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Commit 56962b44 authored by Frederic Weisbecker's avatar Frederic Weisbecker
Browse files

perf: Generalize some arch callchain code 



- 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 (dst, src).

Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
Acked-by: default avatarPaul Mackerras <paulus@samba.org>
Tested-by: default avatarWill Deacon <will.deacon@arm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: David Miller <davem@davemloft.net>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Borislav Petkov <bp@amd64.org>
parent 70791ce9

arch/arm/kernel/perf_event.c

+4 −39
Original line number Diff line number Diff line
@@ -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;

}

arch/powerpc/kernel/perf_callchain.c

+14 −35
Original line number Diff line number Diff line
@@ -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);

		perf_callchain_user_64(entry, regs);

	else

			perf_callchain_user_32(regs, entry);

	}



	return entry;

		perf_callchain_user_32(entry, regs);

}

arch/sh/kernel/perf_callchain.c

+2 −35
Original line number Diff line number Diff line
@@ -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;

}

arch/sparc/kernel/perf_event.c

+15 −31
Original line number Diff line number Diff line
@@ -1283,14 +1283,16 @@ 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);
@@ -1330,8 +1332,8 @@ 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;
@@ -1353,8 +1355,8 @@ 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;
@@ -1376,30 +1378,12 @@ 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);

		perf_callchain_user_32(entry, regs);

	else

			perf_callchain_user_64(regs, entry);

	}

	return entry;

		perf_callchain_user_64(entry, regs);

}

arch/x86/kernel/cpu/perf_event.c

+8 −37
Original line number Diff line number Diff line
@@ -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)