Commit 34d0b5af authored by Paul Mundt's avatar Paul Mundt
Browse files

sh: Convert ptrace to hw_breakpoint API. 



This is the initial step for converting singlestep handling via ptrace
over to hw_breakpoints.

Signed-off-by: default avatarPaul Mundt <lethal@linux-sh.org>
parent 22648735

arch/sh/include/asm/ptrace.h

+6 −0
Original line number Diff line number Diff line
@@ -124,6 +124,12 @@ struct task_struct; 
extern void user_enable_single_step(struct task_struct *);

extern void user_disable_single_step(struct task_struct *);



struct perf_event;

struct perf_sample_data;



extern void ptrace_triggered(struct perf_event *bp, int nmi,

		      struct perf_sample_data *data, struct pt_regs *regs);



#define task_pt_regs(task) \

	((struct pt_regs *) (task_stack_page(task) + THREAD_SIZE) - 1)

arch/sh/kernel/hw_breakpoint.c

+13 −2
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@ 
#include <linux/io.h>

#include <asm/hw_breakpoint.h>

#include <asm/mmu_context.h>

#include <asm/ptrace.h>



struct ubc_context {

	unsigned long pc;
@@ -372,7 +373,7 @@ static int __kprobes hw_breakpoint_handler(struct die_args *args) 
		rcu_read_unlock();

	}



	if (bp) {

	if (bp && bp->overflow_handler != ptrace_triggered) {

		struct arch_hw_breakpoint *info = counter_arch_bp(bp);



		__raw_writel(UBC_CBR_CE | info->len | info->type, UBC_CBR0);
@@ -387,9 +388,19 @@ static int __kprobes hw_breakpoint_handler(struct die_args *args) 
BUILD_TRAP_HANDLER(breakpoint)

{

	unsigned long ex = lookup_exception_vector();

	siginfo_t info;

	int err;

	TRAP_HANDLER_DECL;



	notify_die(DIE_BREAKPOINT, "breakpoint", regs, 0, ex, SIGTRAP);

	err = notify_die(DIE_BREAKPOINT, "breakpoint", regs, 0, ex, SIGTRAP);

	if (err == NOTIFY_STOP)

		return;



	/* Deliver the signal to userspace */

	info.si_signo = SIGTRAP;

	info.si_errno = 0;

	info.si_code = TRAP_HWBKPT;

	force_sig_info(SIGTRAP, &info, current);

}



/*

arch/sh/kernel/ptrace_32.c

+52 −1
Original line number Diff line number Diff line
@@ -2,7 +2,7 @@ 
 * SuperH process tracing

 *

 * Copyright (C) 1999, 2000  Kaz Kojima & Niibe Yutaka

 * Copyright (C) 2002 - 2008  Paul Mundt

 * Copyright (C) 2002 - 2009  Paul Mundt

 *

 * Audit support by Yuichi Nakamura <ynakam@hitachisoft.jp>

 *
@@ -26,6 +26,7 @@ 
#include <linux/tracehook.h>

#include <linux/elf.h>

#include <linux/regset.h>

#include <linux/hw_breakpoint.h>

#include <asm/uaccess.h>

#include <asm/pgtable.h>

#include <asm/system.h>
@@ -63,9 +64,59 @@ static inline int put_stack_long(struct task_struct *task, int offset, 
	return 0;

}



void ptrace_triggered(struct perf_event *bp, int nmi,

		      struct perf_sample_data *data, struct pt_regs *regs)

{

	struct perf_event_attr attr;



	/*

	 * Disable the breakpoint request here since ptrace has defined a

	 * one-shot behaviour for breakpoint exceptions.

	 */

	attr = bp->attr;

	attr.disabled = true;

	modify_user_hw_breakpoint(bp, &attr);

}



static int set_single_step(struct task_struct *tsk, unsigned long addr)

{

	struct thread_struct *thread = &tsk->thread;

	struct perf_event *bp;

	struct perf_event_attr attr;



	bp = thread->ptrace_bps[0];

	if (!bp) {

		hw_breakpoint_init(&attr);



		attr.bp_addr = addr;

		attr.bp_len = HW_BREAKPOINT_LEN_2;

		attr.bp_type = HW_BREAKPOINT_R;



		bp = register_user_hw_breakpoint(&attr, ptrace_triggered, tsk);

		if (IS_ERR(bp))

			return PTR_ERR(bp);



		thread->ptrace_bps[0] = bp;

	} else {

		int err;



		attr = bp->attr;

		attr.bp_addr = addr;

		err = modify_user_hw_breakpoint(bp, &attr);

		if (unlikely(err))

			return err;

	}



	return 0;

}



void user_enable_single_step(struct task_struct *child)

{

	unsigned long pc = get_stack_long(child, offsetof(struct pt_regs, pc));



	set_tsk_thread_flag(child, TIF_SINGLESTEP);



	set_single_step(child, pc);

}



void user_disable_single_step(struct task_struct *child)