paravirt depends on a custom calling convention (callee saved), but expects this from a static inline function that it then forces to be outlined. This is problematic because different compilers or flags can then add a stack guard that violates the calling conventions. Uses extern inline with the out-of-line definition in assembly to prevent compilers from adding stack guards to the outlined version. Other parts of the codebase overwrite KBUILD_CFLAGS, which is *extremely problematic* for extern inline, as the sematics are completely the opposite depending on what C standard is used. http://blahg.josefsipek.net/?p=529 Changes since v4: Take Arnd's and hpa's suggestions properly feature detect gnu_inline attribute to support gcc 4.1. Changes since v3: Take Joe's suggestion to hoist __inline__ and __inline out of conditional block. Changes since v2: Take hpa's _ASM_ARG patch into the set in order to simplify cross 32b/64b x86 assembly and rebase my final patch to use it. Apply Sedat's typo fix to commit message and sign off on it. Take Joe's suggestion to simplify __inline__ and __inline. Add Arnd to list of folks who made helpful suggestions. Changes since v1: Prefer gnu_inline function attribute instead of explicitly setting C standard compiler flag in problematic Makefiles. We should instead carefully evaluate if those Makefiles should be overwriting KBUILD_CFLAGS at all. Dropped the previous first two patches and added a new first patch. H. Peter Anvin (1): x86/asm: add _ASM_ARG* constants for argument registers to <asm/asm.h> Nick Desaulniers (2): compiler-gcc.h: add gnu_inline to all inline declarations x86: paravirt: make native_save_fl extern inline arch/x86/include/asm/asm.h | 59 +++++++++++++++++++++++++++++++++ arch/x86/include/asm/irqflags.h | 2 +- arch/x86/kernel/Makefile | 1 + arch/x86/kernel/irqflags.S | 26 +++++++++++++++ include/linux/compiler-gcc.h | 29 ++++++++++++---- 5 files changed, 109 insertions(+), 8 deletions(-) create mode 100644 arch/x86/kernel/irqflags.S -- 2.18.0.rc1.244.gcf134e6275-goog -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
