (un)register_trace_event()
    ftrace_event_name()            ->    trace_event_name()
    ftrace_trigger_soft_disabled() ->    trace_trigger_soft_disabled()
    ftrace_define_fields_##call()  ->    trace_define_fields_##call()
    ftrace_get_offsets_##call()    ->    trace_get_offsets_##call()

  Structures have been renamed:

    ftrace_event_file              ->    trace_event_file
    ftrace_event_{call,class}      ->    trace_event_{call,class}
    ftrace_event_buffer            ->    trace_event_buffer
    ftrace_subsystem_dir           ->    trace_subsystem_dir
    ftrace_event_raw_##call        ->    trace_event_raw_##call
    ftrace_event_data_offset_##call->    trace_event_data_offset_##call
    ftrace_event_type_funcs_##call ->    trace_event_type_funcs_##call

  And a few various variables and flags have also been updated.

  This has been sitting in linux-next for some time, and I have not
  heard a single complaint about this rename breaking anything.  Mostly
  because these functions, variables and structures are mostly internal
  to the tracing system and are seldom (if ever) used by anything
  external to that"

* tag 'trace-v4.2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (33 commits)
  ring_buffer: Allow to exit the ring buffer benchmark immediately
  ring-buffer-benchmark: Fix the wrong type
  ring-buffer-benchmark: Fix the wrong param in module_param
  ring-buffer: Add enum names for the context levels
  ring-buffer: Remove useless unused tracing_off_permanent()
  ring-buffer: Give NMIs a chance to lock the reader_lock
  ring-buffer: Add trace_recursive checks to ring_buffer_write()
  ring-buffer: Allways do the trace_recursive checks
  ring-buffer: Move recursive check to per_cpu descriptor
  ring-buffer: Add unlikelys to make fast path the default
  tracing: Rename ftrace_get_offsets_##call() to trace_event_get_offsets_##call()
  tracing: Rename ftrace_define_fields_##call() to trace_event_define_fields_##call()
  tracing: Rename ftrace_event_type_funcs_##call to trace_event_type_funcs_##call
  tracing: Rename ftrace_data_offset_##call to trace_event_data_offset_##call
  tracing: Rename ftrace_raw_##call event structures to trace_event_raw_##call
  tracing: Rename ftrace_trigger_soft_disabled() to trace_trigger_soft_disabled()
  tracing: Rename FTRACE_EVENT_FL_* flags to EVENT_FILE_FL_*
  tracing: Rename struct ftrace_subsystem_dir to trace_subsystem_dir
  tracing: Rename ftrace_event_name() to trace_event_name()
  tracing: Rename FTRACE_MAX_EVENT to TRACE_EVENT_TYPE_MAX
  ...
2015-06-26 14:02:43 -07:00
Josh Triplett
3033f14ab7 clone: support passing tls argument via C rather than pt_regs magic
clone has some of the quirkiest syscall handling in the kernel, with a
pile of special cases, historical curiosities, and architecture-specific
calling conventions.  In particular, clone with CLONE_SETTLS accepts a
parameter "tls" that the C entry point completely ignores and some
assembly entry points overwrite; instead, the low-level arch-specific
code pulls the tls parameter out of the arch-specific register captured
as part of pt_regs on entry to the kernel.  That's a massive hack, and
it makes the arch-specific code only work when called via the specific
existing syscall entry points; because of this hack, any new clone-like
system call would have to accept an identical tls argument in exactly
the same arch-specific position, rather than providing a unified system
call entry point across architectures.

The first patch allows architectures to handle the tls argument via
normal C parameter passing, if they opt in by selecting
HAVE_COPY_THREAD_TLS.  The second patch makes 32-bit and 64-bit x86 opt
into this.

These two patches came out of the clone4 series, which isn't ready for
this merge window, but these first two cleanup patches were entirely
uncontroversial and have acks.  I'd like to go ahead and submit these
two so that other architectures can begin building on top of this and
opting into HAVE_COPY_THREAD_TLS.  However, I'm also happy to wait and
send these through the next merge window (along with v3 of clone4) if
anyone would prefer that.

This patch (of 2):

clone with CLONE_SETTLS accepts an argument to set the thread-local
storage area for the new thread.  sys_clone declares an int argument
tls_val in the appropriate point in the argument list (based on the
various CLONE_BACKWARDS variants), but doesn't actually use or pass along
that argument.  Instead, sys_clone calls do_fork, which calls
copy_process, which calls the arch-specific copy_thread, and copy_thread
pulls the corresponding syscall argument out of the pt_regs captured at
kernel entry (knowing what argument of clone that architecture passes tls
in).

Apart from being awful and inscrutable, that also only works because only
one code path into copy_thread can pass the CLONE_SETTLS flag, and that
code path comes from sys_clone with its architecture-specific
argument-passing order.  This prevents introducing a new version of the
clone system call without propagating the same architecture-specific
position of the tls argument.

However, there's no reason to pull the argument out of pt_regs when
sys_clone could just pass it down via C function call arguments.

Introduce a new CONFIG_HAVE_COPY_THREAD_TLS for architectures to opt into,
and a new copy_thread_tls that accepts the tls parameter as an additional
unsigned long (syscall-argument-sized) argument.  Change sys_clone's tls
argument to an unsigned long (which does not change the ABI), and pass
that down to copy_thread_tls.

Architectures that don't opt into copy_thread_tls will continue to ignore
the C argument to sys_clone in favor of the pt_regs captured at kernel
entry, and thus will be unable to introduce new versions of the clone
syscall.

Patch co-authored by Josh Triplett and Thiago Macieira.

Signed-off-by: Josh Triplett <josh@joshtriplett.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Thiago Macieira <thiago.macieira@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-25 17:00:38 -07:00
Steven Rostedt (Red Hat)
2425bcb924 tracing: Rename ftrace_event_{call,class} to trace_event_{call,class}
The name "ftrace" really refers to the function hook infrastructure. It
is not about the trace_events. The structures ftrace_event_call and
ftrace_event_class have nothing to do with the function hooks, and are
really trace_event structures. Rename ftrace_event_* to trace_event_*.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-05-13 14:06:10 -04:00
Catalin Marinas
54e45c169d syscalls: Declare sys_*stat64 prototypes if __ARCH_WANT_(COMPAT_)STAT64
Currently, the sys_stat64, sys_fstat64 and sys_lstat64 prototpyes are
only declared if BITS_PER_LONG == 32. Following commit 0753f70f07
(fs: Build sys_stat64() and friends if __ARCH_WANT_COMPAT_STAT64), the
implementation of these functions is allowed on 64-bit systems for
compat support. The patch changes the condition on the prototype
declaration from BITS_PER_LONG == 32 to defined(__ARCH_WANT_STAT64) ||
defined(__ARCH_WANT_COMPAT_STAT64).

In addition, it moves the sys_fstatat64 prototype under the same #if
block

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
2015-01-27 09:38:00 +00:00
David Drysdale
51f39a1f0c syscalls: implement execveat() system call
This patchset adds execveat(2) for x86, and is derived from Meredydd
Luff's patch from Sept 2012 (https://lkml.org/lkml/2012/9/11/528).

The primary aim of adding an execveat syscall is to allow an
implementation of fexecve(3) that does not rely on the /proc filesystem,
at least for executables (rather than scripts).  The current glibc version
of fexecve(3) is implemented via /proc, which causes problems in sandboxed
or otherwise restricted environments.

Given the desire for a /proc-free fexecve() implementation, HPA suggested
(https://lkml.org/lkml/2006/7/11/556) that an execveat(2) syscall would be
an appropriate generalization.

Also, having a new syscall means that it can take a flags argument without
back-compatibility concerns.  The current implementation just defines the
AT_EMPTY_PATH and AT_SYMLINK_NOFOLLOW flags, but other flags could be
added in future -- for example, flags for new namespaces (as suggested at
https://lkml.org/lkml/2006/7/11/474).

Related history:
 - https://lkml.org/lkml/2006/12/27/123 is an example of someone
   realizing that fexecve() is likely to fail in a chroot environment.
 - http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=514043 covered
   documenting the /proc requirement of fexecve(3) in its manpage, to
   "prevent other people from wasting their time".
 - https://bugzilla.redhat.com/show_bug.cgi?id=241609 described a
   problem where a process that did setuid() could not fexecve()
   because it no longer had access to /proc/self/fd; this has since
   been fixed.

This patch (of 4):

Add a new execveat(2) system call.  execveat() is to execve() as openat()
is to open(): it takes a file descriptor that refers to a directory, and
resolves the filename relative to that.

In addition, if the filename is empty and AT_EMPTY_PATH is specified,
execveat() executes the file to which the file descriptor refers.  This
replicates the functionality of fexecve(), which is a system call in other
UNIXen, but in Linux glibc it depends on opening "/proc/self/fd/<fd>" (and
so relies on /proc being mounted).

The filename fed to the executed program as argv[0] (or the name of the
script fed to a script interpreter) will be of the form "/dev/fd/<fd>"
(for an empty filename) or "/dev/fd/<fd>/<filename>", effectively
reflecting how the executable was found.  This does however mean that
execution of a script in a /proc-less environment won't work; also, script
execution via an O_CLOEXEC file descriptor fails (as the file will not be
accessible after exec).

Based on patches by Meredydd Luff.

Signed-off-by: David Drysdale <drysdale@google.com>
Cc: Meredydd Luff <meredydd@senatehouse.org>
Cc: Shuah Khan <shuah.kh@samsung.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Rich Felker <dalias@aerifal.cx>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-12-13 12:42:51 -08:00
Al Viro
666547ff59 separate kernel- and userland-side msghdr
Kernel-side struct msghdr is (currently) using the same layout as
userland one, but it's not a one-to-one copy - even without considering
32bit compat issues, we have msg_iov, msg_name and msg_control copied
to kernel[1].  It's fairly localized, so we get away with a few functions
where that knowledge is needed (and we could shrink that set even
more).  Pretty much everything deals with the kernel-side variant and
the few places that want userland one just use a bunch of force-casts
to paper over the differences.

The thing is, kernel-side definition of struct msghdr is *not* exposed
in include/uapi - libc doesn't see it, etc.  So we can add struct user_msghdr,
with proper annotations and let the few places that ever deal with those
beasts use it for userland pointers.  Saner typechecking aside, that will
allow to change the layout of kernel-side msghdr - e.g. replace
msg_iov/msg_iovlen there with struct iov_iter, getting rid of the need
to modify the iovec as we copy data to/from it, etc.

We could introduce kernel_msghdr instead, but that would create much more
noise - the absolute majority of the instances would need to have the
type switched to kernel_msghdr and definition of struct msghdr in
include/linux/socket.h is not going to be seen by userland anyway.

This commit just introduces user_msghdr and switches the few places that
are dealing with userland-side msghdr to it.

[1] actually, it's even trickier than that - we copy msg_control for
sendmsg, but keep the userland address on recvmsg.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-11-19 16:22:59 -05:00
Alexei Starovoitov
749730ce42 bpf: enable bpf syscall on x64 and i386
done as separate commit to ease conflict resolution

Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-26 15:05:14 -04:00
Vivek Goyal
f0895685c7 kexec: new syscall kexec_file_load() declaration
This is the new syscall kexec_file_load() declaration/interface.  I have
reserved the syscall number only for x86_64 so far.  Other architectures
(including i386) can reserve syscall number when they enable the support
for this new syscall.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: WANG Chao <chaowang@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-08 15:57:32 -07:00
David Herrmann
9183df25fe shm: add memfd_create() syscall
memfd_create() is similar to mmap(MAP_ANON), but returns a file-descriptor
that you can pass to mmap().  It can support sealing and avoids any
connection to user-visible mount-points.  Thus, it's not subject to quotas
on mounted file-systems, but can be used like malloc()'ed memory, but with
a file-descriptor to it.

memfd_create() returns the raw shmem file, so calls like ftruncate() can
be used to modify the underlying inode.  Also calls like fstat() will
return proper information and mark the file as regular file.  If you want
sealing, you can specify MFD_ALLOW_SEALING.  Otherwise, sealing is not
supported (like on all other regular files).

Compared to O_TMPFILE, it does not require a tmpfs mount-point and is not
subject to a filesystem size limit.  It is still properly accounted to
memcg limits, though, and to the same overcommit or no-overcommit
accounting as all user memory.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Ryan Lortie <desrt@desrt.ca>
Cc: Lennart Poettering <lennart@poettering.net>
Cc: Daniel Mack <zonque@gmail.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-08 15:57:31 -07:00
Linus Torvalds
f4f142ed4e Cleanups and bug fixes to /dev/random, add a new getrandom(2) system
call, which is a superset of OpenBSD's getentropy(2) call, for use
 with userspace crypto libraries such as LibreSSL.  Also add the
 ability to have a kernel thread to pull entropy from hardware rng
 devices into /dev/random.
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Merge tag 'random_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random

Pull randomness updates from Ted Ts'o:
 "Cleanups and bug fixes to /dev/random, add a new getrandom(2) system
  call, which is a superset of OpenBSD's getentropy(2) call, for use
  with userspace crypto libraries such as LibreSSL.

  Also add the ability to have a kernel thread to pull entropy from
  hardware rng devices into /dev/random"

* tag 'random_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random:
  hwrng: Pass entropy to add_hwgenerator_randomness() in bits, not bytes
  random: limit the contribution of the hw rng to at most half
  random: introduce getrandom(2) system call
  hw_random: fix sparse warning (NULL vs 0 for pointer)
  random: use registers from interrupted code for CPU's w/o a cycle counter
  hwrng: add per-device entropy derating
  hwrng: create filler thread
  random: add_hwgenerator_randomness() for feeding entropy from devices
  random: use an improved fast_mix() function
  random: clean up interrupt entropy accounting for archs w/o cycle counters
  random: only update the last_pulled time if we actually transferred entropy
  random: remove unneeded hash of a portion of the entropy pool
  random: always update the entropy pool under the spinlock
2014-08-06 08:16:24 -07:00
Theodore Ts'o
c6e9d6f388 random: introduce getrandom(2) system call
The getrandom(2) system call was requested by the LibreSSL Portable
developers.  It is analoguous to the getentropy(2) system call in
OpenBSD.

The rationale of this system call is to provide resiliance against
file descriptor exhaustion attacks, where the attacker consumes all
available file descriptors, forcing the use of the fallback code where
/dev/[u]random is not available.  Since the fallback code is often not
well-tested, it is better to eliminate this potential failure mode
entirely.

The other feature provided by this new system call is the ability to
request randomness from the /dev/urandom entropy pool, but to block
until at least 128 bits of entropy has been accumulated in the
/dev/urandom entropy pool.  Historically, the emphasis in the
/dev/urandom development has been to ensure that urandom pool is
initialized as quickly as possible after system boot, and preferably
before the init scripts start execution.

This is because changing /dev/urandom reads to block represents an
interface change that could potentially break userspace which is not
acceptable.  In practice, on most x86 desktop and server systems, in
general the entropy pool can be initialized before it is needed (and
in modern kernels, we will printk a warning message if not).  However,
on an embedded system, this may not be the case.  And so with this new
interface, we can provide the functionality of blocking until the
urandom pool has been initialized.  Any userspace program which uses
this new functionality must take care to assure that if it is used
during the boot process, that it will not cause the init scripts or
other portions of the system startup to hang indefinitely.

SYNOPSIS
	#include <linux/random.h>

	int getrandom(void *buf, size_t buflen, unsigned int flags);

DESCRIPTION
	The system call getrandom() fills the buffer pointed to by buf
	with up to buflen random bytes which can be used to seed user
	space random number generators (i.e., DRBG's) or for other
	cryptographic uses.  It should not be used for Monte Carlo
	simulations or other programs/algorithms which are doing
	probabilistic sampling.

	If the GRND_RANDOM flags bit is set, then draw from the
	/dev/random pool instead of the /dev/urandom pool.  The
	/dev/random pool is limited based on the entropy that can be
	obtained from environmental noise, so if there is insufficient
	entropy, the requested number of bytes may not be returned.
	If there is no entropy available at all, getrandom(2) will
	either block, or return an error with errno set to EAGAIN if
	the GRND_NONBLOCK bit is set in flags.

	If the GRND_RANDOM bit is not set, then the /dev/urandom pool
	will be used.  Unlike using read(2) to fetch data from
	/dev/urandom, if the urandom pool has not been sufficiently
	initialized, getrandom(2) will block (or return -1 with the
	errno set to EAGAIN if the GRND_NONBLOCK bit is set in flags).

	The getentropy(2) system call in OpenBSD can be emulated using
	the following function:

            int getentropy(void *buf, size_t buflen)
            {
                    int     ret;

                    if (buflen > 256)
                            goto failure;
                    ret = getrandom(buf, buflen, 0);
                    if (ret < 0)
                            return ret;
                    if (ret == buflen)
                            return 0;
            failure:
                    errno = EIO;
                    return -1;
            }

RETURN VALUE
       On success, the number of bytes that was filled in the buf is
       returned.  This may not be all the bytes requested by the
       caller via buflen if insufficient entropy was present in the
       /dev/random pool, or if the system call was interrupted by a
       signal.

       On error, -1 is returned, and errno is set appropriately.

ERRORS
	EINVAL		An invalid flag was passed to getrandom(2)

	EFAULT		buf is outside the accessible address space.

	EAGAIN		The requested entropy was not available, and
			getentropy(2) would have blocked if the
			GRND_NONBLOCK flag was not set.

	EINTR		While blocked waiting for entropy, the call was
			interrupted by a signal handler; see the description
			of how interrupted read(2) calls on "slow" devices
			are handled with and without the SA_RESTART flag
			in the signal(7) man page.

NOTES
	For small requests (buflen <= 256) getrandom(2) will not
	return EINTR when reading from the urandom pool once the
	entropy pool has been initialized, and it will return all of
	the bytes that have been requested.  This is the recommended
	way to use getrandom(2), and is designed for compatibility
	with OpenBSD's getentropy() system call.

	However, if you are using GRND_RANDOM, then getrandom(2) may
	block until the entropy accounting determines that sufficient
	environmental noise has been gathered such that getrandom(2)
	will be operating as a NRBG instead of a DRBG for those people
	who are working in the NIST SP 800-90 regime.  Since it may
	block for a long time, these guarantees do *not* apply.  The
	user may want to interrupt a hanging process using a signal,
	so blocking until all of the requested bytes are returned
	would be unfriendly.

	For this reason, the user of getrandom(2) MUST always check
	the return value, in case it returns some error, or if fewer
	bytes than requested was returned.  In the case of
	!GRND_RANDOM and small request, the latter should never
	happen, but the careful userspace code (and all crypto code
	should be careful) should check for this anyway!

	Finally, unless you are doing long-term key generation (and
	perhaps not even then), you probably shouldn't be using
	GRND_RANDOM.  The cryptographic algorithms used for
	/dev/urandom are quite conservative, and so should be
	sufficient for all purposes.  The disadvantage of GRND_RANDOM
	is that it can block, and the increased complexity required to
	deal with partially fulfilled getrandom(2) requests.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Zach Brown <zab@zabbo.net>
2014-08-05 16:41:22 -04:00
Kees Cook
48dc92b9fc seccomp: add "seccomp" syscall
This adds the new "seccomp" syscall with both an "operation" and "flags"
parameter for future expansion. The third argument is a pointer value,
used with the SECCOMP_SET_MODE_FILTER operation. Currently, flags must
be 0. This is functionally equivalent to prctl(PR_SET_SECCOMP, ...).

In addition to the TSYNC flag later in this patch series, there is a
non-zero chance that this syscall could be used for configuring a fixed
argument area for seccomp-tracer-aware processes to pass syscall arguments
in the future. Hence, the use of "seccomp" not simply "seccomp_add_filter"
for this syscall. Additionally, this syscall uses operation, flags,
and user pointer for arguments because strictly passing arguments via
a user pointer would mean seccomp itself would be unable to trivially
filter the seccomp syscall itself.

Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Andy Lutomirski <luto@amacapital.net>
2014-07-18 12:13:37 -07:00
Rasmus Villemoes
23c8902d40 mm: constify nmask argument to set_mempolicy()
The nmask argument to set_mempolicy() is const according to the user-space
header numaif.h, and since the kernel does indeed not modify it, it might
as well be declared const in the kernel.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-04 16:54:03 -07:00
Rasmus Villemoes
f7f28ca98b mm: constify nmask argument to mbind()
The nmask argument to mbind() is const according to the userspace header
numaif.h, and since the kernel does indeed not modify it, it might as well
be declared const in the kernel.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-04 16:54:03 -07:00
Linus Torvalds
0a7418f5f5 This includes the final patch to clean up and fix the issue with the
design of tracepoints and how a user could register a tracepoint
 and have that tracepoint not be activated but no error was shown.
 
 The design was for an out of tree module but broke in tree users.
 The clean up was to remove the saving of the hash table of tracepoint
 names such that they can be enabled before they exist (enabling
 a module tracepoint before that module is loaded). This added more
 complexity than needed. The clean up was to remove that code and
 just enable tracepoints that exist or fail if they do not.
 
 This removed a lot of code as well as the complexity that it brought.
 As a side effect, instead of registering a tracepoint by its name,
 the tracepoint needs to be registered with the tracepoint descriptor.
 This removes having to duplicate the tracepoint names that are
 enabled.
 
 The second patch was added that simplified the way modules were
 searched for.
 
 This cleanup required changes that were in the 3.15 queue as well as
 some changes that were added late in the 3.14-rc cycle. This final
 change waited till the two were merged in upstream and then the
 change was added and full tests were run. Unfortunately, the
 test found some errors, but after it was already submitted to the
 for-next branch and not to be rebased. Sparse errors were detected
 by Fengguang Wu's bot tests, and my internal tests discovered that
 the anonymous union initialization triggered a bug in older gcc compilers.
 Luckily, there was a bugzilla for the gcc bug which gave a work around
 to the problem. The third and fourth patch handled the sparse error
 and the gcc bug respectively.
 
 A final patch was tagged along to fix a missing documentation for
 the README file.
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Merge tag 'trace-3.15-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull more tracing updates from Steven Rostedt:
 "This includes the final patch to clean up and fix the issue with the
  design of tracepoints and how a user could register a tracepoint and
  have that tracepoint not be activated but no error was shown.

  The design was for an out of tree module but broke in tree users.  The
  clean up was to remove the saving of the hash table of tracepoint
  names such that they can be enabled before they exist (enabling a
  module tracepoint before that module is loaded).  This added more
  complexity than needed.  The clean up was to remove that code and just
  enable tracepoints that exist or fail if they do not.

  This removed a lot of code as well as the complexity that it brought.
  As a side effect, instead of registering a tracepoint by its name, the
  tracepoint needs to be registered with the tracepoint descriptor.
  This removes having to duplicate the tracepoint names that are
  enabled.

  The second patch was added that simplified the way modules were
  searched for.

  This cleanup required changes that were in the 3.15 queue as well as
  some changes that were added late in the 3.14-rc cycle.  This final
  change waited till the two were merged in upstream and then the change
  was added and full tests were run.  Unfortunately, the test found some
  errors, but after it was already submitted to the for-next branch and
  not to be rebased.  Sparse errors were detected by Fengguang Wu's bot
  tests, and my internal tests discovered that the anonymous union
  initialization triggered a bug in older gcc compilers.  Luckily, there
  was a bugzilla for the gcc bug which gave a work around to the
  problem.  The third and fourth patch handled the sparse error and the
  gcc bug respectively.

  A final patch was tagged along to fix a missing documentation for the
  README file"

* tag 'trace-3.15-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Add missing function triggers dump and cpudump to README
  tracing: Fix anonymous unions in struct ftrace_event_call
  tracepoint: Fix sparse warnings in tracepoint.c
  tracepoint: Simplify tracepoint module search
  tracepoint: Use struct pointer instead of name hash for reg/unreg tracepoints
2014-04-12 13:06:10 -07:00
Mathieu Desnoyers
abb43f6998 tracing: Fix anonymous unions in struct ftrace_event_call
gcc <= 4.5.x has significant limitations with respect to initialization
of anonymous unions within structures. They need to be surrounded by
brackets, _and_ they need to be initialized in the same order in which
they appear in the structure declaration.

Link: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=10676
Link: http://lkml.kernel.org/r/1397077568-3156-1-git-send-email-mathieu.desnoyers@efficios.com

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-04-09 20:02:55 -04:00
Heiko Carstens
5fb6b953bb include/linux/syscalls.h: add sys_renameat2() prototype
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08 09:24:25 -07:00
Rashika Kheria
e3a0cfdc8c include/linux/syscalls.h: add sys32_quotactl() prototype
This eliminates the following warning in quota/compat.c:

  fs/quota/compat.c:43:17: warning: no previous prototype for `sys32_quotactl' [-Wmissing-prototypes]

Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-03 16:21:05 -07:00
Heiko Carstens
ab4f8bba19 s390/compat: automatic zero, sign and pointer conversion of syscalls
Instead of explicitly changing compat system call parameters from e.g.
unsigned long to compat_ulong_t let the COMPAT_SYSCALL_WRAP macros
automatically detect (unsigned) long parameters and zero and sign
extend them automatically.
The resulting binary is completely identical.

In addition add a sys_[system call name] prototype for each system call
wrapper. This will cause compile errors if the prototype does not match
the prototype in include/linux/syscall.h.
Therefore we should now always get the correct zero and sign extension
of system call parameters. Pointers are handled like before.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2014-03-04 09:12:24 +01:00
Peter Zijlstra
6d35ab4809 sched: Add 'flags' argument to sched_{set,get}attr() syscalls
Because of a recent syscall design debate; its deemed appropriate for
each syscall to have a flags argument for future extension; without
immediately requiring new syscalls.

Cc: juri.lelli@gmail.com
Cc: Ingo Molnar <mingo@redhat.com>
Suggested-by: Michael Kerrisk <mtk.manpages@gmail.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140214161929.GL27965@twins.programming.kicks-ass.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-02-21 21:27:10 +01:00
Dario Faggioli
d50dde5a10 sched: Add new scheduler syscalls to support an extended scheduling parameters ABI
Add the syscalls needed for supporting scheduling algorithms
with extended scheduling parameters (e.g., SCHED_DEADLINE).

In general, it makes possible to specify a periodic/sporadic task,
that executes for a given amount of runtime at each instance, and is
scheduled according to the urgency of their own timing constraints,
i.e.:

 - a (maximum/typical) instance execution time,
 - a minimum interval between consecutive instances,
 - a time constraint by which each instance must be completed.

Thus, both the data structure that holds the scheduling parameters of
the tasks and the system calls dealing with it must be extended.
Unfortunately, modifying the existing struct sched_param would break
the ABI and result in potentially serious compatibility issues with
legacy binaries.

For these reasons, this patch:

 - defines the new struct sched_attr, containing all the fields
   that are necessary for specifying a task in the computational
   model described above;

 - defines and implements the new scheduling related syscalls that
   manipulate it, i.e., sched_setattr() and sched_getattr().

Syscalls are introduced for x86 (32 and 64 bits) and ARM only, as a
proof of concept and for developing and testing purposes. Making them
available on other architectures is straightforward.

Since no "user" for these new parameters is introduced in this patch,
the implementation of the new system calls is just identical to their
already existing counterpart. Future patches that implement scheduling
policies able to exploit the new data structure must also take care of
modifying the sched_*attr() calls accordingly with their own purposes.

Signed-off-by: Dario Faggioli <raistlin@linux.it>
[ Rewrote to use sched_attr. ]
Signed-off-by: Juri Lelli <juri.lelli@gmail.com>
[ Removed sched_setscheduler2() for now. ]
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1383831828-15501-3-git-send-email-juri.lelli@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-01-13 13:41:04 +01:00
Linus Torvalds
b29c8306a3 This batch of changes is mostly clean ups and small bug fixes.
The only real feature that was added this release is from Namhyung Kim,
 who introduced "set_graph_notrace" filter that lets you run the function
 graph tracer and not trace particular functions and their call chain.
 
 Tom Zanussi added some updates to the ftrace multibuffer tracing that
 made it more consistent with the top level tracing.
 
 One of the fixes for perf function tracing required an API change in
 RCU; the addition of "rcu_is_watching()". As Paul McKenney is pushing
 that change in this release too, he gave me a branch that included
 all the changes to get that working, and I pulled that into my tree
 in order to complete the perf function tracing fix.
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Merge tag 'trace-3.13' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing update from Steven Rostedt:
 "This batch of changes is mostly clean ups and small bug fixes.  The
  only real feature that was added this release is from Namhyung Kim,
  who introduced "set_graph_notrace" filter that lets you run the
  function graph tracer and not trace particular functions and their
  call chain.

  Tom Zanussi added some updates to the ftrace multibuffer tracing that
  made it more consistent with the top level tracing.

  One of the fixes for perf function tracing required an API change in
  RCU; the addition of "rcu_is_watching()".  As Paul McKenney is pushing
  that change in this release too, he gave me a branch that included all
  the changes to get that working, and I pulled that into my tree in
  order to complete the perf function tracing fix"

* tag 'trace-3.13' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Add rcu annotation for syscall trace descriptors
  tracing: Do not use signed enums with unsigned long long in fgragh output
  tracing: Remove unused function ftrace_off_permanent()
  tracing: Do not assign filp->private_data to freed memory
  tracing: Add helper function tracing_is_disabled()
  tracing: Open tracer when ftrace_dump_on_oops is used
  tracing: Add support for SOFT_DISABLE to syscall events
  tracing: Make register/unregister_ftrace_command __init
  tracing: Update event filters for multibuffer
  recordmcount.pl: Add support for __fentry__
  ftrace: Have control op function callback only trace when RCU is watching
  rcu: Do not trace rcu_is_watching() functions
  ftrace/x86: skip over the breakpoint for ftrace caller
  trace/trace_stat: use rbtree postorder iteration helper instead of opencoding
  ftrace: Add set_graph_notrace filter
  ftrace: Narrow down the protected area of graph_lock
  ftrace: Introduce struct ftrace_graph_data
  ftrace: Get rid of ftrace_graph_filter_enabled
  tracing: Fix potential out-of-bounds in trace_get_user()
  tracing: Show more exact help information about snapshot
2013-11-16 12:23:18 -08:00
Andi Kleen
83460ec8dc syscalls.h: use gcc alias instead of assembler aliases for syscalls
Use standard gcc __attribute__((alias(foo))) to define the syscall aliases
instead of custom assembler macros.

This is far cleaner, and also fixes my LTO kernel build.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-11-13 12:09:12 +09:00
Tom Zanussi
d562aff93b tracing: Add support for SOFT_DISABLE to syscall events
The original SOFT_DISABLE patches didn't add support for soft disable
of syscall events; this adds it.

Add an array of ftrace_event_file pointers indexed by syscall number
to the trace array and remove the existing enabled bitmaps, which as a
result are now redundant.  The ftrace_event_file structs in turn
contain the soft disable flags we need for per-syscall soft disable
accounting.

Adding ftrace_event_files also means we can remove the USE_CALL_FILTER
bit, thus enabling multibuffer filter support for syscall events.

Link: http://lkml.kernel.org/r/6e72b566e85d8df8042f133efbc6c30e21fb017e.1382620672.git.tom.zanussi@linux.intel.com

Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-11-05 17:48:49 -05:00
Tom Zanussi
f306cc82a9 tracing: Update event filters for multibuffer
The trace event filters are still tied to event calls rather than
event files, which means you don't get what you'd expect when using
filters in the multibuffer case:

Before:

  # echo 'bytes_alloc > 8192' > /sys/kernel/debug/tracing/events/kmem/kmalloc/filter
  # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter
  bytes_alloc > 8192
  # mkdir /sys/kernel/debug/tracing/instances/test1
  # echo 'bytes_alloc > 2048' > /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter
  # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter
  bytes_alloc > 2048
  # cat /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter
  bytes_alloc > 2048

Setting the filter in tracing/instances/test1/events shouldn't affect
the same event in tracing/events as it does above.

After:

  # echo 'bytes_alloc > 8192' > /sys/kernel/debug/tracing/events/kmem/kmalloc/filter
  # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter
  bytes_alloc > 8192
  # mkdir /sys/kernel/debug/tracing/instances/test1
  # echo 'bytes_alloc > 2048' > /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter
  # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter
  bytes_alloc > 8192
  # cat /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter
  bytes_alloc > 2048

We'd like to just move the filter directly from ftrace_event_call to
ftrace_event_file, but there are a couple cases that don't yet have
multibuffer support and therefore have to continue using the current
event_call-based filters.  For those cases, a new USE_CALL_FILTER bit
is added to the event_call flags, whose main purpose is to keep the
old behavior for those cases until they can be updated with
multibuffer support; at that point, the USE_CALL_FILTER flag (and the
new associated call_filter_check_discard() function) can go away.

The multibuffer support also made filter_current_check_discard()
redundant, so this change removes that function as well and replaces
it with filter_check_discard() (or call_filter_check_discard() as
appropriate).

Link: http://lkml.kernel.org/r/f16e9ce4270c62f46b2e966119225e1c3cca7e60.1382620672.git.tom.zanussi@linux.intel.com

Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-11-05 16:50:20 -05:00
Sergei Trofimovich
f9597f24c0 syscalls.h: add forward declarations for inplace syscall wrappers
Unclutter -Wmissing-prototypes warning types (enabled at make W=1)

    linux/include/linux/syscalls.h:190:18: warning: no previous prototype for 'SyS_semctl' [-Wmissing-prototypes]
      asmlinkage long SyS##name(__MAP(x,__SC_LONG,__VA_ARGS__)) \
                      ^
    linux/include/linux/syscalls.h:183:2: note: in expansion of macro '__SYSCALL_DEFINEx'
      __SYSCALL_DEFINEx(x, sname, __VA_ARGS__)
      ^
by adding forward declarations right before definitions.

Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:58:25 -07:00
Michal Simek
dfa9771a7c microblaze: fix clone syscall
Fix inadvertent breakage in the clone syscall ABI for Microblaze that
was introduced in commit f3268edbe6 ("microblaze: switch to generic
fork/vfork/clone").

The Microblaze syscall ABI for clone takes the parent tid address in the
4th argument; the third argument slot is used for the stack size.  The
incorrectly-used CLONE_BACKWARDS type assigned parent tid to the 3rd
slot.

This commit restores the original ABI so that existing userspace libc
code will work correctly.

All kernel versions from v3.8-rc1 were affected.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-08-13 17:57:48 -07:00
Al Viro
99e621f796 syscalls.h: slightly reduce the jungles of macros
a) teach __MAP(num, m, <list of type/name pairs>) to take empty
list (with num being 0, of course)
b) fold types__... and args__... declaration and initialization into
SYSCALL_METADATA(num, ...), making their use conditional on num != 0.
That allows to use the SYSCALL_METADATA instead of its near-duplicate
in SYSCALL_DEFINE0.
c) make SYSCALL_METADATA expand to nothing in case if CONFIG_FTRACE_SYSCALLS
is not defined; that allows to make SYSCALL_DEFINE0 and SYSCALL_DEFINEx
definitions independent from CONFIG_FTRACE_SYSCALLS.
d) kill SYSCALL_DEFINE - no users left (SYSCALL_DEFINE[0-6] is, of course,
still alive and well).

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-03-05 15:36:40 -05:00
Al Viro
e1fd1f490f get rid of union semop in sys_semctl(2) arguments
just have the bugger take unsigned long and deal with SETVAL
case (when we use an int member in the union) explicitly.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-03-05 15:14:16 -05:00
Al Viro
2cf0966683 make SYSCALL_DEFINE<n>-generated wrappers do asmlinkage_protect
... and switch i386 to HAVE_SYSCALL_WRAPPERS, killing open-coded
uses of asmlinkage_protect() in a bunch of syscalls.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-03-03 22:58:33 -05:00
Al Viro
22d1a35da0 make HAVE_SYSCALL_WRAPPERS unconditional
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-03-03 22:58:30 -05:00