Commit 6749ef0b authored by Benjamin Herrenschmidt's avatar Benjamin Herrenschmidt
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Revert "powerpc/hw-breakpoint: Use generic hw-breakpoint interfaces for new PPC ptrace flags" 



This reverts commit 1b788400.

It causes oopses when passed incorrect arguments and has a
design fault using IPIs with interrupts disabled.

Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
---
parent 933b90a9

Documentation/powerpc/ptrace.txt

+0 −16
Original line number Diff line number Diff line
@@ -127,22 +127,6 @@ Some examples of using the structure to: 
  p.addr2           = (uint64_t) end_range;

  p.condition_value = 0;



- set a watchpoint in server processors (BookS)



  p.version         = 1;

  p.trigger_type    = PPC_BREAKPOINT_TRIGGER_RW;

  p.addr_mode       = PPC_BREAKPOINT_MODE_RANGE_INCLUSIVE;

  or

  p.addr_mode       = PPC_BREAKPOINT_MODE_EXACT;



  p.condition_mode  = PPC_BREAKPOINT_CONDITION_NONE;

  p.addr            = (uint64_t) begin_range;

  /* For PPC_BREAKPOINT_MODE_RANGE_INCLUSIVE addr2 needs to be specified, where

   * addr2 - addr <= 8 Bytes.

   */

  p.addr2           = (uint64_t) end_range;

  p.condition_value = 0;



3. PTRACE_DELHWDEBUG



Takes an integer which identifies an existing breakpoint or watchpoint

arch/powerpc/kernel/ptrace.c

+6 −71
Original line number Diff line number Diff line
@@ -1336,12 +1336,6 @@ static int set_dac_range(struct task_struct *child, 
static long ppc_set_hwdebug(struct task_struct *child,

		     struct ppc_hw_breakpoint *bp_info)

{

#ifdef CONFIG_HAVE_HW_BREAKPOINT

	int len = 0;

	struct thread_struct *thread = &(child->thread);

	struct perf_event *bp;

	struct perf_event_attr attr;

#endif /* CONFIG_HAVE_HW_BREAKPOINT */

#ifndef CONFIG_PPC_ADV_DEBUG_REGS

	unsigned long dabr;

#endif
@@ -1385,9 +1379,13 @@ static long ppc_set_hwdebug(struct task_struct *child, 
	 */

	if ((bp_info->trigger_type & PPC_BREAKPOINT_TRIGGER_RW) == 0 ||

	    (bp_info->trigger_type & ~PPC_BREAKPOINT_TRIGGER_RW) != 0 ||

	    bp_info->addr_mode != PPC_BREAKPOINT_MODE_EXACT ||

	    bp_info->condition_mode != PPC_BREAKPOINT_CONDITION_NONE)

		return -EINVAL;



	if (child->thread.dabr)

		return -ENOSPC;



	if ((unsigned long)bp_info->addr >= TASK_SIZE)

		return -EIO;
@@ -1397,63 +1395,15 @@ static long ppc_set_hwdebug(struct task_struct *child, 
		dabr |= DABR_DATA_READ;

	if (bp_info->trigger_type & PPC_BREAKPOINT_TRIGGER_WRITE)

		dabr |= DABR_DATA_WRITE;

#ifdef CONFIG_HAVE_HW_BREAKPOINT

	if (ptrace_get_breakpoints(child) < 0)

		return -ESRCH;



	/*

	 * Check if the request is for 'range' breakpoints. We can

	 * support it if range < 8 bytes.

	 */

	if (bp_info->addr_mode == PPC_BREAKPOINT_MODE_RANGE_INCLUSIVE) {

		len = bp_info->addr2 - bp_info->addr;

	} else if (bp_info->addr_mode != PPC_BREAKPOINT_MODE_EXACT) {

		ptrace_put_breakpoints(child);

		return -EINVAL;

	}

	bp = thread->ptrace_bps[0];

	if (bp) {

		ptrace_put_breakpoints(child);

		return -ENOSPC;

	}



	/* Create a new breakpoint request if one doesn't exist already */

	hw_breakpoint_init(&attr);

	attr.bp_addr = (unsigned long)bp_info->addr & ~HW_BREAKPOINT_ALIGN;

	attr.bp_len = len;

	arch_bp_generic_fields(dabr & (DABR_DATA_WRITE | DABR_DATA_READ),

								&attr.bp_type);



	thread->ptrace_bps[0] = bp = register_user_hw_breakpoint(&attr,

					       ptrace_triggered, NULL, child);

	if (IS_ERR(bp)) {

		thread->ptrace_bps[0] = NULL;

		ptrace_put_breakpoints(child);

		return PTR_ERR(bp);

	}



	ptrace_put_breakpoints(child);

	return 1;

#endif /* CONFIG_HAVE_HW_BREAKPOINT */



	if (bp_info->addr_mode != PPC_BREAKPOINT_MODE_EXACT)

		return -EINVAL;



	if (child->thread.dabr)

		return -ENOSPC;



	child->thread.dabr = dabr;



	return 1;

#endif /* !CONFIG_PPC_ADV_DEBUG_DVCS */

}



static long ppc_del_hwdebug(struct task_struct *child, long addr, long data)

{

#ifdef CONFIG_HAVE_HW_BREAKPOINT

	int ret = 0;

	struct thread_struct *thread = &(child->thread);

	struct perf_event *bp;

#endif /* CONFIG_HAVE_HW_BREAKPOINT */

#ifdef CONFIG_PPC_ADV_DEBUG_REGS

	int rc;
@@ -1473,25 +1423,10 @@ static long ppc_del_hwdebug(struct task_struct *child, long addr, long data) 
#else

	if (data != 1)

		return -EINVAL;



#ifdef CONFIG_HAVE_HW_BREAKPOINT

	if (ptrace_get_breakpoints(child) < 0)

		return -ESRCH;



	bp = thread->ptrace_bps[0];

	if (bp) {

		unregister_hw_breakpoint(bp);

		thread->ptrace_bps[0] = NULL;

	} else

		ret = -ENOENT;

	ptrace_put_breakpoints(child);

	return ret;

#else /* CONFIG_HAVE_HW_BREAKPOINT */

	if (child->thread.dabr == 0)

		return -ENOENT;



	child->thread.dabr = 0;

#endif /* CONFIG_HAVE_HW_BREAKPOINT */



	return 0;

#endif
@@ -1598,7 +1533,7 @@ long arch_ptrace(struct task_struct *child, long request, 
		dbginfo.data_bp_alignment = 4;

#endif

		dbginfo.sizeof_condition = 0;

		dbginfo.features = PPC_DEBUG_FEATURE_DATA_BP_RANGE;

		dbginfo.features = 0;

#endif /* CONFIG_PPC_ADV_DEBUG_REGS */



		if (!access_ok(VERIFY_WRITE, datavp,