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| author | Thomas Gleixner <tglx@linutronix.de> | 2021-10-15 02:09:37 +0300 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2021-10-22 12:04:46 +0300 |
| commit | daddee24731938781b7876d20335ea3754d23484 (patch) | |
| tree | 813540fbc6ce16fe4cc8ffce5e6fa326c2b12afa /arch/x86/kernel/fpu/xstate.c | |
| parent | 1c253ff2287fe31307a67938c4487936db967ff5 (diff) | |
| download | linux-daddee24731938781b7876d20335ea3754d23484.tar.xz | |
x86/fpu: Mop up xfeatures_mask_uabi()
Use the new fpu_user_cfg to retrieve the information instead of
xfeatures_mask_uabi() which will be no longer correct when dynamically
enabled features become available.
Using fpu_user_cfg is appropriate when setting XCOMP_BV in the
init_fpstate since it has space allocated for "max_features". But,
normal fpstates might only have space for default xfeatures. Since
XRSTOR* derives the format of the XSAVE buffer from XCOMP_BV, this can
lead to XRSTOR reading out of bounds.
So when copying actively used fpstate, simply read the XCOMP_BV features
bits directly out of the fpstate instead.
This correction courtesy of Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211014230739.408879849@linutronix.de
Diffstat (limited to 'arch/x86/kernel/fpu/xstate.c')
| -rw-r--r-- | arch/x86/kernel/fpu/xstate.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index 8b496c0eb1a5..9f92abd230db 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -770,7 +770,7 @@ void __init fpu__init_system_xstate(unsigned int legacy_size) cpuid_count(XSTATE_CPUID, 1, &eax, &ebx, &ecx, &edx); fpu_kernel_cfg.max_features |= ecx + ((u64)edx << 32); - if ((xfeatures_mask_uabi() & XFEATURE_MASK_FPSSE) != XFEATURE_MASK_FPSSE) { + if ((fpu_kernel_cfg.max_features & XFEATURE_MASK_FPSSE) != XFEATURE_MASK_FPSSE) { /* * This indicates that something really unexpected happened * with the enumeration. Disable XSAVE and try to continue @@ -815,7 +815,7 @@ void __init fpu__init_system_xstate(unsigned int legacy_size) * supervisor xstates: */ update_regset_xstate_info(fpu_user_cfg.max_size, - xfeatures_mask_uabi()); + fpu_user_cfg.max_features); fpu__init_prepare_fx_sw_frame(); setup_init_fpu_buf(); @@ -853,7 +853,7 @@ void fpu__resume_cpu(void) * Restore XCR0 on xsave capable CPUs: */ if (cpu_feature_enabled(X86_FEATURE_XSAVE)) - xsetbv(XCR_XFEATURE_ENABLED_MASK, xfeatures_mask_uabi()); + xsetbv(XCR_XFEATURE_ENABLED_MASK, fpu_user_cfg.max_features); /* * Restore IA32_XSS. The same CPUID bit enumerates support |