[RFC PATCH 3/6] perf: Generalize some arch callchain code
in [Kernel]
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From: Frederic Weisbecker on 1 Jul 2010 11:40 - Most archs use one callchain buffer per cpu, except x86 that needs to deal with NMIs. Provide a default perf_callchain_buffer() implementation that x86 overrides. - Centralize all the kernel/user regs handling and invoke new arch handlers from there: perf_callchain_user() / perf_callchain_kernel() That avoid all the user_mode(), current->mm checks and so... - Invert some parameters in perf_callchain_*() helpers: entry to the left, regs to the right, following the traditional (src, dst). I'm not sure what stack_trace_flush() and flushw_user() do in sparc, I've just moved them inside the callchain_user handlers, I'm not sure this is the right thing. Signed-off-by: Frederic Weisbecker <fweisbec(a)gmail.com> Cc: Ingo Molnar <mingo(a)elte.hu> Cc: Peter Zijlstra <a.p.zijlstra(a)chello.nl> Cc: Arnaldo Carvalho de Melo <acme(a)redhat.com> Cc: Paul Mackerras <paulus(a)samba.org> Cc: Stephane Eranian <eranian(a)google.com> Cc: David Miller <davem(a)davemloft.net> Cc: Paul Mundt <lethal(a)linux-sh.org> Cc: Will Deacon <will.deacon(a)arm.com> Cc: Borislav Petkov <bp(a)amd64.org> --- arch/arm/kernel/perf_event.c | 43 +++--------------------------- arch/powerpc/kernel/perf_callchain.c | 49 +++++++++------------------------ arch/sh/kernel/perf_callchain.c | 37 +------------------------ arch/sparc/kernel/perf_event.c | 46 ++++++++++--------------------- arch/x86/kernel/cpu/perf_event.c | 45 +++++------------------------- include/linux/perf_event.h | 10 ++++++- kernel/perf_event.c | 40 ++++++++++++++++++++++++++- 7 files changed, 90 insertions(+), 180 deletions(-) diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c index 41de647..ddb5134 100644 --- a/arch/arm/kernel/perf_event.c +++ b/arch/arm/kernel/perf_event.c @@ -3044,17 +3044,13 @@ user_backtrace(struct frame_tail *tail, return buftail.fp - 1; } -static void -perf_callchain_user(struct pt_regs *regs, - struct perf_callchain_entry *entry) +void +perf_callchain_user(struct perf_callchain_entry *entry, struct pt_regs *regs) { struct frame_tail *tail; perf_callchain_store(entry, PERF_CONTEXT_USER); - if (!user_mode(regs)) - regs = task_pt_regs(current); - tail = (struct frame_tail *)regs->ARM_fp - 1; while (tail && !((unsigned long)tail & 0x3)) @@ -3075,9 +3071,8 @@ callchain_trace(struct stackframe *fr, return 0; } -static void -perf_callchain_kernel(struct pt_regs *regs, - struct perf_callchain_entry *entry) +void +perf_callchain_kernel(struct perf_callchain_entry *entry, struct pt_regs *regs) { struct stackframe fr; @@ -3088,33 +3083,3 @@ perf_callchain_kernel(struct pt_regs *regs, fr.pc = regs->ARM_pc; walk_stackframe(&fr, callchain_trace, entry); } - -static void -perf_do_callchain(struct pt_regs *regs, - struct perf_callchain_entry *entry) -{ - int is_user; - - if (!regs) - return; - - is_user = user_mode(regs); - - if (!is_user) - perf_callchain_kernel(regs, entry); - - if (current->mm) - perf_callchain_user(regs, entry); -} - -static DEFINE_PER_CPU(struct perf_callchain_entry, pmc_irq_entry); - -struct perf_callchain_entry * -perf_callchain(struct pt_regs *regs) -{ - struct perf_callchain_entry *entry = &__get_cpu_var(pmc_irq_entry); - - entry->nr = 0; - perf_do_callchain(regs, entry); - return entry; -} diff --git a/arch/powerpc/kernel/perf_callchain.c b/arch/powerpc/kernel/perf_callchain.c index a286c2e..f7a85ed 100644 --- a/arch/powerpc/kernel/perf_callchain.c +++ b/arch/powerpc/kernel/perf_callchain.c @@ -46,8 +46,8 @@ static int valid_next_sp(unsigned long sp, unsigned long prev_sp) return 0; } -static void perf_callchain_kernel(struct pt_regs *regs, - struct perf_callchain_entry *entry) +void +perf_callchain_kernel(struct perf_callchain_entry *entry, struct pt_regs *regs) { unsigned long sp, next_sp; unsigned long next_ip; @@ -221,8 +221,8 @@ static int sane_signal_64_frame(unsigned long sp) puc == (unsigned long) &sf->uc; } -static void perf_callchain_user_64(struct pt_regs *regs, - struct perf_callchain_entry *entry) +static void perf_callchain_user_64(struct perf_callchain_entry *entry, + struct pt_regs *regs) { unsigned long sp, next_sp; unsigned long next_ip; @@ -303,8 +303,8 @@ static int read_user_stack_32(unsigned int __user *ptr, unsigned int *ret) return __get_user_inatomic(*ret, ptr); } -static inline void perf_callchain_user_64(struct pt_regs *regs, - struct perf_callchain_entry *entry) +static inline void perf_callchain_user_64(struct perf_callchain_entry *entry, + struct pt_regs *regs) { } @@ -423,8 +423,8 @@ static unsigned int __user *signal_frame_32_regs(unsigned int sp, return mctx->mc_gregs; } -static void perf_callchain_user_32(struct pt_regs *regs, - struct perf_callchain_entry *entry) +static void perf_callchain_user_32(struct perf_callchain_entry *entry, + struct pt_regs *regs) { unsigned int sp, next_sp; unsigned int next_ip; @@ -471,32 +471,11 @@ static void perf_callchain_user_32(struct pt_regs *regs, } } -/* - * Since we can't get PMU interrupts inside a PMU interrupt handler, - * we don't need separate irq and nmi entries here. - */ -static DEFINE_PER_CPU(struct perf_callchain_entry, cpu_perf_callchain); - -struct perf_callchain_entry *perf_callchain(struct pt_regs *regs) +void +perf_callchain_user(struct perf_callchain_entry *entry, struct pt_regs *regs) { - struct perf_callchain_entry *entry = &__get_cpu_var(cpu_perf_callchain); - - entry->nr = 0; - - if (!user_mode(regs)) { - perf_callchain_kernel(regs, entry); - if (current->mm) - regs = task_pt_regs(current); - else - regs = NULL; - } - - if (regs) { - if (current_is_64bit()) - perf_callchain_user_64(regs, entry); - else - perf_callchain_user_32(regs, entry); - } - - return entry; + if (current_is_64bit()) + perf_callchain_user_64(entry, regs); + else + perf_callchain_user_32(entry, regs); } diff --git a/arch/sh/kernel/perf_callchain.c b/arch/sh/kernel/perf_callchain.c index 00143f3..ef076a9 100644 --- a/arch/sh/kernel/perf_callchain.c +++ b/arch/sh/kernel/perf_callchain.c @@ -44,44 +44,11 @@ static const struct stacktrace_ops callchain_ops = { .address = callchain_address, }; -static void -perf_callchain_kernel(struct pt_regs *regs, struct perf_callchain_entry *entry) +void +perf_callchain_kernel(struct perf_callchain_entry *entry, struct pt_regs *regs) { perf_callchain_store(entry, PERF_CONTEXT_KERNEL); perf_callchain_store(entry, regs->pc); unwind_stack(NULL, regs, NULL, &callchain_ops, entry); } - -static void -perf_do_callchain(struct pt_regs *regs, struct perf_callchain_entry *entry) -{ - int is_user; - - if (!regs) - return; - - is_user = user_mode(regs); - - /* - * Only the kernel side is implemented for now. - */ - if (!is_user) - perf_callchain_kernel(regs, entry); -} - -/* - * No need for separate IRQ and NMI entries. - */ -static DEFINE_PER_CPU(struct perf_callchain_entry, callchain); - -struct perf_callchain_entry *perf_callchain(struct pt_regs *regs) -{ - struct perf_callchain_entry *entry = &__get_cpu_var(callchain); - - entry->nr = 0; - - perf_do_callchain(regs, entry); - - return entry; -} diff --git a/arch/sparc/kernel/perf_event.c b/arch/sparc/kernel/perf_event.c index fbac5ad..7f0e44e 100644 --- a/arch/sparc/kernel/perf_event.c +++ b/arch/sparc/kernel/perf_event.c @@ -1282,14 +1282,16 @@ void __init init_hw_perf_events(void) register_die_notifier(&perf_event_nmi_notifier); } -static void perf_callchain_kernel(struct pt_regs *regs, - struct perf_callchain_entry *entry) +void perf_callchain_kernel(struct perf_callchain_entry *entry, + struct pt_regs *regs) { unsigned long ksp, fp; #ifdef CONFIG_FUNCTION_GRAPH_TRACER int graph = 0; #endif + stack_trace_flush(); + perf_callchain_store(entry, PERF_CONTEXT_KERNEL); perf_callchain_store(entry, regs->tpc); @@ -1329,8 +1331,8 @@ static void perf_callchain_kernel(struct pt_regs *regs, } while (entry->nr < PERF_MAX_STACK_DEPTH); } -static void perf_callchain_user_64(struct pt_regs *regs, - struct perf_callchain_entry *entry) +static void perf_callchain_user_64(struct perf_callchain_entry *entry, + struct pt_regs *regs) { unsigned long ufp; @@ -1352,8 +1354,8 @@ static void perf_callchain_user_64(struct pt_regs *regs, } while (entry->nr < PERF_MAX_STACK_DEPTH); } -static void perf_callchain_user_32(struct pt_regs *regs, - struct perf_callchain_entry *entry) +static void perf_callchain_user_32(struct perf_callchain_entry *entry, + struct pt_regs *regs) { unsigned long ufp; @@ -1375,30 +1377,12 @@ static void perf_callchain_user_32(struct pt_regs *regs, } while (entry->nr < PERF_MAX_STACK_DEPTH); } -/* Like powerpc we can't get PMU interrupts within the PMU handler, - * so no need for separate NMI and IRQ chains as on x86. - */ -static DEFINE_PER_CPU(struct perf_callchain_entry, callchain); - -struct perf_callchain_entry *perf_callchain(struct pt_regs *regs) +void +perf_callchain_user(struct perf_callchain_entry *entry, struct pt_regs *regs) { - struct perf_callchain_entry *entry = &__get_cpu_var(callchain); - - entry->nr = 0; - if (!user_mode(regs)) { - stack_trace_flush(); - perf_callchain_kernel(regs, entry); - if (current->mm) - regs = task_pt_regs(current); - else - regs = NULL; - } - if (regs) { - flushw_user(); - if (test_thread_flag(TIF_32BIT)) - perf_callchain_user_32(regs, entry); - else - perf_callchain_user_64(regs, entry); - } - return entry; + flushw_user(); + if (test_thread_flag(TIF_32BIT)) + perf_callchain_user_32(entry, regs); + else + perf_callchain_user_64(entry, regs); } diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c index 8af28ca..39f8421 100644 --- a/arch/x86/kernel/cpu/perf_event.c +++ b/arch/x86/kernel/cpu/perf_event.c @@ -1571,9 +1571,7 @@ const struct pmu *hw_perf_event_init(struct perf_event *event) * callchain support */ - -static DEFINE_PER_CPU(struct perf_callchain_entry, pmc_irq_entry); -static DEFINE_PER_CPU(struct perf_callchain_entry, pmc_nmi_entry); +static DEFINE_PER_CPU(struct perf_callchain_entry, perf_callchain_entry_nmi); static void @@ -1607,8 +1605,8 @@ static const struct stacktrace_ops backtrace_ops = { .walk_stack = print_context_stack_bp, }; -static void -perf_callchain_kernel(struct pt_regs *regs, struct perf_callchain_entry *entry) +void +perf_callchain_kernel(struct perf_callchain_entry *entry, struct pt_regs *regs) { perf_callchain_store(entry, PERF_CONTEXT_KERNEL); perf_callchain_store(entry, regs->ip); @@ -1653,14 +1651,12 @@ perf_callchain_user32(struct pt_regs *regs, struct perf_callchain_entry *entry) } #endif -static void -perf_callchain_user(struct pt_regs *regs, struct perf_callchain_entry *entry) +void +perf_callchain_user(struct perf_callchain_entry *entry, struct pt_regs *regs) { struct stack_frame frame; const void __user *fp; - if (!user_mode(regs)) - regs = task_pt_regs(current); fp = (void __user *)regs->bp; @@ -1687,42 +1683,17 @@ perf_callchain_user(struct pt_regs *regs, struct perf_callchain_entry *entry) } } -static void -perf_do_callchain(struct pt_regs *regs, struct perf_callchain_entry *entry) -{ - int is_user; - - if (!regs) - return; - - is_user = user_mode(regs); - - if (!is_user) - perf_callchain_kernel(regs, entry); - - if (current->mm) - perf_callchain_user(regs, entry); -} - -struct perf_callchain_entry *perf_callchain(struct pt_regs *regs) +struct perf_callchain_entry *perf_callchain_buffer(void) { - struct perf_callchain_entry *entry; - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { /* TODO: We don't support guest os callchain now */ return NULL; } if (in_nmi()) - entry = &__get_cpu_var(pmc_nmi_entry); - else - entry = &__get_cpu_var(pmc_irq_entry); - - entry->nr = 0; - - perf_do_callchain(regs, entry); + return &__get_cpu_var(perf_callchain_entry_nmi); - return entry; + return &__get_cpu_var(perf_callchain_entry); } unsigned long perf_instruction_pointer(struct pt_regs *regs) diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 3588804..4db61dd 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -976,7 +976,15 @@ extern int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks extern void perf_event_comm(struct task_struct *tsk); extern void perf_event_fork(struct task_struct *tsk); -extern struct perf_callchain_entry *perf_callchain(struct pt_regs *regs); +/* Callchains */ +DECLARE_PER_CPU(struct perf_callchain_entry, perf_callchain_entry); + +extern void perf_callchain_user(struct perf_callchain_entry *entry, + struct pt_regs *regs); +extern void perf_callchain_kernel(struct perf_callchain_entry *entry, + struct pt_regs *regs); +extern struct perf_callchain_entry *perf_callchain_buffer(void); + static inline void perf_callchain_store(struct perf_callchain_entry *entry, u64 ip) diff --git a/kernel/perf_event.c b/kernel/perf_event.c index c772a3d..02efde6 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -2937,13 +2937,49 @@ void perf_event_do_pending(void) __perf_pending_run(); } +DEFINE_PER_CPU(struct perf_callchain_entry, perf_callchain_entry); + /* * Callchain support -- arch specific */ -__weak struct perf_callchain_entry *perf_callchain(struct pt_regs *regs) +__weak struct perf_callchain_entry *perf_callchain_buffer(void) { - return NULL; + return &__get_cpu_var(perf_callchain_entry); +} + +__weak void perf_callchain_kernel(struct perf_callchain_entry *entry, + struct pt_regs *regs) +{ +} + +__weak void perf_callchain_user(struct perf_callchain_entry *entry, + struct pt_regs *regs) +{ +} + +static struct perf_callchain_entry *perf_callchain(struct pt_regs *regs) +{ + struct perf_callchain_entry *entry; + + entry = perf_callchain_buffer(); + if (!entry) + return NULL; + + entry->nr = 0; + + if (!user_mode(regs)) { + perf_callchain_kernel(entry, regs); + if (current->mm) + regs = task_pt_regs(current); + else + regs = NULL; + } + + if (regs) + perf_callchain_user(entry, regs); + + return entry; } -- 1.6.2.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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