* [PATCH v2] x86-64/entry: add instruction suffix to SYSRET
@ 2019-12-16 10:40 Jan Beulich
2020-01-09 11:37 ` [tip: x86/asm] x86/entry/64: Add " tip-bot2 for Jan Beulich
0 siblings, 1 reply; 2+ messages in thread
From: Jan Beulich @ 2019-12-16 10:40 UTC (permalink / raw)
To: Andy Lutomirski; +Cc: the arch/x86 maintainers, lkml
ignore_sysret contains an unsuffixed 'sysret' instruction. gas
correctly interprets this as sysretl, but leaving it up to gas to
guess when there is no register operand that implies a size is bad
practice, and upstream gas is likely to warn about this in the future.
Use 'sysretl' explicitly. This does not change the assembled output.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andy Lutomirski <luto@kernel.org>
---
v2: Use re-written description from Andy.
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -1728,7 +1728,7 @@ END(nmi)
SYM_CODE_START(ignore_sysret)
UNWIND_HINT_EMPTY
mov $-ENOSYS, %eax
- sysret
+ sysretl
SYM_CODE_END(ignore_sysret)
#endif
^ permalink raw reply [flat|nested] 2+ messages in thread
* [tip: x86/asm] x86/entry/64: Add instruction suffix to SYSRET
2019-12-16 10:40 [PATCH v2] x86-64/entry: add instruction suffix to SYSRET Jan Beulich
@ 2020-01-09 11:37 ` tip-bot2 for Jan Beulich
0 siblings, 0 replies; 2+ messages in thread
From: tip-bot2 for Jan Beulich @ 2020-01-09 11:37 UTC (permalink / raw)
To: linux-tip-commits
Cc: Jan Beulich, Borislav Petkov, Andy Lutomirski, x86, LKML
The following commit has been merged into the x86/asm branch of tip:
Commit-ID: b2b1d94cdfd4e906d3936dab2850096a4a0c2017
Gitweb: https://git.kernel.org/tip/b2b1d94cdfd4e906d3936dab2850096a4a0c2017
Author: Jan Beulich <jbeulich@suse.com>
AuthorDate: Mon, 16 Dec 2019 11:40:03 +01:00
Committer: Borislav Petkov <bp@suse.de>
CommitterDate: Thu, 09 Jan 2020 12:33:43 +01:00
x86/entry/64: Add instruction suffix to SYSRET
ignore_sysret() contains an unsuffixed SYSRET instruction. gas correctly
interprets this as SYSRETL, but leaving it up to gas to guess when there
is no register operand that implies a size is bad practice, and upstream
gas is likely to warn about this in the future. Use SYSRETL explicitly.
This does not change the assembled output.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/038a7c35-062b-a285-c6d2-653b56585844@suse.com
---
arch/x86/entry/entry_64.S | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 76942cb..f2bb91e 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -1728,7 +1728,7 @@ SYM_CODE_END(nmi)
SYM_CODE_START(ignore_sysret)
UNWIND_HINT_EMPTY
mov $-ENOSYS, %eax
- sysret
+ sysretl
SYM_CODE_END(ignore_sysret)
#endif
^ permalink raw reply related [flat|nested] 2+ messages in thread
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