Commit graph

4105 commits

Author SHA1 Message Date
Tobias Huschle
307b675cf0 s390/wti: Add debugfs file to display missed grace periods per cpu
Introduce a new debug file which allows to determine how many warning
track grace periods were missed on each CPU.
The new file can be found as /sys/kernel/debug/s390/wti

It is formatted as:
       CPU0       CPU1   [...]    CPUx
        xyz        xyz   [...]     xyz

Acked-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Mete Durlu <meted@linux.ibm.com>
Signed-off-by: Tobias Huschle <huschle@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-08-29 22:56:35 +02:00
Tobias Huschle
42419bcdfd s390/wti: Add wti accounting for missed grace periods
A virtual CPU that has received a warning-track interrupt may fail to
acknowledge the interrupt within the warning-track grace period.
While this is usually not a problem, it will become necessary to
investigate if there is a large number of such missed warning-track
interrupts. Therefore, it is necessary to track these events.
The information is tracked through the s390 debug facility and can be
found under /sys/kernel/debug/s390dbf/wti/.

The hex_ascii output is formatted as:
 <pid> <symbol>

The values pid and current psw are collected when a warning track
interrupt is received. Symbol is either the kernel symbol matching the
collected psw or redacted to <user> when running in user space.

Each line represents the currently executing process when a warning
track interrupt was received which was then not acknowledged within its
grace period.

Acked-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Mete Durlu <meted@linux.ibm.com>
Signed-off-by: Tobias Huschle <huschle@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-08-29 22:56:34 +02:00
Tobias Huschle
cafeff5a03 s390/wti: Prepare graceful CPU pre-emption on wti reception
When a warning track interrupt is received, the kernel has only a very
limited amount of time to make sure, that the CPU can be yielded as
gracefully as possible before being pre-empted by the hypervisor.

The interrupt handler for the wti therefore unparks a kernel thread
which has being created on boot re-using the CPU hotplug kernel thread
infrastructure. These threads exist per CPU and are assigned the
highest possible real-time priority. This makes sure, that said threads
will execute as soon as possible as the scheduler should pre-empt any
other running user tasks to run the real-time thread.

Furthermore, the interrupt handler disables all I/O interrupts to
prevent additional interrupt processing on the soon-preempted CPU.
Interrupt handlers are likely to take kernel locks, which in the worst
case, will be kept while the interrupt handler is pre-empted from itself
underlying physical CPU. In that case, all tasks or interrupt handlers
on other CPUs would have to wait for the pre-empted CPU being dispatched
again. By preventing further interrupt processing, this risk is
minimized.

Once the CPU gets dispatched again, the real-time kernel thread regains
control, reenables interrupts and parks itself again.

Acked-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Mete Durlu <meted@linux.ibm.com>
Signed-off-by: Tobias Huschle <huschle@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-08-29 22:56:34 +02:00
Tobias Huschle
2c6c9ccc76 s390/wti: Introduce infrastructure for warning track interrupt
The warning-track interrupt (wti) provides a notification that the
receiving CPU will be pre-empted from its physical CPU within a short
time frame. This time frame is called grace period and depends on the
machine type. Giving up the CPU on time may prevent a task to get stuck
while holding a resource.

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Mete Durlu <meted@linux.ibm.com>
Signed-off-by: Tobias Huschle <huschle@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-08-29 22:56:34 +02:00
Vasily Gorbik
36dff49b96 s390/ftrace: Avoid extra serialization for graph caller patching
The only context where ftrace_enable_ftrace_graph_caller()
or ftrace_disable_ftrace_graph_caller() is called also calls
ftrace_arch_code_modify_post_process(), which already performs
text_poke_sync_lock().

ftrace_run_update_code()
	arch_ftrace_update_code()
		ftrace_modify_all_code()
			ftrace_enable_ftrace_graph_caller()/ftrace_disable_ftrace_graph_caller()
	ftrace_arch_code_modify_post_process()
		text_poke_sync_lock()

Remove the redundant serialization.

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-08-29 22:56:34 +02:00
Vasily Gorbik
5200614080 s390/ftrace: Use get/copy_from_kernel_nofault consistently
Use get/copy_from_kernel_nofault to access the kernel text consistently.
Replace memcmp() in ftrace_init_nop() to ensure that in case of
inconsistencies in the 'mcount' table, the kernel reports a failure
instead of potentially crashing.

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-08-29 22:56:34 +02:00
Vasily Gorbik
efd9cd019e s390/ftrace: Avoid trampolines if possible
When a sequential instruction fetching facility is present, it is safe
to patch ftrace NOPs in function prologues. All of them are 8-byte
aligned.

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-08-29 22:56:34 +02:00
Vasily Gorbik
30799152c3 s390/kprobes: Avoid stop machine if possible
Avoid stop machine on kprobes arm/disarm when sequential instruction
fetching is present.

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-08-29 22:56:34 +02:00
Vasily Gorbik
bb91ed0ee3 s390/setup: Recognize sequential instruction fetching facility
When sequential instruction fetching facility is present,
certain guarantees are provided for code patching. In particular,
atomic overwrites within 8 aligned bytes is safe from an
instruction-fetching point of view.

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-08-29 22:56:34 +02:00
Sven Schnelle
ee3daf7c05 s390/entry: Unify save_area_sync and save_area_async
In the past two save areas existed because interrupt handlers
and system call / program check handlers where entered with
interrupts enabled. To prevent a handler from overwriting the
save areas from the previous handler, interrupts used the async
save area, while system call and program check handler used the
sync save area.

Since the removal of critical section cleanup from entry.S, handlers are
entered with interrupts disabled. When the interrupts are re-enabled,
the save area is no longer need. Therefore merge both save areas into one.

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-08-29 22:56:34 +02:00
Vasily Gorbik
acb684d3b0 s390/disassembler: Add instructions
Add more instructions to the kernel disassembler.

Reviewed-by: Jens Remus <jremus@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-08-29 22:56:33 +02:00
Jens Remus
73c81973b4 s390/disassembler: Use proper format specifiers for operand values
Treat register numbers as unsigned. Treat signed operand values as
signed.

This resolves multiple instances of the Cppcheck warning:

warning: %i in format string (no. 1) requires 'int' but the argument
  type is 'unsigned int'. [invalidPrintfArgType_sint]

Acked-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-08-29 22:56:33 +02:00
Vasily Gorbik
a84dd0d8ae s390/ftrace: Avoid calling unwinder in ftrace_return_address()
ftrace_return_address() is called extremely often from
performance-critical code paths when debugging features like
CONFIG_TRACE_IRQFLAGS are enabled. For example, with debug_defconfig,
ftrace selftests on my LPAR currently execute ftrace_return_address()
as follows:

ftrace_return_address(0) - 0 times (common code uses __builtin_return_address(0) instead)
ftrace_return_address(1) - 2,986,805,401 times (with this patch applied)
ftrace_return_address(2) - 140 times
ftrace_return_address(>2) - 0 times

The use of __builtin_return_address(n) was replaced by return_address()
with an unwinder call by commit cae74ba8c2 ("s390/ftrace:
Use unwinder instead of __builtin_return_address()") because
__builtin_return_address(n) simply walks the stack backchain and doesn't
check for reaching the stack top. For shallow stacks with fewer than
"n" frames, this results in reads at low addresses and random
memory accesses.

While calling the fully functional unwinder "works", it is very slow
for this purpose. Moreover, potentially following stack switches and
walking past IRQ context is simply wrong thing to do for
ftrace_return_address().

Reimplement return_address() to essentially be __builtin_return_address(n)
with checks for reaching the stack top. Since the ftrace_return_address(n)
argument is always a constant, keep the implementation in the header,
allowing both GCC and Clang to unroll the loop and optimize it to the
bare minimum.

Fixes: cae74ba8c2 ("s390/ftrace: Use unwinder instead of __builtin_return_address()")
Cc: stable@vger.kernel.org
Reported-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Acked-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-08-27 20:16:48 +02:00
Vasily Gorbik
d759be2823 s390/ftrace: Use kernel ftrace trampoline for modules
Now that both the kernel modules area and the kernel image itself are
located within 4 GB, there is no longer a need to maintain a separate
ftrace_plt trampoline. Use the existing trampoline in the kernel.

Reviewed-by: Ilya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-08-27 20:16:48 +02:00
Vasily Gorbik
017f1f0d39 s390/ftrace: Remove unused ftrace_plt_template*
Unused since commit b860b9346e ("s390/ftrace: remove dead code").

Reviewed-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-08-27 20:16:48 +02:00
Heiko Carstens
6708948e36 s390/early: Dump register contents and call trace for early crashes
If the early program check handler cannot resolve a program check dump
register contents and a call trace to the console before loading a disabled
wait psw. This makes debugging much easier.

Emit an extra message with early_printk() for cases where regular printk()
via the early console is not yet working so that at least some information
is available.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Acked-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-08-22 19:28:11 +02:00
Heiko Carstens
0bc6a69f5f s390/early: Add __init to __do_early_pgm_check()
__do_early_pgm_check() is a function which is only needed during early
setup code. Mark it __init in order to save a few bytes.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Acked-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-08-22 19:28:11 +02:00
Thomas Richter
b495e71015 s390/cpum_sf: Remove WARN_ON_ONCE statements
Remove WARN_ON_ONCE statements. These have not triggered in the
past.

Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Acked-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-08-22 19:28:11 +02:00
Thomas Richter
14a34130e0 s390/cpum_sf: Rework debug_sprintf_event() messages
Rework debug messages:
 - Remove most of the debug_sprintf_event() invocations.
 - Do not split string format statements
 - Remove colon after function name.

Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Acked-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-08-22 19:28:10 +02:00
Alexander Gordeev
1642285e51 s390/boot: Fix KASLR base offset off by __START_KERNEL bytes
Symbol offsets to the KASLR base do not match symbol address in
the vmlinux image. That is the result of setting the KASLR base
to the beginning of .text section as result of an optimization.

Revert that optimization and allocate virtual memory for the
whole kernel image including __START_KERNEL bytes as per the
linker script. That allows keeping the semantics of the KASLR
base offset in sync with other architectures.

Rename __START_KERNEL to TEXT_OFFSET, since it represents the
offset of the .text section within the kernel image, rather than
a virtual address.

Still skip mapping TEXT_OFFSET bytes to save memory on pgtables
and provoke exceptions in case an attempt to access this area is
made, as no kernel symbol may reside there.

In case CONFIG_KASAN is enabled the location counter might exceed
the value of TEXT_OFFSET, while the decompressor linker script
forcefully resets it to TEXT_OFFSET, which leads to a sections
overlap link failure. Use MAX() expression to avoid that.

Reported-by: Omar Sandoval <osandov@osandov.com>
Closes: https://lore.kernel.org/linux-s390/ZnS8dycxhtXBZVky@telecaster.dhcp.thefacebook.com/
Fixes: 56b1069c40 ("s390/boot: Rework deployment of the kernel image")
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Acked-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-08-22 19:24:13 +02:00
Thomas Richter
6d9a732d8a s390/cpum_sf: Ignore qsi() return code
qsi() executes the instruction qsi (query sample information)
and stores the result of the query in a sample information block
pointed to by the function argument. The instruction does not
change the condition code register. The return code is always
zero. No need to check for errors. Remove now unreferenced
macros PMC_FAILURE and RS_INIT_FAILURE_QSI.

Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Acked-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-08-21 16:17:01 +02:00
Thomas Richter
742a755716 s390/cpum_sf: Ignore lsctl() return code in sf_disable()
sf_disable() returns the condition code of instruction lsctl (load
sampling controls). However the parameter to lsctl() in
sf_disable() is a sample control block containing
all zeroes. This invocation of lsctl() does not fail and returns
always zero even when there is no authorization for sampling
on the machine. In short, sampling can be always turned off.
Ignore the return code of sf_disable() and change the function
return to void.

Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Acked-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-08-21 16:17:01 +02:00
Alexander Gordeev
a3ca27c405 s390/mm: Prevent lowcore vs identity mapping overlap
The identity mapping position in virtual memory is randomized
together with the kernel mapping. That position can never
overlap with the lowcore even when the lowcore is relocated.

Prevent overlapping with the lowcore to allow independent
positioning of the identity mapping. With the current value
of the alternative lowcore address of 0x70000 the overlap
could happen in case the identity mapping is placed at zero.

This is a prerequisite for uncoupling of randomization base
of kernel image and identity mapping in virtual memory.

Acked-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-08-21 16:14:45 +02:00
Jann Horn
92a10d3861 runtime constants: move list of constants to vmlinux.lds.h
Refactor the list of constant variables into a macro.
This should make it easier to add more constants in the future.

Signed-off-by: Jann Horn <jannh@google.com>
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2024-08-19 09:48:14 +02:00
Heiko Carstens
85878ff1b3 s390/entry: Move early_pgm_check_handler() to init text section
Save some bytes and move early_pgm_check_handler() to init text
section.

Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-08-07 20:52:53 +02:00
Heiko Carstens
3c4d0ae067 s390/traps: Handle early warnings gracefully
Add missing warning handling to the early program check handler. This
way a warning is printed to the console as soon as the early console
is setup, and the kernel continues to boot.

Before this change a disabled wait psw was loaded instead and the
machine was silently stopped without giving an idea about what
happened.

Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-08-07 20:52:53 +02:00
Heiko Carstens
f101b305a7 s390/entry: Make early program check handler relocated lowcore aware
Add the missing pieces so the early program check handler also works
with a relocated lowcore. Right now the result of an early program
check in case of a relocated lowcore would be a program check loop.

Fixes: 8f1e70adb1 ("s390/boot: Add cmdline option to relocate lowcore")
Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-08-07 20:52:53 +02:00
Heiko Carstens
f2bb5b97b5 s390/entry: Move early program check handler to entry.S
Have all program check handlers in one file to make future changes easy.

Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-08-07 20:52:53 +02:00
Thomas Richter
e09e58f425 s390/cpum_sf: Use variable name cpuhw consistently
All functions but setup_pmc_cpu() use a local variable named
cpuhw to refer to struct cpu_hw_sf.
In setup_pmc_cpu() rename variable cpusf to cpuhw. This makes
the naming scheme consistent with all other functions.
No functional change.

Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Acked-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-08-07 20:52:53 +02:00
Thomas Richter
6bc565a99e s390/cpum_sf: Define and initialize variable
Define and initialize a variable in one place.
Remove space between cast and variable.
No functional change.

Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Acked-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-08-07 20:52:53 +02:00
Thomas Richter
b201828290 s390/cpum_sf: Use hwc as variable consistently
In hw_perf_event_update() and cpumsf_pmu_enable() use variable hwc
consistently to access event's hardware related data.
No functional change.

Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Acked-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-08-07 20:52:53 +02:00
Thomas Richter
d4559eabc1 s390/cpum_cf: Move defines from header file to source file
The macros PERF_CPUM_CF_MAX_CTR and PERF_EVENT_CPUM_CF_DIAG
are used in only one source file arch/s390/kernel/perf_cpum_cf.c.
Move these defines from the header file
arch/s390/include/asm/perf_event.h to the only user.
No functional change.

Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Acked-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-08-07 20:52:53 +02:00
Thomas Richter
52d6ef92a4 s390/cpum_sf: Move defines from header file to source file
Some defines in common header file arch/s390/include/asm/perf_event.h
are only used in one source file arch/s390/kernel/perf_cpum_sf.c.
Move these defines from header to source file.
No functional change.

Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Acked-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-08-07 20:52:53 +02:00
Thomas Richter
501cab2b1d s390/cpum_sf: Rename macro to consistent prefix
Rename macro SAMPLE_FREQ_MODE to SAMPL_FREQ_MODE to make its
prefix consistent with all other macro starting with prefix
SAMPL_XXX.
No functional change.

Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Acked-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-08-07 20:52:52 +02:00
Thomas Richter
ea95be4bda s390/cpum_sf: Remove unused defines REG_NONE and REG_OVERFLOW
Member hw_perf_event::reg.reg is set but never used, so remove it.
Defines REG_NONE and REG_OVERFLOW are not referenced anymore.
The initialization to zero takes place in function
perf_event_alloc() where
  ...
  event = kmem_cache_alloc_node(perf_event_cache,
		                GFP_KERNEL | __GFP_ZERO, node);
  ...

makes sure memory allocated for the event is zero'ed.
This is done in the kernel's common code in kernel/events/core.c
The struct perf_event contains member hw_perf_event as in

  struct perf_event {
   ....
   struct hw_perf_event hw;
   ....
  };

This contained sub-structure is also initialized to zero.
No functional change.

Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Acked-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-08-07 20:52:52 +02:00
Thomas Richter
8a6fe8f21e s390/cpum_sf: Use refcount_t instead of atomic_t
Replace atomic_t by refcount_t for reference counting of events.

Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Acked-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-08-07 20:52:52 +02:00
Heiko Carstens
75c10d5377 s390/vmlinux.lds.S: Move ro_after_init section behind rodata section
The .data.rel.ro and .got section were added between the rodata and
ro_after_init data section, which adds an RW mapping in between all RO
mapping of the kernel image:

---[ Kernel Image Start ]---
0x000003ffe0000000-0x000003ffe0e00000        14M PMD RO X
0x000003ffe0e00000-0x000003ffe0ec7000       796K PTE RO X
0x000003ffe0ec7000-0x000003ffe0f00000       228K PTE RO NX
0x000003ffe0f00000-0x000003ffe1300000         4M PMD RO NX
0x000003ffe1300000-0x000003ffe1331000       196K PTE RO NX
0x000003ffe1331000-0x000003ffe13b3000       520K PTE RW NX <---
0x000003ffe13b3000-0x000003ffe13d5000       136K PTE RO NX
0x000003ffe13d5000-0x000003ffe1400000       172K PTE RW NX
0x000003ffe1400000-0x000003ffe1500000         1M PMD RW NX
0x000003ffe1500000-0x000003ffe1700000         2M PTE RW NX
0x000003ffe1700000-0x000003ffe1800000         1M PMD RW NX
0x000003ffe1800000-0x000003ffe187e000       504K PTE RW NX
---[ Kernel Image End ]---

Move the ro_after_init data section again right behind the rodata
section to prevent interleaving RO and RW mappings:

---[ Kernel Image Start ]---
0x000003ffe0000000-0x000003ffe0e00000        14M PMD RO X
0x000003ffe0e00000-0x000003ffe0ec7000       796K PTE RO X
0x000003ffe0ec7000-0x000003ffe0f00000       228K PTE RO NX
0x000003ffe0f00000-0x000003ffe1300000         4M PMD RO NX
0x000003ffe1300000-0x000003ffe1353000       332K PTE RO NX
0x000003ffe1353000-0x000003ffe1400000       692K PTE RW NX
0x000003ffe1400000-0x000003ffe1500000         1M PMD RW NX
0x000003ffe1500000-0x000003ffe1700000         2M PTE RW NX
0x000003ffe1700000-0x000003ffe1800000         1M PMD RW NX
0x000003ffe1800000-0x000003ffe187e000       504K PTE RW NX
---[ Kernel Image End ]---

Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-31 16:30:20 +02:00
Heiko Carstens
0a34c027a3 s390/alternatives: Remove unused empty header file
Remove the unused and empty arch/s390/kernel/alternative.h header
file which was added by mistake.

Fixes: 5ade5be4ed ("s390: Add infrastructure to patch lowcore accesses")
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-31 16:30:20 +02:00
Heiko Carstens
4734406c39 s390/fpu: Re-add exception handling in load_fpu_state()
With the recent rewrite of the fpu code exception handling for the
lfpc instruction within load_fpu_state() was erroneously removed.

Add it again to prevent that loading invalid floating point register
values cause an unhandled specification exception.

Fixes: 8c09871a95 ("s390/fpu: limit save and restore to used registers")
Cc: stable@vger.kernel.org
Reported-by: Aristeu Rozanski <aris@redhat.com>
Tested-by: Aristeu Rozanski <aris@redhat.com>
Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-31 16:30:20 +02:00
Linus Torvalds
65ad409e63 more s390 updates for 6.11 merge window
- Fix KMSAN build breakage caused by the conflict between s390 and
   mm-stable trees
 
 - Add KMSAN page markers for ptdump
 
 - Add runtime constant support
 
 - Fix __pa/__va for modules under non-GPL licenses by exporting necessary
   vm_layout struct with EXPORT_SYMBOL to prevent linkage problems
 
 - Fix an endless loop in the CF_DIAG event stop in the CPU Measurement
   Counter Facility code when the counter set size is zero
 
 - Remove the PROTECTED_VIRTUALIZATION_GUEST config option and enable
   its functionality by default
 
 - Support allocation of multiple MSI interrupts per device and improve
   logging of architecture-specific limitations
 
 - Add support for lowcore relocation as a debugging feature to catch
   all null ptr dereferences in the kernel address space, improving
   detection beyond the current implementation's limited write access
   protection
 
 - Clean up and rework CPU alternatives to allow for callbacks and early
   patching for the lowcore relocation
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Merge tag 's390-6.11-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

Pull more s390 updates from Vasily Gorbik:

 - Fix KMSAN build breakage caused by the conflict between s390 and
   mm-stable trees

 - Add KMSAN page markers for ptdump

 - Add runtime constant support

 - Fix __pa/__va for modules under non-GPL licenses by exporting
   necessary vm_layout struct with EXPORT_SYMBOL to prevent linkage
   problems

 - Fix an endless loop in the CF_DIAG event stop in the CPU Measurement
   Counter Facility code when the counter set size is zero

 - Remove the PROTECTED_VIRTUALIZATION_GUEST config option and enable
   its functionality by default

 - Support allocation of multiple MSI interrupts per device and improve
   logging of architecture-specific limitations

 - Add support for lowcore relocation as a debugging feature to catch
   all null ptr dereferences in the kernel address space, improving
   detection beyond the current implementation's limited write access
   protection

 - Clean up and rework CPU alternatives to allow for callbacks and early
   patching for the lowcore relocation

* tag 's390-6.11-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (39 commits)
  s390: Remove protvirt and kvm config guards for uv code
  s390/boot: Add cmdline option to relocate lowcore
  s390/kdump: Make kdump ready for lowcore relocation
  s390/entry: Make system_call() ready for lowcore relocation
  s390/entry: Make ret_from_fork() ready for lowcore relocation
  s390/entry: Make __switch_to() ready for lowcore relocation
  s390/entry: Make restart_int_handler() ready for lowcore relocation
  s390/entry: Make mchk_int_handler() ready for lowcore relocation
  s390/entry: Make int handlers ready for lowcore relocation
  s390/entry: Make pgm_check_handler() ready for lowcore relocation
  s390/entry: Add base register to CHECK_VMAP_STACK/CHECK_STACK macro
  s390/entry: Add base register to SIEEXIT macro
  s390/entry: Add base register to MBEAR macro
  s390/entry: Make __sie64a() ready for lowcore relocation
  s390/head64: Make startup code ready for lowcore relocation
  s390: Add infrastructure to patch lowcore accesses
  s390/atomic_ops: Disable flag outputs constraint for GCC versions below 14.2.0
  s390/entry: Move SIE indicator flag to thread info
  s390/nmi: Simplify ptregs setup
  s390/alternatives: Remove alternative facility list
  ...
2024-07-26 10:47:53 -07:00
Joel Granados
78eb4ea25c sysctl: treewide: constify the ctl_table argument of proc_handlers
const qualify the struct ctl_table argument in the proc_handler function
signatures. This is a prerequisite to moving the static ctl_table
structs into .rodata data which will ensure that proc_handler function
pointers cannot be modified.

This patch has been generated by the following coccinelle script:

```
  virtual patch

  @r1@
  identifier ctl, write, buffer, lenp, ppos;
  identifier func !~ "appldata_(timer|interval)_handler|sched_(rt|rr)_handler|rds_tcp_skbuf_handler|proc_sctp_do_(hmac_alg|rto_min|rto_max|udp_port|alpha_beta|auth|probe_interval)";
  @@

  int func(
  - struct ctl_table *ctl
  + const struct ctl_table *ctl
    ,int write, void *buffer, size_t *lenp, loff_t *ppos);

  @r2@
  identifier func, ctl, write, buffer, lenp, ppos;
  @@

  int func(
  - struct ctl_table *ctl
  + const struct ctl_table *ctl
    ,int write, void *buffer, size_t *lenp, loff_t *ppos)
  { ... }

  @r3@
  identifier func;
  @@

  int func(
  - struct ctl_table *
  + const struct ctl_table *
    ,int , void *, size_t *, loff_t *);

  @r4@
  identifier func, ctl;
  @@

  int func(
  - struct ctl_table *ctl
  + const struct ctl_table *ctl
    ,int , void *, size_t *, loff_t *);

  @r5@
  identifier func, write, buffer, lenp, ppos;
  @@

  int func(
  - struct ctl_table *
  + const struct ctl_table *
    ,int write, void *buffer, size_t *lenp, loff_t *ppos);

```

* Code formatting was adjusted in xfs_sysctl.c to comply with code
  conventions. The xfs_stats_clear_proc_handler,
  xfs_panic_mask_proc_handler and xfs_deprecated_dointvec_minmax where
  adjusted.

* The ctl_table argument in proc_watchdog_common was const qualified.
  This is called from a proc_handler itself and is calling back into
  another proc_handler, making it necessary to change it as part of the
  proc_handler migration.

Co-developed-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Co-developed-by: Joel Granados <j.granados@samsung.com>
Signed-off-by: Joel Granados <j.granados@samsung.com>
2024-07-24 20:59:29 +02:00
Janosch Frank
6dc2e98d5f s390: Remove protvirt and kvm config guards for uv code
Removing the CONFIG_PROTECTED_VIRTUALIZATION_GUEST ifdefs and config
option as well as CONFIG_KVM ifdefs in uv files.

Having this configurable has been more of a pain than a help.
It's time to remove the ifdefs and the config option.

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23 16:02:33 +02:00
Sven Schnelle
97cee3dd4a s390/kdump: Make kdump ready for lowcore relocation
In preparation of having lowcore at different address than zero,
add the base register to all lowcore accesses in store_status()
and __do_machine_kdump().

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23 16:02:32 +02:00
Sven Schnelle
361f6ec2fe s390/entry: Make system_call() ready for lowcore relocation
In preparation of having lowcore at different address than zero,
add the base register to all lowcore accesses in system_call().

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23 16:02:32 +02:00
Sven Schnelle
9b3dcae128 s390/entry: Make ret_from_fork() ready for lowcore relocation
In preparation of having lowcore at different address than zero,
add the base register to all lowcore accesses in ret_from_fork().

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23 16:02:32 +02:00
Sven Schnelle
7cc86dee44 s390/entry: Make __switch_to() ready for lowcore relocation
In preparation of having lowcore at different address than zero,
add the base register to all lowcore accesses in __switch_to().

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23 16:02:32 +02:00
Sven Schnelle
4064b71112 s390/entry: Make restart_int_handler() ready for lowcore relocation
In preparation of having lowcore at different address than zero,
add the base register to all lowcore accesses in restart_int_handler().

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23 16:02:32 +02:00
Sven Schnelle
0001b7bbc5 s390/entry: Make mchk_int_handler() ready for lowcore relocation
In preparation of having lowcore at different address than zero,
add the base register to all lowcore accesses in mcck_int_handler().

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23 16:02:32 +02:00
Sven Schnelle
bd2c55b307 s390/entry: Make int handlers ready for lowcore relocation
In preparation of having lowcore at different address than zero,
add the base register to all lowcore accesses in the ext/io interrupt
handlers.

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23 16:02:32 +02:00
Sven Schnelle
9e1e275fa2 s390/entry: Make pgm_check_handler() ready for lowcore relocation
In preparation of having lowcore at different address than zero,
add the base register to all lowcore accesses in pgm_check_handler().

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23 16:02:32 +02:00