Re: [GIT PULL] scheduler fixes

Ingo Molnar
2009-10-01T06:11:26Z

* Eric Dumazet <eric.dumazet@gmail.com> wrote:

> [PATCH] x86: Dont generate cmpxchg8b_emu if CONFIG_X86_CMPXCHG64=y
>
> cmpxchg8b_emu helper wont be used if CONFIG_X86_CMPXCHG64=y
>
> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
> ---
> arch/x86/kernel/i386_ksyms_32.c | 2 ++
> arch/x86/lib/Makefile | 6 ++++--
> 2 files changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kernel/i386_ksyms_32.c b/arch/x86/kernel/i386_ksyms_32.c
> index 1736c5a..9c3bd4a 100644
> --- a/arch/x86/kernel/i386_ksyms_32.c
> +++ b/arch/x86/kernel/i386_ksyms_32.c
> @@ -15,8 +15,10 @@ EXPORT_SYMBOL(mcount);
> * the export, but dont use it from C code, it is used
> * by assembly code and is not using C calling convention!
> */
> +#ifndef CONFIG_X86_CMPXCHG64
> extern void cmpxchg8b_emu(void);
> EXPORT_SYMBOL(cmpxchg8b_emu);
> +#endif
>
> /* Networking helper routines. */
> EXPORT_SYMBOL(csum_partial_copy_generic);
> diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile
> index 3e549b8..c309b82 100644
> --- a/arch/x86/lib/Makefile
> +++ b/arch/x86/lib/Makefile
> @@ -15,8 +15,10 @@ ifeq ($(CONFIG_X86_32),y)
> obj-y += atomic64_32.o
> lib-y += checksum_32.o
> lib-y += strstr_32.o
> - lib-y += semaphore_32.o string_32.o cmpxchg8b_emu.o
> -
> + lib-y += semaphore_32.o string_32.o
> +ifeq ($(CONFIG_X86_CMPXCHG64),n)
> + lib-y += cmpxchg8b_emu.o
> +endif
> lib-$(CONFIG_X86_USE_3DNOW) += mmx_32.o
> else
> obj-y += io_64.o iomap_copy_64.o

That's not enough - the inline assembly code in
arch/x86/include/asm/cmpxchg_32.h should also not reference
cmpxchg8b_emu in that case.

Ingo