umka/trace_lbr.c

125 lines
2.7 KiB
C

/*
SPDX-License-Identifier: GPL-2.0-or-later
UMKa - User-Mode KolibriOS developer tools
Copyright (C) 2019-2020,2022-2023 Ivan Baravy <dunkaist@gmail.com>
Copyright (C) 2021 Magomed Kostoev <mkostoevr@yandex.ru>
*/
#include <stdint.h>
#include <stdlib.h>
#include <stdio.h>
#ifndef _WIN32
#include <unistd.h>
#include <fcntl.h>
#endif
#include "umka.h"
#define MSR_IA32_DEBUGCTL 0x1d9
#define MSR_IA32_DEBUGCTL_LBR 0x1 // enable profiling
#define MSR_IA32_DEBUGCTL_BTF 0x2 // profile only branches if EFLAGS.TF
#define MSR_IA32_LASTBRANCHFROMIP 0x1db
#define MSR_IA32_LASTBRANCHTOIP 0x1dc
int msrfd;
uint64_t rdmsr(uint32_t reg)
{
uint64_t data = 0;
#ifndef _WIN32
if (pread(msrfd, &data, sizeof data, reg) != sizeof data) {
perror("rdmsr: pread");
exit(1);
}
#else
(void)reg;
printf("STUB: %s:%d", __FILE__, __LINE__);
#endif
return data;
}
void wrmsr(uint32_t reg, uint64_t data)
{
#ifndef _WIN32
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);
#else
(void)reg;
(void)data;
printf("STUB: %s:%d", __FILE__, __LINE__);
#endif
}
void handle_sigtrap(int signo) {
(void)signo;
#ifndef _WIN32
uint64_t from = rdmsr(MSR_IA32_LASTBRANCHFROMIP);
uint64_t to = rdmsr(MSR_IA32_LASTBRANCHTOIP);
if (from >= (uintptr_t)coverage_begin && from < (uintptr_t)coverage_end) {
coverage_table[from - (uintptr_t)coverage_begin].from_cnt++;
}
if (to >= (uintptr_t)coverage_begin && to < (uintptr_t)coverage_end) {
coverage_table[to - (uintptr_t)coverage_begin].to_cnt++;
}
wrmsr(MSR_IA32_DEBUGCTL, MSR_IA32_DEBUGCTL_LBR + MSR_IA32_DEBUGCTL_BTF);
#else
printf("STUB: %s:%d", __FILE__, __LINE__);
#endif
}
uint32_t set_eflags_tf(uint32_t tf);
void trace_lbr_begin(void) {
#ifndef _WIN32
struct sigaction action;
action.sa_handler = &handle_sigtrap;
action.sa_flags = 0;
sigaction(SIGTRAP, &action, NULL);
wrmsr(MSR_IA32_DEBUGCTL, MSR_IA32_DEBUGCTL_LBR + MSR_IA32_DEBUGCTL_BTF);
msrfd = open("/dev/cpu/0/msr", O_RDONLY);
if (msrfd < 0) {
perror("rdmsr: open");
exit(1);
}
#else
printf("STUB: %s:%d", __FILE__, __LINE__);
#endif
}
void trace_lbr_end(void) {
#ifndef _WIN32
wrmsr(MSR_IA32_DEBUGCTL, 0);
close(msrfd);
#else
printf("STUB: %s:%d", __FILE__, __LINE__);
#endif
}
uint32_t trace_lbr_pause(void) {
return set_eflags_tf(0u);
}
void trace_lbr_resume(uint32_t value) {
set_eflags_tf(value);
}