umka/trace_lbr.c

87 lines
1.9 KiB
C

#define _GNU_SOURCE
#include <stdint.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <signal.h>
#include <sched.h>
#include "kolibri.h"
int covfd, msrfd;
uint64_t rdmsr(uint32_t reg)
{
uint64_t data;
if (pread(msrfd, &data, sizeof data, reg) != sizeof data) {
perror("rdmsr: pread");
exit(1);
}
return data;
}
void wrmsr(uint32_t reg, uint64_t data)
{
int fd;
fd = open("/dev/cpu/0/msr", O_WRONLY);
if (fd < 0) {
perror("wrmsr: open");
exit(1);
}
if (pwrite(fd, &data, sizeof data, reg) != sizeof data) {
perror("wrmsr: pwrite");
exit(1);
}
close(fd);
return;
}
void handle_sigtrap() {
uint64_t from = rdmsr(0x1db);
uint64_t to = rdmsr(0x1dc);
if ((from >= (uintptr_t)coverage_begin && from < (uintptr_t)coverage_end) ||
(to >= (uintptr_t)coverage_begin && to < (uintptr_t)coverage_end)) {
write(covfd, &from, 4);
write(covfd, &to, 4);
}
wrmsr(0x1d9, 3);
}
void trace_lbr_begin() {
printf("hello from lbr!\n");
struct sigaction action;
action.sa_sigaction = &handle_sigtrap;
action.sa_flags = SA_SIGINFO;
sigaction(SIGTRAP, &action, NULL);
cpu_set_t my_set;
CPU_ZERO(&my_set);
CPU_SET(0, &my_set);
sched_setaffinity(0, sizeof(cpu_set_t), &my_set);
wrmsr(0x1d9, 3);
msrfd = open("/dev/cpu/0/msr", O_RDONLY);
if (msrfd < 0) {
perror("rdmsr: open");
exit(1);
}
char coverage_filename[32];
sprintf(coverage_filename, "coverage.%i", getpid());
covfd = open(coverage_filename, O_WRONLY | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH);
set_eflags_tf(1);
}
void trace_lbr_end() {
set_eflags_tf(0);
wrmsr(0x1d9, 0);
close(msrfd);
close(covfd);
}