msrtool: Read both MSR values from file in diff mode

Previously, msrtool would assume that MSR values should be compared
between stored value in file and current value in hardware which msrtool
was running on. This does not always fit the use case and with this
change msrtool can now compare two sets of MSR values stored in a file.
If only one MSR value is stored in the file, msrtool will behave as
before, and read the second MSR value from hardware.

This change means that msrtool does not always need access to the system
MSR functions so it can now be run as a regular user when using diff
mode with both MSR values stored in the file.

Signed-off-by: Peter Stuge <peter@stuge.se>
Acked-by: Stefan Reinauer <stepan@coresystems.de>


git-svn-id: svn://svn.coreboot.org/coreboot/trunk@5033 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1

util/msrtool/msrtool.c

@@ -93,6 +93,16 @@ static void *add_target(const struct targetdef *t) {
 	return targets;
 }
 
+static int found_system() {
+	if (!sys || (sys && !sys->name)) {
+		fprintf(stderr, "Unable to detect the current operating system!\n");
+		fprintf(stderr, "On Linux, please run 'modprobe msr' and try again.\n");
+		fprintf(stderr, "Please send a report or patch to coreboot@coreboot.org. Thanks for your help!\n");
+		fprintf(stderr, "\n");
+	}
+	return (sys && sys->name);
+}
+
 int do_stream(const char *streamfn, uint8_t ignoreinput) {
 	char tmpfn[20], line[256];
 	uint8_t tn;
@@ -132,6 +142,8 @@ int do_stream(const char *streamfn, uint8_t ignoreinput) {
 		}
 	}
 
+	if (!found_system())
+		goto done;
 	if (!sys->open(cpu, SYS_RDONLY))
 		goto done;
 	if (ignoreinput) {
@@ -180,9 +192,9 @@ done:
 }
 
 int do_diff(const char *difffn) {
-	char tmpfn[20], line[512], *m1start;
+	char tmpfn[20], line[512], *m1start, *m2start;
 	size_t len;
-	int ret = 1, tmp, m1pos;
+	int ret = 1, tmp, m1pos, sys_opened = 0;
 	FILE *fin = NULL, *fout = stdout;
 	uint8_t rev = 0;
 	uint32_t addr, linenum;
@@ -199,8 +211,6 @@ int do_diff(const char *difffn) {
 		return 1;
 	}
 
-	if (!sys->open(cpu, SYS_RDONLY))
-		goto done;
 	for (linenum = 1; NULL != fgets(line, sizeof(line), fin); ++linenum) {
 		tmp = strncmp("0x", line, 2) ? 0 : 2;
 		if (sscanf(line + tmp, "%8x %n%*x", &addr, &m1pos) < 1)
@@ -208,12 +218,24 @@ int do_diff(const char *difffn) {
 		m1start = line + tmp + m1pos;
 		for (len = strlen(m1start) - 1; NULL != strchr("\r\n", m1start[len]); --len)
 			m1start[len] = 0;
-		if (!str2msr(m1start, &m1, NULL)) {
+		if (!str2msr(m1start, &m1, &m2start)) {
-			fprintf(stderr, "%s:%d: invalid MSR value '%s'\n", difffn, linenum, m1start);
+			fprintf(stderr, "%s:%d: invalid MSR1 value '%s'\n", difffn, linenum, m1start);
 			continue;
 		}
+		while (' ' == *m2start)
+			++m2start;
+		if (!str2msr(m2start, &m2, NULL)) {
+			fprintf(stderr, "%s:%d: invalid MSR2 value '%s' - reading from hardware!\n", difffn, linenum, m2start);
+			if (!sys_opened) {
+				if (!found_system())
+					goto done;
+				sys_opened = sys->open(cpu, SYS_RDONLY);
+				if (!sys_opened)
+					goto done;
+			}
 			if (!sys->rdmsr(cpu, addr, &m2))
 				goto done;
+		}
 		if (diff_msr(fout, addr, rev ? m2 : m1, rev ? m1 : m2))
 			fprintf(fout, "\n");
 	}
@@ -222,6 +244,7 @@ int do_diff(const char *difffn) {
 	else
 		ret = 0;
 done:
+	if (sys_opened)
 		sys->close(cpu);
 	if (strcmp(difffn, "-")) {
 		if (ret)
@@ -351,13 +374,6 @@ int main(int argc, char *argv[]) {
 		return 0;
 	}
 
-	if (sys && !sys->name) {
-		fprintf(stderr, "Unable to detect the current operating system!\n");
-		fprintf(stderr, "On Linux, please do 'modprobe msr' and retry.\n");
-		fprintf(stderr, "Please send a report or patch to coreboot@coreboot.org. Thanks for your help!\n");
-		fprintf(stderr, "\n");
-	}
-
 	if (!targets_found || !targets) {
 		fprintf(stderr, "Unable to detect a known target; can not decode any MSRs! (Use -t to force)\n");
 		fprintf(stderr, "Please send a report or patch to coreboot@coreboot.org. Thanks for your help!\n");
@@ -370,9 +386,6 @@ int main(int argc, char *argv[]) {
 		return 0;
 	}
 
-	if (sys && !sys->name)
-		return 1;
-
 	if (listmsrs) {
 		if (streamfn)
 			return do_stream(streamfn, 1);
@@ -388,9 +401,6 @@ int main(int argc, char *argv[]) {
 	if (streamfn)
 		return do_stream(streamfn, 0);
 
-	if (!sys->open(cpu, SYS_RDONLY))
-		return 1;
-
 	if (difffn) {
 		ret = do_diff(difffn);
 		goto done;
@@ -402,6 +412,11 @@ int main(int argc, char *argv[]) {
 		goto done;
 	}
 
+	if (!found_system())
+		return 1;
+	if (!sys->open(cpu, SYS_RDONLY))
+		return 1;
+
 	for (; optind < argc; optind++) {
 		addr = msraddrbyname(argv[optind]);
 		if (!sys->rdmsr(cpu, addr, &msrval))