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authorRalf Baechle <ralf@linux-mips.org>2006-04-04 15:09:06 +0100
committerRalf Baechle <ralf@linux-mips.org>2006-04-19 04:14:22 +0200
commit193dd2ce2a4a1c5b2e7814544572424d497069db (patch)
treecca42417c505a8f68e2d2accc83d392fb7221432
parent62a442155ea58a17497b487324b27ec2f2dc5c5c (diff)
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[MIPS] R2: Implement shadow register allocation without spinlock.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
-rw-r--r--arch/mips/kernel/traps.c41
1 files changed, 18 insertions, 23 deletions
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index 61efc61c45e2..081e6ed5bb62 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -961,15 +961,19 @@ void *set_except_vector(int n, void *addr)
#ifdef CONFIG_CPU_MIPSR2
/*
- * Shadow register allocation
+ * MIPSR2 shadow register set allocation
* FIXME: SMP...
*/
-/* MIPSR2 shadow register sets */
-struct shadow_registers {
- spinlock_t sr_lock; /* */
- int sr_supported; /* Number of shadow register sets supported */
- int sr_allocated; /* Bitmap of allocated shadow registers */
+static struct shadow_registers {
+ /*
+ * Number of shadow register sets supported
+ */
+ unsigned long sr_supported;
+ /*
+ * Bitmap of allocated shadow registers
+ */
+ unsigned long sr_allocated;
} shadow_registers;
void mips_srs_init(void)
@@ -980,7 +984,6 @@ void mips_srs_init(void)
shadow_registers.sr_supported);
#endif
shadow_registers.sr_allocated = 1; /* Set 0 used by kernel */
- spin_lock_init(&shadow_registers.sr_lock);
}
int mips_srs_max(void)
@@ -991,32 +994,24 @@ int mips_srs_max(void)
int mips_srs_alloc(void)
{
struct shadow_registers *sr = &shadow_registers;
- unsigned long flags;
int set;
- spin_lock_irqsave(&sr->sr_lock, flags);
+again:
+ set = find_first_zero_bit(&sr->sr_allocated, sr->sr_supported);
+ if (set >= sr->sr_supported)
+ return -1;
- for (set = 0; set < sr->sr_supported; set++) {
- if ((sr->sr_allocated & (1 << set)) == 0) {
- sr->sr_allocated |= 1 << set;
- spin_unlock_irqrestore(&sr->sr_lock, flags);
- return set;
- }
- }
+ if (test_and_set_bit(set, &sr->sr_allocated))
+ goto again;
- /* None available */
- spin_unlock_irqrestore(&sr->sr_lock, flags);
- return -1;
+ return set;
}
void mips_srs_free (int set)
{
struct shadow_registers *sr = &shadow_registers;
- unsigned long flags;
- spin_lock_irqsave(&sr->sr_lock, flags);
- sr->sr_allocated &= ~(1 << set);
- spin_unlock_irqrestore(&sr->sr_lock, flags);
+ clear_bit(set, &sr->sr_allocated);
}
static void *set_vi_srs_handler(int n, void *addr, int srs)