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Commit | Line | Data |
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c0a62f2b GKH |
1 | From 3202e35ec1c8fc19cea24253ff83edf702a60a02 Mon Sep 17 00:00:00 2001 |
2 | From: Ravi Bangoria <ravi.bangoria@linux.ibm.com> | |
3 | Date: Sat, 11 May 2019 08:12:17 +0530 | |
4 | Subject: powerpc/perf: Fix MMCRA corruption by bhrb_filter | |
5 | ||
6 | From: Ravi Bangoria <ravi.bangoria@linux.ibm.com> | |
7 | ||
8 | commit 3202e35ec1c8fc19cea24253ff83edf702a60a02 upstream. | |
9 | ||
10 | Consider a scenario where user creates two events: | |
11 | ||
12 | 1st event: | |
13 | attr.sample_type |= PERF_SAMPLE_BRANCH_STACK; | |
14 | attr.branch_sample_type = PERF_SAMPLE_BRANCH_ANY; | |
15 | fd = perf_event_open(attr, 0, 1, -1, 0); | |
16 | ||
17 | This sets cpuhw->bhrb_filter to 0 and returns valid fd. | |
18 | ||
19 | 2nd event: | |
20 | attr.sample_type |= PERF_SAMPLE_BRANCH_STACK; | |
21 | attr.branch_sample_type = PERF_SAMPLE_BRANCH_CALL; | |
22 | fd = perf_event_open(attr, 0, 1, -1, 0); | |
23 | ||
24 | It overrides cpuhw->bhrb_filter to -1 and returns with error. | |
25 | ||
26 | Now if power_pmu_enable() gets called by any path other than | |
27 | power_pmu_add(), ppmu->config_bhrb(-1) will set MMCRA to -1. | |
28 | ||
29 | Fixes: 3925f46bb590 ("powerpc/perf: Enable branch stack sampling framework") | |
30 | Cc: stable@vger.kernel.org # v3.10+ | |
31 | Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com> | |
32 | Reviewed-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com> | |
33 | Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> | |
34 | Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> | |
35 | ||
36 | --- | |
37 | arch/powerpc/perf/core-book3s.c | 6 ++++-- | |
38 | arch/powerpc/perf/power8-pmu.c | 3 +++ | |
39 | arch/powerpc/perf/power9-pmu.c | 3 +++ | |
40 | 3 files changed, 10 insertions(+), 2 deletions(-) | |
41 | ||
42 | --- a/arch/powerpc/perf/core-book3s.c | |
43 | +++ b/arch/powerpc/perf/core-book3s.c | |
44 | @@ -1827,6 +1827,7 @@ static int power_pmu_event_init(struct p | |
45 | int n; | |
46 | int err; | |
47 | struct cpu_hw_events *cpuhw; | |
48 | + u64 bhrb_filter; | |
49 | ||
50 | if (!ppmu) | |
51 | return -ENOENT; | |
52 | @@ -1932,13 +1933,14 @@ static int power_pmu_event_init(struct p | |
53 | err = power_check_constraints(cpuhw, events, cflags, n + 1); | |
54 | ||
55 | if (has_branch_stack(event)) { | |
56 | - cpuhw->bhrb_filter = ppmu->bhrb_filter_map( | |
57 | + bhrb_filter = ppmu->bhrb_filter_map( | |
58 | event->attr.branch_sample_type); | |
59 | ||
60 | - if (cpuhw->bhrb_filter == -1) { | |
61 | + if (bhrb_filter == -1) { | |
62 | put_cpu_var(cpu_hw_events); | |
63 | return -EOPNOTSUPP; | |
64 | } | |
65 | + cpuhw->bhrb_filter = bhrb_filter; | |
66 | } | |
67 | ||
68 | put_cpu_var(cpu_hw_events); | |
69 | --- a/arch/powerpc/perf/power8-pmu.c | |
70 | +++ b/arch/powerpc/perf/power8-pmu.c | |
71 | @@ -29,6 +29,7 @@ enum { | |
72 | #define POWER8_MMCRA_IFM1 0x0000000040000000UL | |
73 | #define POWER8_MMCRA_IFM2 0x0000000080000000UL | |
74 | #define POWER8_MMCRA_IFM3 0x00000000C0000000UL | |
75 | +#define POWER8_MMCRA_BHRB_MASK 0x00000000C0000000UL | |
76 | ||
77 | /* | |
78 | * Raw event encoding for PowerISA v2.07 (Power8): | |
79 | @@ -243,6 +244,8 @@ static u64 power8_bhrb_filter_map(u64 br | |
80 | ||
81 | static void power8_config_bhrb(u64 pmu_bhrb_filter) | |
82 | { | |
83 | + pmu_bhrb_filter &= POWER8_MMCRA_BHRB_MASK; | |
84 | + | |
85 | /* Enable BHRB filter in PMU */ | |
86 | mtspr(SPRN_MMCRA, (mfspr(SPRN_MMCRA) | pmu_bhrb_filter)); | |
87 | } | |
88 | --- a/arch/powerpc/perf/power9-pmu.c | |
89 | +++ b/arch/powerpc/perf/power9-pmu.c | |
90 | @@ -100,6 +100,7 @@ enum { | |
91 | #define POWER9_MMCRA_IFM1 0x0000000040000000UL | |
92 | #define POWER9_MMCRA_IFM2 0x0000000080000000UL | |
93 | #define POWER9_MMCRA_IFM3 0x00000000C0000000UL | |
94 | +#define POWER9_MMCRA_BHRB_MASK 0x00000000C0000000UL | |
95 | ||
96 | /* Nasty Power9 specific hack */ | |
97 | #define PVR_POWER9_CUMULUS 0x00002000 | |
98 | @@ -308,6 +309,8 @@ static u64 power9_bhrb_filter_map(u64 br | |
99 | ||
100 | static void power9_config_bhrb(u64 pmu_bhrb_filter) | |
101 | { | |
102 | + pmu_bhrb_filter &= POWER9_MMCRA_BHRB_MASK; | |
103 | + | |
104 | /* Enable BHRB filter in PMU */ | |
105 | mtspr(SPRN_MMCRA, (mfspr(SPRN_MMCRA) | pmu_bhrb_filter)); | |
106 | } |