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| author | Jason Wessel <jason.wessel@windriver.com> | 2010-11-04 17:33:01 -0500 |
|---|---|---|
| committer | Frederic Weisbecker <fweisbec@gmail.com> | 2010-11-12 14:51:55 +0100 |
| commit | 3c502e7a0255d82621ff25d60cc816624830497e (patch) | |
| tree | 1f30638f22ef9ed748fac1f73cb18169efe49ae7 /kernel | |
| parent | 6c0aca288e726405b01dacb12cac556454d34b2a (diff) | |
| download | linux-3c502e7a0255d82621ff25d60cc816624830497e.tar.bz2 | |
perf,hw_breakpoint: Initialize hardware api earlier
When using early debugging, the kernel does not initialize the
hw_breakpoint API early enough and causes the late initialization of
the kernel debugger to fail. The boot arguments are:
earlyprintk=vga ekgdboc=kbd kgdbwait
Then simply type "go" at the kdb prompt and boot. The kernel will
later emit the message:
kgdb: Could not allocate hwbreakpoints
And at that point the kernel debugger will cease to work correctly.
The solution is to initialize the hw_breakpoint at the same time that
all the other perf call backs are initialized instead of using a
core_initcall() initialization which happens well after the kernel
debugger can make use of hardware breakpoints.
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
CC: Frederic Weisbecker <fweisbec@gmail.com>
CC: Ingo Molnar <mingo@elte.hu>
CC: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <4CD3396D.1090308@windriver.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/hw_breakpoint.c | 3 | ||||
| -rw-r--r-- | kernel/perf_event.c | 6 |
2 files changed, 7 insertions, 2 deletions
diff --git a/kernel/hw_breakpoint.c b/kernel/hw_breakpoint.c index 2c9120f0afca..e5325825aeb6 100644 --- a/kernel/hw_breakpoint.c +++ b/kernel/hw_breakpoint.c @@ -620,7 +620,7 @@ static struct pmu perf_breakpoint = { .read = hw_breakpoint_pmu_read, }; -static int __init init_hw_breakpoint(void) +int __init init_hw_breakpoint(void) { unsigned int **task_bp_pinned; int cpu, err_cpu; @@ -655,6 +655,5 @@ static int __init init_hw_breakpoint(void) return -ENOMEM; } -core_initcall(init_hw_breakpoint); diff --git a/kernel/perf_event.c b/kernel/perf_event.c index 517d827f4982..05b7d8c72c6c 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -31,6 +31,7 @@ #include <linux/kernel_stat.h> #include <linux/perf_event.h> #include <linux/ftrace_event.h> +#include <linux/hw_breakpoint.h> #include <asm/irq_regs.h> @@ -6295,6 +6296,8 @@ perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu) void __init perf_event_init(void) { + int ret; + perf_event_init_all_cpus(); init_srcu_struct(&pmus_srcu); perf_pmu_register(&perf_swevent); @@ -6302,4 +6305,7 @@ void __init perf_event_init(void) perf_pmu_register(&perf_task_clock); perf_tp_register(); perf_cpu_notifier(perf_cpu_notify); + + ret = init_hw_breakpoint(); + WARN(ret, "hw_breakpoint initialization failed with: %d", ret); } |