On Sat, Apr 16, 2011 at 01:03:13AM +0200, Richard Weinberger wrote:
> In some cases gcc-4.6 will optimize away current_thread_info().
> To prevent gcc from doing so the stack address has to be obtained
> via inline asm.
>
> LKML-Reference: http://marc.info/?i=201104132150.05623.rich...@nod.at
>
> Signed-off-by: Richard Weinberger <rich...@nod.at>
Acked-by: Kirill A. Shutemov <kir...@shutemov.name>
Also reproducible with gcc version 4.5.2 (Ubuntu/Linaro 4.5.2-8ubuntu4).
> ---
> arch/um/include/asm/thread_info.h | 5 ++++-
> 1 files changed, 4 insertions(+), 1 deletions(-)
>
> diff --git a/arch/um/include/asm/thread_info.h
> b/arch/um/include/asm/thread_info.h
> index e2cf786..5bd1bad 100644
> --- a/arch/um/include/asm/thread_info.h
> +++ b/arch/um/include/asm/thread_info.h
> @@ -49,7 +49,10 @@ static inline struct thread_info *current_thread_info(void)
> {
> struct thread_info *ti;
> unsigned long mask = THREAD_SIZE - 1;
> - ti = (struct thread_info *) (((unsigned long) &ti) & ~mask);
> + void *p;
> +
> + asm volatile ("" : "=r" (p) : "0" (&ti));
> + ti = (struct thread_info *) (((unsigned long)p) & ~mask);
> return ti;
> }
>
> --
> 1.6.6.1
>
> --
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--
Kirill A. Shutemov
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