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authorJason Wessel <jason.wessel@windriver.com>2010-01-29 02:04:43 +0300
committerIngo Molnar <mingo@elte.hu>2010-01-30 10:42:21 +0300
commit5352ae638e2d7d5c9b2e4d528676bbf2af6fd6f3 (patch)
tree95bab4d28f7c91bc5b7e79b3e1c879dfe96c52b9 /include/linux/hw_breakpoint.h
parentcc0967490c1c3824bc5b75718b6ca8a51d9f2617 (diff)
downloadlinux-5352ae638e2d7d5c9b2e4d528676bbf2af6fd6f3.tar.xz
perf, hw_breakpoint, kgdb: Do not take mutex for kernel debugger
This patch fixes the regression in functionality where the kernel debugger and the perf API do not nicely share hw breakpoint reservations. The kernel debugger cannot use any mutex_lock() calls because it can start the kernel running from an invalid context. A mutex free version of the reservation API needed to get created for the kernel debugger to safely update hw breakpoint reservations. The possibility for a breakpoint reservation to be concurrently processed at the time that kgdb interrupts the system is improbable. Should this corner case occur the end user is warned, and the kernel debugger will prohibit updating the hardware breakpoint reservations. Any time the kernel debugger reserves a hardware breakpoint it will be a system wide reservation. Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: kgdb-bugreport@lists.sourceforge.net Cc: K.Prasad <prasad@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: torvalds@linux-foundation.org LKML-Reference: <1264719883-7285-3-git-send-email-jason.wessel@windriver.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'include/linux/hw_breakpoint.h')
-rw-r--r--include/linux/hw_breakpoint.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/hw_breakpoint.h b/include/linux/hw_breakpoint.h
index 41235c93e4e9..070ba0621738 100644
--- a/include/linux/hw_breakpoint.h
+++ b/include/linux/hw_breakpoint.h
@@ -75,6 +75,8 @@ extern int __register_perf_hw_breakpoint(struct perf_event *bp);
extern void unregister_hw_breakpoint(struct perf_event *bp);
extern void unregister_wide_hw_breakpoint(struct perf_event **cpu_events);
+extern int dbg_reserve_bp_slot(struct perf_event *bp);
+extern int dbg_release_bp_slot(struct perf_event *bp);
extern int reserve_bp_slot(struct perf_event *bp);
extern void release_bp_slot(struct perf_event *bp);