[tip:,x86/urgent] x86/entry_32: Add VERW just before userspace transition

Message ID 170839092663.398.4327574535537349249.tip-bot2@tip-bot2
State New
Headers
Series [tip:,x86/urgent] x86/entry_32: Add VERW just before userspace transition |

Commit Message

tip-bot2 for Thomas Gleixner Feb. 20, 2024, 1:02 a.m. UTC
  The following commit has been merged into the x86/urgent branch of tip:

Commit-ID:     a0e2dab44d22b913b4c228c8b52b2a104434b0b3
Gitweb:        https://git.kernel.org/tip/a0e2dab44d22b913b4c228c8b52b2a104434b0b3
Author:        Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
AuthorDate:    Tue, 13 Feb 2024 18:22:08 -08:00
Committer:     Dave Hansen <dave.hansen@linux.intel.com>
CommitterDate: Mon, 19 Feb 2024 16:31:46 -08:00

x86/entry_32: Add VERW just before userspace transition

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
---
 arch/x86/entry/entry_32.S | 3 +++
 1 file changed, 3 insertions(+)
  

Patch

diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S
index c73047b..fba4276 100644
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -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: