184 lines
5.4 KiB
C
184 lines
5.4 KiB
C
/*
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* Copyright 2010 Tilera Corporation. All Rights Reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation, version 2.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
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* NON INFRINGEMENT. See the GNU General Public License for
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* more details.
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*/
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#include <linux/cache.h>
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#include <linux/delay.h>
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#include <linux/uaccess.h>
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#include <linux/module.h>
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#include <linux/mm.h>
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#include <linux/atomic.h>
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#include <arch/chip.h>
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/* This page is remapped on startup to be hash-for-home. */
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int atomic_locks[PAGE_SIZE / sizeof(int)] __page_aligned_bss;
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int *__atomic_hashed_lock(volatile void *v)
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{
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/* NOTE: this code must match "sys_cmpxchg" in kernel/intvec_32.S */
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/*
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* Use bits [3, 3 + ATOMIC_HASH_SHIFT) as the lock index.
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* Using mm works here because atomic_locks is page aligned.
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*/
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unsigned long ptr = __insn_mm((unsigned long)v >> 1,
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(unsigned long)atomic_locks,
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2, (ATOMIC_HASH_SHIFT + 2) - 1);
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return (int *)ptr;
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}
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#ifdef CONFIG_SMP
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/* Return whether the passed pointer is a valid atomic lock pointer. */
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static int is_atomic_lock(int *p)
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{
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return p >= &atomic_locks[0] && p < &atomic_locks[ATOMIC_HASH_SIZE];
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}
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void __atomic_fault_unlock(int *irqlock_word)
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{
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BUG_ON(!is_atomic_lock(irqlock_word));
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BUG_ON(*irqlock_word != 1);
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*irqlock_word = 0;
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}
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#endif /* CONFIG_SMP */
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static inline int *__atomic_setup(volatile void *v)
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{
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/* Issue a load to the target to bring it into cache. */
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*(volatile int *)v;
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return __atomic_hashed_lock(v);
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}
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int _atomic_xchg(int *v, int n)
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{
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return __atomic_xchg(v, __atomic_setup(v), n).val;
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}
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EXPORT_SYMBOL(_atomic_xchg);
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int _atomic_xchg_add(int *v, int i)
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{
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return __atomic_xchg_add(v, __atomic_setup(v), i).val;
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}
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EXPORT_SYMBOL(_atomic_xchg_add);
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int _atomic_xchg_add_unless(int *v, int a, int u)
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{
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/*
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* Note: argument order is switched here since it is easier
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* to use the first argument consistently as the "old value"
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* in the assembly, as is done for _atomic_cmpxchg().
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*/
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return __atomic_xchg_add_unless(v, __atomic_setup(v), u, a).val;
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}
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EXPORT_SYMBOL(_atomic_xchg_add_unless);
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int _atomic_cmpxchg(int *v, int o, int n)
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{
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return __atomic_cmpxchg(v, __atomic_setup(v), o, n).val;
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}
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EXPORT_SYMBOL(_atomic_cmpxchg);
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unsigned long _atomic_or(volatile unsigned long *p, unsigned long mask)
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{
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return __atomic_or((int *)p, __atomic_setup(p), mask).val;
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}
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EXPORT_SYMBOL(_atomic_or);
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unsigned long _atomic_andn(volatile unsigned long *p, unsigned long mask)
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{
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return __atomic_andn((int *)p, __atomic_setup(p), mask).val;
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}
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EXPORT_SYMBOL(_atomic_andn);
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unsigned long _atomic_xor(volatile unsigned long *p, unsigned long mask)
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{
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return __atomic_xor((int *)p, __atomic_setup(p), mask).val;
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}
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EXPORT_SYMBOL(_atomic_xor);
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long long _atomic64_xchg(long long *v, long long n)
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{
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return __atomic64_xchg(v, __atomic_setup(v), n);
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}
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EXPORT_SYMBOL(_atomic64_xchg);
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long long _atomic64_xchg_add(long long *v, long long i)
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{
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return __atomic64_xchg_add(v, __atomic_setup(v), i);
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}
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EXPORT_SYMBOL(_atomic64_xchg_add);
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long long _atomic64_xchg_add_unless(long long *v, long long a, long long u)
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{
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/*
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* Note: argument order is switched here since it is easier
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* to use the first argument consistently as the "old value"
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* in the assembly, as is done for _atomic_cmpxchg().
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*/
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return __atomic64_xchg_add_unless(v, __atomic_setup(v), u, a);
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}
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EXPORT_SYMBOL(_atomic64_xchg_add_unless);
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long long _atomic64_cmpxchg(long long *v, long long o, long long n)
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{
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return __atomic64_cmpxchg(v, __atomic_setup(v), o, n);
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}
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EXPORT_SYMBOL(_atomic64_cmpxchg);
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/*
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* If any of the atomic or futex routines hit a bad address (not in
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* the page tables at kernel PL) this routine is called. The futex
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* routines are never used on kernel space, and the normal atomics and
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* bitops are never used on user space. So a fault on kernel space
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* must be fatal, but a fault on userspace is a futex fault and we
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* need to return -EFAULT. Note that the context this routine is
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* invoked in is the context of the "_atomic_xxx()" routines called
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* by the functions in this file.
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*/
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struct __get_user __atomic_bad_address(int __user *addr)
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{
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if (unlikely(!access_ok(VERIFY_WRITE, addr, sizeof(int))))
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panic("Bad address used for kernel atomic op: %p\n", addr);
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return (struct __get_user) { .err = -EFAULT };
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}
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void __init __init_atomic_per_cpu(void)
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{
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/* Validate power-of-two and "bigger than cpus" assumption */
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BUILD_BUG_ON(ATOMIC_HASH_SIZE & (ATOMIC_HASH_SIZE-1));
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BUG_ON(ATOMIC_HASH_SIZE < nr_cpu_ids);
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/*
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* On TILEPro we prefer to use a single hash-for-home
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* page, since this means atomic operations are less
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* likely to encounter a TLB fault and thus should
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* in general perform faster. You may wish to disable
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* this in situations where few hash-for-home tiles
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* are configured.
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*/
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BUG_ON((unsigned long)atomic_locks % PAGE_SIZE != 0);
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/* The locks must all fit on one page. */
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BUILD_BUG_ON(ATOMIC_HASH_SIZE * sizeof(int) > PAGE_SIZE);
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/*
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* We use the page offset of the atomic value's address as
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* an index into atomic_locks, excluding the low 3 bits.
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* That should not produce more indices than ATOMIC_HASH_SIZE.
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*/
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BUILD_BUG_ON((PAGE_SIZE >> 3) > ATOMIC_HASH_SIZE);
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}
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