diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2021-06-23 14:02:20 +0200 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2021-06-23 19:47:35 +0200 |
| commit | 30a304a138738d71a09c730ca8044e9662de0dbf (patch) | |
| tree | 23d96c22795456f369d22f31b278c7300d8e4327 | |
| parent | e84ba47e313dbc097bf859bb6e4f9219883d5f78 (diff) | |
| download | linux-30a304a138738d71a09c730ca8044e9662de0dbf.tar.bz2 | |
x86/fpu: Mask PKRU from kernel XRSTOR[S] operations
As the PKRU state is managed separately restoring it from the xstate
buffer would be counterproductive as it might either restore a stale
value or reinit the PKRU state to 0.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210623121456.606745195@linutronix.de
| -rw-r--r-- | arch/x86/include/asm/fpu/internal.h | 4 | ||||
| -rw-r--r-- | arch/x86/include/asm/fpu/xstate.h | 10 | ||||
| -rw-r--r-- | arch/x86/kernel/fpu/xstate.c | 1 | ||||
| -rw-r--r-- | arch/x86/mm/extable.c | 2 |
4 files changed, 14 insertions, 3 deletions
diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h index 521774320e6a..2a484f5f2413 100644 --- a/arch/x86/include/asm/fpu/internal.h +++ b/arch/x86/include/asm/fpu/internal.h @@ -259,7 +259,7 @@ static inline void fxsave(struct fxregs_state *fx) */ static inline void os_xrstor_booting(struct xregs_state *xstate) { - u64 mask = -1; + u64 mask = xfeatures_mask_fpstate(); u32 lmask = mask; u32 hmask = mask >> 32; int err; @@ -388,7 +388,7 @@ extern void __restore_fpregs_from_fpstate(union fpregs_state *fpstate, u64 mask) static inline void restore_fpregs_from_fpstate(union fpregs_state *fpstate) { - __restore_fpregs_from_fpstate(fpstate, -1); + __restore_fpregs_from_fpstate(fpstate, xfeatures_mask_fpstate()); } extern int copy_fpstate_to_sigframe(void __user *buf, void __user *fp, int size); diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h index 4ff4a0093a48..109dfcc75299 100644 --- a/arch/x86/include/asm/fpu/xstate.h +++ b/arch/x86/include/asm/fpu/xstate.h @@ -111,6 +111,16 @@ static inline u64 xfeatures_mask_restore_user(void) return xfeatures_mask_all & XFEATURE_MASK_USER_RESTORE; } +/* + * Like xfeatures_mask_restore_user() but additionally restors the + * supported supervisor states. + */ +static inline u64 xfeatures_mask_fpstate(void) +{ + return xfeatures_mask_all & \ + (XFEATURE_MASK_USER_RESTORE | XFEATURE_MASK_SUPERVISOR_SUPPORTED); +} + static inline u64 xfeatures_mask_independent(void) { if (!boot_cpu_has(X86_FEATURE_ARCH_LBR)) diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index 9fd124a001b0..21a10a66c4e4 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -60,6 +60,7 @@ static short xsave_cpuid_features[] __initdata = { * XSAVE buffer, both supervisor and user xstates. */ u64 xfeatures_mask_all __ro_after_init; +EXPORT_SYMBOL_GPL(xfeatures_mask_all); static unsigned int xstate_offsets[XFEATURE_MAX] __ro_after_init = { [ 0 ... XFEATURE_MAX - 1] = -1}; diff --git a/arch/x86/mm/extable.c b/arch/x86/mm/extable.c index 2c5cccd77b8b..e1664e9f969c 100644 --- a/arch/x86/mm/extable.c +++ b/arch/x86/mm/extable.c @@ -65,7 +65,7 @@ __visible bool ex_handler_fprestore(const struct exception_table_entry *fixup, WARN_ONCE(1, "Bad FPU state detected at %pB, reinitializing FPU registers.", (void *)instruction_pointer(regs)); - __restore_fpregs_from_fpstate(&init_fpstate, -1); + __restore_fpregs_from_fpstate(&init_fpstate, xfeatures_mask_fpstate()); return true; } EXPORT_SYMBOL_GPL(ex_handler_fprestore); |