diff options
Diffstat (limited to 'arch/x86/entry')
| -rw-r--r-- | arch/x86/entry/common.c | 4 | ||||
| -rw-r--r-- | arch/x86/entry/entry_32.S | 8 |
2 files changed, 11 insertions, 1 deletions
diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c index 3f8e22615812..9747876980b5 100644 --- a/arch/x86/entry/common.c +++ b/arch/x86/entry/common.c @@ -33,6 +33,7 @@ #include <asm/cpufeature.h> #include <asm/fpu/api.h> #include <asm/nospec-branch.h> +#include <asm/io_bitmap.h> #define CREATE_TRACE_POINTS #include <trace/events/syscalls.h> @@ -196,6 +197,9 @@ __visible inline void prepare_exit_to_usermode(struct pt_regs *regs) /* Reload ti->flags; we may have rescheduled above. */ cached_flags = READ_ONCE(ti->flags); + if (unlikely(cached_flags & _TIF_IO_BITMAP)) + tss_update_io_bitmap(); + fpregs_assert_state_consistent(); if (unlikely(cached_flags & _TIF_NEED_FPU_LOAD)) switch_fpu_return(); diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S index 09fe5606a118..5832b11f01bb 100644 --- a/arch/x86/entry/entry_32.S +++ b/arch/x86/entry/entry_32.S @@ -739,6 +739,11 @@ SYM_CODE_START(__switch_to_asm) pushl %ebx pushl %edi pushl %esi + /* + * Flags are saved to prevent AC leakage. This could go + * away if objtool would have 32bit support to verify + * the STAC/CLAC correctness. + */ pushfl /* switch stack */ @@ -761,8 +766,9 @@ SYM_CODE_START(__switch_to_asm) FILL_RETURN_BUFFER %ebx, RSB_CLEAR_LOOPS, X86_FEATURE_RSB_CTXSW #endif - /* restore callee-saved registers */ + /* Restore flags or the incoming task to restore AC state. */ popfl + /* restore callee-saved registers */ popl %esi popl %edi popl %ebx |