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Subject[PATCH v3 4/5] MIPS/Perf-events: Work with the new callchain interface
Date
This is the MIPS part of the following commits by Frederic Weisbecker:

- f72c1a931e311bb7780fee19e41a89ac42cab50e
perf: Factorize callchain context handling

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

- 56962b4449af34070bb1994621ef4f0265eed4d8
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).

- 70791ce9ba68a5921c9905ef05d23f62a90bc10c
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.

- c1a65932fd7216fdc9a0db8bbffe1d47842f862c
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: Wu Zhangjin <wuzhangjin@gmail.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Deng-Cheng Zhu <dengcheng.zhu@gmail.com>
---
arch/mips/kernel/perf_event.c | 63 ++++-------------------------------------
1 files changed, 6 insertions(+), 57 deletions(-)
diff --git a/arch/mips/kernel/perf_event.c b/arch/mips/kernel/perf_event.c
index 3d55761..8f7d2f8 100644
--- a/arch/mips/kernel/perf_event.c
+++ b/arch/mips/kernel/perf_event.c
@@ -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;
-}
--
1.7.1


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