1 files changed, 31 insertions, 21 deletions

diff --git a/arch/powerpc/kernel/hw_breakpoint.c b/arch/powerpc/kernel/hw_breakpoint.c
index f36274d426ed..58ce3d37c2a3 100644
--- a/arch/powerpc/kernel/hw_breakpoint.c
+++ b/arch/powerpc/kernel/hw_breakpoint.c
@@ -222,33 +222,49 @@ void thread_change_pc(struct task_struct *tsk, struct pt_regs *regs)
 	tsk->thread.last_hit_ubp = NULL;
 }
 
-static bool is_larx_stcx_instr(struct pt_regs *regs, unsigned int instr)
+static bool dar_within_range(unsigned long dar, struct arch_hw_breakpoint *info)
 {
-	int ret, type;
-	struct instruction_op op;
+	return ((info->address <= dar) && (dar - info->address < info->len));
+}
 
-	ret = analyse_instr(&op, regs, instr);
-	type = GETTYPE(op.type);
-	return (!ret && (type == LARX || type == STCX));
+static bool
+dar_range_overlaps(unsigned long dar, int size, struct arch_hw_breakpoint *info)
+{
+	return ((dar <= info->address + info->len - 1) &&
+		(dar + size - 1 >= info->address));
 }
 
 /*
  * Handle debug exception notifications.
  */
 static bool stepping_handler(struct pt_regs *regs, struct perf_event *bp,
-			     unsigned long addr)
+			     struct arch_hw_breakpoint *info)
 {
 	unsigned int instr = 0;
+	int ret, type, size;
+	struct instruction_op op;
+	unsigned long addr = info->address;
 
 	if (__get_user_inatomic(instr, (unsigned int *)regs->nip))
 		goto fail;
 
-	if (is_larx_stcx_instr(regs, instr)) {
+	ret = analyse_instr(&op, regs, instr);
+	type = GETTYPE(op.type);
+	size = GETSIZE(op.type);
+
+	if (!ret && (type == LARX || type == STCX)) {
 		printk_ratelimited("Breakpoint hit on instruction that can't be emulated."
 				   " Breakpoint at 0x%lx will be disabled.\n", addr);
 		goto disable;
 	}
 
+	/*
+	 * If it's extraneous event, we still need to emulate/single-
+	 * step the instruction, but we don't generate an event.
+	 */
+	if (size && !dar_range_overlaps(regs->dar, size, info))
+		info->type |= HW_BRK_TYPE_EXTRANEOUS_IRQ;
+
 	/* Do not emulate user-space instructions, instead single-step them */
 	if (user_mode(regs)) {
 		current->thread.last_hit_ubp = bp;
@@ -280,7 +296,6 @@ int hw_breakpoint_handler(struct die_args *args)
 	struct perf_event *bp;
 	struct pt_regs *regs = args->regs;
 	struct arch_hw_breakpoint *info;
-	unsigned long dar = regs->dar;
 
 	/* Disable breakpoints during exception handling */
 	hw_breakpoint_disable();
@@ -312,19 +327,14 @@ int hw_breakpoint_handler(struct die_args *args)
 		goto out;
 	}
 
-	/*
-	 * Verify if dar lies within the address range occupied by the symbol
-	 * being watched to filter extraneous exceptions.  If it doesn't,
-	 * we still need to single-step the instruction, but we don't
-	 * generate an event.
-	 */
 	info->type &= ~HW_BRK_TYPE_EXTRANEOUS_IRQ;
-	if (!((bp->attr.bp_addr <= dar) &&
-	      (dar - bp->attr.bp_addr < bp->attr.bp_len)))
-		info->type |= HW_BRK_TYPE_EXTRANEOUS_IRQ;
-
-	if (!IS_ENABLED(CONFIG_PPC_8xx) && !stepping_handler(regs, bp, info->address))
-		goto out;
+	if (IS_ENABLED(CONFIG_PPC_8xx)) {
+		if (!dar_within_range(regs->dar, info))
+			info->type |= HW_BRK_TYPE_EXTRANEOUS_IRQ;
+	} else {
+		if (!stepping_handler(regs, bp, info))
+			goto out;
+	}
 
 	/*
 	 * As a policy, the callback is invoked in a 'trigger-after-execute'