This is a note to let you know that I've just added the patch titled
x86/entry/64: Add instruction suffix to SYSRET
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
x86-entry-64-add-instruction-suffix-to-sysret.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From b2b1d94cdfd4e906d3936dab2850096a4a0c2017 Mon Sep 17 00:00:00 2001
From: Jan Beulich <jbeulich@xxxxxxxx>
Date: Mon, 16 Dec 2019 11:40:03 +0100
Subject: x86/entry/64: Add instruction suffix to SYSRET
From: Jan Beulich <jbeulich@xxxxxxxx>
commit b2b1d94cdfd4e906d3936dab2850096a4a0c2017 upstream.
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@xxxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Acked-by: Andy Lutomirski <luto@xxxxxxxxxx>
Link: https://lkml.kernel.org/r/038a7c35-062b-a285-c6d2-653b56585844@xxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/entry/entry_64.S | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -1759,7 +1759,7 @@ END(nmi)
ENTRY(ignore_sysret)
UNWIND_HINT_EMPTY
mov $-ENOSYS, %eax
- sysret
+ sysretl
END(ignore_sysret)
ENTRY(rewind_stack_do_exit)
Patches currently in stable-queue which might be from jbeulich@xxxxxxxx are
queue-4.19/x86-entry-64-add-instruction-suffix-to-sysret.patch
