Messages in this thread Patch in this message | | | From | Yu-cheng Yu <> | Subject | [PATCH v4 07/10] x86/fpu/xstate: Update copy_kernel_to_xregs_err() for XSAVES supervisor states | Date | Tue, 12 May 2020 07:54:41 -0700 |
| |
The function copy_kernel_to_xregs_err() uses XRSTOR, which can work with standard or compacted format without supervisor xstates. However, when supervisor xstates are present, XRSTORS must be used. Fix it by using XRSTORS when XSAVES is enabled.
I also considered if there were additional cases where XRSTOR might be mistakenly called instead of XRSTORS. There are only three XRSTOR sites in kernel:
1. copy_kernel_to_xregs_booting(), already switches between XRSTOR and XRSTORS based on X86_FEATURE_XSAVES. 2. copy_user_to_xregs(), which *needs* XRSTOR because it is copying from userspace and must never copy supervisor state with XRSTORS. 3. copy_kernel_to_xregs_err() mistakenly used XRSTOR only. Fixed it.
Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com> Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com> --- arch/x86/include/asm/fpu/internal.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h index a42fcb4b690d..42159f45bf9c 100644 --- a/arch/x86/include/asm/fpu/internal.h +++ b/arch/x86/include/asm/fpu/internal.h @@ -400,7 +400,10 @@ static inline int copy_kernel_to_xregs_err(struct xregs_state *xstate, u64 mask) u32 hmask = mask >> 32; int err; - XSTATE_OP(XRSTOR, xstate, lmask, hmask, err); + if (static_cpu_has(X86_FEATURE_XSAVES)) + XSTATE_OP(XRSTORS, xstate, lmask, hmask, err); + else + XSTATE_OP(XRSTOR, xstate, lmask, hmask, err); return err; } -- 2.21.0
| |