Re: [PATCH] ix86: fix vDSO build

From: Andrew Morton
Date: Wed Jul 09 2014 - 19:30:39 EST


On Thu, 03 Jul 2014 15:35:07 +0100 "Jan Beulich" <JBeulich@xxxxxxxx> wrote:

> Relying on static functions used just once to get inlined (and
> subsequently have dead code paths eliminated) is wrong: Compilers are
> free to decide whether they do this, regardless of optimization level.
> With this not happening for vdso_addr() (observed with gcc 4.1.x), an
> unresolved reference to align_vdso_addr() causes the build to fail.
>
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
> Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
> ---
> arch/x86/vdso/vma.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> --- 3.16-rc3/arch/x86/vdso/vma.c
> +++ 3.16-rc3-x86-vdso-build/arch/x86/vdso/vma.c
> @@ -62,6 +62,9 @@ struct linux_binprm;
> Only used for the 64-bit and x32 vdsos. */
> static unsigned long vdso_addr(unsigned long start, unsigned len)
> {
> +#ifdef CONFIG_X86_32
> + return 0;
> +#else
> unsigned long addr, end;
> unsigned offset;
> end = (start + PMD_SIZE - 1) & PMD_MASK;
> @@ -83,6 +86,7 @@ static unsigned long vdso_addr(unsigned
> addr = align_vdso_addr(addr);
>
> return addr;
> +#endif
> }
>
> static int map_vdso(const struct vdso_image *image, bool calculate_addr)

Tested-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
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