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linux/arch/mips/include/asm/bitops.h
Ralf Baechle 7837314d14 MIPS: Get rid of branches to .subsections. 
It was a nice optimization - on paper at least.  In practice it results in
branches that may exceed the maximum legal range for a branch.  We can
fight that problem with -ffunction-sections but -ffunction-sections again
is incompatible with -pg used by the function tracer.

By rewriting the loop around all simple LL/SC blocks to C we reduce the
amount of inline assembler and at the same time allow GCC to often fill
the branch delay slots with something sensible or whatever else clever
optimization it may have up in its sleeve.

With this optimization gone we also no longer need -ffunction-sections,
so drop it.

This optimization was originally introduced in 2.6.21, commit
5999eca25c1fd4b9b9aca7833b04d10fe4bc877d (linux-mips.org) rsp.
f65e4fa8e0 (kernel.org).

Original fix for the issues which caused me to pull this optimization by
Paul Gortmaker <paul.gortmaker@windriver.com>.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2010-10-29 19:08:24 +01:00

685 lines
16 KiB
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/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (c) 1994 - 1997, 99, 2000, 06, 07 Ralf Baechle (ralf@linux-mips.org)
* Copyright (c) 1999, 2000 Silicon Graphics, Inc.
*/
#ifndef _ASM_BITOPS_H
#define _ASM_BITOPS_H
#ifndef _LINUX_BITOPS_H
#error only <linux/bitops.h> can be included directly
#endif
#include <linux/compiler.h>
#include <linux/irqflags.h>
#include <linux/types.h>
#include <asm/barrier.h>
#include <asm/bug.h>
#include <asm/byteorder.h> /* sigh ... */
#include <asm/cpu-features.h>
#include <asm/sgidefs.h>
#include <asm/war.h>
#if _MIPS_SZLONG == 32
#define SZLONG_LOG 5
#define SZLONG_MASK 31UL
#define __LL "ll "
#define __SC "sc "
#define __INS "ins "
#define __EXT "ext "
#elif _MIPS_SZLONG == 64
#define SZLONG_LOG 6
#define SZLONG_MASK 63UL
#define __LL "lld "
#define __SC "scd "
#define __INS "dins "
#define __EXT "dext "
#endif
/*
* clear_bit() doesn't provide any barrier for the compiler.
*/
#define smp_mb__before_clear_bit() smp_mb__before_llsc()
#define smp_mb__after_clear_bit() smp_llsc_mb()
/*
* set_bit - Atomically set a bit in memory
* @nr: the bit to set
* @addr: the address to start counting from
*
* This function is atomic and may not be reordered. See __set_bit()
* if you do not require the atomic guarantees.
* Note that @nr may be almost arbitrarily large; this function is not
* restricted to acting on a single-word quantity.
*/
static inline void set_bit(unsigned long nr, volatile unsigned long *addr)
{
unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
unsigned short bit = nr & SZLONG_MASK;
unsigned long temp;
if (kernel_uses_llsc && R10000_LLSC_WAR) {
__asm__ __volatile__(
" .set mips3 \n"
"1: " __LL "%0, %1 # set_bit \n"
" or %0, %2 \n"
" " __SC "%0, %1 \n"
" beqzl %0, 1b \n"
" .set mips0 \n"
: "=&r" (temp), "=m" (*m)
: "ir" (1UL << bit), "m" (*m));
#ifdef CONFIG_CPU_MIPSR2
} else if (kernel_uses_llsc && __builtin_constant_p(bit)) {
do {
__asm__ __volatile__(
" " __LL "%0, %1 # set_bit \n"
" " __INS "%0, %3, %2, 1 \n"
" " __SC "%0, %1 \n"
: "=&r" (temp), "+m" (*m)
: "ir" (bit), "r" (~0));
} while (unlikely(!temp));
#endif /* CONFIG_CPU_MIPSR2 */
} else if (kernel_uses_llsc) {
do {
__asm__ __volatile__(
" .set mips3 \n"
" " __LL "%0, %1 # set_bit \n"
" or %0, %2 \n"
" " __SC "%0, %1 \n"
" .set mips0 \n"
: "=&r" (temp), "+m" (*m)
: "ir" (1UL << bit));
} while (unlikely(!temp));
} else {
volatile unsigned long *a = addr;
unsigned long mask;
unsigned long flags;
a += nr >> SZLONG_LOG;
mask = 1UL << bit;
raw_local_irq_save(flags);
*a |= mask;
raw_local_irq_restore(flags);
}
}
/*
* clear_bit - Clears a bit in memory
* @nr: Bit to clear
* @addr: Address to start counting from
*
* clear_bit() is atomic and may not be reordered. However, it does
* not contain a memory barrier, so if it is used for locking purposes,
* you should call smp_mb__before_clear_bit() and/or smp_mb__after_clear_bit()
* in order to ensure changes are visible on other processors.
*/
static inline void clear_bit(unsigned long nr, volatile unsigned long *addr)
{
unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
unsigned short bit = nr & SZLONG_MASK;
unsigned long temp;
if (kernel_uses_llsc && R10000_LLSC_WAR) {
__asm__ __volatile__(
" .set mips3 \n"
"1: " __LL "%0, %1 # clear_bit \n"
" and %0, %2 \n"
" " __SC "%0, %1 \n"
" beqzl %0, 1b \n"
" .set mips0 \n"
: "=&r" (temp), "+m" (*m)
: "ir" (~(1UL << bit)));
#ifdef CONFIG_CPU_MIPSR2
} else if (kernel_uses_llsc && __builtin_constant_p(bit)) {
do {
__asm__ __volatile__(
" " __LL "%0, %1 # clear_bit \n"
" " __INS "%0, $0, %2, 1 \n"
" " __SC "%0, %1 \n"
: "=&r" (temp), "+m" (*m)
: "ir" (bit));
} while (unlikely(!temp));
#endif /* CONFIG_CPU_MIPSR2 */
} else if (kernel_uses_llsc) {
do {
__asm__ __volatile__(
" .set mips3 \n"
" " __LL "%0, %1 # clear_bit \n"
" and %0, %2 \n"
" " __SC "%0, %1 \n"
" .set mips0 \n"
: "=&r" (temp), "+m" (*m)
: "ir" (~(1UL << bit)));
} while (unlikely(!temp));
} else {
volatile unsigned long *a = addr;
unsigned long mask;
unsigned long flags;
a += nr >> SZLONG_LOG;
mask = 1UL << bit;
raw_local_irq_save(flags);
*a &= ~mask;
raw_local_irq_restore(flags);
}
}
/*
* clear_bit_unlock - Clears a bit in memory
* @nr: Bit to clear
* @addr: Address to start counting from
*
* clear_bit() is atomic and implies release semantics before the memory
* operation. It can be used for an unlock.
*/
static inline void clear_bit_unlock(unsigned long nr, volatile unsigned long *addr)
{
smp_mb__before_clear_bit();
clear_bit(nr, addr);
}
/*
* change_bit - Toggle a bit in memory
* @nr: Bit to change
* @addr: Address to start counting from
*
* change_bit() is atomic and may not be reordered.
* Note that @nr may be almost arbitrarily large; this function is not
* restricted to acting on a single-word quantity.
*/
static inline void change_bit(unsigned long nr, volatile unsigned long *addr)
{
unsigned short bit = nr & SZLONG_MASK;
if (kernel_uses_llsc && R10000_LLSC_WAR) {
unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
unsigned long temp;
__asm__ __volatile__(
" .set mips3 \n"
"1: " __LL "%0, %1 # change_bit \n"
" xor %0, %2 \n"
" " __SC "%0, %1 \n"
" beqzl %0, 1b \n"
" .set mips0 \n"
: "=&r" (temp), "+m" (*m)
: "ir" (1UL << bit));
} else if (kernel_uses_llsc) {
unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
unsigned long temp;
do {
__asm__ __volatile__(
" .set mips3 \n"
" " __LL "%0, %1 # change_bit \n"
" xor %0, %2 \n"
" " __SC "%0, %1 \n"
" .set mips0 \n"
: "=&r" (temp), "+m" (*m)
: "ir" (1UL << bit));
} while (unlikely(!temp));
} else {
volatile unsigned long *a = addr;
unsigned long mask;
unsigned long flags;
a += nr >> SZLONG_LOG;
mask = 1UL << bit;
raw_local_irq_save(flags);
*a ^= mask;
raw_local_irq_restore(flags);
}
}
/*
* test_and_set_bit - Set a bit and return its old value
* @nr: Bit to set
* @addr: Address to count from
*
* This operation is atomic and cannot be reordered.
* It also implies a memory barrier.
*/
static inline int test_and_set_bit(unsigned long nr,
volatile unsigned long *addr)
{
unsigned short bit = nr & SZLONG_MASK;
unsigned long res;
smp_mb__before_llsc();
if (kernel_uses_llsc && R10000_LLSC_WAR) {
unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
unsigned long temp;
__asm__ __volatile__(
" .set mips3 \n"
"1: " __LL "%0, %1 # test_and_set_bit \n"
" or %2, %0, %3 \n"
" " __SC "%2, %1 \n"
" beqzl %2, 1b \n"
" and %2, %0, %3 \n"
" .set mips0 \n"
: "=&r" (temp), "+m" (*m), "=&r" (res)
: "r" (1UL << bit)
: "memory");
} else if (kernel_uses_llsc) {
unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
unsigned long temp;
do {
__asm__ __volatile__(
" .set mips3 \n"
" " __LL "%0, %1 # test_and_set_bit \n"
" or %2, %0, %3 \n"
" " __SC "%2, %1 \n"
" .set mips0 \n"
: "=&r" (temp), "+m" (*m), "=&r" (res)
: "r" (1UL << bit)
: "memory");
} while (unlikely(!res));
res = temp & (1UL << bit);
} else {
volatile unsigned long *a = addr;
unsigned long mask;
unsigned long flags;
a += nr >> SZLONG_LOG;
mask = 1UL << bit;
raw_local_irq_save(flags);
res = (mask & *a);
*a |= mask;
raw_local_irq_restore(flags);
}
smp_llsc_mb();
return res != 0;
}
/*
* test_and_set_bit_lock - Set a bit and return its old value
* @nr: Bit to set
* @addr: Address to count from
*
* This operation is atomic and implies acquire ordering semantics
* after the memory operation.
*/
static inline int test_and_set_bit_lock(unsigned long nr,
volatile unsigned long *addr)
{
unsigned short bit = nr & SZLONG_MASK;
unsigned long res;
if (kernel_uses_llsc && R10000_LLSC_WAR) {
unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
unsigned long temp;
__asm__ __volatile__(
" .set mips3 \n"
"1: " __LL "%0, %1 # test_and_set_bit \n"
" or %2, %0, %3 \n"
" " __SC "%2, %1 \n"
" beqzl %2, 1b \n"
" and %2, %0, %3 \n"
" .set mips0 \n"
: "=&r" (temp), "+m" (*m), "=&r" (res)
: "r" (1UL << bit)
: "memory");
} else if (kernel_uses_llsc) {
unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
unsigned long temp;
do {
__asm__ __volatile__(
" .set mips3 \n"
" " __LL "%0, %1 # test_and_set_bit \n"
" or %2, %0, %3 \n"
" " __SC "%2, %1 \n"
" .set mips0 \n"
: "=&r" (temp), "+m" (*m), "=&r" (res)
: "r" (1UL << bit)
: "memory");
} while (unlikely(!res));
res = temp & (1UL << bit);
} else {
volatile unsigned long *a = addr;
unsigned long mask;
unsigned long flags;
a += nr >> SZLONG_LOG;
mask = 1UL << bit;
raw_local_irq_save(flags);
res = (mask & *a);
*a |= mask;
raw_local_irq_restore(flags);
}
smp_llsc_mb();
return res != 0;
}
/*
* test_and_clear_bit - Clear a bit and return its old value
* @nr: Bit to clear
* @addr: Address to count from
*
* This operation is atomic and cannot be reordered.
* It also implies a memory barrier.
*/
static inline int test_and_clear_bit(unsigned long nr,
volatile unsigned long *addr)
{
unsigned short bit = nr & SZLONG_MASK;
unsigned long res;
smp_mb__before_llsc();
if (kernel_uses_llsc && R10000_LLSC_WAR) {
unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
unsigned long temp;
__asm__ __volatile__(
" .set mips3 \n"
"1: " __LL "%0, %1 # test_and_clear_bit \n"
" or %2, %0, %3 \n"
" xor %2, %3 \n"
" " __SC "%2, %1 \n"
" beqzl %2, 1b \n"
" and %2, %0, %3 \n"
" .set mips0 \n"
: "=&r" (temp), "+m" (*m), "=&r" (res)
: "r" (1UL << bit)
: "memory");
#ifdef CONFIG_CPU_MIPSR2
} else if (kernel_uses_llsc && __builtin_constant_p(nr)) {
unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
unsigned long temp;
do {
__asm__ __volatile__(
" " __LL "%0, %1 # test_and_clear_bit \n"
" " __EXT "%2, %0, %3, 1 \n"
" " __INS "%0, $0, %3, 1 \n"
" " __SC "%0, %1 \n"
: "=&r" (temp), "+m" (*m), "=&r" (res)
: "ir" (bit)
: "memory");
} while (unlikely(!temp));
#endif
} else if (kernel_uses_llsc) {
unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
unsigned long temp;
do {
__asm__ __volatile__(
" .set mips3 \n"
" " __LL "%0, %1 # test_and_clear_bit \n"
" or %2, %0, %3 \n"
" xor %2, %3 \n"
" " __SC "%2, %1 \n"
" .set mips0 \n"
: "=&r" (temp), "+m" (*m), "=&r" (res)
: "r" (1UL << bit)
: "memory");
} while (unlikely(!res));
res = temp & (1UL << bit);
} else {
volatile unsigned long *a = addr;
unsigned long mask;
unsigned long flags;
a += nr >> SZLONG_LOG;
mask = 1UL << bit;
raw_local_irq_save(flags);
res = (mask & *a);
*a &= ~mask;
raw_local_irq_restore(flags);
}
smp_llsc_mb();
return res != 0;
}
/*
* test_and_change_bit - Change a bit and return its old value
* @nr: Bit to change
* @addr: Address to count from
*
* This operation is atomic and cannot be reordered.
* It also implies a memory barrier.
*/
static inline int test_and_change_bit(unsigned long nr,
volatile unsigned long *addr)
{
unsigned short bit = nr & SZLONG_MASK;
unsigned long res;
smp_mb__before_llsc();
if (kernel_uses_llsc && R10000_LLSC_WAR) {
unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
unsigned long temp;
__asm__ __volatile__(
" .set mips3 \n"
"1: " __LL "%0, %1 # test_and_change_bit \n"
" xor %2, %0, %3 \n"
" " __SC "%2, %1 \n"
" beqzl %2, 1b \n"
" and %2, %0, %3 \n"
" .set mips0 \n"
: "=&r" (temp), "+m" (*m), "=&r" (res)
: "r" (1UL << bit)
: "memory");
} else if (kernel_uses_llsc) {
unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
unsigned long temp;
do {
__asm__ __volatile__(
" .set mips3 \n"
" " __LL "%0, %1 # test_and_change_bit \n"
" xor %2, %0, %3 \n"
" " __SC "\t%2, %1 \n"
" .set mips0 \n"
: "=&r" (temp), "+m" (*m), "=&r" (res)
: "r" (1UL << bit)
: "memory");
} while (unlikely(!res));
res = temp & (1UL << bit);
} else {
volatile unsigned long *a = addr;
unsigned long mask;
unsigned long flags;
a += nr >> SZLONG_LOG;
mask = 1UL << bit;
raw_local_irq_save(flags);
res = (mask & *a);
*a ^= mask;
raw_local_irq_restore(flags);
}
smp_llsc_mb();
return res != 0;
}
#include <asm-generic/bitops/non-atomic.h>
/*
* __clear_bit_unlock - Clears a bit in memory
* @nr: Bit to clear
* @addr: Address to start counting from
*
* __clear_bit() is non-atomic and implies release semantics before the memory
* operation. It can be used for an unlock if no other CPUs can concurrently
* modify other bits in the word.
*/
static inline void __clear_bit_unlock(unsigned long nr, volatile unsigned long *addr)
{
smp_mb();
__clear_bit(nr, addr);
}
/*
* Return the bit position (0..63) of the most significant 1 bit in a word
* Returns -1 if no 1 bit exists
*/
static inline unsigned long __fls(unsigned long word)
{
int num;
if (BITS_PER_LONG == 32 &&
__builtin_constant_p(cpu_has_clo_clz) && cpu_has_clo_clz) {
__asm__(
" .set push \n"
" .set mips32 \n"
" clz %0, %1 \n"
" .set pop \n"
: "=r" (num)
: "r" (word));
return 31 - num;
}
if (BITS_PER_LONG == 64 &&
__builtin_constant_p(cpu_has_mips64) && cpu_has_mips64) {
__asm__(
" .set push \n"
" .set mips64 \n"
" dclz %0, %1 \n"
" .set pop \n"
: "=r" (num)
: "r" (word));
return 63 - num;
}
num = BITS_PER_LONG - 1;
#if BITS_PER_LONG == 64
if (!(word & (~0ul << 32))) {
num -= 32;
word <<= 32;
}
#endif
if (!(word & (~0ul << (BITS_PER_LONG-16)))) {
num -= 16;
word <<= 16;
}
if (!(word & (~0ul << (BITS_PER_LONG-8)))) {
num -= 8;
word <<= 8;
}
if (!(word & (~0ul << (BITS_PER_LONG-4)))) {
num -= 4;
word <<= 4;
}
if (!(word & (~0ul << (BITS_PER_LONG-2)))) {
num -= 2;
word <<= 2;
}
if (!(word & (~0ul << (BITS_PER_LONG-1))))
num -= 1;
return num;
}
/*
* __ffs - find first bit in word.
* @word: The word to search
*
* Returns 0..SZLONG-1
* Undefined if no bit exists, so code should check against 0 first.
*/
static inline unsigned long __ffs(unsigned long word)
{
return __fls(word & -word);
}
/*
* fls - find last bit set.
* @word: The word to search
*
* This is defined the same way as ffs.
* Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
*/
static inline int fls(int x)
{
int r;
if (__builtin_constant_p(cpu_has_clo_clz) && cpu_has_clo_clz) {
__asm__("clz %0, %1" : "=r" (x) : "r" (x));
return 32 - x;
}
r = 32;
if (!x)
return 0;
if (!(x & 0xffff0000u)) {
x <<= 16;
r -= 16;
}
if (!(x & 0xff000000u)) {
x <<= 8;
r -= 8;
}
if (!(x & 0xf0000000u)) {
x <<= 4;
r -= 4;
}
if (!(x & 0xc0000000u)) {
x <<= 2;
r -= 2;
}
if (!(x & 0x80000000u)) {
x <<= 1;
r -= 1;
}
return r;
}
#include <asm-generic/bitops/fls64.h>
/*
* ffs - find first bit set.
* @word: The word to search
*
* This is defined the same way as
* the libc and compiler builtin ffs routines, therefore
* differs in spirit from the above ffz (man ffs).
*/
static inline int ffs(int word)
{
if (!word)
return 0;
return fls(word & -word);
}
#include <asm-generic/bitops/ffz.h>
#include <asm-generic/bitops/find.h>
#ifdef __KERNEL__
#include <asm-generic/bitops/sched.h>
#include <asm/arch_hweight.h>
#include <asm-generic/bitops/const_hweight.h>
#include <asm-generic/bitops/ext2-non-atomic.h>
#include <asm-generic/bitops/ext2-atomic.h>
#include <asm-generic/bitops/minix.h>
#endif /* __KERNEL__ */
#endif /* _ASM_BITOPS_H */
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