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| author | Chang S. Bae <chang.seok.bae@intel.com> | 2021-10-26 15:25:24 +0300 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2021-10-28 15:35:27 +0300 |
| commit | 6a3e0651b4a00daa314c59d6e4228dfa7a986983 (patch) | |
| tree | e76af3abe0f57c4d9dc67be5d07a2d8a3dd4e45f /tools/testing/selftests/x86/Makefile | |
| parent | 2308ee57d93d896618dd65c996429c9d3e469fe0 (diff) | |
| download | linux-6a3e0651b4a00daa314c59d6e4228dfa7a986983.tar.xz | |
selftests/x86/amx: Add test cases for AMX state management
AMX TILEDATA is a very large XSAVE feature. It could have caused
nasty XSAVE buffer space waste in two places:
* Signal stacks
* Kernel task_struct->fpu buffers
To avoid this waste, neither of these buffers have AMX state by
default. The non-default features are called "dynamic" features.
There is an arch_prctl(ARCH_REQ_XCOMP_PERM) which allows a task
to declare that it wants to use AMX or other "dynamic" XSAVE
features. This arch_prctl() ensures that sufficient sigaltstack
space is available before it will succeed. It also expands the
task_struct buffer.
Functions of this test:
* Test arch_prctl(ARCH_REQ_XCOMP_PERM). Ensure that it checks for
proper sigaltstack sizing and that the sizing is enforced for
future sigaltstack calls.
* Ensure that ARCH_REQ_XCOMP_PERM is inherited across fork()
* Ensure that TILEDATA use before the prctl() is fatal
* Ensure that TILEDATA is cleared across fork()
Note: Generally, compiler support is needed to do something with
AMX. Instead, directly load AMX state from userspace with a
plain XSAVE. Do not depend on the compiler.
[ dhansen: bunches of cleanups ]
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211026122524.7BEDAA95@davehans-spike.ostc.intel.com
Diffstat (limited to 'tools/testing/selftests/x86/Makefile')
| -rw-r--r-- | tools/testing/selftests/x86/Makefile | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/tools/testing/selftests/x86/Makefile b/tools/testing/selftests/x86/Makefile index b4142cd1c5c2..8a1f62ab3c8e 100644 --- a/tools/testing/selftests/x86/Makefile +++ b/tools/testing/selftests/x86/Makefile @@ -18,7 +18,7 @@ TARGETS_C_32BIT_ONLY := entry_from_vm86 test_syscall_vdso unwind_vdso \ test_FCMOV test_FCOMI test_FISTTP \ vdso_restorer TARGETS_C_64BIT_ONLY := fsgsbase sysret_rip syscall_numbering \ - corrupt_xstate_header + corrupt_xstate_header amx # Some selftests require 32bit support enabled also on 64bit systems TARGETS_C_32BIT_NEEDED := ldt_gdt ptrace_syscall |