diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2021-10-22 01:55:19 +0300 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2021-10-26 11:52:35 +0300 |
| commit | 5529acf47ec31ece0815f69d43f5e6a1e485a0f3 (patch) | |
| tree | 7e310408156c2da2497511d8bf13971836292078 /arch/x86/kernel/fpu/xstate.h | |
| parent | 8bf26758ca9659866b844dd51037314b4c0fa6bd (diff) | |
| download | linux-5529acf47ec31ece0815f69d43f5e6a1e485a0f3.tar.xz | |
x86/fpu: Add sanity checks for XFD
Add debug functionality to ensure that the XFD MSR is up to date for XSAVE*
and XRSTOR* operations.
[ tglx: Improve comment. ]
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211021225527.10184-16-chang.seok.bae@intel.com
Diffstat (limited to 'arch/x86/kernel/fpu/xstate.h')
| -rw-r--r-- | arch/x86/kernel/fpu/xstate.h | 34 |
1 files changed, 30 insertions, 4 deletions
diff --git a/arch/x86/kernel/fpu/xstate.h b/arch/x86/kernel/fpu/xstate.h index 32a4dee4de3b..29024244965b 100644 --- a/arch/x86/kernel/fpu/xstate.h +++ b/arch/x86/kernel/fpu/xstate.h @@ -130,6 +130,12 @@ static inline u64 xfeatures_mask_independent(void) : "D" (st), "m" (*st), "a" (lmask), "d" (hmask) \ : "memory") +#if defined(CONFIG_X86_64) && defined(CONFIG_X86_DEBUG_FPU) +extern void xfd_validate_state(struct fpstate *fpstate, u64 mask, bool rstor); +#else +static inline void xfd_validate_state(struct fpstate *fpstate, u64 mask, bool rstor) { } +#endif + /* * Save processor xstate to xsave area. * @@ -144,6 +150,7 @@ static inline void os_xsave(struct fpstate *fpstate) int err; WARN_ON_FPU(!alternatives_patched); + xfd_validate_state(fpstate, mask, false); XSTATE_XSAVE(&fpstate->regs.xsave, lmask, hmask, err); @@ -156,12 +163,23 @@ static inline void os_xsave(struct fpstate *fpstate) * * Uses XRSTORS when XSAVES is used, XRSTOR otherwise. */ -static inline void os_xrstor(struct xregs_state *xstate, u64 mask) +static inline void os_xrstor(struct fpstate *fpstate, u64 mask) +{ + u32 lmask = mask; + u32 hmask = mask >> 32; + + xfd_validate_state(fpstate, mask, true); + XSTATE_XRESTORE(&fpstate->regs.xsave, lmask, hmask); +} + +/* Restore of supervisor state. Does not require XFD */ +static inline void os_xrstor_supervisor(struct fpstate *fpstate) { + u64 mask = xfeatures_mask_supervisor(); u32 lmask = mask; u32 hmask = mask >> 32; - XSTATE_XRESTORE(xstate, lmask, hmask); + XSTATE_XRESTORE(&fpstate->regs.xsave, lmask, hmask); } /* @@ -184,11 +202,14 @@ static inline int xsave_to_user_sigframe(struct xregs_state __user *buf) * internally, e.g. PKRU. That's user space ABI and also required * to allow the signal handler to modify PKRU. */ - u64 mask = current->thread.fpu.fpstate->user_xfeatures; + struct fpstate *fpstate = current->thread.fpu.fpstate; + u64 mask = fpstate->user_xfeatures; u32 lmask = mask; u32 hmask = mask >> 32; int err; + xfd_validate_state(fpstate, mask, false); + stac(); XSTATE_OP(XSAVE, buf, lmask, hmask, err); clac(); @@ -206,6 +227,8 @@ static inline int xrstor_from_user_sigframe(struct xregs_state __user *buf, u64 u32 hmask = mask >> 32; int err; + xfd_validate_state(current->thread.fpu.fpstate, mask, true); + stac(); XSTATE_OP(XRSTOR, xstate, lmask, hmask, err); clac(); @@ -217,12 +240,15 @@ static inline int xrstor_from_user_sigframe(struct xregs_state __user *buf, u64 * Restore xstate from kernel space xsave area, return an error code instead of * an exception. */ -static inline int os_xrstor_safe(struct xregs_state *xstate, u64 mask) +static inline int os_xrstor_safe(struct fpstate *fpstate, u64 mask) { + struct xregs_state *xstate = &fpstate->regs.xsave; u32 lmask = mask; u32 hmask = mask >> 32; int err; + /* Must enforce XFD update here */ + if (cpu_feature_enabled(X86_FEATURE_XSAVES)) XSTATE_OP(XRSTORS, xstate, lmask, hmask, err); else |