From: Geert Uytterhoeven on
On Sun, Mar 14, 2010 at 15:30, Andreas Schwab <schwab(a)linux-m68k.org> wrote:
> Geert Uytterhoeven <geert(a)linux-m68k.org> writes:
>
>> |   CC      mm/memcontrol.o
>> | {standard input}: Assembler messages:
>> | {standard input}:4076: Error: operands mismatch -- statement `subl
>> 12(%fp),170(%a0)' ignored
>>
>> Seems like we have bad asm constraints in
>>
>> static inline int atomic_sub_and_test(int i, atomic_t *v)
>> {
>>         char c;
>>         __asm__ __volatile__("subl %2,%1; seq %0" : "=d" (c), "+m"
>> (*v): "g" (i));
>
> Surely "g" is wrong, sub only accepts a data register as source operand
> when the destination is in memory.

From cd2b57976949934df61c4406af344294011d5c16 Mon Sep 17 00:00:00 2001
From: Geert Uytterhoeven <geert(a)linux-m68k.org>
Date: Sun, 21 Mar 2010 10:52:21 +0100
Subject: [PATCH] m68k: Fix asm constraints for atomic_sub_and_test()
and atomic_add_negative()

Recently, we started seeing this on allmodconfig builds:

CC mm/memcontrol.o
{standard input}: Assembler messages:
{standard input}:4076: Error: operands mismatch -- statement `subl
12(%fp),170(%a0)' ignored

Correct the asm constraint, like done for m68knommu.

Signed-off-by: Geert Uytterhoeven <geert(a)linux-m68k.org>
---
arch/m68k/include/asm/atomic_mm.h | 8 ++++++--
1 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/m68k/include/asm/atomic_mm.h
b/arch/m68k/include/asm/atomic_mm.h
index 88b7af2..d9d2ed6 100644
--- a/arch/m68k/include/asm/atomic_mm.h
+++ b/arch/m68k/include/asm/atomic_mm.h
@@ -148,14 +148,18 @@ static inline int atomic_xchg(atomic_t *v, int new)
static inline int atomic_sub_and_test(int i, atomic_t *v)
{
char c;
- __asm__ __volatile__("subl %2,%1; seq %0" : "=d" (c), "+m" (*v): "g" (i));
+ __asm__ __volatile__("subl %2,%1; seq %0"
+ : "=d" (c), "+m" (*v)
+ : "id" (i));
return c != 0;
}

static inline int atomic_add_negative(int i, atomic_t *v)
{
char c;
- __asm__ __volatile__("addl %2,%1; smi %0" : "=d" (c), "+m" (*v): "g" (i));
+ __asm__ __volatile__("addl %2,%1; smi %0"
+ : "=d" (c), "+m" (*v)
+ : "id" (i));
return c != 0;
}

--
1.6.0.4

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert(a)linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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