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Commit 98f92f2f authored by Deng-Cheng Zhu's avatar Deng-Cheng Zhu Committed by Ralf Baechle
Browse files

MIPS, Perf-events: Work with the new callchain interface 



This is the MIPS part of the following commits by Frederic Weisbecker:

- f72c1a93
    perf: Factorize callchain context handling

    Store the kernel and user contexts from the generic layer instead
    of archs, this gathers some repetitive code.

- 56962b44
    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).

- 70791ce9
    perf: Generalize callchain_store()

    callchain_store() is the same on every archs, inline it in
    perf_event.h and rename it to perf_callchain_store() to avoid
    any collision.

    This removes repetitive code.

- c1a65932
    perf: Drop unappropriate tests on arch callchains

    Drop the TASK_RUNNING test on user tasks for callchains as
    this check doesn't seem to make any sense.

    Also remove the tests for !current that is not supposed to
    happen and current->pid as this should be handled at the
    generic level, with exclude_idle attribute.

Reported-by: default avatarWu Zhangjin <wuzhangjin@gmail.com>
Acked-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
Acked-by: default avatarDavid Daney <ddaney@caviumnetworks.com>
Signed-off-by: default avatarDeng-Cheng Zhu <dengcheng.zhu@gmail.com>
To: a.p.zijlstra@chello.nl
To: will.deacon@arm.com
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: paulus@samba.org
Cc: mingo@elte.hu
Cc: acme@redhat.com
Cc: dengcheng.zhu@gmail.com
Cc: matt@console-pimps.org
Cc: sshtylyov@mvista.com
Patchwork: http://patchwork.linux-mips.org/patch/2014/


Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
parent c049b6a5

arch/mips/kernel/perf_event.c

+6 −57
Original line number Diff line number Diff line
@@ -534,21 +534,13 @@ handle_associated_event(struct cpu_hw_events *cpuc, 
#include "perf_event_mipsxx.c"



/* Callchain handling code. */

static inline void

callchain_store(struct perf_callchain_entry *entry,

		u64 ip)

{

	if (entry->nr < PERF_MAX_STACK_DEPTH)

		entry->ip[entry->nr++] = ip;

}



/*

 * Leave userspace callchain empty for now. When we find a way to trace

 * the user stack callchains, we add here.

 */

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)

{

}
@@ -561,23 +553,21 @@ static void save_raw_perf_callchain(struct perf_callchain_entry *entry, 
	while (!kstack_end(sp)) {

		addr = *sp++;

		if (__kernel_text_address(addr)) {

			callchain_store(entry, addr);

			perf_callchain_store(entry, addr);

			if (entry->nr >= PERF_MAX_STACK_DEPTH)

				break;

		}

	}

}



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 = regs->regs[29];

#ifdef CONFIG_KALLSYMS

	unsigned long ra = regs->regs[31];

	unsigned long pc = regs->cp0_epc;



	callchain_store(entry, PERF_CONTEXT_KERNEL);

	if (raw_show_trace || !__kernel_text_address(pc)) {

		unsigned long stack_page =

			(unsigned long)task_stack_page(current);
@@ -587,53 +577,12 @@ perf_callchain_kernel(struct pt_regs *regs, 
		return;

	}

	do {

		callchain_store(entry, pc);

		perf_callchain_store(entry, pc);

		if (entry->nr >= PERF_MAX_STACK_DEPTH)

			break;

		pc = unwind_stack(current, &sp, pc, &ra);

	} while (pc);

#else

	callchain_store(entry, PERF_CONTEXT_KERNEL);

	save_raw_perf_callchain(entry, sp);

#endif

}
 


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 (!current || !current->pid)

		return;



	if (is_user && current->state != TASK_RUNNING)

		return;



	if (!is_user) {

		perf_callchain_kernel(regs, entry);

		if (current->mm)

			regs = task_pt_regs(current);

		else

			regs = NULL;

	}

	if (regs)

		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;

}