Commit 6b424efa authored by Ravi Bangoria's avatar Ravi Bangoria Committed by Michael Ellerman
Browse files

powerpc/watchpoint: Use loop for thread_struct->ptrace_bps 



ptrace_bps is already an array of size HBP_NUM_MAX. But we use
hardcoded index 0 while fetching/updating it. Convert such code
to loop over array.

ptrace interface to use multiple watchpoint remains same. eg:
two PPC_PTRACE_SETHWDEBUG calls will create two watchpoint if
underneath hw supports it.

Signed-off-by: default avatarRavi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Reviewed-by: default avatarMichael Neuling <mikey@neuling.org>
Link: https://lore.kernel.org/r/20200514111741.97993-11-ravi.bangoria@linux.ibm.com
parent 303e6a9d

arch/powerpc/kernel/hw_breakpoint.c

+5 −2
Original line number Diff line number Diff line
@@ -420,10 +420,13 @@ NOKPROBE_SYMBOL(hw_breakpoint_exceptions_notify); 
 */

void flush_ptrace_hw_breakpoint(struct task_struct *tsk)

{

	int i;

	struct thread_struct *t = &tsk->thread;



	unregister_hw_breakpoint(t->ptrace_bps[0]);

	t->ptrace_bps[0] = NULL;

	for (i = 0; i < nr_wp_slots(); i++) {

		unregister_hw_breakpoint(t->ptrace_bps[i]);

		t->ptrace_bps[i] = NULL;

	}

}



void hw_breakpoint_pmu_read(struct perf_event *bp)

arch/powerpc/kernel/process.c

+5 −1
Original line number Diff line number Diff line
@@ -1604,6 +1604,9 @@ int copy_thread_tls(unsigned long clone_flags, unsigned long usp, 
	void (*f)(void);

	unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;

	struct thread_info *ti = task_thread_info(p);

#ifdef CONFIG_HAVE_HW_BREAKPOINT

	int i;

#endif



	klp_init_thread_info(p);
@@ -1663,7 +1666,8 @@ int copy_thread_tls(unsigned long clone_flags, unsigned long usp, 
	p->thread.ksp_limit = (unsigned long)end_of_stack(p);

#endif

#ifdef CONFIG_HAVE_HW_BREAKPOINT

	p->thread.ptrace_bps[0] = NULL;

	for (i = 0; i < nr_wp_slots(); i++)

		p->thread.ptrace_bps[i] = NULL;

#endif



	p->thread.fp_save_area = NULL;

arch/powerpc/kernel/ptrace/ptrace-noadv.c

+21 −7
Original line number Diff line number Diff line
@@ -168,6 +168,19 @@ int ptrace_set_debugreg(struct task_struct *task, unsigned long addr, unsigned l 
	return 0;

}



#ifdef CONFIG_HAVE_HW_BREAKPOINT

static int find_empty_ptrace_bp(struct thread_struct *thread)

{

	int i;



	for (i = 0; i < nr_wp_slots(); i++) {

		if (!thread->ptrace_bps[i])

			return i;

	}

	return -1;

}

#endif



static int find_empty_hw_brk(struct thread_struct *thread)

{

	int i;
@@ -217,8 +230,9 @@ long ppc_set_hwdebug(struct task_struct *child, struct ppc_hw_breakpoint *bp_inf 
		len = 1;

	else

		return -EINVAL;

	bp = thread->ptrace_bps[0];

	if (bp)



	i = find_empty_ptrace_bp(thread);

	if (i < 0)

		return -ENOSPC;



	/* Create a new breakpoint request if one doesn't exist already */
@@ -228,13 +242,13 @@ long ppc_set_hwdebug(struct task_struct *child, struct ppc_hw_breakpoint *bp_inf 
	arch_bp_generic_fields(brk.type, &attr.bp_type);



	bp = register_user_hw_breakpoint(&attr, ptrace_triggered, NULL, child);

	thread->ptrace_bps[0] = bp;

	thread->ptrace_bps[i] = bp;

	if (IS_ERR(bp)) {

		thread->ptrace_bps[0] = NULL;

		thread->ptrace_bps[i] = NULL;

		return PTR_ERR(bp);

	}



	return 1;

	return i + 1;

#endif /* CONFIG_HAVE_HW_BREAKPOINT */



	if (bp_info->addr_mode != PPC_BREAKPOINT_MODE_EXACT)
@@ -263,10 +277,10 @@ long ppc_del_hwdebug(struct task_struct *child, long data) 
		return -EINVAL;



#ifdef CONFIG_HAVE_HW_BREAKPOINT

	bp = thread->ptrace_bps[0];

	bp = thread->ptrace_bps[data - 1];

	if (bp) {

		unregister_hw_breakpoint(bp);

		thread->ptrace_bps[0] = NULL;

		thread->ptrace_bps[data - 1] = NULL;

	} else {

		ret = -ENOENT;

	}

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