Bit 0x100 of a page table, segment table of region table entry
can be used to disallow code execution for the virtual addresses
associated with the entry.
There is one tricky bit, the system call to return from a signal
is part of the signal frame written to the user stack. With a
non-executable stack this would stop working. To avoid breaking
things the protection fault handler checks the opcode that caused
the fault for 0x0a77 (sys_sigreturn) and 0x0aad (sys_rt_sigreturn)
and injects a system call. This is preferable to the alternative
solution with a stub function in the vdso because it works for
vdso=off and statically linked binaries as well.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
The "topology=off" kernel parameter is supposed to prevent the kernel
to use hardware topology information to generate scheduling domains
etc.
For an unknown reason I implemented this in a very odd way back then:
instead of simply clearing the MACHINE_HAS_TOPOLOGY flag within the
lowcore I added a second variable which indicated that topology
information should not be used. This is more than suboptimal since it
partially doesn't work. For the fake NUMA case topology information
is still considered and scheduling domains will be created based on
this.
To fix this and to simplify the code get rid of the extra variable and
implement the "topology=off" case like it is done for other features.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Old gcc versions can't handle a bogus early clobber on a Q constraint:
arch/s390/kernel/early.c: In function 'memmove_early.part.1':
arch/s390/kernel/early.c:432:2: error: '&' constraint used with no register class
Simply remove it to fix this.
Reported-by: Stefan Haberland <sth@linux.vnet.ibm.com>
Fixes: d543a106f9 ("s390: fix initrd corruptions with gcov/kcov instrumented kernels")
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
The early C code within arch/s390/kernel/early.c saves ipl parameters
before the bss section is cleared. When doing that it jumps to code
that is potentially gcov/kcov instrumented. That code in turn will
corrupt an initrd that potentially may reside in the not yet ready to
be used bss section.
Instead of excluding more and more code from gcov/kcov instrumentation
provide an early memmove function which will be used to save ipl
parameters. The verification if these parameters are actually valid
will be done later.
Reviewed-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Convert s390 to use a field in the struct lowcore for the CPU
preemption count. It is a bit cheaper to access a lowcore field
compared to a thread_info variable and it removes the depencency
on a task related structure.
bloat-o-meter on the vmlinux image for the default configuration
(CONFIG_PREEMPT_NONE=y) reports a small reduction in text size:
add/remove: 0/0 grow/shrink: 18/578 up/down: 228/-5448 (-5220)
A larger improvement is achieved with the default configuration
but with CONFIG_PREEMPT=y and CONFIG_DEBUG_PREEMPT=n:
add/remove: 2/6 grow/shrink: 59/4477 up/down: 1618/-228762 (-227144)
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Merge clock_sync_cpu into stp_sync_clock and split out the update
of the global and per-CPU clock fields into clock_sync_global
and clock_sync_local.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
These files were only including module.h for exception table
related functions. We've now separated that content out into its
own file "extable.h" so now move over to that and avoid all the
extra header content in module.h that we don't really need to compile
these files.
The additions of uaccess.h are to deal with implict includes like:
arch/s390/kernel/traps.c: In function 'do_report_trap':
arch/s390/kernel/traps.c:56:4: error: implicit declaration of function 'extable_fixup' [-Werror=implicit-function-declaration]
arch/s390/kernel/traps.c: In function 'illegal_op':
arch/s390/kernel/traps.c:173:3: error: implicit declaration of function 'get_user' [-Werror=implicit-function-declaration]
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux-s390@vger.kernel.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
It is possible to specify a user offset for the TOD clock, e.g. +2 hours.
The TOD clock will carry this offset even if the clock is synchronized
with STP. This makes the time stamps acquired with get_sync_clock()
useless as another LPAR migth use a different TOD offset.
Use the PTFF instrution to get the TOD epoch difference and subtract
it from the TOD clock value to get a physical timestamp. As the epoch
difference contains the sync check delta as well the LPAR offset value
to the physical clock needs to be refreshed after each clock
synchronization.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Lets provide the basic machine information for dump_stack on
s390. This enables the "Hardware name:" line and results in
output like
[...]
Oops: 0004 ilc:2 [#1] SMP
Modules linked in:
CPU: 1 PID: 74 Comm: sh Not tainted 4.5.0+ #205
Hardware name: IBM 2964 NC9 704 (KVM)
[...]
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Lockdep is initialized at compile time now. Get rid of lockdep_init().
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Krinkin <krinkin.m.u@gmail.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Cc: mm-commits@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Yet another leftover from the 31 bit era. The usual operation
"y = x & PSW_ADDR_INSN" with the PSW_ADDR_INSN mask is a nop for
CONFIG_64BIT.
Therefore remove all usages and hope the code is a bit less confusing.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
This is a leftover from the 31 bit area. For CONFIG_64BIT the usual
operation "y = x | PSW_ADDR_AMODE" is a nop. Therefore remove all
usages of PSW_ADDR_AMODE and make the code a bit less confusing.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
To collect the CPU registers of the crashed system allocated a single
page with memblock_alloc_base and use it as a copy buffer. Replace the
stop-and-store-status sigp with a store-status-at-address sigp in
smp_save_dump_cpus() and smp_store_status(). In both cases the target
CPU is already stopped and store-status-at-address avoids the detour
via the absolute zero page.
For kexec simplify s390_reset_system and call store_status() before
the prefix register of the boot CPU has been set to zero. Use STPX
to store the prefix register and remove dump_prefix_page.
Acked-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
If the kernel detects that the s390 hardware supports the vector
facility, it is enabled by default at an early stage. To force
it off, use the novx kernel parameter. Note that there is a small
time window, where the vector facility is enabled before it is
forced to be off.
With enabling the vector facility by default, the FPU save and
restore functions can be improved. They do not longer require
to manage expensive control register updates to enable or disable
the vector enablement control for particular processes.
Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Introduce /sys/debug/kernel/diag_stat with a statistic how many diagnose
calls have been done by each CPU in the system.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Remove the 31 bit support in order to reduce maintenance cost and
effectively remove dead code. Since a couple of years there is no
distribution left that comes with a 31 bit kernel.
The 31 bit kernel also has been broken since more than a year before
anybody noticed. In addition I added a removal warning to the kernel
shown at ipl for 5 minutes: a960062e58 ("s390: add 31 bit warning
message") which let everybody know about the plan to remove 31 bit
code. We didn't get any response.
Given that the last 31 bit only machine was introduced in 1999 let's
remove the code.
Anybody with 31 bit user space code can still use the compat mode.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Until we have hard performance data about the effects of CAD in the
spinlock loop disable the instruction by default.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Add the compare-and-delay instruction to the spin-lock and rw-lock
retry loops. A CPU executing the compare-and-delay instruction stops
until the lock value has changed. This is done to make the locking
code for contended locks to behave better in regard to the multi-
hreading facility. A thread of a core executing a compare-and-delay
will allow the other threads of a core to get a larger share of the
core resources.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
If the function tracer is enabled, allow to set kprobes on the first
instruction of a function (which is the function trace caller):
If no kprobe is set handling of enabling and disabling function tracing
of a function simply patches the first instruction. Either it is a nop
(right now it's an unconditional branch, which skips the mcount block),
or it's a branch to the ftrace_caller() function.
If a kprobe is being placed on a function tracer calling instruction
we encode if we actually have a nop or branch in the remaining bytes
after the breakpoint instruction (illegal opcode).
This is possible, since the size of the instruction used for the nop
and branch is six bytes, while the size of the breakpoint is only
two bytes.
Therefore the first two bytes contain the illegal opcode and the last
four bytes contain either "0" for nop or "1" for branch. The kprobes
code will then execute/simulate the correct instruction.
Instruction patching for kprobes and function tracer is always done
with stop_machine(). Therefore we don't have any races where an
instruction is patched concurrently on a different cpu.
Besides that also the program check handler which executes the function
trace caller instruction won't be executed concurrently to any
stop_machine() execution.
This allows to keep full fault based kprobes handling which generates
correct pt_regs contents automatically.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
The vector extension introduces 32 128-bit vector registers and a set of
instruction to operate on the vector registers.
The kernel can control the use of vector registers for the problem state
program with a bit in control register 0. Once enabled for a process the
kernel needs to retain the content of the vector registers on context
switch. The signal frame is extended to include the vector registers.
Two new register sets NT_S390_VXRS_LOW and NT_S390_VXRS_HIGH are added
to the regset interface for the debugger and core dumps.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
The original bootmem allocator is getting replaced by memblock. To
cover the needs of the s390 kdump implementation the physical memory
list is used.
With this patch the bootmem allocator and its bitmaps are completely
removed from s390.
Signed-off-by: Philipp Hachtmann <phacht@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
The zEC12 machines introduced the local-clearing control for the IDTE
and IPTE instruction. If the control is set only the TLB of the local
CPU is cleared of entries, either all entries of a single address space
for IDTE, or the entry for a single page-table entry for IPTE.
Without the local-clearing control the TLB flush is broadcasted to all
CPUs in the configuration, which is expensive.
The reset of the bit mask of the CPUs that need flushing after a
non-local IDTE is tricky. As TLB entries for an address space remain
in the TLB even if the address space is detached a new bit field is
required to keep track of attached CPUs vs. CPUs in the need of a
flush. After a non-local flush with IDTE the bit-field of attached CPUs
is copied to the bit-field of CPUs in need of a flush. The ordering
of operations on cpu_attach_mask, attach_count and mm_cpumask(mm) is
such that an underindication in mm_cpumask(mm) is prevented but an
overindication in mm_cpumask(mm) is possible.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
MACHINE_HAS_MVCOS is used exactly once when the machine is brought up.
There is no need to cache the flag in the machine_flags.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
The new function calls the old ones. The sclp_event_mask_early() is removed
and replaced by one invocation of sclp_set_event_mask(0, 0).
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Currently we have hardcoded the HSA size to 32 MiB. With this patch the
HSA size is determined dynamically via SCLP in early.c.
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
With dirty and referenced bits implemented in software it is unnecessary
to initialize the storage key for every page. With this patch not a single
storage key operation is done for a system that does not use KVM.
For KVM set_pte_at/pgste_set_key will do the initialization for the guest
view of the storage key when the mapping for the page is established in
the host.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
The current memory detection loop will detect all present memory of
a machine. This is true even if the user specified the "mem=" parameter
on the kernel command line.
This can be a problem since the memory detection may cause a fully
populated host page table for the guest, even for those parts of the
memory that the guest will never use afterwards.
So fix this and only detect memory up to a user supplied "mem=" limit
if specified.
Reported-by: Michael Johanssen <johanssn@de.ibm.com>
Reviewed-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
The set-program-parameter (SPP) instruction has been renamed to
load-program-parameter (LPP) (see SA23-2260). Reflect this change
and rename all macro/instruction references.
Also remove the duplicate SPP/LPP entry in the kernel disassembler
instruction list.
Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Fix name clash with some common code device drivers and add "tod"
to all tod clock access function names.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Make use of the pfmf instruction, if available, to initialize storage keys
of whole 1MB or 2GB frames instead of initializing every single page with
the sske instruction.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
MACHINE_HAS_PFMF and MACHINE_HAS_HPAGE actually have the same semantics:
the cpu has the EDAT1 facility installed in zArch mode. So remove one
of the feature flags in machine_flags and rename the other one to EDAT1.
The two old macros simply get mapped to MACHINE_HAS_EDAT1.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Change return code handling of the stsi() function:
In case function code 0 was specified the return value is the
current configuration level (already shifted). That way all
the code that actually copied the stsi_0() function can go
away.
Otherwise the return value is 0 (success) or negative to
indicate an error (currently only -EOPNOTSUPP).
Also stsi() is no longer an inline function. The function is
not performance critical, but every caller would generate an
exception table entry for this function.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This is the s390 port of 70627654 "x86, extable: Switch to relative
exception table entries".
Reduces the size of our exception tables by 50% on 64 bit builds.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
The maximum nesting of the cpu topology is evaluated when /proc/sysinfo
is the first time read. This happens without a lock and a concurrent
reader on a different cpu can see and use an invalid intermediate value.
Besides the fact that this race is quite unlikely the worst thing that
could happen is that /proc/sysinfo would contain bogus information about
the machine's cpu topology.
Nevertheless this should be fixed. So move the detection code to the
early machine detection code and since now the value is early available
use it in the topology code as well.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Allow user-space processes to use transactional execution (TX).
If the TX facility is available user space programs can use
transactions for fine-grained serialization based on the data
objects that are referenced during a transaction. This is
useful for lockless data structures and speculative compiler
optimizations.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
So far, large page support was completely disabled with
CONFIG_DEBUG_PAGEALLOC, although it would be sufficient if only the
large page kernel mapping was disabled. This patch enables large page
support with CONFIG_DEBUG_PAGEALLOC, while it prevents the large kernel
mapping in that case.
Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Follow x86 and MIPS and sort the main exception table at build time.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Remove the file name from the comment at top of many files. In most
cases the file name was wrong anyway, so it's rather pointless.
Also unify the IBM copyright statement. We did have a lot of sightly
different statements and wanted to change them one after another
whenever a file gets touched. However that never happened. Instead
people start to take the old/"wrong" statements to use as a template
for new files.
So unify all of them in one go.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
The early_pgm_check_handler() function is also used after the
init phase in s390_reset_system(). Therefore it must not be in
the init section.
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
The store clock fast instruction saves a couple of instructions compared
to the store clock instruction. Always use stckf instead of stck if it
is available.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Currently the following mechanisms are available to move active
Linux on System z instances between machines:
* z/VM 6.2 SSI (Single System Image)
* Suspend/resume
For moving Linux instances in this patch the term LGR (Linux Guest
Relocation) is used. Because such an operation is critical, it
should be detectable from Linux. With this patch for both, a live
system and a kernel dump, the information about LGRs is accessible.
To identify a guest, stsi and stfle data is used. A new function
lgr_info_log() compares the current data (lgr_info_cur) with the
last recorded one (lgr_info_last). In case the two data sets differ,
lgr_info_cur is logged to the "lgr" s390dbf.
The following trigger points call lgr_info_log():
* panic
* die
* kdump
* LGR timer
* PSW restart
* QDIO recovery
* resume
This patch also changes the s390dbf hex_ascii view. Now only printable ASCII
characters are shown.
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
The current code in setup_boot_command_line() uses a heuristic to
detect an EBCDIC command line. It checks if any of the bytes in
the command line has bit one (0x80) set. In that case it is assumed
that we have an EBCDIC string and the complete command line is
converted.
On s390 there are cases where the boot loader provides a kernel
command line that is NULL terminated, but has random data after
the NULL termination. In that case, setup_boot_command_line()
might misinterpret an ASCII string for an EBCDIC string. A
subsequent string conversion can then damage the ASCII string.
This patch solves the problem by checking for NULL termination.
If no EBCDIC character has been found until the the NULL
termination has been found, we now assume that we have an ASCII
string.
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
In ESA mode STCKF is not defined even if the facility bit is enabled.
To prevent an illegal operation we must also check if we run a 64 bit kernel.
To make the check perform well add the STCKF bit to the machine flags.
Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Split out addressing mode bits from PSW_BASE_BITS, rename PSW_BASE_BITS
to PSW_MASK_BASE, get rid of psw_user32_bits, remove unused function
enabled_wait(), introduce PSW_MASK_USER, and drop PSW_MASK_MERGE macros.
Change psw_kernel_bits / psw_user_bits to contain only the bits that
are always set in the respective mode.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
When IPL'ing from a block device and an NSS should be created we must
make sure that the kernel image and the initrd are in different 1MB
segments. Otherwise creating the NSS will fail.
So we make sure the initrd is 4MB behind the end of the kernel image
like we do already when IPL via the VM reader is performed.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Use snprintf() here as well so we won't have to deal with this again.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This patch fixed bugzilla #12965:
https://bugzilla.kernel.org/show_bug.cgi?id=12965
The original code contains some inproper use of sprintf
function where a buffer is used both as input string
as well as output string. It should remember the written
bytes in the previous and use that as the offset for
later writing. Also replace sprintf with snprintf.
Signed-off-by: Chen Liu <chenliu@asset.uwaterloo.ca>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
