powerpc/watchpoint: Introduce macros for watchpoint length

We are hadrcoding length everywhere in the watchpoint code. Introduce
macros for the length and use them.
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20191017093204.7511-2-ravi.bangoria@linux.ibm.com

arch/powerpc/include/asm/hw_breakpoint.h

@@ -33,6 +33,9 @@ struct arch_hw_breakpoint {
 #define HW_BRK_TYPE_PRIV_ALL	(HW_BRK_TYPE_USER | HW_BRK_TYPE_KERNEL | \
 				 HW_BRK_TYPE_HYP)
 
+#define DABR_MAX_LEN	8
+#define DAWR_MAX_LEN	512
+
 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 #include <linux/kdebug.h>
 #include <asm/reg.h>

arch/powerpc/kernel/hw_breakpoint.c

@@ -163,9 +163,9 @@ int hw_breakpoint_arch_parse(struct perf_event *bp,
 	 */
 	if (!ppc_breakpoint_available())
 		return -ENODEV;
-	length_max = 8; /* DABR */
+	length_max = DABR_MAX_LEN; /* DABR */
 	if (dawr_enabled()) {
-		length_max = 512 ; /* 64 doublewords */
+		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))

arch/powerpc/kernel/ptrace.c

@@ -2425,7 +2425,7 @@ static int ptrace_set_debugreg(struct task_struct *task, unsigned long addr,
 		return -EIO;
 	hw_brk.address = data & (~HW_BRK_TYPE_DABR);
 	hw_brk.type = (data & HW_BRK_TYPE_DABR) | HW_BRK_TYPE_PRIV_ALL;
-	hw_brk.len = 8;
+	hw_brk.len = DABR_MAX_LEN;
 	set_bp = (data) && (hw_brk.type & HW_BRK_TYPE_RDWR);
 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 	bp = thread->ptrace_bps[0];
@@ -2456,7 +2456,7 @@ static int ptrace_set_debugreg(struct task_struct *task, unsigned long addr,
 	/* Create a new breakpoint request if one doesn't exist already */
 	hw_breakpoint_init(&attr);
 	attr.bp_addr = hw_brk.address;
-	attr.bp_len = 8;
+	attr.bp_len = DABR_MAX_LEN;
 	arch_bp_generic_fields(hw_brk.type,
 			       &attr.bp_type);
 
@@ -2882,7 +2882,7 @@ static long ppc_set_hwdebug(struct task_struct *child,
 
 	brk.address = bp_info->addr & ~7UL;
 	brk.type = HW_BRK_TYPE_TRANSLATE;
-	brk.len = 8;
+	brk.len = DABR_MAX_LEN;
 	if (bp_info->trigger_type & PPC_BREAKPOINT_TRIGGER_READ)
 		brk.type |= HW_BRK_TYPE_READ;
 	if (bp_info->trigger_type & PPC_BREAKPOINT_TRIGGER_WRITE)

arch/powerpc/xmon/xmon.c

@@ -933,7 +933,7 @@ static void insert_cpu_bpts(void)
 	if (dabr.enabled) {
 		brk.address = dabr.address;
 		brk.type = (dabr.enabled & HW_BRK_TYPE_DABR) | HW_BRK_TYPE_PRIV_ALL;
-		brk.len = 8;
+		brk.len = DABR_MAX_LEN;
 		__set_breakpoint(&brk);
 	}