From e313d43cbab5b933027c6292f5c49c6cce0f9c4f Mon Sep 17 00:00:00 2001
From: Lauri Kasanen <cand@gmx.com>
Date: Fri, 28 May 2021 12:32:57 +0300
Subject: [PATCH] Disassembly, tracing

---
 main.c | 95 +++++++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 91 insertions(+), 4 deletions(-)

diff --git a/main.c b/main.c
index d3d1e97..62a6fc7 100644
--- a/main.c
+++ b/main.c
@@ -16,6 +16,7 @@
 
 #define _GNU_SOURCE
 
+#include <ctype.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <getopt.h>
@@ -37,6 +38,7 @@
 #define PROGSTART 0x20000000
 
 #define MSR_64	(1UL<<63)
+#define MSR_FP	(1UL<<13)
 #define MSR_LE	(1UL<<0)
 
 enum {
@@ -262,6 +264,43 @@ static void getfpregs(const int vcpu, struct kvm_fpu *fpregs) {
 	}
 }
 
+static void disassemble(const char binpath[], char *disasm, const unsigned len) {
+
+	char buf[PATH_MAX];
+	snprintf(buf, PATH_MAX,
+		"objdump -b binary -m powerpc --no-show-raw-insn -D %s",
+		binpath);
+	buf[PATH_MAX - 1] = '\0';
+
+	FILE *f = popen(buf, "r");
+	if (!f) {
+		printf("Disassembly failed, trace won't have disas\n");
+		return;
+	}
+
+	while (fgets(buf, PATH_MAX, f)) {
+		if (buf[0] != ' ')
+			continue;
+		const char *ptr = strchr(buf, ':');
+		if (!ptr)
+			continue;
+		nukenewline(buf);
+
+		const unsigned addr = strtol(buf, NULL, 16) / 4 * 32;
+		if (addr / 32 + 1 >= len)
+			abort();
+
+		ptr++;
+		while (isspace(*ptr))
+			ptr++;
+
+		strncpy(&disasm[addr], ptr, 32);
+		disasm[addr + 31] = '\0';
+	}
+
+	pclose(f);
+}
+
 int main(int argc, char **argv) {
 
 	const struct option longopts[] = {
@@ -286,7 +325,8 @@ int main(int argc, char **argv) {
 	char dumps[MAXDUMPS][PATH_MAX];
 	unsigned num_dumps = 0;
 	uint8_t *ram, *progmem;
-	const char *binpath;
+	const char *binpath = NULL;
+	const char *disasm = NULL;
 
 	// Yes, we're frugal
 	if (posix_memalign((void **) &ram, 64 * 1024, RAMSIZE))
@@ -298,7 +338,7 @@ int main(int argc, char **argv) {
 
 	regs.lr = -1;
 	regs.pc = PROGSTART;
-	regs.msr = MSR_64 | MSR_LE;
+	regs.msr = MSR_64 | MSR_FP | MSR_LE;
 
 	while (1) {
 		const int c = getopt_long(argc, argv, opts, longopts, NULL);
@@ -380,6 +420,14 @@ int main(int argc, char **argv) {
 		abort();
 	fclose(binary);
 
+
+	if (trace) {
+		const unsigned disaslen = binlen / 4 + 64;
+		disasm = calloc(disaslen, 32);
+
+		disassemble(binpath, (char *) disasm, disaslen);
+	}
+
 	kvm = open("/dev/kvm", O_RDWR | O_CLOEXEC);
 	if (kvm < 0) {
 		printf("Failed to open kvm, perhaps you lack permissions?\n");
@@ -438,13 +486,51 @@ int main(int argc, char **argv) {
 		abort();
 
 	// Runtime
+	uint64_t pc = PROGSTART;
+	unsigned i;
 	while (1) {
 		if (ioctl(vcpu, KVM_RUN, NULL) == -1)
 			abort();
-		printf("Exited because %u\n", run->exit_reason);
+
+		if (ioctl(vcpu, KVM_GET_REGS, &regs) == -1)
+			abort();
+		//printf("PC %lx LR %lx\n", regs.pc, regs.lr);
+
+		if (run->exit_reason == KVM_EXIT_DEBUG) {
+			if (trace) {
+				getfpregs(vcpu, &fpregs);
+
+				fprintf(trace, "%lx: %s\n", pc, &disasm[(pc - PROGSTART) / 4 * 32]);
+				for (i = 0; i < 32; i++) {
+					if (i % 8 == 0)
+						fprintf(trace, "GPR: ");
+					fprintf(trace, "%08lx", regs.gpr[i]);
+					if (i % 8 == 7)
+						fprintf(trace, "\n");
+					else
+						fprintf(trace, " ");
+				}
+				for (i = 0; i < 32; i++) {
+					if (i % 8 == 0)
+						fprintf(trace, "FPR: ");
+					fprintf(trace, "%08lx", fpregs.fpr[i]);
+					if (i % 8 == 7)
+						fprintf(trace, "\n");
+					else
+						fprintf(trace, " ");
+				}
+			}
+		} else if (regs.pc < PROGSTART || regs.pc > PROGSTART + binlen) {
+			// Normal exit by blr
+			break;
+		} else {
+			printf("Unexpected exit because %u\n", run->exit_reason);
+			break;
+		}
+
+		pc = regs.pc;
 	}
 
-	unsigned i;
 	for (i = 0; i < num_dumps; i++) {
 		dump(dumps[i], ram);
 	}
@@ -453,5 +539,6 @@ int main(int argc, char **argv) {
 	free(progmem);
 	free(ram);
 	free((char *) binpath);
+	free((char *) disasm);
 	return 0;
 }
-- 
2.30.2