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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 <tglx@linutronix.de>
CC: Ingo Molnar <mingo@redhat.com>
CC: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
This commit is contained in:
Jason Wessel 2010-05-20 21:04:30 -05:00
parent 031acd8c42
commit 0bb9fef913
1 changed files with 17 additions and 12 deletions
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29
arch/x86/kernel/cpu/common.c
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@ -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: