From cbda6aa10bd2d97e38f4d26a03a0b2183ad580ba Mon Sep 17 00:00:00 2001 From: Michael Ellerman Date: Wed, 15 May 2013 20:19:30 +0000 Subject: powerpc/perf: Revert to original NO_SIPR logic This is a revert and then some of commit 860aad7 "Add regs_no_sipr()". This workaround was only needed on early chip versions. As before NO_SIPR becomes a static flag of the PMU struct. Signed-off-by: Michael Ellerman Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/perf/core-book3s.c | 30 ++++++------------------------ 1 file changed, 6 insertions(+), 24 deletions(-) (limited to 'arch/powerpc/perf/core-book3s.c') diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c index 426180b84978..b2f873bc891b 100644 --- a/arch/powerpc/perf/core-book3s.c +++ b/arch/powerpc/perf/core-book3s.c @@ -110,7 +110,7 @@ static inline void power_pmu_bhrb_read(struct cpu_hw_events *cpuhw) {} static bool regs_use_siar(struct pt_regs *regs) { - return !!(regs->result & 1); + return !!regs->result; } /* @@ -181,11 +181,6 @@ static bool regs_sipr(struct pt_regs *regs) return !!(regs->dsisr & sipr); } -static bool regs_no_sipr(struct pt_regs *regs) -{ - return !!(regs->result & 2); -} - static inline u32 perf_flags_from_msr(struct pt_regs *regs) { if (regs->msr & MSR_PR) @@ -208,7 +203,7 @@ static inline u32 perf_get_misc_flags(struct pt_regs *regs) * SIAR which should give slightly more reliable * results */ - if (regs_no_sipr(regs)) { + if (ppmu->flags & PPMU_NO_SIPR) { unsigned long siar = mfspr(SPRN_SIAR); if (siar >= PAGE_OFFSET) return PERF_RECORD_MISC_KERNEL; @@ -239,22 +234,9 @@ static inline void perf_read_regs(struct pt_regs *regs) int use_siar; regs->dsisr = mmcra; - regs->result = 0; - - if (ppmu->flags & PPMU_NO_SIPR) - regs->result |= 2; - - /* - * On power8 if we're in random sampling mode, the SIER is updated. - * If we're in continuous sampling mode, we don't have SIPR. - */ - if (ppmu->flags & PPMU_HAS_SIER) { - if (marked) - regs->dar = mfspr(SPRN_SIER); - else - regs->result |= 2; - } + if (ppmu->flags & PPMU_HAS_SIER) + regs->dar = mfspr(SPRN_SIER); /* * If this isn't a PMU exception (eg a software event) the SIAR is @@ -279,12 +261,12 @@ static inline void perf_read_regs(struct pt_regs *regs) use_siar = 1; else if ((ppmu->flags & PPMU_NO_CONT_SAMPLING)) use_siar = 0; - else if (!regs_no_sipr(regs) && regs_sipr(regs)) + else if (!(ppmu->flags & PPMU_NO_SIPR) && regs_sipr(regs)) use_siar = 0; else use_siar = 1; - regs->result |= use_siar; + regs->result = use_siar; } /* -- cgit v1.2.3 From 58a032c3b106adcd2b83b7e631de3b79f238cdd2 Mon Sep 17 00:00:00 2001 From: Michael Ellerman Date: Wed, 15 May 2013 20:19:31 +0000 Subject: powerpc/perf: Add missing SIER support Commit 8f61aa3 "Add support for SIER" missed updates to siar_valid() and perf_get_data_addr(). In both cases we need to check the SIER instead of mmcra. Signed-off-by: Michael Ellerman Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/perf/core-book3s.c | 37 +++++++++++++++++++++++++------------ 1 file changed, 25 insertions(+), 12 deletions(-) (limited to 'arch/powerpc/perf/core-book3s.c') diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c index b2f873bc891b..845c867444e6 100644 --- a/arch/powerpc/perf/core-book3s.c +++ b/arch/powerpc/perf/core-book3s.c @@ -136,22 +136,30 @@ static inline unsigned long perf_ip_adjust(struct pt_regs *regs) * If we're not doing instruction sampling, give them the SDAR * (sampled data address). If we are doing instruction sampling, then * only give them the SDAR if it corresponds to the instruction - * pointed to by SIAR; this is indicated by the [POWER6_]MMCRA_SDSYNC or - * the [POWER7P_]MMCRA_SDAR_VALID bit in MMCRA. + * pointed to by SIAR; this is indicated by the [POWER6_]MMCRA_SDSYNC, the + * [POWER7P_]MMCRA_SDAR_VALID bit in MMCRA, or the SDAR_VALID bit in SIER. */ static inline void perf_get_data_addr(struct pt_regs *regs, u64 *addrp) { unsigned long mmcra = regs->dsisr; - unsigned long sdsync; + bool sdar_valid; - if (ppmu->flags & PPMU_SIAR_VALID) - sdsync = POWER7P_MMCRA_SDAR_VALID; - else if (ppmu->flags & PPMU_ALT_SIPR) - sdsync = POWER6_MMCRA_SDSYNC; - else - sdsync = MMCRA_SDSYNC; + if (ppmu->flags & PPMU_HAS_SIER) + sdar_valid = regs->dar & SIER_SDAR_VALID; + else { + unsigned long sdsync; + + if (ppmu->flags & PPMU_SIAR_VALID) + sdsync = POWER7P_MMCRA_SDAR_VALID; + else if (ppmu->flags & PPMU_ALT_SIPR) + sdsync = POWER6_MMCRA_SDSYNC; + else + sdsync = MMCRA_SDSYNC; - if (!(mmcra & MMCRA_SAMPLE_ENABLE) || (mmcra & sdsync)) + sdar_valid = mmcra & sdsync; + } + + if (!(mmcra & MMCRA_SAMPLE_ENABLE) || sdar_valid) *addrp = mfspr(SPRN_SDAR); } @@ -290,8 +298,13 @@ static inline int siar_valid(struct pt_regs *regs) unsigned long mmcra = regs->dsisr; int marked = mmcra & MMCRA_SAMPLE_ENABLE; - if ((ppmu->flags & PPMU_SIAR_VALID) && marked) - return mmcra & POWER7P_MMCRA_SIAR_VALID; + if (marked) { + if (ppmu->flags & PPMU_HAS_SIER) + return regs->dar & SIER_SIAR_VALID; + + if (ppmu->flags & PPMU_SIAR_VALID) + return mmcra & POWER7P_MMCRA_SIAR_VALID; + } return 1; } -- cgit v1.2.3 From 6772faa1ba22eba18d087c2459030a683b65be57 Mon Sep 17 00:00:00 2001 From: Michael Ellerman Date: Wed, 5 Jun 2013 17:58:20 +0000 Subject: powerpc/perf: Fix deadlock caused by calling printk() in PMU exception In commit bc09c21 "Fix finding overflowed PMC in interrupt" we added a printk() to the PMU exception handler. Unfortunately that is not safe. The problem is that the PMU exception may run even when interrupts are soft disabled, aka NMI context. We do this so that we can profile parts of the kernel that have interrupts soft-disabled. But by calling printk() from the exception handler, we can potentially deadlock in the printk code on logbuf_lock, eg: [c00000038ba575c0] c000000000081928 .vprintk_emit+0xa8/0x540 [c00000038ba576a0] c0000000007bcde8 .printk+0x48/0x58 [c00000038ba57710] c000000000076504 .perf_event_interrupt+0x2d4/0x490 [c00000038ba57810] c00000000001f6f8 .performance_monitor_exception+0x48/0x60 [c00000038ba57880] c0000000000032cc performance_monitor_common+0x14c/0x180 --- Exception: f01 (Performance Monitor) at c0000000007b25d4 ._raw_spin_lock_irq +0x64/0xc0 [c00000038ba57bf0] c00000000007ed90 .devkmsg_read+0xd0/0x5a0 [c00000038ba57d00] c0000000001c2934 .vfs_read+0xc4/0x1e0 [c00000038ba57d90] c0000000001c2cd8 .SyS_read+0x58/0xd0 [c00000038ba57e30] c000000000009d54 syscall_exit+0x0/0x98 --- Exception: c01 (System Call) at 00001fffffbf6f7c SP (3ffff6d4de10) is in userspace Fix it by making sure we only call printk() when we are not in NMI context. Signed-off-by: Michael Ellerman Cc: # 3.9 Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/perf/core-book3s.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/powerpc/perf/core-book3s.c') diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c index 845c867444e6..29c6482890c8 100644 --- a/arch/powerpc/perf/core-book3s.c +++ b/arch/powerpc/perf/core-book3s.c @@ -1758,7 +1758,7 @@ static void perf_event_interrupt(struct pt_regs *regs) } } } - if ((!found) && printk_ratelimit()) + if (!found && !nmi && printk_ratelimit()) printk(KERN_WARNING "Can't find PMC that caused IRQ\n"); /* -- cgit v1.2.3