selftests/powerpc: Add test to check if TM SPRs are corrupted

Testing that the TM SPRs are behaving the way they should. Uses more
threads than cpus to see if the following register values persist with
context switching:
- the FS (failure summary) flag in TEXASR
- TFIAR and TFHAR

Signed-off-by: Rashmica Gupta <rashmicy@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

tools/testing/selftests/powerpc/tm/.gitignore

@@ -5,3 +5,4 @@ tm-signal-stack
 tm-vmxcopy
 tm-fork
 tm-tar
+tm-tmspr

tools/testing/selftests/powerpc/tm/Makefile

@@ -1,4 +1,4 @@
-TEST_PROGS := tm-resched-dscr tm-syscall tm-signal-msr-resv tm-signal-stack tm-vmxcopy tm-fork tm-tar
+TEST_PROGS := tm-resched-dscr tm-syscall tm-signal-msr-resv tm-signal-stack tm-vmxcopy tm-fork tm-tar tm-tmspr
 
 all: $(TEST_PROGS)
 
@@ -6,6 +6,7 @@ $(TEST_PROGS): ../harness.c ../utils.c
 
 tm-syscall: tm-syscall-asm.S
 tm-syscall: CFLAGS += -mhtm -I../../../../../usr/include
+tm-tmspr: CFLAGS += -pthread
 
 include ../../lib.mk
 

tools/testing/selftests/powerpc/tm/tm-tmspr.c

@@ -0,0 +1,143 @@
+/*
+ * Copyright 2015, Michael Neuling, IBM Corp.
+ * Licensed under GPLv2.
+ *
+ * Original: Michael Neuling 3/4/2014
+ * Modified: Rashmica Gupta 8/12/2015
+ *
+ * Check if any of the Transaction Memory SPRs get corrupted.
+ * - TFIAR  - stores address of location of transaction failure
+ * - TFHAR  - stores address of software failure handler (if transaction
+ *   fails)
+ * - TEXASR - lots of info about the transacion(s)
+ *
+ * (1) create more threads than cpus
+ * (2) in each thread:
+ * 	(a) set TFIAR and TFHAR a unique value
+ * 	(b) loop for awhile, continually checking to see if
+ * 	either register has been corrupted.
+ *
+ * (3) Loop:
+ * 	(a) begin transaction
+ *    	(b) abort transaction
+ *	(c) check TEXASR to see if FS has been corrupted
+ *
+ */
+
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <pthread.h>
+#include <string.h>
+
+#include "utils.h"
+#include "tm.h"
+
+int	num_loops	= 10000;
+int	passed = 1;
+
+void tfiar_tfhar(void *in)
+{
+	int i, cpu;
+	unsigned long tfhar, tfhar_rd, tfiar, tfiar_rd;
+	cpu_set_t cpuset;
+
+	CPU_ZERO(&cpuset);
+	cpu = (unsigned long)in >> 1;
+	CPU_SET(cpu, &cpuset);
+	sched_setaffinity(0, sizeof(cpuset), &cpuset);
+
+	/* TFIAR: Last bit has to be high so userspace can read register */
+	tfiar = ((unsigned long)in) + 1;
+	tfiar += 2;
+	mtspr(SPRN_TFIAR, tfiar);
+
+	/* TFHAR: Last two bits are reserved */
+	tfhar = ((unsigned long)in);
+	tfhar &= ~0x3UL;
+	tfhar += 4;
+	mtspr(SPRN_TFHAR, tfhar);
+
+	for (i = 0; i < num_loops; i++)	{
+		tfhar_rd = mfspr(SPRN_TFHAR);
+		tfiar_rd = mfspr(SPRN_TFIAR);
+		if ( (tfhar != tfhar_rd) || (tfiar != tfiar_rd) ) {
+			passed = 0;
+			return;
+		}
+	}
+	return;
+}
+
+void texasr(void *in)
+{
+	unsigned long i;
+	uint64_t result = 0;
+
+	for (i = 0; i < num_loops; i++) {
+		asm __volatile__(
+			"tbegin.;"
+			"beq    3f ;"
+			"tabort. 0 ;"
+			"tend.;"
+
+			/* Abort handler */
+			"3: ;"
+			::: "memory");
+
+                /* Check the TEXASR */
+                result = mfspr(SPRN_TEXASR);
+		if ((result & TEXASR_FS) == 0) {
+			passed = 0;
+			return;
+		}
+	}
+	return;
+}
+
+int test_tmspr()
+{
+	pthread_t 	thread;
+	int	   	thread_num;
+	unsigned long	i;
+
+	SKIP_IF(!have_htm());
+
+	/* To cause some context switching */
+	thread_num = 10 * sysconf(_SC_NPROCESSORS_ONLN);
+
+	/* Test TFIAR and TFHAR */
+	for (i = 0 ; i < thread_num ; i += 2){
+		if (pthread_create(&thread, NULL, (void*)tfiar_tfhar, (void *)i))
+			return EXIT_FAILURE;
+	}
+	if (pthread_join(thread, NULL) != 0)
+		return EXIT_FAILURE;
+
+	/* Test TEXASR */
+	for (i = 0 ; i < thread_num ; i++){
+		if (pthread_create(&thread, NULL, (void*)texasr, (void *)i))
+			return EXIT_FAILURE;
+	}
+	if (pthread_join(thread, NULL) != 0)
+		return EXIT_FAILURE;
+
+	if (passed)
+		return 0;
+	else
+		return 1;
+}
+
+int main(int argc, char *argv[])
+{
+	if (argc > 1) {
+		if (strcmp(argv[1], "-h") == 0) {
+			printf("Syntax:\t [<num loops>]\n");
+			return 0;
+		} else {
+			num_loops = atoi(argv[1]);
+		}
+	}
+	return test_harness(test_tmspr, "tm_tmspr");
+}