[PATCH] um: Adjust current_thread_info() for newer gcc versions

From: Richard Weinberger
Date: Fri Apr 22 2011 - 06:20:59 EST


In some cases gcc >= 4.5.2 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@xxxxxx

Acked-by: Kirill A. Shutemov <kirill@xxxxxxxxxxxxx>
Signed-off-by: Richard Weinberger <richard@xxxxxx>
---
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;
}

--
1.7.4.2

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