This is a note to let you know that I've just added the patch titled
Kconfig: add config option for asm goto w/ outputs
to the 5.4-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:
kconfig-add-config-option-for-asm-goto-w-outputs.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 587f17018a2c6c414e41a312b002faaef60cf423 Mon Sep 17 00:00:00 2001
From: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
Date: Fri, 14 Feb 2020 14:18:11 -0800
Subject: Kconfig: add config option for asm goto w/ outputs
From: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
commit 587f17018a2c6c414e41a312b002faaef60cf423 upstream.
This allows C code to make use of compilers with support for output
variables along the fallthrough path via preprocessor define:
CONFIG_CC_HAS_ASM_GOTO_OUTPUT
[ This is not used anywhere yet, and currently released compilers don't
support this yet, but it's coming, and I have some local experimental
patches to take advantage of it when it does - Linus ]
Signed-off-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
init/Kconfig | 4 ++++
1 file changed, 4 insertions(+)
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -38,6 +38,10 @@ config CC_HAS_ASM_GOTO_TIED_OUTPUT
# Detect buggy gcc and clang, fixed in gcc-11 clang-14.
def_bool $(success,echo 'int foo(int *x) { asm goto (".long (%l[bar]) - .\n": "+m"(*x) ::: bar); return *x; bar: return 0; }' | $CC -x c - -c -o /dev/null)
+config CC_HAS_ASM_GOTO_OUTPUT
+ depends on CC_HAS_ASM_GOTO
+ def_bool $(success,echo 'int foo(int x) { asm goto ("": "=r"(x) ::: bar); return x; bar: return 0; }' | $(CC) -x c - -c -o /dev/null)
+
config TOOLS_SUPPORT_RELR
def_bool $(success,env "CC=$(CC)" "LD=$(LD)" "NM=$(NM)" "OBJCOPY=$(OBJCOPY)" $(srctree)/scripts/tools-support-relr.sh)
Patches currently in stable-queue which might be from ndesaulniers@xxxxxxxxxx are
queue-5.4/kconfig-add-option-for-asm-goto-w-tied-outputs-to-workaround-clang-13-bug.patch
queue-5.4/kconfig-add-config-option-for-asm-goto-w-outputs.patch
