* Re: smp_mb() in asm-mips/bitops.h
2007-06-07 7:53 smp_mb() in asm-mips/bitops.h Atsushi Nemoto
@ 2007-06-07 12:23 ` Ralf Baechle
2007-06-07 14:41 ` Atsushi Nemoto
2007-06-13 15:56 ` Atsushi Nemoto
0 siblings, 2 replies; 5+ messages in thread
From: Ralf Baechle @ 2007-06-07 12:23 UTC (permalink / raw)
To: Atsushi Nemoto; +Cc: linux-mips
On Thu, Jun 07, 2007 at 04:53:01PM +0900, Atsushi Nemoto wrote:
> I found some funny usages of smp_mb() in asm-mips/bitops.h:
Funny indeed ;-) Below patch should do the trick.
Due to very inagressive memory reordering on the few non-strongly ordered
MIPS SMP systems I am somewhat confident this didn't break anything but
if so, Sibyte and PMC-Sierra RM9000 SMP systems are affected.
Ralf
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/include/asm-mips/bitops.h b/include/asm-mips/bitops.h
index d995413..ffe245b 100644
--- a/include/asm-mips/bitops.h
+++ b/include/asm-mips/bitops.h
@@ -238,10 +238,11 @@ static inline int test_and_set_bit(unsigned long nr,
volatile unsigned long *addr)
{
unsigned short bit = nr & SZLONG_MASK;
+ unsigned long res;
if (cpu_has_llsc && R10000_LLSC_WAR) {
unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
- unsigned long temp, res;
+ unsigned long temp;
__asm__ __volatile__(
" .set mips3 \n"
@@ -254,11 +255,9 @@ static inline int test_and_set_bit(unsigned long nr,
: "=&r" (temp), "=m" (*m), "=&r" (res)
: "r" (1UL << bit), "m" (*m)
: "memory");
-
- return res != 0;
} else if (cpu_has_llsc) {
unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
- unsigned long temp, res;
+ unsigned long temp;
__asm__ __volatile__(
" .set push \n"
@@ -277,25 +276,22 @@ static inline int test_and_set_bit(unsigned long nr,
: "=&r" (temp), "=m" (*m), "=&r" (res)
: "r" (1UL << bit), "m" (*m)
: "memory");
-
- return res != 0;
} else {
volatile unsigned long *a = addr;
unsigned long mask;
- int retval;
unsigned long flags;
a += nr >> SZLONG_LOG;
mask = 1UL << bit;
raw_local_irq_save(flags);
- retval = (mask & *a) != 0;
+ res = (mask & *a);
*a |= mask;
raw_local_irq_restore(flags);
-
- return retval;
}
smp_mb();
+
+ return res != 0;
}
/*
@@ -310,6 +306,7 @@ static inline int test_and_clear_bit(unsigned long nr,
volatile unsigned long *addr)
{
unsigned short bit = nr & SZLONG_MASK;
+ unsigned long res;
if (cpu_has_llsc && R10000_LLSC_WAR) {
unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
@@ -327,12 +324,10 @@ static inline int test_and_clear_bit(unsigned long nr,
: "=&r" (temp), "=m" (*m), "=&r" (res)
: "r" (1UL << bit), "m" (*m)
: "memory");
-
- return res != 0;
#ifdef CONFIG_CPU_MIPSR2
} else if (__builtin_constant_p(nr)) {
unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
- unsigned long temp, res;
+ unsigned long temp;
__asm__ __volatile__(
"1: " __LL "%0, %1 # test_and_clear_bit \n"
@@ -346,12 +341,10 @@ static inline int test_and_clear_bit(unsigned long nr,
: "=&r" (temp), "=m" (*m), "=&r" (res)
: "ri" (bit), "m" (*m)
: "memory");
-
- return res;
#endif
} else if (cpu_has_llsc) {
unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
- unsigned long temp, res;
+ unsigned long temp;
__asm__ __volatile__(
" .set push \n"
@@ -371,25 +364,22 @@ static inline int test_and_clear_bit(unsigned long nr,
: "=&r" (temp), "=m" (*m), "=&r" (res)
: "r" (1UL << bit), "m" (*m)
: "memory");
-
- return res != 0;
} else {
volatile unsigned long *a = addr;
unsigned long mask;
- int retval;
unsigned long flags;
a += nr >> SZLONG_LOG;
mask = 1UL << bit;
raw_local_irq_save(flags);
- retval = (mask & *a) != 0;
+ res = (mask & *a);
*a &= ~mask;
raw_local_irq_restore(flags);
-
- return retval;
}
smp_mb();
+
+ return res != 0;
}
/*
@@ -404,10 +394,11 @@ static inline int test_and_change_bit(unsigned long nr,
volatile unsigned long *addr)
{
unsigned short bit = nr & SZLONG_MASK;
+ unsigned long res;
if (cpu_has_llsc && R10000_LLSC_WAR) {
unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
- unsigned long temp, res;
+ unsigned long temp;
__asm__ __volatile__(
" .set mips3 \n"
@@ -420,11 +411,9 @@ static inline int test_and_change_bit(unsigned long nr,
: "=&r" (temp), "=m" (*m), "=&r" (res)
: "r" (1UL << bit), "m" (*m)
: "memory");
-
- return res != 0;
} else if (cpu_has_llsc) {
unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
- unsigned long temp, res;
+ unsigned long temp;
__asm__ __volatile__(
" .set push \n"
@@ -443,24 +432,22 @@ static inline int test_and_change_bit(unsigned long nr,
: "=&r" (temp), "=m" (*m), "=&r" (res)
: "r" (1UL << bit), "m" (*m)
: "memory");
-
- return res != 0;
} else {
volatile unsigned long *a = addr;
- unsigned long mask, retval;
+ unsigned long mask;
unsigned long flags;
a += nr >> SZLONG_LOG;
mask = 1UL << bit;
raw_local_irq_save(flags);
- retval = (mask & *a) != 0;
+ res = (mask & *a);
*a ^= mask;
raw_local_irq_restore(flags);
-
- return retval;
}
smp_mb();
+
+ return res != 0;
}
#include <asm-generic/bitops/non-atomic.h>
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