* [PATCH] um: Adjust current_thread_info() for gcc-4.6
@ 2011-04-15 23:03 Richard Weinberger
2011-04-22 0:10 ` Kirill A. Shutemov
0 siblings, 1 reply; 3+ messages in thread
From: Richard Weinberger @ 2011-04-15 23:03 UTC (permalink / raw)
To: linux-kernel; +Cc: user-mode-linux-devel, Richard Weinberger
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.richard@nod.at
Signed-off-by: Richard Weinberger <richard@nod.at>
---
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
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] um: Adjust current_thread_info() for gcc-4.6
2011-04-15 23:03 [PATCH] um: Adjust current_thread_info() for gcc-4.6 Richard Weinberger
@ 2011-04-22 0:10 ` Kirill A. Shutemov
2011-04-22 9:58 ` Richard Weinberger
0 siblings, 1 reply; 3+ messages in thread
From: Kirill A. Shutemov @ 2011-04-22 0:10 UTC (permalink / raw)
To: Richard Weinberger; +Cc: linux-kernel, user-mode-linux-devel
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.richard@nod.at
>
> Signed-off-by: Richard Weinberger <richard@nod.at>
Acked-by: Kirill A. Shutemov <kirill@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
^ permalink raw reply [flat|nested] 3+ messages in thread
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2011-04-15 23:03 [PATCH] um: Adjust current_thread_info() for gcc-4.6 Richard Weinberger
2011-04-22 0:10 ` Kirill A. Shutemov
2011-04-22 9:58 ` Richard Weinberger
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