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authorK.Prasad <prasad@linux.vnet.ibm.com>2010-06-15 11:35:19 +0530
committerPaul Mackerras <paulus@samba.org>2010-06-22 19:40:50 +1000
commit5aae8a53708025d4e718f0d2e7c2f766779ddc71 (patch)
treed151e2c29e78248cee620cf5094a15316abd17d2 /arch/powerpc/kernel/machine_kexec_64.c
parentf7136c5150c29846d7a1d09109449d96b2f63445 (diff)
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powerpc, hw_breakpoints: Implement hw_breakpoints for 64-bit server processors
Implement perf-events based hw-breakpoint interfaces for PowerPC 64-bit server (Book III S) processors. This allows access to a given location to be used as an event that can be counted or profiled by the perf_events subsystem. This is done using the DABR (data breakpoint register), which can also be used for process debugging via ptrace. When perf_event hw_breakpoint support is configured in, the perf_event subsystem manages the DABR and arbitrates access to it, and ptrace then creates a perf_event when it is requested to set a data breakpoint. [Adopted suggestions from Paul Mackerras <paulus@samba.org> to - emulate_step() all system-wide breakpoints and single-step only the per-task breakpoints - perform arch-specific cleanup before unregistration through arch_unregister_hw_breakpoint() ] Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'arch/powerpc/kernel/machine_kexec_64.c')
-rw-r--r--arch/powerpc/kernel/machine_kexec_64.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/machine_kexec_64.c b/arch/powerpc/kernel/machine_kexec_64.c
index 26f9900f773c..6c7c546aa1be 100644
--- a/arch/powerpc/kernel/machine_kexec_64.c
+++ b/arch/powerpc/kernel/machine_kexec_64.c
@@ -25,6 +25,7 @@
#include <asm/sections.h> /* _end */
#include <asm/prom.h>
#include <asm/smp.h>
+#include <asm/hw_breakpoint.h>
int default_machine_kexec_prepare(struct kimage *image)
{
@@ -165,6 +166,7 @@ static void kexec_smp_down(void *arg)
while(kexec_all_irq_disabled == 0)
cpu_relax();
mb(); /* make sure all irqs are disabled before this */
+ hw_breakpoint_disable();
/*
* Now every CPU has IRQs off, we can clear out any pending
* IPIs and be sure that no more will come in after this.
@@ -180,6 +182,7 @@ static void kexec_prepare_cpus_wait(int wait_state)
{
int my_cpu, i, notified=-1;
+ hw_breakpoint_disable();
my_cpu = get_cpu();
/* Make sure each CPU has atleast made it to the state we need */
for (i=0; i < NR_CPUS; i++) {