2023-07-21 17:07:38

by Brian Gerst

Subject: [PATCH v2 3/6] 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 <[email protected]>
---
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 70150298f8bd..b16272395f1a 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.
*/
--
2.41.0

2023-10-05 16:17:28

by tip-bot2 for Alexey Makhalov

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 <[email protected]>
AuthorDate: Fri, 21 Jul 2023 12:10:14 -04:00
Committer: Ingo Molnar <[email protected]>
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 <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
---
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.
*/