linux-kernel - [tip: x86/entry] x86/entry/compat: Combine return value test from syscall handler

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Message-ID: <169649451603.3135.3339730852325076665.tip-bot2@tip-bot2>
Date:   Thu, 05 Oct 2023 08:28:36 -0000
From:   "tip-bot2 for Brian Gerst" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Brian Gerst <brgerst@...il.com>, Ingo Molnar <mingo@...nel.org>,
        x86@...nel.org, linux-kernel@...r.kernel.org
Subject: [tip: x86/entry] x86/entry/compat: Combine return value test from
 syscall handler

The following commit has been merged into the x86/entry branch of tip:

Commit-ID:     eec62f61e134d6711f98d4005c6439f24d03d54f
Gitweb:        https://git.kernel.org/tip/eec62f61e134d6711f98d4005c6439f24d03d54f
Author:        Brian Gerst <brgerst@...il.com>
AuthorDate:    Fri, 21 Jul 2023 12:10:14 -04:00
Committer:     Ingo Molnar <mingo@...nel.org>
CommitterDate: Thu, 05 Oct 2023 10:06:42 +02:00

x86/entry/compat: Combine return value test from syscall handler

Move the sysret32_from_system_call label to remove a duplicate test of
the return value from the syscall handler.

Signed-off-by: Brian Gerst <brgerst@...il.com>
Signed-off-by: Ingo Molnar <mingo@...nel.org>
Link: https://lore.kernel.org/r/20230721161018.50214-4-brgerst@gmail.com
---
 arch/x86/entry/entry_64_compat.S |  9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/arch/x86/entry/entry_64_compat.S b/arch/x86/entry/entry_64_compat.S
index 7015029..b162723 100644
--- a/arch/x86/entry/entry_64_compat.S
+++ b/arch/x86/entry/entry_64_compat.S
@@ -118,9 +118,6 @@ SYM_INNER_LABEL(entry_SYSENTER_compat_after_hwframe, SYM_L_GLOBAL)
 
 	movq	%rsp, %rdi
 	call	do_SYSENTER_32
-	/* XEN PV guests always use IRET path */
-	ALTERNATIVE "testl %eax, %eax; jz swapgs_restore_regs_and_return_to_usermode", \
-		    "jmp swapgs_restore_regs_and_return_to_usermode", X86_FEATURE_XENPV
 	jmp	sysret32_from_system_call
 
 .Lsysenter_fix_flags:
@@ -212,13 +209,15 @@ SYM_INNER_LABEL(entry_SYSCALL_compat_after_hwframe, SYM_L_GLOBAL)
 
 	movq	%rsp, %rdi
 	call	do_fast_syscall_32
+
+sysret32_from_system_call:
 	/* XEN PV guests always use IRET path */
 	ALTERNATIVE "testl %eax, %eax; jz swapgs_restore_regs_and_return_to_usermode", \
 		    "jmp swapgs_restore_regs_and_return_to_usermode", X86_FEATURE_XENPV
 
-	/* Opportunistic SYSRET */
-sysret32_from_system_call:
 	/*
+	 * Opportunistic SYSRET
+	 *
 	 * We are not going to return to userspace from the trampoline
 	 * stack. So let's erase the thread stack right now.
 	 */