From 7d99331e4793b52d488e911876ef11d843c6c8c9 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Wed, 24 Nov 2010 17:45:49 +0000 Subject: [PATCH] ARM: hw_breakpoint: reset control registers in hotplug path The ARMv7 debug architecture doesn't make any guarantees about the contents of debug control registers following a debug logic reset. This patch ensures that we reset the control registers when a cpu comes ONLINE (for example, with hotplug) so that when we enable monitor mode while inserting a breakpoint we won't exhibit random behaviour. Signed-off-by: Will Deacon --- arch/arm/kernel/hw_breakpoint.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/arch/arm/kernel/hw_breakpoint.c b/arch/arm/kernel/hw_breakpoint.c index 793959ec898..515a3c44c11 100644 --- a/arch/arm/kernel/hw_breakpoint.c +++ b/arch/arm/kernel/hw_breakpoint.c @@ -764,7 +764,7 @@ out: /* * One-time initialisation. */ -static void __init reset_ctrl_regs(void *unused) +static void reset_ctrl_regs(void *unused) { int i; @@ -799,6 +799,18 @@ static void __init reset_ctrl_regs(void *unused) } } +static int __cpuinit dbg_reset_notify(struct notifier_block *self, + unsigned long action, void *cpu) +{ + if (action == CPU_ONLINE) + smp_call_function_single((int)cpu, reset_ctrl_regs, NULL, 1); + return NOTIFY_OK; +} + +static struct notifier_block __cpuinitdata dbg_reset_nb = { + .notifier_call = dbg_reset_notify, +}; + static int __init arch_hw_breakpoint_init(void) { int ret = 0; @@ -846,6 +858,8 @@ static int __init arch_hw_breakpoint_init(void) hook_ifault_code(2, hw_breakpoint_pending, SIGTRAP, TRAP_HWBKPT, "breakpoint debug exception"); + /* Register hotplug notifier. */ + register_cpu_notifier(&dbg_reset_nb); out: return ret; } -- 2.46.0