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