diff options
Diffstat (limited to 'arch/x86/entry/entry_32.S')
| -rw-r--r-- | arch/x86/entry/entry_32.S | 8 |
1 files changed, 7 insertions, 1 deletions
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 |