From 587f17018a2c6c414e41a312b002faaef60cf423 Mon Sep 17 00:00:00 2001
From: Nick Desaulniers <ndesaulniers@google.com>
Date: Fri, 14 Feb 2020 14:18:11 -0800
Subject: [PATCH] Kconfig: add config option for asm goto w/ outputs
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@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
init/Kconfig | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/init/Kconfig b/init/Kconfig
index 2d12d38cdd88..b5294bcba61d 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -36,6 +36,10 @@ config CC_CAN_LINK
config CC_HAS_ASM_GOTO
def_bool $(success,$(srctree)/scripts/gcc-goto.sh $(CC))
+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)