From 0bb9fef9134cf4fdcfce02f9adc22d3d0725cc29 Mon Sep 17 00:00:00 2001 From: Jason Wessel Date: Thu, 20 May 2010 21:04:30 -0500 Subject: [PATCH] x86,early dr regs,kgdb: Allow kernel debugger early dr register access If the kernel debugger was configured, attached and started with kgdbwait, the hardware breakpoint registers should get restored by the kgdb code which is managing the dr registers. CC: x86@kernel.org CC: Thomas Gleixner CC: Ingo Molnar CC: H. Peter Anvin Signed-off-by: Jason Wessel --- arch/x86/kernel/cpu/common.c | 29 +++++++++++++++++------------ 1 file changed, 17 insertions(+), 12 deletions(-) diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index c1c00d0b1692..cc83a002786e 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1084,6 +1084,20 @@ static void clear_all_debug_regs(void) } } +#ifdef CONFIG_KGDB +/* + * Restore debug regs if using kgdbwait and you have a kernel debugger + * connection established. + */ +static void dbg_restore_debug_regs(void) +{ + if (unlikely(kgdb_connected && arch_kgdb_ops.correct_hw_break)) + arch_kgdb_ops.correct_hw_break(); +} +#else /* ! CONFIG_KGDB */ +#define dbg_restore_debug_regs() +#endif /* ! CONFIG_KGDB */ + /* * cpu_init() initializes state that is per-CPU. Some data is already * initialized (naturally) in the bootstrap process, such as the GDT @@ -1174,18 +1188,8 @@ void __cpuinit cpu_init(void) load_TR_desc(); load_LDT(&init_mm.context); -#ifdef CONFIG_KGDB - /* - * If the kgdb is connected no debug regs should be altered. This - * is only applicable when KGDB and a KGDB I/O module are built - * into the kernel and you are using early debugging with - * kgdbwait. KGDB will control the kernel HW breakpoint registers. - */ - if (kgdb_connected && arch_kgdb_ops.correct_hw_break) - arch_kgdb_ops.correct_hw_break(); - else -#endif - clear_all_debug_regs(); + clear_all_debug_regs(); + dbg_restore_debug_regs(); fpu_init(); @@ -1239,6 +1243,7 @@ void __cpuinit cpu_init(void) #endif clear_all_debug_regs(); + dbg_restore_debug_regs(); /* * Force FPU initialization: -- 2.20.1