diff options
Diffstat (limited to 'arch/ppc64/kernel/pmc.c')
-rw-r--r-- | arch/ppc64/kernel/pmc.c | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/arch/ppc64/kernel/pmc.c b/arch/ppc64/kernel/pmc.c new file mode 100644 index 000000000000..67be773f9c00 --- /dev/null +++ b/arch/ppc64/kernel/pmc.c | |||
@@ -0,0 +1,67 @@ | |||
1 | /* | ||
2 | * linux/arch/ppc64/kernel/pmc.c | ||
3 | * | ||
4 | * Copyright (C) 2004 David Gibson, IBM Corporation. | ||
5 | * | ||
6 | * This program is free software; you can redistribute it and/or | ||
7 | * modify it under the terms of the GNU General Public License | ||
8 | * as published by the Free Software Foundation; either version | ||
9 | * 2 of the License, or (at your option) any later version. | ||
10 | */ | ||
11 | |||
12 | #include <linux/config.h> | ||
13 | #include <linux/errno.h> | ||
14 | #include <linux/spinlock.h> | ||
15 | #include <linux/module.h> | ||
16 | |||
17 | #include <asm/processor.h> | ||
18 | #include <asm/pmc.h> | ||
19 | |||
20 | /* Ensure exceptions are disabled */ | ||
21 | static void dummy_perf(struct pt_regs *regs) | ||
22 | { | ||
23 | unsigned int mmcr0 = mfspr(SPRN_MMCR0); | ||
24 | |||
25 | mmcr0 &= ~(MMCR0_PMXE|MMCR0_PMAO); | ||
26 | mtspr(SPRN_MMCR0, mmcr0); | ||
27 | } | ||
28 | |||
29 | static spinlock_t pmc_owner_lock = SPIN_LOCK_UNLOCKED; | ||
30 | static void *pmc_owner_caller; /* mostly for debugging */ | ||
31 | perf_irq_t perf_irq = dummy_perf; | ||
32 | |||
33 | int reserve_pmc_hardware(perf_irq_t new_perf_irq) | ||
34 | { | ||
35 | int err = 0; | ||
36 | |||
37 | spin_lock(&pmc_owner_lock); | ||
38 | |||
39 | if (pmc_owner_caller) { | ||
40 | printk(KERN_WARNING "reserve_pmc_hardware: " | ||
41 | "PMC hardware busy (reserved by caller %p)\n", | ||
42 | pmc_owner_caller); | ||
43 | err = -EBUSY; | ||
44 | goto out; | ||
45 | } | ||
46 | |||
47 | pmc_owner_caller = __builtin_return_address(0); | ||
48 | perf_irq = new_perf_irq ? : dummy_perf; | ||
49 | |||
50 | out: | ||
51 | spin_unlock(&pmc_owner_lock); | ||
52 | return err; | ||
53 | } | ||
54 | EXPORT_SYMBOL_GPL(reserve_pmc_hardware); | ||
55 | |||
56 | void release_pmc_hardware(void) | ||
57 | { | ||
58 | spin_lock(&pmc_owner_lock); | ||
59 | |||
60 | WARN_ON(! pmc_owner_caller); | ||
61 | |||
62 | pmc_owner_caller = NULL; | ||
63 | perf_irq = dummy_perf; | ||
64 | |||
65 | spin_unlock(&pmc_owner_lock); | ||
66 | } | ||
67 | EXPORT_SYMBOL_GPL(release_pmc_hardware); | ||