diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arc/include/asm/atomic.h | 232 | ||||
| -rw-r--r-- | arch/arc/include/asm/barrier.h | 42 | ||||
| -rw-r--r-- | arch/arc/include/asm/bitops.h | 516 | ||||
| -rw-r--r-- | arch/arc/include/asm/cmpxchg.h | 143 | ||||
| -rw-r--r-- | arch/arc/include/asm/smp.h | 34 |
5 files changed, 967 insertions, 0 deletions
diff --git a/arch/arc/include/asm/atomic.h b/arch/arc/include/asm/atomic.h new file mode 100644 index 0000000..83f03ca --- /dev/null +++ b/arch/arc/include/asm/atomic.h @@ -0,0 +1,232 @@ +/* + * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#ifndef _ASM_ARC_ATOMIC_H +#define _ASM_ARC_ATOMIC_H + +#ifdef __KERNEL__ + +#ifndef __ASSEMBLY__ + +#include <linux/types.h> +#include <linux/compiler.h> +#include <asm/cmpxchg.h> +#include <asm/barrier.h> +#include <asm/smp.h> + +#define atomic_read(v) ((v)->counter) + +#ifdef CONFIG_ARC_HAS_LLSC + +#define atomic_set(v, i) (((v)->counter) = (i)) + +static inline void atomic_add(int i, atomic_t *v) +{ + unsigned int temp; + + __asm__ __volatile__( + "1: llock %0, [%1] \n" + " add %0, %0, %2 \n" + " scond %0, [%1] \n" + " bnz 1b \n" + : "=&r"(temp) /* Early clobber, to prevent reg reuse */ + : "r"(&v->counter), "ir"(i) + : "cc"); +} + +static inline void atomic_sub(int i, atomic_t *v) +{ + unsigned int temp; + + __asm__ __volatile__( + "1: llock %0, [%1] \n" + " sub %0, %0, %2 \n" + " scond %0, [%1] \n" + " bnz 1b \n" + : "=&r"(temp) + : "r"(&v->counter), "ir"(i) + : "cc"); +} + +/* add and also return the new value */ +static inline int atomic_add_return(int i, atomic_t *v) +{ + unsigned int temp; + + __asm__ __volatile__( + "1: llock %0, [%1] \n" + " add %0, %0, %2 \n" + " scond %0, [%1] \n" + " bnz 1b \n" + : "=&r"(temp) + : "r"(&v->counter), "ir"(i) + : "cc"); + + return temp; +} + +static inline int atomic_sub_return(int i, atomic_t *v) +{ + unsigned int temp; + + __asm__ __volatile__( + "1: llock %0, [%1] \n" + " sub %0, %0, %2 \n" + " scond %0, [%1] \n" + " bnz 1b \n" + : "=&r"(temp) + : "r"(&v->counter), "ir"(i) + : "cc"); + + return temp; +} + +static inline void atomic_clear_mask(unsigned long mask, unsigned long *addr) +{ + unsigned int temp; + + __asm__ __volatile__( + "1: llock %0, [%1] \n" + " bic %0, %0, %2 \n" + " scond %0, [%1] \n" + " bnz 1b \n" + : "=&r"(temp) + : "r"(addr), "ir"(mask) + : "cc"); +} + +#else /* !CONFIG_ARC_HAS_LLSC */ + +#ifndef CONFIG_SMP + + /* violating atomic_xxx API locking protocol in UP for optimization sake */ +#define atomic_set(v, i) (((v)->counter) = (i)) + +#else + +static inline void atomic_set(atomic_t *v, int i) +{ + /* + * Independent of hardware support, all of the atomic_xxx() APIs need + * to follow the same locking rules to make sure that a "hardware" + * atomic insn (e.g. LD) doesn't clobber an "emulated" atomic insn + * sequence + * + * Thus atomic_set() despite being 1 insn (and seemingly atomic) + * requires the locking. + */ + unsigned long flags; + + atomic_ops_lock(flags); + v->counter = i; + atomic_ops_unlock(flags); +} +#endif + +/* + * Non hardware assisted Atomic-R-M-W + * Locking would change to irq-disabling only (UP) and spinlocks (SMP) + */ + +static inline void atomic_add(int i, atomic_t *v) +{ + unsigned long flags; + + atomic_ops_lock(flags); + v->counter += i; + atomic_ops_unlock(flags); +} + +static inline void atomic_sub(int i, atomic_t *v) +{ + unsigned long flags; + + atomic_ops_lock(flags); + v->counter -= i; + atomic_ops_unlock(flags); +} + +static inline int atomic_add_return(int i, atomic_t *v) +{ + unsigned long flags; + unsigned long temp; + + atomic_ops_lock(flags); + temp = v->counter; + temp += i; + v->counter = temp; + atomic_ops_unlock(flags); + + return temp; +} + +static inline int atomic_sub_return(int i, atomic_t *v) +{ + unsigned long flags; + unsigned long temp; + + atomic_ops_lock(flags); + temp = v->counter; + temp -= i; + v->counter = temp; + atomic_ops_unlock(flags); + + return temp; +} + +static inline void atomic_clear_mask(unsigned long mask, unsigned long *addr) +{ + unsigned long flags; + + atomic_ops_lock(flags); + *addr &= ~mask; + atomic_ops_unlock(flags); +} + +#endif /* !CONFIG_ARC_HAS_LLSC */ + +/** + * __atomic_add_unless - add unless the number is a given value + * @v: pointer of type atomic_t + * @a: the amount to add to v... + * @u: ...unless v is equal to u. + * + * Atomically adds @a to @v, so long as it was not @u. + * Returns the old value of @v + */ +#define __atomic_add_unless(v, a, u) \ +({ \ + int c, old; \ + c = atomic_read(v); \ + while (c != (u) && (old = atomic_cmpxchg((v), c, c + (a))) != c)\ + c = old; \ + c; \ +}) + +#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0) + +#define atomic_inc(v) atomic_add(1, v) +#define atomic_dec(v) atomic_sub(1, v) + +#define atomic_inc_and_test(v) (atomic_add_return(1, v) == 0) +#define atomic_dec_and_test(v) (atomic_sub_return(1, v) == 0) +#define atomic_inc_return(v) atomic_add_return(1, (v)) +#define atomic_dec_return(v) atomic_sub_return(1, (v)) +#define atomic_sub_and_test(i, v) (atomic_sub_return(i, v) == 0) + +#define atomic_add_negative(i, v) (atomic_add_return(i, v) < 0) + +#define ATOMIC_INIT(i) { (i) } + +#include <asm-generic/atomic64.h> + +#endif + +#endif + +#endif diff --git a/arch/arc/include/asm/barrier.h b/arch/arc/include/asm/barrier.h new file mode 100644 index 0000000..f6cb7c4 --- /dev/null +++ b/arch/arc/include/asm/barrier.h @@ -0,0 +1,42 @@ +/* + * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#ifndef __ASM_BARRIER_H +#define __ASM_BARRIER_H + +#ifndef __ASSEMBLY__ + +/* TODO-vineetg: Need to see what this does, don't we need sync anywhere */ +#define mb() __asm__ __volatile__ ("" : : : "memory") +#define rmb() mb() +#define wmb() mb() +#define set_mb(var, value) do { var = value; mb(); } while (0) +#define set_wmb(var, value) do { var = value; wmb(); } while (0) +#define read_barrier_depends() mb() + +/* TODO-vineetg verify the correctness of macros here */ +#ifdef CONFIG_SMP +#define smp_mb() mb() +#define smp_rmb() rmb() +#define smp_wmb() wmb() +#else +#define smp_mb() barrier() +#define smp_rmb() barrier() +#define smp_wmb() barrier() +#endif + +#define smp_mb__before_atomic_dec() barrier() +#define smp_mb__after_atomic_dec() barrier() +#define smp_mb__before_atomic_inc() barrier() +#define smp_mb__after_atomic_inc() barrier() + +#define smp_read_barrier_depends() do { } while (0) + +#endif + +#endif diff --git a/arch/arc/include/asm/bitops.h b/arch/arc/include/asm/bitops.h new file mode 100644 index 0000000..647a83a --- /dev/null +++ b/arch/arc/include/asm/bitops.h @@ -0,0 +1,516 @@ +/* + * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#ifndef _ASM_BITOPS_H +#define _ASM_BITOPS_H + +#ifndef _LINUX_BITOPS_H +#error only <linux/bitops.h> can be included directly +#endif + +#ifdef __KERNEL__ + +#ifndef __ASSEMBLY__ + +#include <linux/types.h> +#include <linux/compiler.h> + +/* + * Hardware assisted read-modify-write using ARC700 LLOCK/SCOND insns. + * The Kconfig glue ensures that in SMP, this is only set if the container + * SoC/platform has cross-core coherent LLOCK/SCOND + */ +#if defined(CONFIG_ARC_HAS_LLSC) + +static inline void set_bit(unsigned long nr, volatile unsigned long *m) +{ + unsigned int temp; + + m += nr >> 5; + + if (__builtin_constant_p(nr)) + nr &= 0x1f; + + __asm__ __volatile__( + "1: llock %0, [%1] \n" + " bset %0, %0, %2 \n" + " scond %0, [%1] \n" + " bnz 1b \n" + : "=&r"(temp) + : "r"(m), "ir"(nr) + : "cc"); +} + +static inline void clear_bit(unsigned long nr, volatile unsigned long *m) +{ + unsigned int temp; + + m += nr >> 5; + + if (__builtin_constant_p(nr)) + nr &= 0x1f; + + __asm__ __volatile__( + "1: llock %0, [%1] \n" + " bclr %0, %0, %2 \n" + " scond %0, [%1] \n" + " bnz 1b \n" + : "=&r"(temp) + : "r"(m), "ir"(nr) + : "cc"); +} + +static inline void change_bit(unsigned long nr, volatile unsigned long *m) +{ + unsigned int temp; + + m += nr >> 5; + + if (__builtin_constant_p(nr)) + nr &= 0x1f; + + __asm__ __volatile__( + "1: llock %0, [%1] \n" + " bxor %0, %0, %2 \n" + " scond %0, [%1] \n" + " bnz 1b \n" + : "=&r"(temp) + : "r"(m), "ir"(nr) + : "cc"); +} + +/* + * Semantically: + * Test the bit + * if clear + * set it and return 0 (old value) + * else + * return 1 (old value). + * + * Since ARC lacks a equivalent h/w primitive, the bit is set unconditionally + * and the old value of bit is returned + */ +static inline int test_and_set_bit(unsigned long nr, volatile unsigned long *m) +{ + unsigned long old, temp; + + m += nr >> 5; + + if (__builtin_constant_p(nr)) + nr &= 0x1f; + + __asm__ __volatile__( + "1: llock %0, [%2] \n" + " bset %1, %0, %3 \n" + " scond %1, [%2] \n" + " bnz 1b \n" + : "=&r"(old), "=&r"(temp) + : "r"(m), "ir"(nr) + : "cc"); + + return (old & (1 << nr)) != 0; +} + +static inline int +test_and_clear_bit(unsigned long nr, volatile unsigned long *m) +{ + unsigned int old, temp; + + m += nr >> 5; + + if (__builtin_constant_p(nr)) + nr &= 0x1f; + + __asm__ __volatile__( + "1: llock %0, [%2] \n" + " bclr %1, %0, %3 \n" + " scond %1, [%2] \n" + " bnz 1b \n" + : "=&r"(old), "=&r"(temp) + : "r"(m), "ir"(nr) + : "cc"); + + return (old & (1 << nr)) != 0; +} + +static inline int +test_and_change_bit(unsigned long nr, volatile unsigned long *m) +{ + unsigned int old, temp; + + m += nr >> 5; + + if (__builtin_constant_p(nr)) + nr &= 0x1f; + + __asm__ __volatile__( + "1: llock %0, [%2] \n" + " bxor %1, %0, %3 \n" + " scond %1, [%2] \n" + " bnz 1b \n" + : "=&r"(old), "=&r"(temp) + : "r"(m), "ir"(nr) + : "cc"); + + return (old & (1 << nr)) != 0; +} + +#else /* !CONFIG_ARC_HAS_LLSC */ + +#include <asm/smp.h> + +/* + * Non hardware assisted Atomic-R-M-W + * Locking would change to irq-disabling only (UP) and spinlocks (SMP) + * + * There's "significant" micro-optimization in writing our own variants of + * bitops (over generic variants) + * + * (1) The generic APIs have "signed" @nr while we have it "unsigned" + * This avoids extra code to be generated for pointer arithmatic, since + * is "not sure" that index is NOT -ve + * (2) Utilize the fact that ARCompact bit fidding insn (BSET/BCLR/ASL) etc + * only consider bottom 5 bits of @nr, so NO need to mask them off. + * (GCC Quirk: however for constant @nr we still need to do the masking + * at compile time) + */ + +static inline void set_bit(unsigned long nr, volatile unsigned long *m) +{ + unsigned long temp, flags; + m += nr >> 5; + + if (__builtin_constant_p(nr)) + nr &= 0x1f; + + bitops_lock(flags); + + temp = *m; + *m = temp | (1UL << nr); + + bitops_unlock(flags); +} + +static inline void clear_bit(unsigned long nr, volatile unsigned long *m) +{ + unsigned long temp, flags; + m += nr >> 5; + + if (__builtin_constant_p(nr)) + nr &= 0x1f; + + bitops_lock(flags); + + temp = *m; + *m = temp & ~(1UL << nr); + + bitops_unlock(flags); +} + +static inline void change_bit(unsigned long nr, volatile unsigned long *m) +{ + unsigned long temp, flags; + m += nr >> 5; + + if (__builtin_constant_p(nr)) + nr &= 0x1f; + + bitops_lock(flags); + + temp = *m; + *m = temp ^ (1UL << nr); + + bitops_unlock(flags); +} + +static inline int test_and_set_bit(unsigned long nr, volatile unsigned long *m) +{ + unsigned long old, flags; + m += nr >> 5; + + if (__builtin_constant_p(nr)) + nr &= 0x1f; + + bitops_lock(flags); + + old = *m; + *m = old | (1 << nr); + + bitops_unlock(flags); + + return (old & (1 << nr)) != 0; +} + +static inline int +test_and_clear_bit(unsigned long nr, volatile unsigned long *m) +{ + unsigned long old, flags; + m += nr >> 5; + + if (__builtin_constant_p(nr)) + nr &= 0x1f; + + bitops_lock(flags); + + old = *m; + *m = old & ~(1 << nr); + + bitops_unlock(flags); + + return (old & (1 << nr)) != 0; +} + +static inline int +test_and_change_bit(unsigned long nr, volatile unsigned long *m) +{ + unsigned long old, flags; + m += nr >> 5; + + if (__builtin_constant_p(nr)) + nr &= 0x1f; + + bitops_lock(flags); + + old = *m; + *m = old ^ (1 << nr); + + bitops_unlock(flags); + + return (old & (1 << nr)) != 0; +} + +#endif /* CONFIG_ARC_HAS_LLSC */ + +/*************************************** + * Non atomic variants + **************************************/ + +static inline void __set_bit(unsigned long nr, volatile unsigned long *m) +{ + unsigned long temp; + m += nr >> 5; + + if (__builtin_constant_p(nr)) + nr &= 0x1f; + + temp = *m; + *m = temp | (1UL << nr); +} + +static inline void __clear_bit(unsigned long nr, volatile unsigned long *m) +{ + unsigned long temp; + m += nr >> 5; + + if (__builtin_constant_p(nr)) + nr &= 0x1f; + + temp = *m; + *m = temp & ~(1UL << nr); +} + +static inline void __change_bit(unsigned long nr, volatile unsigned long *m) +{ + unsigned long temp; + m += nr >> 5; + + if (__builtin_constant_p(nr)) + nr &= 0x1f; + + temp = *m; + *m = temp ^ (1UL << nr); +} + +static inline int +__test_and_set_bit(unsigned long nr, volatile unsigned long *m) +{ + unsigned long old; + m += nr >> 5; + + if (__builtin_constant_p(nr)) + nr &= 0x1f; + + old = *m; + *m = old | (1 << nr); + + return (old & (1 << nr)) != 0; +} + +static inline int +__test_and_clear_bit(unsigned long nr, volatile unsigned long *m) +{ + unsigned long old; + m += nr >> 5; + + if (__builtin_constant_p(nr)) + nr &= 0x1f; + + old = *m; + *m = old & ~(1 << nr); + + return (old & (1 << nr)) != 0; +} + +static inline int +__test_and_change_bit(unsigned long nr, volatile unsigned long *m) +{ + unsigned long old; + m += nr >> 5; + + if (__builtin_constant_p(nr)) + nr &= 0x1f; + + old = *m; + *m = old ^ (1 << nr); + + return (old & (1 << nr)) != 0; +} + +/* + * This routine doesn't need to be atomic. + */ +static inline int +__constant_test_bit(unsigned int nr, const volatile unsigned long *addr) +{ + return ((1UL << (nr & 31)) & + (((const volatile unsigned int *)addr)[nr >> 5])) != 0; +} + +static inline int +__test_bit(unsigned int nr, const volatile unsigned long *addr) +{ + unsigned long mask; + + addr += nr >> 5; + + /* ARC700 only considers 5 bits in bit-fiddling insn */ + mask = 1 << nr; + + return ((mask & *addr) != 0); +} + +#define test_bit(nr, addr) (__builtin_constant_p(nr) ? \ + __constant_test_bit((nr), (addr)) : \ + __test_bit((nr), (addr))) + +/* + * Count the number of zeros, starting from MSB + * Helper for fls( ) friends + * This is a pure count, so (1-32) or (0-31) doesn't apply + * It could be 0 to 32, based on num of 0's in there + * clz(0x8000_0000) = 0, clz(0xFFFF_FFFF)=0, clz(0) = 32, clz(1) = 31 + */ +static inline __attribute__ ((const)) int clz(unsigned int x) +{ + unsigned int res; + + __asm__ __volatile__( + " norm.f %0, %1 \n" + " mov.n %0, 0 \n" + " add.p %0, %0, 1 \n" + : "=r"(res) + : "r"(x) + : "cc"); + + return res; +} + +static inline int constant_fls(int x) +{ + int 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; +} + +/* + * fls = Find Last Set in word + * @result: [1-32] + * fls(1) = 1, fls(0x80000000) = 32, fls(0) = 0 + */ +static inline __attribute__ ((const)) int fls(unsigned long x) +{ + if (__builtin_constant_p(x)) + return constant_fls(x); + + return 32 - clz(x); +} + +/* + * __fls: Similar to fls, but zero based (0-31) + */ +static inline __attribute__ ((const)) int __fls(unsigned long x) +{ + if (!x) + return 0; + else + return fls(x) - 1; +} + +/* + * ffs = Find First Set in word (LSB to MSB) + * @result: [1-32], 0 if all 0's + */ +#define ffs(x) ({ unsigned long __t = (x); fls(__t & -__t); }) + +/* + * __ffs: Similar to ffs, but zero based (0-31) + */ +static inline __attribute__ ((const)) int __ffs(unsigned long word) +{ + if (!word) + return word; + + return ffs(word) - 1; +} + +/* + * ffz = Find First Zero in word. + * @return:[0-31], 32 if all 1's + */ +#define ffz(x) __ffs(~(x)) + +/* TODO does this affect uni-processor code */ +#define smp_mb__before_clear_bit() barrier() +#define smp_mb__after_clear_bit() barrier() + +#include <asm-generic/bitops/hweight.h> +#include <asm-generic/bitops/fls64.h> +#include <asm-generic/bitops/sched.h> +#include <asm-generic/bitops/lock.h> + +#include <asm-generic/bitops/find.h> +#include <asm-generic/bitops/le.h> +#include <asm-generic/bitops/ext2-atomic-setbit.h> + +#endif /* !__ASSEMBLY__ */ + +#endif /* __KERNEL__ */ + +#endif diff --git a/arch/arc/include/asm/cmpxchg.h b/arch/arc/include/asm/cmpxchg.h new file mode 100644 index 0000000..03cd689 --- /dev/null +++ b/arch/arc/include/asm/cmpxchg.h @@ -0,0 +1,143 @@ +/* + * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#ifndef __ASM_ARC_CMPXCHG_H +#define __ASM_ARC_CMPXCHG_H + +#include <linux/types.h> +#include <asm/smp.h> + +#ifdef CONFIG_ARC_HAS_LLSC + +static inline unsigned long +__cmpxchg(volatile void *ptr, unsigned long expected, unsigned long new) +{ + unsigned long prev; + + __asm__ __volatile__( + "1: llock %0, [%1] \n" + " brne %0, %2, 2f \n" + " scond %3, [%1] \n" + " bnz 1b \n" + "2: \n" + : "=&r"(prev) + : "r"(ptr), "ir"(expected), + "r"(new) /* can't be "ir". scond can't take limm for "b" */ + : "cc"); + + return prev; +} + +#else + +static inline unsigned long +__cmpxchg(volatile void *ptr, unsigned long expected, unsigned long new) +{ + unsigned long flags; + int prev; + volatile unsigned long *p = ptr; + + atomic_ops_lock(flags); + prev = *p; + if (prev == expected) + *p = new; + atomic_ops_unlock(flags); + return prev; +} + +#endif /* CONFIG_ARC_HAS_LLSC */ + +#define cmpxchg(ptr, o, n) ((typeof(*(ptr)))__cmpxchg((ptr), \ + (unsigned long)(o), (unsigned long)(n))) + +/* + * Since not supported natively, ARC cmpxchg() uses atomic_ops_lock (UP/SMP) + * just to gaurantee semantics. + * atomic_cmpxchg() needs to use the same locks as it's other atomic siblings + * which also happens to be atomic_ops_lock. + * + * Thus despite semantically being different, implementation of atomic_cmpxchg() + * is same as cmpxchg(). + */ +#define atomic_cmpxchg(v, o, n) ((int)cmpxchg(&((v)->counter), (o), (n))) + + +/* + * xchg (reg with memory) based on "Native atomic" EX insn + */ +static inline unsigned long __xchg(unsigned long val, volatile void *ptr, + int size) +{ + extern unsigned long __xchg_bad_pointer(void); + + switch (size) { + case 4: + __asm__ __volatile__( + " ex %0, [%1] \n" + : "+r"(val) + : "r"(ptr) + : "memory"); + + return val; + } + return __xchg_bad_pointer(); +} + +#define _xchg(ptr, with) ((typeof(*(ptr)))__xchg((unsigned long)(with), (ptr), \ + sizeof(*(ptr)))) + +/* + * On ARC700, EX insn is inherently atomic, so by default "vanilla" xchg() need + * not require any locking. However there's a quirk. + * ARC lacks native CMPXCHG, thus emulated (see above), using external locking - + * incidently it "reuses" the same atomic_ops_lock used by atomic APIs. + * Now, llist code uses cmpxchg() and xchg() on same data, so xchg() needs to + * abide by same serializing rules, thus ends up using atomic_ops_lock as well. + * + * This however is only relevant if SMP and/or ARC lacks LLSC + * if (UP or LLSC) + * xchg doesn't need serialization + * else <==> !(UP or LLSC) <==> (!UP and !LLSC) <==> (SMP and !LLSC) + * xchg needs serialization + */ + +#if !defined(CONFIG_ARC_HAS_LLSC) && defined(CONFIG_SMP) + +#define xchg(ptr, with) \ +({ \ + unsigned long flags; \ + typeof(*(ptr)) old_val; \ + \ + atomic_ops_lock(flags); \ + old_val = _xchg(ptr, with); \ + atomic_ops_unlock(flags); \ + old_val; \ +}) + +#else + +#define xchg(ptr, with) _xchg(ptr, with) + +#endif + +/* + * "atomic" variant of xchg() + * REQ: It needs to follow the same serialization rules as other atomic_xxx() + * Since xchg() doesn't always do that, it would seem that following defintion + * is incorrect. But here's the rationale: + * SMP : Even xchg() takes the atomic_ops_lock, so OK. + * LLSC: atomic_ops_lock are not relevent at all (even if SMP, since LLSC + * is natively "SMP safe", no serialization required). + * UP : other atomics disable IRQ, so no way a difft ctxt atomic_xchg() + * could clobber them. atomic_xchg() itself would be 1 insn, so it + * can't be clobbered by others. Thus no serialization required when + * atomic_xchg is involved. + */ +#define atomic_xchg(v, new) (xchg(&((v)->counter), new)) + +#endif diff --git a/arch/arc/include/asm/smp.h b/arch/arc/include/asm/smp.h new file mode 100644 index 0000000..4341f3b --- /dev/null +++ b/arch/arc/include/asm/smp.h @@ -0,0 +1,34 @@ +/* + * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#ifndef __ASM_ARC_SMP_H +#define __ASM_ARC_SMP_H + +/* + * ARC700 doesn't support atomic Read-Modify-Write ops. + * Originally Interrupts had to be disabled around code to gaurantee atomicity. + * The LLOCK/SCOND insns allow writing interrupt-hassle-free based atomic ops + * based on retry-if-irq-in-atomic (with hardware assist). + * However despite these, we provide the IRQ disabling variant + * + * (1) These insn were introduced only in 4.10 release. So for older released + * support needed. + */ +#ifndef CONFIG_ARC_HAS_LLSC + +#include <linux/irqflags.h> + +#define atomic_ops_lock(flags) local_irq_save(flags) +#define atomic_ops_unlock(flags) local_irq_restore(flags) + +#define bitops_lock(flags) local_irq_save(flags) +#define bitops_unlock(flags) local_irq_restore(flags) + +#endif /* !CONFIG_ARC_HAS_LLSC */ + +#endif |