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Commit 9422de3e authored by Michael Neuling's avatar Michael Neuling Committed by Benjamin Herrenschmidt
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powerpc: Hardware breakpoints rewrite to handle non DABR breakpoint registers 



This is a rewrite so that we don't assume we are using the DABR throughout the
code.  We now use the arch_hw_breakpoint to store the breakpoint in a generic
manner in the thread_struct, rather than storing the raw DABR value.

The ptrace GET/SET_DEBUGREG interface currently passes the raw DABR in from
userspace.  We keep this functionality, so that future changes (like the POWER8
DAWR), will still fake the DABR to userspace.

Signed-off-by: default avatarMichael Neuling <mikey@neuling.org>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent a8190a59

arch/powerpc/include/asm/debug.h

+9 −6
Original line number Diff line number Diff line
@@ -4,6 +4,8 @@ 
#ifndef _ASM_POWERPC_DEBUG_H

#define _ASM_POWERPC_DEBUG_H



#include <asm/hw_breakpoint.h>



struct pt_regs;



extern struct dentry *powerpc_debugfs_root;
@@ -15,7 +17,7 @@ extern int (*__debugger_ipi)(struct pt_regs *regs); 
extern int (*__debugger_bpt)(struct pt_regs *regs);

extern int (*__debugger_sstep)(struct pt_regs *regs);

extern int (*__debugger_iabr_match)(struct pt_regs *regs);

extern int (*__debugger_dabr_match)(struct pt_regs *regs);

extern int (*__debugger_break_match)(struct pt_regs *regs);

extern int (*__debugger_fault_handler)(struct pt_regs *regs);



#define DEBUGGER_BOILERPLATE(__NAME) \
@@ -31,7 +33,7 @@ DEBUGGER_BOILERPLATE(debugger_ipi) 
DEBUGGER_BOILERPLATE(debugger_bpt)

DEBUGGER_BOILERPLATE(debugger_sstep)

DEBUGGER_BOILERPLATE(debugger_iabr_match)

DEBUGGER_BOILERPLATE(debugger_dabr_match)

DEBUGGER_BOILERPLATE(debugger_break_match)

DEBUGGER_BOILERPLATE(debugger_fault_handler)



#else
@@ -40,16 +42,17 @@ static inline int debugger_ipi(struct pt_regs *regs) { return 0; } 
static inline int debugger_bpt(struct pt_regs *regs) { return 0; }

static inline int debugger_sstep(struct pt_regs *regs) { return 0; }

static inline int debugger_iabr_match(struct pt_regs *regs) { return 0; }

static inline int debugger_dabr_match(struct pt_regs *regs) { return 0; }

static inline int debugger_break_match(struct pt_regs *regs) { return 0; }

static inline int debugger_fault_handler(struct pt_regs *regs) { return 0; }

#endif



extern int set_dabr(unsigned long dabr, unsigned long dabrx);

int set_break(struct arch_hw_breakpoint *brk);

#ifdef CONFIG_PPC_ADV_DEBUG_REGS

extern void do_send_trap(struct pt_regs *regs, unsigned long address,

			 unsigned long error_code, int signal_code, int brkpt);

#else

extern void do_dabr(struct pt_regs *regs, unsigned long address,



extern void do_break(struct pt_regs *regs, unsigned long address,

		     unsigned long error_code);

#endif

arch/powerpc/include/asm/hw_breakpoint.h

+26 −7
Original line number Diff line number Diff line
@@ -24,16 +24,30 @@ 
#define _PPC_BOOK3S_64_HW_BREAKPOINT_H



#ifdef	__KERNEL__

#ifdef CONFIG_HAVE_HW_BREAKPOINT



struct arch_hw_breakpoint {

	unsigned long	address;

	unsigned long	dabrx;

	int		type;

	u8		len; /* length of the target data symbol */

	bool		extraneous_interrupt;

	u16		type;

	u16		len; /* length of the target data symbol */

};



/* Note: Don't change the the first 6 bits below as they are in the same order

 * as the dabr and dabrx.

 */

#define HW_BRK_TYPE_READ		0x01

#define HW_BRK_TYPE_WRITE		0x02

#define HW_BRK_TYPE_TRANSLATE		0x04

#define HW_BRK_TYPE_USER		0x08

#define HW_BRK_TYPE_KERNEL		0x10

#define HW_BRK_TYPE_HYP			0x20

#define HW_BRK_TYPE_EXTRANEOUS_IRQ	0x80



/* bits that overlap with the bottom 3 bits of the dabr */

#define HW_BRK_TYPE_RDWR	(HW_BRK_TYPE_READ | HW_BRK_TYPE_WRITE)

#define HW_BRK_TYPE_DABR	(HW_BRK_TYPE_RDWR | HW_BRK_TYPE_TRANSLATE)

#define HW_BRK_TYPE_PRIV_ALL	(HW_BRK_TYPE_USER | HW_BRK_TYPE_KERNEL | \

				 HW_BRK_TYPE_HYP)



#ifdef CONFIG_HAVE_HW_BREAKPOINT

#include <linux/kdebug.h>

#include <asm/reg.h>

#include <asm/debug.h>
@@ -62,7 +76,12 @@ extern void ptrace_triggered(struct perf_event *bp, 
			struct perf_sample_data *data, struct pt_regs *regs);

static inline void hw_breakpoint_disable(void)

{

	set_dabr(0, 0);

	struct arch_hw_breakpoint brk;



	brk.address = 0;

	brk.type = 0;

	brk.len = 0;

	set_break(&brk);

}

extern void thread_change_pc(struct task_struct *tsk, struct pt_regs *regs);

arch/powerpc/include/asm/processor.h

+2 −2
Original line number Diff line number Diff line
@@ -33,6 +33,7 @@ 
#include <linux/cache.h>

#include <asm/ptrace.h>

#include <asm/types.h>

#include <asm/hw_breakpoint.h>



/* We do _not_ want to define new machine types at all, those must die

 * in favor of using the device-tree
@@ -225,8 +226,7 @@ struct thread_struct { 
	struct perf_event *last_hit_ubp;

#endif /* CONFIG_HAVE_HW_BREAKPOINT */

#endif

	unsigned long	dabr;		/* Data address breakpoint register */

	unsigned long	dabrx;		/*      ... extension  */

	struct arch_hw_breakpoint hw_brk; /* info on the hardware breakpoint */

	unsigned long	trap_nr;	/* last trap # on this thread */

#ifdef CONFIG_ALTIVEC

	/* Complete AltiVec register set */

arch/powerpc/include/asm/reg.h

+0 −3
Original line number Diff line number Diff line
@@ -206,9 +206,6 @@ 
#define   DAWRX_KERNEL	(1UL << 1)

#define   DAWRX_HYP	(1UL << 2)

#define SPRN_DABR	0x3F5	/* Data Address Breakpoint Register */

#define   DABR_TRANSLATION	(1UL << 2)

#define   DABR_DATA_WRITE	(1UL << 1)

#define   DABR_DATA_READ	(1UL << 0)

#define SPRN_DABR2	0x13D	/* e300 */

#define SPRN_DABRX	0x3F7	/* Data Address Breakpoint Register Extension */

#define   DABRX_USER	(1UL << 0)

arch/powerpc/kernel/exceptions-64s.S

+1 −1
Original line number Diff line number Diff line
@@ -1251,7 +1251,7 @@ handle_dabr_fault: 
	ld      r4,_DAR(r1)

	ld      r5,_DSISR(r1)

	addi    r3,r1,STACK_FRAME_OVERHEAD

	bl      .do_dabr

	bl      .do_break

12:	b       .ret_from_except_lite