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Commit 0bb9fef9 authored by Jason Wessel's avatar Jason Wessel
Browse files

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: default avatarJason Wessel <jason.wessel@windriver.com>
parent 031acd8c

arch/x86/kernel/cpu/common.c

+17 −12
Original line number Original line Diff line number Diff line
@@ -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

 * cpu_init() initializes state that is per-CPU. Some data is already

 * initialized (naturally) in the bootstrap process, such as the GDT

 * initialized (naturally) in the bootstrap process, such as the GDT
@@ -1174,18 +1188,8 @@ void __cpuinit cpu_init(void) 
	load_TR_desc();

	load_TR_desc();

	load_LDT(&init_mm.context);

	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();

	fpu_init();
@@ -1239,6 +1243,7 @@ void __cpuinit cpu_init(void) 
#endif

#endif





	clear_all_debug_regs();

	clear_all_debug_regs();

	dbg_restore_debug_regs();





	/*

	/*

	 * Force FPU initialization:

	 * Force FPU initialization: