[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Message-ID: <20080816073926.GA19546@Krystal>
Date: Sat, 16 Aug 2008 03:39:26 -0400
From: Mathieu Desnoyers <mathieu.desnoyers@...ymtl.ca>
To: "H. Peter Anvin" <hpa@...or.com>
Cc: Jeremy Fitzhardinge <jeremy@...p.org>,
Andrew Morton <akpm@...ux-foundation.org>,
Ingo Molnar <mingo@...e.hu>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Joe Perches <joe@...ches.com>, linux-kernel@...r.kernel.org
Subject: [PATCH] x86_64 : support atomic ops with 64 bits integer values
x86_64 add/sub atomic ops does not seems to accept integer values bigger
than 32 bits as immediates. Intel's add/sub documentation specifies they
have to be passed as registers.
http://gcc.gnu.org/onlinedocs/gcc-4.3.0/gcc/Machine-Constraints.html#Machine-Constraints
states :
e
32-bit signed integer constant, or a symbolic reference known to fit that range (for immediate operands in sign-extending x86-64 instructions).
Z
32-bit unsigned integer constant, or a symbolic reference known to fit that range (for immediate operands in zero-extending x86-64 instructions).
Since add/sub does sign extension, using the "e" constraint seems appropriate.
It applies to 2.6.27-rc, 2.6.26, 2.6.25...
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@...ymtl.ca>
CC: Jeremy Fitzhardinge <jeremy@...p.org>
CC: "H. Peter Anvin" <hpa@...or.com>
CC: Andrew Morton <akpm@...ux-foundation.org>
CC: Ingo Molnar <mingo@...e.hu>
CC: Linus Torvalds <torvalds@...ux-foundation.org>
CC: Joe Perches <joe@...ches.com>
---
include/asm-x86/atomic_64.h | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
Index: linux-2.6-lttng/include/asm-x86/atomic_64.h
===================================================================
--- linux-2.6-lttng.orig/include/asm-x86/atomic_64.h 2008-08-16 03:19:35.000000000 -0400
+++ linux-2.6-lttng/include/asm-x86/atomic_64.h 2008-08-16 03:21:18.000000000 -0400
@@ -228,7 +228,7 @@ static inline void atomic64_add(long i,
{
asm volatile(LOCK_PREFIX "addq %1,%0"
: "=m" (v->counter)
- : "ir" (i), "m" (v->counter));
+ : "er" (i), "m" (v->counter));
}
/**
@@ -242,7 +242,7 @@ static inline void atomic64_sub(long i,
{
asm volatile(LOCK_PREFIX "subq %1,%0"
: "=m" (v->counter)
- : "ir" (i), "m" (v->counter));
+ : "er" (i), "m" (v->counter));
}
/**
@@ -260,7 +260,7 @@ static inline int atomic64_sub_and_test(
asm volatile(LOCK_PREFIX "subq %2,%0; sete %1"
: "=m" (v->counter), "=qm" (c)
- : "ir" (i), "m" (v->counter) : "memory");
+ : "er" (i), "m" (v->counter) : "memory");
return c;
}
@@ -341,7 +341,7 @@ static inline int atomic64_add_negative(
asm volatile(LOCK_PREFIX "addq %2,%0; sets %1"
: "=m" (v->counter), "=qm" (c)
- : "ir" (i), "m" (v->counter) : "memory");
+ : "er" (i), "m" (v->counter) : "memory");
return c;
}
--
Mathieu Desnoyers
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists