linux.git/tools/testing/selftests/vDSO, branch vsnprintf

Merge tag 'powerpc-6.13-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

2024-11-23T18:44:31+00:00

Pull powerpc updates from Michael Ellerman:

 - Rework kfence support for the HPT MMU to work on systems with >= 16TB
   of RAM.

 - Remove the powerpc "maple" platform, used by the "Yellow Dog
   Powerstation".

 - Add support for DYNAMIC_FTRACE_WITH_CALL_OPS,
   DYNAMIC_FTRACE_WITH_DIRECT_CALLS & BPF Trampolines.

 - Add support for running KVM nested guests on Power11.

 - Other small features, cleanups and fixes.

Thanks to Amit Machhiwal, Arnd Bergmann, Christophe Leroy, Costa
Shulyupin, David Hunter, David Wang, Disha Goel, Gautam Menghani, Geert
Uytterhoeven, Hari Bathini, Julia Lawall, Kajol Jain, Keith Packard,
Lukas Bulwahn, Madhavan Srinivasan, Markus Elfring, Michal Suchanek,
Ming Lei, Mukesh Kumar Chaurasiya, Nathan Chancellor, Naveen N Rao,
Nicholas Piggin, Nysal Jan K.A, Paulo Miguel Almeida, Pavithra Prakash,
Ritesh Harjani (IBM), Rob Herring (Arm), Sachin P Bappalige, Shen
Lichuan, Simon Horman, Sourabh Jain, Thomas Weißschuh, Thorsten Blum,
Thorsten Leemhuis, Venkat Rao Bagalkote, Zhang Zekun, and zhang jiao.

* tag 'powerpc-6.13-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (89 commits)
  EDAC/powerpc: Remove PPC_MAPLE drivers
  powerpc/perf: Add per-task/process monitoring to vpa_pmu driver
  powerpc/kvm: Add vpa latency counters to kvm_vcpu_arch
  docs: ABI: sysfs-bus-event_source-devices-vpa-pmu: Document sysfs event format entries for vpa_pmu
  powerpc/perf: Add perf interface to expose vpa counters
  MAINTAINERS: powerpc: Mark Maddy as "M"
  powerpc/Makefile: Allow overriding CPP
  powerpc-km82xx.c: replace of_node_put() with __free
  ps3: Correct some typos in comments
  powerpc/kexec: Fix return of uninitialized variable
  macintosh: Use common error handling code in via_pmu_led_init()
  powerpc/powermac: Use of_property_match_string() in pmac_has_backlight_type()
  powerpc: remove dead config options for MPC85xx platform support
  powerpc/xive: Use cpumask_intersects()
  selftests/powerpc: Remove the path after initialization.
  powerpc/xmon: symbol lookup length fixed
  powerpc/ep8248e: Use %pa to format resource_size_t
  powerpc/ps3: Reorganize kerneldoc parameter names
  KVM: PPC: Book3S HV: Fix kmv -> kvm typo
  powerpc/sstep: make emulate_vsx_load and emulate_vsx_store static
  ...

powerpc/vdso: Flag VDSO64 entry points as functions

2024-10-16T02:37:37+00:00

On powerpc64 as shown below by readelf, vDSO functions symbols have
type NOTYPE.

$ powerpc64-linux-gnu-readelf -a arch/powerpc/kernel/vdso/vdso64.so.dbg
ELF Header:
  Magic:   7f 45 4c 46 02 02 01 00 00 00 00 00 00 00 00 00
  Class:                             ELF64
  Data:                              2's complement, big endian
  Version:                           1 (current)
  OS/ABI:                            UNIX - System V
  ABI Version:                       0
  Type:                              DYN (Shared object file)
  Machine:                           PowerPC64
  Version:                           0x1
...

Symbol table '.dynsym' contains 12 entries:
   Num:    Value          Size Type    Bind   Vis      Ndx Name
...
     1: 0000000000000524    84 NOTYPE  GLOBAL DEFAULT    8 __[...]@@LINUX_2.6.15
...
     4: 0000000000000000     0 OBJECT  GLOBAL DEFAULT  ABS LINUX_2.6.15
     5: 00000000000006c0    48 NOTYPE  GLOBAL DEFAULT    8 __[...]@@LINUX_2.6.15

Symbol table '.symtab' contains 56 entries:
   Num:    Value          Size Type    Bind   Vis      Ndx Name
...
    45: 0000000000000000     0 OBJECT  GLOBAL DEFAULT  ABS LINUX_2.6.15
    46: 00000000000006c0    48 NOTYPE  GLOBAL DEFAULT    8 __kernel_getcpu
    47: 0000000000000524    84 NOTYPE  GLOBAL DEFAULT    8 __kernel_clock_getres

To overcome that, commit ba83b3239e65 ("selftests: vDSO: fix vDSO
symbols lookup for powerpc64") was applied to have selftests also
look for NOTYPE symbols, but the correct fix should be to flag VDSO
entry points as functions.

The original commit that brought VDSO support into powerpc/64 has the
following explanation:

    Note that the symbols exposed by the vDSO aren't "normal" function symbols, apps
    can't be expected to link against them directly, the vDSO's are both seen
    as if they were linked at 0 and the symbols just contain offsets to the
    various functions.  This is done on purpose to avoid a relocation step
    (ppc64 functions normally have descriptors with abs addresses in them).
    When glibc uses those functions, it's expected to use it's own trampolines
    that know how to reach them.

The descriptors it's talking about are the OPD function descriptors
used on ABI v1 (big endian). But it would be more correct for a text
symbol to have type function, even if there's no function descriptor
for it.

glibc has a special case already for handling the VDSO symbols which
creates a fake opd pointing at the kernel symbol. So changing the VDSO
symbol type to function shouldn't affect that.

For ABI v2, there is no function descriptors and VDSO functions can
safely have function type.

So lets flag VDSO entry points as functions and revert the
selftest change.

Link: https://github.com/mpe/linux-fullhistory/commit/5f2dd691b62da9d9cc54b938f8b29c22c93cb805
Fixes: ba83b3239e65 ("selftests: vDSO: fix vDSO symbols lookup for powerpc64")
Signed-off-by: Christophe Leroy 
Reviewed-By: Segher Boessenkool 
Signed-off-by: Michael Ellerman 
Link: https://patch.msgid.link/b6ad2f1ee9887af3ca5ecade2a56f4acda517a85.1728512263.git.christophe.leroy@csgroup.eu

selftests: vDSO: Explicitly include sched.h

2024-10-08T21:48:09+00:00

The previous commit introduced the use of CLONE_NEWTIME without including
 which contains its definition.

Add an explicit include of  to ensure that CLONE_NEWTIME
is correctly defined before it is used.

Fixes: 2aec90036dcd ("selftests: vDSO: ensure vgetrandom works in a time namespace")
Signed-off-by: Yu Liao 
Signed-off-by: Shuah Khan

selftests: vDSO: improve getrandom and chacha error messages

2024-10-08T21:21:52+00:00

Improve the error and skip condition messages to let the developer know
precisely where a test has failed. Also make better use of the ksft api
for this.

Signed-off-by: Jason A. Donenfeld 
Signed-off-by: Shuah Khan

selftests: vDSO: unconditionally build getrandom test

2024-10-08T21:21:36+00:00

Rather than building on supported archs, build on all archs, and then
use the presence of the symbol in the vDSO to either skip the test or
move forward with it.

Note that this means that this test no longer checks whether the symbol
was correctly added to the kernel. But hopefully this will be clear
enough to developers and we'll cross our fingers that symbols aren't
removed by accident and not caught after this change.

Signed-off-by: Jason A. Donenfeld 
Signed-off-by: Shuah Khan

selftests: vDSO: unconditionally build chacha test

2024-10-08T21:21:29+00:00

Rather than using symlinks to find the vgetrandom-chacha.S file for each
arch, store this in a file that uses the compiler to determine
architecture, and then make use of weak symbols to skip the test on
architectures that don't provide the code.

Signed-off-by: Jason A. Donenfeld 
Signed-off-by: Shuah Khan

selftests: vDSO: align getrandom states to cache line

2024-10-01T14:30:58+00:00

This prevents false sharing, which makes a large difference on machines
with several NUMA nodes, such as on a dual socket Intel(R) Xeon(R) Gold
6338 CPU @ 2.00GHz, where the "bench-multi" test goes from 2.7s down to
1.9s. While this is just test code, it also forms the basis of how folks
will wind up implementing this in libraries, so we should implement this
simple cache alignment improvement here.

Suggested-by: Florian Weimer 
Cc: Adhemerval Zanella 
Signed-off-by: Jason A. Donenfeld 
Signed-off-by: Shuah Khan

Merge tag 'linux_kselftest-next-6.12-rc1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest

2024-09-29T15:37:03+00:00

Pull kselftest fix from Shuah Khan:
 "One urgent fix to vDSO as automated testing is failing due to this
  bug"

* tag 'linux_kselftest-next-6.12-rc1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest:
  selftests: vDSO: align stack for O2-optimized memcpy

selftests: vDSO: align stack for O2-optimized memcpy

2024-09-27T18:17:12+00:00

When switching on -O2, gcc generates SSE2 instructions that assume a
16-byte aligned stack, which the standalone test's start point wasn't
aligning. Fix this with the usual alignment sequence.

Fixes: ecb8bd70d51 ("selftests: vDSO: build tests with O2 optimization")
Reported-by: kernel test robot 
Closes: https://lore.kernel.org/oe-lkp/202409241558.98e13f6f-oliver.sang@intel.com
Signed-off-by: Jason A. Donenfeld 
Signed-off-by: Shuah Khan

selftests: vDSO: check cpu caps before running chacha test

2024-09-16T11:22:04+00:00

Some archs -- arm64 and s390x -- implemented chacha using instructions
that are available most places, but aren't always available. The kernel
handles this just fine, but the selftest does not. Check the hwcaps
before running, and skip the test if the cpu doesn't support it. As
well, on s390x, always emit the fallback instructions of an alternative
block, to ensure maximum compatibility.

Co-developed-by: Heiko Carstens 
Signed-off-by: Heiko Carstens 
Signed-off-by: Jason A. Donenfeld