4 files changed, 54 insertions, 23 deletions

diff --git a/arch/powerpc/kernel/dawr.c b/arch/powerpc/kernel/dawr.c
index 5f66b95b6858..cc14aa6c4a1b 100644
--- a/arch/powerpc/kernel/dawr.c
+++ b/arch/powerpc/kernel/dawr.c
@@ -30,10 +30,10 @@ int set_dawr(struct arch_hw_breakpoint *brk)
 	 * DAWR length is stored in field MDR bits 48:53.  Matches range in
 	 * doublewords (64 bits) baised by -1 eg. 0b000000=1DW and
 	 * 0b111111=64DW.
-	 * brk->len is in bytes.
+	 * brk->hw_len is in bytes.
 	 * This aligns up to double word size, shifts and does the bias.
 	 */
-	mrd = ((brk->len + 7) >> 3) - 1;
+	mrd = ((brk->hw_len + 7) >> 3) - 1;
 	dawrx |= (mrd & 0x3f) << (63 - 53);
 
 	if (ppc_md.set_dawr)
@@ -54,7 +54,7 @@ static ssize_t dawr_write_file_bool(struct file *file,
 				    const char __user *user_buf,
 				    size_t count, loff_t *ppos)
 {
-	struct arch_hw_breakpoint null_brk = {0, 0, 0};
+	struct arch_hw_breakpoint null_brk = {0};
 	size_t rc;
 
 	/* Send error to user if they hypervisor won't allow us to write DAWR */
diff --git a/arch/powerpc/kernel/hw_breakpoint.c b/arch/powerpc/kernel/hw_breakpoint.c
index 677041cb3c3e..f36274d426ed 100644
--- a/arch/powerpc/kernel/hw_breakpoint.c
+++ b/arch/powerpc/kernel/hw_breakpoint.c
@@ -127,15 +127,58 @@ int arch_bp_generic_fields(int type, int *gen_bp_type)
 }
 
 /*
+ * Watchpoint match range is always doubleword(8 bytes) aligned on
+ * powerpc. If the given range is crossing doubleword boundary, we
+ * need to increase the length such that next doubleword also get
+ * covered. Ex,
+ *
+ *          address   len = 6 bytes
+ *                |=========.
+ *   |------------v--|------v--------|
+ *   | | | | | | | | | | | | | | | | |
+ *   |---------------|---------------|
+ *    <---8 bytes--->
+ *
+ * In this case, we should configure hw as:
+ *   start_addr = address & ~HW_BREAKPOINT_ALIGN
+ *   len = 16 bytes
+ *
+ * @start_addr and @end_addr are inclusive.
+ */
+static int hw_breakpoint_validate_len(struct arch_hw_breakpoint *hw)
+{
+	u16 max_len = DABR_MAX_LEN;
+	u16 hw_len;
+	unsigned long start_addr, end_addr;
+
+	start_addr = hw->address & ~HW_BREAKPOINT_ALIGN;
+	end_addr = (hw->address + hw->len - 1) | HW_BREAKPOINT_ALIGN;
+	hw_len = end_addr - start_addr + 1;
+
+	if (dawr_enabled()) {
+		max_len = DAWR_MAX_LEN;
+		/* DAWR region can't cross 512 bytes boundary */
+		if ((start_addr >> 9) != (end_addr >> 9))
+			return -EINVAL;
+	}
+
+	if (hw_len > max_len)
+		return -EINVAL;
+
+	hw->hw_len = hw_len;
+	return 0;
+}
+
+/*
  * Validate the arch-specific HW Breakpoint register settings
  */
 int hw_breakpoint_arch_parse(struct perf_event *bp,
 			     const struct perf_event_attr *attr,
 			     struct arch_hw_breakpoint *hw)
 {
-	int ret = -EINVAL, length_max;
+	int ret = -EINVAL;
 
-	if (!bp)
+	if (!bp || !attr->bp_len)
 		return ret;
 
 	hw->type = HW_BRK_TYPE_TRANSLATE;
@@ -155,26 +198,10 @@ int hw_breakpoint_arch_parse(struct perf_event *bp,
 	hw->address = attr->bp_addr;
 	hw->len = attr->bp_len;
 
-	/*
-	 * Since breakpoint length can be a maximum of HW_BREAKPOINT_LEN(8)
-	 * and breakpoint addresses are aligned to nearest double-word
-	 * HW_BREAKPOINT_ALIGN by rounding off to the lower address, the
-	 * 'symbolsize' should satisfy the check below.
-	 */
 	if (!ppc_breakpoint_available())
 		return -ENODEV;
-	length_max = DABR_MAX_LEN; /* DABR */
-	if (dawr_enabled()) {
-		length_max = DAWR_MAX_LEN; /* 64 doublewords */
-		/* DAWR region can't cross 512 boundary */
-		if ((attr->bp_addr >> 9) !=
-		    ((attr->bp_addr + attr->bp_len - 1) >> 9))
-			return -EINVAL;
-	}
-	if (hw->len >
-	    (length_max - (hw->address & HW_BREAKPOINT_ALIGN)))
-		return -EINVAL;
-	return 0;
+
+	return hw_breakpoint_validate_len(hw);
 }
 
 /*
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 639ceae7da9d..4df94b6e2f32 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -715,6 +715,8 @@ static void set_debug_reg_defaults(struct thread_struct *thread)
 {
 	thread->hw_brk.address = 0;
 	thread->hw_brk.type = 0;
+	thread->hw_brk.len = 0;
+	thread->hw_brk.hw_len = 0;
 	if (ppc_breakpoint_available())
 		set_breakpoint(&thread->hw_brk);
 }
@@ -816,6 +818,7 @@ static inline bool hw_brk_match(struct arch_hw_breakpoint *a,
 		return false;
 	if (a->len != b->len)
 		return false;
+	/* no need to check hw_len. it's calculated from address and len */
 	return true;
 }
 
diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
index eba39a5f6294..c2dc93157b99 100644
--- a/arch/powerpc/kernel/ptrace.c
+++ b/arch/powerpc/kernel/ptrace.c
@@ -2426,6 +2426,7 @@ static int ptrace_set_debugreg(struct task_struct *task, unsigned long addr,
 	hw_brk.address = data & (~HW_BRK_TYPE_DABR);
 	hw_brk.type = (data & HW_BRK_TYPE_DABR) | HW_BRK_TYPE_PRIV_ALL;
 	hw_brk.len = DABR_MAX_LEN;
+	hw_brk.hw_len = DABR_MAX_LEN;
 	set_bp = (data) && (hw_brk.type & HW_BRK_TYPE_RDWR);
 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 	bp = thread->ptrace_bps[0];