Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 5.4 271/411] Kconfig: add config option for asm goto w/ outputs | Date | Mon, 13 Jun 2022 12:09:04 +0200 |
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From: Nick Desaulniers <ndesaulniers@google.com>
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@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- 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)
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