As done for entry_64, add support for executing VERW late in exit to user path for 32-bit mode. Signed-off-by: Pawan Gupta <pawan.kumar.gupta@xxxxxxxxxxxxxxx> --- arch/x86/entry/entry_32.S | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S index 6e6af42e044a..bbf77d2aab2e 100644 --- a/arch/x86/entry/entry_32.S +++ b/arch/x86/entry/entry_32.S @@ -886,6 +886,9 @@ SYM_FUNC_START(entry_SYSENTER_32) popfl popl %eax + /* Mitigate CPU data sampling attacks .e.g. MDS */ + USER_CLEAR_CPU_BUFFERS + /* * Return back to the vDSO, which will pop ecx and edx. * Don't bother with DS and ES (they already contain __USER_DS). @@ -954,6 +957,9 @@ restore_all_switch_stack: /* Restore user state */ RESTORE_REGS pop=4 # skip orig_eax/error_code + + /* Mitigate CPU data sampling attacks .e.g. MDS */ + USER_CLEAR_CPU_BUFFERS .Lirq_return: /* * ARCH_HAS_MEMBARRIER_SYNC_CORE rely on IRET core serialization @@ -1146,6 +1152,8 @@ SYM_CODE_START(asm_exc_nmi) /* Not on SYSENTER stack. */ call exc_nmi + /* Mitigate CPU data sampling attacks .e.g. MDS */ + USER_CLEAR_CPU_BUFFERS jmp .Lnmi_return .Lnmi_from_sysenter_stack: -- 2.34.1
