powerpc/watchpoint: Support for 8xx in ptrace-hwbreak.c selftest

On the 8xx, signals are generated after executing the instruction. So
no need to manually single-step on 8xx. Also, 8xx __set_dabr()
currently ignores length and hardcodes the length to 8 bytes. So all
unaligned and 512 byte testcase will fail on 8xx. Ignore those
testcases on 8xx.
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/20191017093204.7511-8-ravi.bangoria@linux.ibm.com

tools/testing/selftests/powerpc/ptrace/ptrace-hwbreak.c

@@ -22,6 +22,11 @@
 #include <sys/wait.h>
 #include "ptrace.h"
 
+#define SPRN_PVR	0x11F
+#define PVR_8xx		0x00500000
+
+bool is_8xx;
+
 /*
  * Use volatile on all global var so that compiler doesn't
  * optimise their load/stores. Otherwise selftest can fail.
@@ -205,13 +210,15 @@ static void check_success(pid_t child_pid, const char *name, const char *type,
 
 	printf("%s, %s, len: %d: Ok\n", name, type, len);
 
-	/*
-	 * For ptrace registered watchpoint, signal is generated
-	 * before executing load/store. Singlestep the instruction
-	 * and then continue the test.
-	 */
-	ptrace(PTRACE_SINGLESTEP, child_pid, NULL, 0);
-	wait(NULL);
+	if (!is_8xx) {
+		/*
+		 * For ptrace registered watchpoint, signal is generated
+		 * before executing load/store. Singlestep the instruction
+		 * and then continue the test.
+		 */
+		ptrace(PTRACE_SINGLESTEP, child_pid, NULL, 0);
+		wait(NULL);
+	}
 }
 
 static void ptrace_set_debugreg(pid_t child_pid, unsigned long wp_addr)
@@ -447,8 +454,10 @@ run_tests(pid_t child_pid, struct ppc_debug_info *dbginfo, bool dawr)
 	test_set_debugreg(child_pid);
 	if (dbginfo->features & PPC_DEBUG_FEATURE_DATA_BP_RANGE) {
 		test_sethwdebug_exact(child_pid);
-		test_sethwdebug_range_aligned(child_pid);
-		if (dawr) {
+
+		if (!is_8xx)
+			test_sethwdebug_range_aligned(child_pid);
+		if (dawr && !is_8xx) {
 			test_sethwdebug_range_unaligned(child_pid);
 			test_sethwdebug_range_unaligned_dar(child_pid);
 			test_sethwdebug_dawr_max_range(child_pid);
@@ -489,5 +498,10 @@ static int ptrace_hwbreak(void)
 
 int main(int argc, char **argv, char **envp)
 {
+	int pvr = 0;
+	asm __volatile__ ("mfspr %0,%1" : "=r"(pvr) : "i"(SPRN_PVR));
+	if (pvr == PVR_8xx)
+		is_8xx = true;
+
 	return test_harness(ptrace_hwbreak, "ptrace-hwbreak");
 }