Revision 05d43ed8a89c159ff641d472f970e3f1baa66318 authored by H. Peter Anvin on 29 January 2010, 06:14:43 UTC, committed by Linus Torvalds on 29 January 2010, 16:22:01 UTC
Now that the previous commit made it possible to do the personality setting at the point of no return, we do just that for ELF binaries. And suddenly all the reasons for that insane TIF_ABI_PENDING bit go away, and we can just make SET_PERSONALITY() just do the obvious thing for a 32-bit compat process. Everything becomes much more straightforward this way. Signed-off-by: H. Peter Anvin <hpa@zytor.com> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 221af7f
atomic64.c
/*
* Generic implementation of 64-bit atomics using spinlocks,
* useful on processors that don't have 64-bit atomic instructions.
*
* Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/types.h>
#include <linux/cache.h>
#include <linux/spinlock.h>
#include <linux/init.h>
#include <linux/module.h>
#include <asm/atomic.h>
/*
* We use a hashed array of spinlocks to provide exclusive access
* to each atomic64_t variable. Since this is expected to used on
* systems with small numbers of CPUs (<= 4 or so), we use a
* relatively small array of 16 spinlocks to avoid wasting too much
* memory on the spinlock array.
*/
#define NR_LOCKS 16
/*
* Ensure each lock is in a separate cacheline.
*/
static union {
spinlock_t lock;
char pad[L1_CACHE_BYTES];
} atomic64_lock[NR_LOCKS] __cacheline_aligned_in_smp;
static inline spinlock_t *lock_addr(const atomic64_t *v)
{
unsigned long addr = (unsigned long) v;
addr >>= L1_CACHE_SHIFT;
addr ^= (addr >> 8) ^ (addr >> 16);
return &atomic64_lock[addr & (NR_LOCKS - 1)].lock;
}
long long atomic64_read(const atomic64_t *v)
{
unsigned long flags;
spinlock_t *lock = lock_addr(v);
long long val;
spin_lock_irqsave(lock, flags);
val = v->counter;
spin_unlock_irqrestore(lock, flags);
return val;
}
EXPORT_SYMBOL(atomic64_read);
void atomic64_set(atomic64_t *v, long long i)
{
unsigned long flags;
spinlock_t *lock = lock_addr(v);
spin_lock_irqsave(lock, flags);
v->counter = i;
spin_unlock_irqrestore(lock, flags);
}
EXPORT_SYMBOL(atomic64_set);
void atomic64_add(long long a, atomic64_t *v)
{
unsigned long flags;
spinlock_t *lock = lock_addr(v);
spin_lock_irqsave(lock, flags);
v->counter += a;
spin_unlock_irqrestore(lock, flags);
}
EXPORT_SYMBOL(atomic64_add);
long long atomic64_add_return(long long a, atomic64_t *v)
{
unsigned long flags;
spinlock_t *lock = lock_addr(v);
long long val;
spin_lock_irqsave(lock, flags);
val = v->counter += a;
spin_unlock_irqrestore(lock, flags);
return val;
}
EXPORT_SYMBOL(atomic64_add_return);
void atomic64_sub(long long a, atomic64_t *v)
{
unsigned long flags;
spinlock_t *lock = lock_addr(v);
spin_lock_irqsave(lock, flags);
v->counter -= a;
spin_unlock_irqrestore(lock, flags);
}
EXPORT_SYMBOL(atomic64_sub);
long long atomic64_sub_return(long long a, atomic64_t *v)
{
unsigned long flags;
spinlock_t *lock = lock_addr(v);
long long val;
spin_lock_irqsave(lock, flags);
val = v->counter -= a;
spin_unlock_irqrestore(lock, flags);
return val;
}
EXPORT_SYMBOL(atomic64_sub_return);
long long atomic64_dec_if_positive(atomic64_t *v)
{
unsigned long flags;
spinlock_t *lock = lock_addr(v);
long long val;
spin_lock_irqsave(lock, flags);
val = v->counter - 1;
if (val >= 0)
v->counter = val;
spin_unlock_irqrestore(lock, flags);
return val;
}
EXPORT_SYMBOL(atomic64_dec_if_positive);
long long atomic64_cmpxchg(atomic64_t *v, long long o, long long n)
{
unsigned long flags;
spinlock_t *lock = lock_addr(v);
long long val;
spin_lock_irqsave(lock, flags);
val = v->counter;
if (val == o)
v->counter = n;
spin_unlock_irqrestore(lock, flags);
return val;
}
EXPORT_SYMBOL(atomic64_cmpxchg);
long long atomic64_xchg(atomic64_t *v, long long new)
{
unsigned long flags;
spinlock_t *lock = lock_addr(v);
long long val;
spin_lock_irqsave(lock, flags);
val = v->counter;
v->counter = new;
spin_unlock_irqrestore(lock, flags);
return val;
}
EXPORT_SYMBOL(atomic64_xchg);
int atomic64_add_unless(atomic64_t *v, long long a, long long u)
{
unsigned long flags;
spinlock_t *lock = lock_addr(v);
int ret = 1;
spin_lock_irqsave(lock, flags);
if (v->counter != u) {
v->counter += a;
ret = 0;
}
spin_unlock_irqrestore(lock, flags);
return ret;
}
EXPORT_SYMBOL(atomic64_add_unless);
static int init_atomic64_lock(void)
{
int i;
for (i = 0; i < NR_LOCKS; ++i)
spin_lock_init(&atomic64_lock[i].lock);
return 0;
}
pure_initcall(init_atomic64_lock);
![swh spinner](/static/img/swh-spinner.gif)
Computing file changes ...