powerpc/watchpoint: Use builtin ALIGN*() macros

Currently we calculate hw aligned start and end addresses manually.
Replace them with builtin ALIGN_DOWN() and ALIGN() macros.

So far end_addr was inclusive but this patch makes it exclusive (by
avoiding -1) for better readability.
Suggested-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Michael Neuling <mikey@neuling.org>
Link: https://lore.kernel.org/r/20200514111741.97993-13-ravi.bangoria@linux.ibm.com

arch/powerpc/include/asm/hw_breakpoint.h

@@ -34,10 +34,11 @@ struct arch_hw_breakpoint {
 #define HW_BRK_TYPE_PRIV_ALL	(HW_BRK_TYPE_USER | HW_BRK_TYPE_KERNEL | \
 				 HW_BRK_TYPE_HYP)
 
+/* Minimum granularity */
 #ifdef CONFIG_PPC_8xx
-#define HW_BREAKPOINT_ALIGN 0x3
+#define HW_BREAKPOINT_SIZE  0x4
 #else
-#define HW_BREAKPOINT_ALIGN 0x7
+#define HW_BREAKPOINT_SIZE  0x8
 #endif
 
 #define DABR_MAX_LEN	8

arch/powerpc/kernel/hw_breakpoint.c

@@ -146,10 +146,10 @@ int arch_bp_generic_fields(int type, int *gen_bp_type)
  *    <---8 bytes--->
  *
  * In this case, we should configure hw as:
- *   start_addr = address & ~HW_BREAKPOINT_ALIGN
+ *   start_addr = address & ~(HW_BREAKPOINT_SIZE - 1)
  *   len = 16 bytes
  *
- * @start_addr and @end_addr are inclusive.
+ * @start_addr is inclusive but @end_addr is exclusive.
  */
 static int hw_breakpoint_validate_len(struct arch_hw_breakpoint *hw)
 {
@@ -157,14 +157,14 @@ static int hw_breakpoint_validate_len(struct arch_hw_breakpoint *hw)
 	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;
+	start_addr = ALIGN_DOWN(hw->address, HW_BREAKPOINT_SIZE);
+	end_addr = ALIGN(hw->address + hw->len, HW_BREAKPOINT_SIZE);
+	hw_len = end_addr - start_addr;
 
 	if (dawr_enabled()) {
 		max_len = DAWR_MAX_LEN;
 		/* DAWR region can't cross 512 bytes boundary */
-		if ((start_addr >> 9) != (end_addr >> 9))
+		if (ALIGN(start_addr, SZ_512M) != ALIGN(end_addr - 1, SZ_512M))
 			return -EINVAL;
 	} else if (IS_ENABLED(CONFIG_PPC_8xx)) {
 		/* 8xx can setup a range without limitation */

arch/powerpc/kernel/process.c

@@ -800,12 +800,12 @@ static inline int set_breakpoint_8xx(struct arch_hw_breakpoint *brk)
 	unsigned long lctrl1 = LCTRL1_CTE_GT | LCTRL1_CTF_LT | LCTRL1_CRWE_RW |
 			       LCTRL1_CRWF_RW;
 	unsigned long lctrl2 = LCTRL2_LW0EN | LCTRL2_LW0LADC | LCTRL2_SLW0EN;
-	unsigned long start_addr = brk->address & ~HW_BREAKPOINT_ALIGN;
-	unsigned long end_addr = (brk->address + brk->len - 1) | HW_BREAKPOINT_ALIGN;
+	unsigned long start_addr = ALIGN_DOWN(brk->address, HW_BREAKPOINT_SIZE);
+	unsigned long end_addr = ALIGN(brk->address + brk->len, HW_BREAKPOINT_SIZE);
 
 	if (start_addr == 0)
 		lctrl2 |= LCTRL2_LW0LA_F;
-	else if (end_addr == ~0U)
+	else if (end_addr == 0)
 		lctrl2 |= LCTRL2_LW0LA_E;
 	else
 		lctrl2 |= LCTRL2_LW0LA_EandF;
@@ -821,7 +821,7 @@ static inline int set_breakpoint_8xx(struct arch_hw_breakpoint *brk)
 		lctrl1 |= LCTRL1_CRWE_WO | LCTRL1_CRWF_WO;
 
 	mtspr(SPRN_CMPE, start_addr - 1);
-	mtspr(SPRN_CMPF, end_addr + 1);
+	mtspr(SPRN_CMPF, end_addr);
 	mtspr(SPRN_LCTRL1, lctrl1);
 	mtspr(SPRN_LCTRL2, lctrl2);
 

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

@@ -216,7 +216,7 @@ long ppc_set_hwdebug(struct task_struct *child, struct ppc_hw_breakpoint *bp_inf
 	if ((unsigned long)bp_info->addr >= TASK_SIZE)
 		return -EIO;
 
-	brk.address = bp_info->addr & ~HW_BREAKPOINT_ALIGN;
+	brk.address = ALIGN_DOWN(bp_info->addr, HW_BREAKPOINT_SIZE);
 	brk.type = HW_BRK_TYPE_TRANSLATE;
 	brk.len = DABR_MAX_LEN;
 	if (bp_info->trigger_type & PPC_BREAKPOINT_TRIGGER_READ)