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MIPS: Allow kernel use of LL/SC to be separate from the presence of LL/SC.

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On some CPUs, it is more efficient to disable and enable interrupts in the
kernel rather than use ll/sc for atomic operations.  But if we were to set
cpu_has_llsc to false, we would break the userspace futex interface (in
asm/futex.h).

We separate the two concepts, with a new predicate kernel_uses_llsc, that
lets us disable the kernel's use of ll/sc while still allowing the futex
code to use it.

Also there were a couple of cases in bitops.h where we were using ll/sc
unconditionally even if cpu_has_llsc were false.

Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
David Daney
2009-07-13 11:15:19 -07:00
committed by Ralf Baechle
parent f7ade3c168
commit b791d1193a
6 changed files with 50 additions and 47 deletions
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34
arch/mips/include/asm/bitops.h
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@@ -61,7 +61,7 @@ static inline void set_bit(unsigned long nr, volatile unsigned long *addr)
unsigned short bit = nr & SZLONG_MASK;
unsigned long temp;
if (cpu_has_llsc && R10000_LLSC_WAR) {
if (kernel_uses_llsc && R10000_LLSC_WAR) {
__asm__ __volatile__(
" .set mips3 \n"
"1: " __LL "%0, %1 # set_bit \n"
@@ -72,7 +72,7 @@ static inline void set_bit(unsigned long nr, volatile unsigned long *addr)
: "=&r" (temp), "=m" (*m)
: "ir" (1UL << bit), "m" (*m));
#ifdef CONFIG_CPU_MIPSR2
} else if (__builtin_constant_p(bit)) {
} else if (kernel_uses_llsc && __builtin_constant_p(bit)) {
__asm__ __volatile__(
"1: " __LL "%0, %1 # set_bit \n"
" " __INS "%0, %4, %2, 1 \n"
@@ -84,7 +84,7 @@ static inline void set_bit(unsigned long nr, volatile unsigned long *addr)
: "=&r" (temp), "=m" (*m)
: "ir" (bit), "m" (*m), "r" (~0));
#endif /* CONFIG_CPU_MIPSR2 */
} else if (cpu_has_llsc) {
} else if (kernel_uses_llsc) {
__asm__ __volatile__(
" .set mips3 \n"
"1: " __LL "%0, %1 # set_bit \n"
@@ -126,7 +126,7 @@ static inline void clear_bit(unsigned long nr, volatile unsigned long *addr)
unsigned short bit = nr & SZLONG_MASK;
unsigned long temp;
if (cpu_has_llsc && R10000_LLSC_WAR) {
if (kernel_uses_llsc && R10000_LLSC_WAR) {
__asm__ __volatile__(
" .set mips3 \n"
"1: " __LL "%0, %1 # clear_bit \n"
@@ -137,7 +137,7 @@ static inline void clear_bit(unsigned long nr, volatile unsigned long *addr)
: "=&r" (temp), "=m" (*m)
: "ir" (~(1UL << bit)), "m" (*m));
#ifdef CONFIG_CPU_MIPSR2
} else if (__builtin_constant_p(bit)) {
} else if (kernel_uses_llsc && __builtin_constant_p(bit)) {
__asm__ __volatile__(
"1: " __LL "%0, %1 # clear_bit \n"
" " __INS "%0, $0, %2, 1 \n"
@@ -149,7 +149,7 @@ static inline void clear_bit(unsigned long nr, volatile unsigned long *addr)
: "=&r" (temp), "=m" (*m)
: "ir" (bit), "m" (*m));
#endif /* CONFIG_CPU_MIPSR2 */
} else if (cpu_has_llsc) {
} else if (kernel_uses_llsc) {
__asm__ __volatile__(
" .set mips3 \n"
"1: " __LL "%0, %1 # clear_bit \n"
@@ -202,7 +202,7 @@ static inline void change_bit(unsigned long nr, volatile unsigned long *addr)
{
unsigned short bit = nr & SZLONG_MASK;
if (cpu_has_llsc && R10000_LLSC_WAR) {
if (kernel_uses_llsc && R10000_LLSC_WAR) {
unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
unsigned long temp;
@@ -215,7 +215,7 @@ static inline void change_bit(unsigned long nr, volatile unsigned long *addr)
" .set mips0 \n"
: "=&r" (temp), "=m" (*m)
: "ir" (1UL << bit), "m" (*m));
} else if (cpu_has_llsc) {
} else if (kernel_uses_llsc) {
unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
unsigned long temp;
@@ -260,7 +260,7 @@ static inline int test_and_set_bit(unsigned long nr,
smp_llsc_mb();
if (cpu_has_llsc && R10000_LLSC_WAR) {
if (kernel_uses_llsc && R10000_LLSC_WAR) {
unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
unsigned long temp;
@@ -275,7 +275,7 @@ static inline int test_and_set_bit(unsigned long nr,
: "=&r" (temp), "=m" (*m), "=&r" (res)
: "r" (1UL << bit), "m" (*m)
: "memory");
} else if (cpu_has_llsc) {
} else if (kernel_uses_llsc) {
unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
unsigned long temp;
@@ -328,7 +328,7 @@ static inline int test_and_set_bit_lock(unsigned long nr,
unsigned short bit = nr & SZLONG_MASK;
unsigned long res;
if (cpu_has_llsc && R10000_LLSC_WAR) {
if (kernel_uses_llsc && R10000_LLSC_WAR) {
unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
unsigned long temp;
@@ -343,7 +343,7 @@ static inline int test_and_set_bit_lock(unsigned long nr,
: "=&r" (temp), "=m" (*m), "=&r" (res)
: "r" (1UL << bit), "m" (*m)
: "memory");
} else if (cpu_has_llsc) {
} else if (kernel_uses_llsc) {
unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
unsigned long temp;
@@ -397,7 +397,7 @@ static inline int test_and_clear_bit(unsigned long nr,
smp_llsc_mb();
if (cpu_has_llsc && R10000_LLSC_WAR) {
if (kernel_uses_llsc && R10000_LLSC_WAR) {
unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
unsigned long temp;
@@ -414,7 +414,7 @@ static inline int test_and_clear_bit(unsigned long nr,
: "r" (1UL << bit), "m" (*m)
: "memory");
#ifdef CONFIG_CPU_MIPSR2
} else if (__builtin_constant_p(nr)) {
} else if (kernel_uses_llsc && __builtin_constant_p(nr)) {
unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
unsigned long temp;
@@ -431,7 +431,7 @@ static inline int test_and_clear_bit(unsigned long nr,
: "ir" (bit), "m" (*m)
: "memory");
#endif
} else if (cpu_has_llsc) {
} else if (kernel_uses_llsc) {
unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
unsigned long temp;
@@ -487,7 +487,7 @@ static inline int test_and_change_bit(unsigned long nr,
smp_llsc_mb();
if (cpu_has_llsc && R10000_LLSC_WAR) {
if (kernel_uses_llsc && R10000_LLSC_WAR) {
unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
unsigned long temp;
@@ -502,7 +502,7 @@ static inline int test_and_change_bit(unsigned long nr,
: "=&r" (temp), "=m" (*m), "=&r" (res)
: "r" (1UL << bit), "m" (*m)
: "memory");
} else if (cpu_has_llsc) {
} else if (kernel_uses_llsc) {
unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
unsigned long temp;