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x86,early dr regs,kgdb: Allow kernel debugger early dr register access

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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: