1 files changed, 330 insertions, 0 deletions
diff --git a/arch/tile/lib/atomic_32.c b/arch/tile/lib/atomic_32.c
new file mode 100644
index 00000000000..8040b42a8ee
--- /dev/null
+++ b/arch/tile/lib/atomic_32.c
@@ -0,0 +1,330 @@
+/*
+ * 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 <asm/atomic.h>
+#include <asm/futex.h>
+#include <arch/chip.h>
+
+/* See <asm/atomic_32.h> */
+#if ATOMIC_LOCKS_FOUND_VIA_TABLE()
+
+/*
+ * A block of memory containing locks for atomic ops. Each instance of this
+ * struct will be homed on a different CPU.
+ */
+struct atomic_locks_on_cpu {
+	int lock[ATOMIC_HASH_L2_SIZE];
+} __attribute__((aligned(ATOMIC_HASH_L2_SIZE * 4)));
+
+static DEFINE_PER_CPU(struct atomic_locks_on_cpu, atomic_lock_pool);
+
+/* The locks we'll use until __init_atomic_per_cpu is called. */
+static struct atomic_locks_on_cpu __initdata initial_atomic_locks;
+
+/* Hash into this vector to get a pointer to lock for the given atomic. */
+struct atomic_locks_on_cpu *atomic_lock_ptr[ATOMIC_HASH_L1_SIZE]
+	__write_once = {
+	[0 ... ATOMIC_HASH_L1_SIZE-1] (&initial_atomic_locks)
+};
+
+#else /* ATOMIC_LOCKS_FOUND_VIA_TABLE() */
+
+/* This page is remapped on startup to be hash-for-home. */
+int atomic_locks[PAGE_SIZE / sizeof(int) /* Only ATOMIC_HASH_SIZE is used */]
+  __attribute__((aligned(PAGE_SIZE), section(".bss.page_aligned")));
+
+#endif /* ATOMIC_LOCKS_FOUND_VIA_TABLE() */
+
+static inline int *__atomic_hashed_lock(volatile void *v)
+{
+	/* NOTE: this code must match "sys_cmpxchg" in kernel/intvec.S */
+#if ATOMIC_LOCKS_FOUND_VIA_TABLE()
+	unsigned long i =
+		(unsigned long) v & ((PAGE_SIZE-1) & -sizeof(long long));
+	unsigned long n = __insn_crc32_32(0, i);
+
+	/* Grab high bits for L1 index. */
+	unsigned long l1_index = n >> ((sizeof(n) * 8) - ATOMIC_HASH_L1_SHIFT);
+	/* Grab low bits for L2 index. */
+	unsigned long l2_index = n & (ATOMIC_HASH_L2_SIZE - 1);
+
+	return &atomic_lock_ptr[l1_index]->lock[l2_index];
+#else
+	/*
+	 * 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;
+#endif
+}
+
+#ifdef CONFIG_SMP
+/* Return whether the passed pointer is a valid atomic lock pointer. */
+static int is_atomic_lock(int *p)
+{
+#if ATOMIC_LOCKS_FOUND_VIA_TABLE()
+	int i;
+	for (i = 0; i < ATOMIC_HASH_L1_SIZE; ++i) {
+
+		if (p >= &atomic_lock_ptr[i]->lock[0] &&
+		    p < &atomic_lock_ptr[i]->lock[ATOMIC_HASH_L2_SIZE]) {
+			return 1;
+		}
+	}
+	return 0;
+#else
+	return p >= &atomic_locks[0] && p < &atomic_locks[ATOMIC_HASH_SIZE];
+#endif
+}
+
+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(atomic_t *v, int n)
+{
+	return __atomic_xchg(&v->counter, __atomic_setup(v), n).val;
+}
+EXPORT_SYMBOL(_atomic_xchg);
+
+int _atomic_xchg_add(atomic_t *v, int i)
+{
+	return __atomic_xchg_add(&v->counter, __atomic_setup(v), i).val;
+}
+EXPORT_SYMBOL(_atomic_xchg_add);
+
+int _atomic_xchg_add_unless(atomic_t *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->counter, __atomic_setup(v), u, a)
+		.val;
+}
+EXPORT_SYMBOL(_atomic_xchg_add_unless);
+
+int _atomic_cmpxchg(atomic_t *v, int o, int n)
+{
+	return __atomic_cmpxchg(&v->counter, __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);
+
+
+u64 _atomic64_xchg(atomic64_t *v, u64 n)
+{
+	return __atomic64_xchg(&v->counter, __atomic_setup(v), n);
+}
+EXPORT_SYMBOL(_atomic64_xchg);
+
+u64 _atomic64_xchg_add(atomic64_t *v, u64 i)
+{
+	return __atomic64_xchg_add(&v->counter, __atomic_setup(v), i);
+}
+EXPORT_SYMBOL(_atomic64_xchg_add);
+
+u64 _atomic64_xchg_add_unless(atomic64_t *v, u64 a, u64 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->counter, __atomic_setup(v),
+					  u, a);
+}
+EXPORT_SYMBOL(_atomic64_xchg_add_unless);
+
+u64 _atomic64_cmpxchg(atomic64_t *v, u64 o, u64 n)
+{
+	return __atomic64_cmpxchg(&v->counter, __atomic_setup(v), o, n);
+}
+EXPORT_SYMBOL(_atomic64_cmpxchg);
+
+
+static inline int *__futex_setup(int __user *v)
+{
+	/*
+	 * Issue a prefetch to the counter to bring it into cache.
+	 * As for __atomic_setup, but we can't do a read into the L1
+	 * since it might fault; instead we do a prefetch into the L2.
+	 */
+	__insn_prefetch(v);
+	return __atomic_hashed_lock((int __force *)v);
+}
+
+struct __get_user futex_set(int __user *v, int i)
+{
+	return __atomic_xchg((int __force *)v, __futex_setup(v), i);
+}
+
+struct __get_user futex_add(int __user *v, int n)
+{
+	return __atomic_xchg_add((int __force *)v, __futex_setup(v), n);
+}
+
+struct __get_user futex_or(int __user *v, int n)
+{
+	return __atomic_or((int __force *)v, __futex_setup(v), n);
+}
+
+struct __get_user futex_andn(int __user *v, int n)
+{
+	return __atomic_andn((int __force *)v, __futex_setup(v), n);
+}
+
+struct __get_user futex_xor(int __user *v, int n)
+{
+	return __atomic_xor((int __force *)v, __futex_setup(v), n);
+}
+
+struct __get_user futex_cmpxchg(int __user *v, int o, int n)
+{
+	return __atomic_cmpxchg((int __force *)v, __futex_setup(v), o, n);
+}
+
+/*
+ * 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 };
+}
+
+
+#if CHIP_HAS_CBOX_HOME_MAP()
+static int __init noatomichash(char *str)
+{
+	pr_warning("noatomichash is deprecated.\n");
+	return 1;
+}
+__setup("noatomichash", noatomichash);
+#endif
+
+void __init __init_atomic_per_cpu(void)
+{
+#if ATOMIC_LOCKS_FOUND_VIA_TABLE()
+
+	unsigned int i;
+	int actual_cpu;
+
+	/*
+	 * Before this is called from setup, we just have one lock for
+	 * all atomic objects/operations.  Here we replace the
+	 * elements of atomic_lock_ptr so that they point at per_cpu
+	 * integers.  This seemingly over-complex approach stems from
+	 * the fact that DEFINE_PER_CPU defines an entry for each cpu
+	 * in the grid, not each cpu from 0..ATOMIC_HASH_SIZE-1.  But
+	 * for efficient hashing of atomics to their locks we want a
+	 * compile time constant power of 2 for the size of this
+	 * table, so we use ATOMIC_HASH_SIZE.
+	 *
+	 * Here we populate atomic_lock_ptr from the per cpu
+	 * atomic_lock_pool, interspersing by actual cpu so that
+	 * subsequent elements are homed on consecutive cpus.
+	 */
+
+	actual_cpu = cpumask_first(cpu_possible_mask);
+
+	for (i = 0; i < ATOMIC_HASH_L1_SIZE; ++i) {
+		/*
+		 * Preincrement to slightly bias against using cpu 0,
+		 * which has plenty of stuff homed on it already.
+		 */
+		actual_cpu = cpumask_next(actual_cpu, cpu_possible_mask);
+		if (actual_cpu >= nr_cpu_ids)
+			actual_cpu = cpumask_first(cpu_possible_mask);
+
+		atomic_lock_ptr[i] = &per_cpu(atomic_lock_pool, actual_cpu);
+	}
+
+#else /* ATOMIC_LOCKS_FOUND_VIA_TABLE() */
+
+	/* Validate power-of-two and "bigger than cpus" assumption */
+	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. */
+	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.
+	 */
+	BUG_ON((PAGE_SIZE >> 3) > ATOMIC_HASH_SIZE);
+
+#endif /* ATOMIC_LOCKS_FOUND_VIA_TABLE() */
+
+	/* The futex code makes this assumption, so we validate it here. */
+	BUG_ON(sizeof(atomic_t) != sizeof(int));
+}