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: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Paul Mackerras <paulus@samba.org>
Tested-by: Will 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>
diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c
index a07c3b1..0e3bbdb 100644
--- a/arch/arm/kernel/perf_event.c
+++ b/arch/arm/kernel/perf_event.c
@@ -3044,17 +3044,13 @@
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 @@
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 @@
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;
-}