From: Richard Weinberger <richard@nod.at>
Date: Wed, 27 Apr 2011 22:26:54 +0000 (-0700)
Subject: um: adjust current_thread_info() for newer gcc versions
X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=534e3adbd22efa327e6ff27cf2d8ebaad8382ecd;p=openwrt%2Fstaging%2Fblogic.git

um: adjust current_thread_info() for newer gcc versions

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.

Signed-off-by: Richard Weinberger <richard@nod.at>
Acked-by: Kirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/arch/um/include/asm/thread_info.h b/arch/um/include/asm/thread_info.h
index e2cf786bda0a..5bd1bad33fab 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;
 }