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x86/entry_32: Add VERW just before userspace transition

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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@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/all/20240213-delay-verw-v8-3-a6216d83edb7%40linux.intel.com
This commit is contained in:
Pawan Gupta 2024-02-13 18:22:08 -08:00 committed by Dave Hansen
parent 3c7501722e
commit a0e2dab44d
1 changed files with 3 additions and 0 deletions
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3
arch/x86/entry/entry_32.S
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@ -885,6 +885,7 @@ SYM_FUNC_START(entry_SYSENTER_32)
BUG_IF_WRONG_CR3 no_user_check=1
popfl
popl %eax
CLEAR_CPU_BUFFERS
/*
* Return back to the vDSO, which will pop ecx and edx.
@ -954,6 +955,7 @@ restore_all_switch_stack:
/* Restore user state */
RESTORE_REGS pop=4 # skip orig_eax/error_code
CLEAR_CPU_BUFFERS
.Lirq_return:
/*
* ARCH_HAS_MEMBARRIER_SYNC_CORE rely on IRET core serialization
@ -1146,6 +1148,7 @@ SYM_CODE_START(asm_exc_nmi)
/* Not on SYSENTER stack. */
call exc_nmi
CLEAR_CPU_BUFFERS
jmp .Lnmi_return
.Lnmi_from_sysenter_stack: