From 5352ae638e2d7d5c9b2e4d528676bbf2af6fd6f3 Mon Sep 17 00:00:00 2001 From: Jason Wessel Date: Thu, 28 Jan 2010 17:04:43 -0600 Subject: 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 Acked-by: Frederic Weisbecker Cc: kgdb-bugreport@lists.sourceforge.net Cc: K.Prasad Cc: Peter Zijlstra Cc: Alan Stern Cc: torvalds@linux-foundation.org LKML-Reference: <1264719883-7285-3-git-send-email-jason.wessel@windriver.com> Signed-off-by: Ingo Molnar --- include/linux/hw_breakpoint.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux/hw_breakpoint.h') 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); -- cgit v1.2.2 From cd757645fbdc34a8343c04bb0e74e06fccc2cb10 Mon Sep 17 00:00:00 2001 From: Mahesh Salgaonkar Date: Sat, 30 Jan 2010 10:25:18 +0530 Subject: perf: Make bp_len type to u64 generic across the arch Change 'bp_len' type to __u64 to make it work across archs as the s390 architecture watch point length can be upto 2^64. reference: http://lkml.org/lkml/2010/1/25/212 This is an ABI change that is not backward compatible with the previous hardware breakpoint info layout integrated in this development cycle, a rebuilt of perf tools is necessary for versions based on 2.6.33-rc1 - 2.6.33-rc6 to work with a kernel based on this patch. Signed-off-by: Mahesh Salgaonkar Acked-by: Peter Zijlstra Cc: Ananth N Mavinakayanahalli Cc: "K. Prasad" Cc: Maneesh Soni Cc: Heiko Carstens Cc: Martin LKML-Reference: <20100130045518.GA20776@in.ibm.com> Signed-off-by: Frederic Weisbecker --- include/linux/hw_breakpoint.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux/hw_breakpoint.h') diff --git a/include/linux/hw_breakpoint.h b/include/linux/hw_breakpoint.h index 070ba0621738..5977b724f7c6 100644 --- a/include/linux/hw_breakpoint.h +++ b/include/linux/hw_breakpoint.h @@ -44,7 +44,7 @@ static inline int hw_breakpoint_type(struct perf_event *bp) return bp->attr.bp_type; } -static inline int hw_breakpoint_len(struct perf_event *bp) +static inline unsigned long hw_breakpoint_len(struct perf_event *bp) { return bp->attr.bp_len; } -- cgit v1.2.2