From 93a04a3416da12647c47840ebe2bb812fcb801d0 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Mon, 29 Nov 2010 16:56:01 +0000 Subject: ARM: hw_breakpoint: do not allocate new breakpoints with preemption disabled The watchpoint single-stepping code calls register_user_hw_breakpoint to register a mismatch breakpoint for stepping over the watchpoint. This is performed with preemption disabled, which is unsafe as we may end up scheduling whilst in_atomic(). Furthermore, using the perf API is rather overkill since we are already in the hw-breakpoint backend and only require access to reserved breakpoints anyway. This patch reworks the watchpoint stepping code so that we don't require another perf_event for the mismatch breakpoint. Instead, we hold a separate arch_hw_breakpoint_ctrl struct inside the watchpoint which is used exclusively for stepping. We can check whether or not stepping is enabled when installing or uninstalling the watchpoint and operate on the breakpoint accordingly. Signed-off-by: Will Deacon --- arch/arm/include/asm/hw_breakpoint.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/arm/include/asm/hw_breakpoint.h') diff --git a/arch/arm/include/asm/hw_breakpoint.h b/arch/arm/include/asm/hw_breakpoint.h index 4d8ae9d67abe..881429d0b849 100644 --- a/arch/arm/include/asm/hw_breakpoint.h +++ b/arch/arm/include/asm/hw_breakpoint.h @@ -20,7 +20,7 @@ struct arch_hw_breakpoint_ctrl { struct arch_hw_breakpoint { u32 address; u32 trigger; - struct perf_event *suspended_wp; + struct arch_hw_breakpoint_ctrl step_ctrl; struct arch_hw_breakpoint_ctrl ctrl; }; -- cgit