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/*
* Copyright (C) 2013 Intel Corporation
* Authors: Tony Luck
*
* This software may be redistributed and/or modified under the terms of
* the GNU General Public License ("GPL") version 2 only as published by the
* Free Software Foundation.
*/
/*
* Set up to get zapped by a machine check (injected elsewhere)
* recovery function reports physical address of new page - so
* we can inject to that and repeat over and over.
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <time.h>
#include <fcntl.h>
#include <signal.h>
#include <sys/mman.h>
static int pagesize;
/*
* get information about address from /proc/{pid}/pagemap
* Assumes target address is mapped as 4K (not hugepage)
*/
unsigned long long vtop(unsigned long long addr)
{
unsigned long long pinfo;
long offset = addr / pagesize * (sizeof pinfo);
int fd;
char pagemapname[64];
sprintf(pagemapname, "/proc/%d/pagemap", getpid());
fd = open(pagemapname, O_RDONLY);
if (fd == -1) {
perror(pagemapname);
exit(1);
}
if (pread(fd, &pinfo, sizeof pinfo, offset) != sizeof pinfo) {
perror(pagemapname);
exit(1);
}
close(fd);
if ((pinfo & (1ull << 63)) == 0) {
printf("page not present\n");
exit(1);
}
return ((pinfo & 0x007fffffffffffffull) << 12) + (addr & (pagesize - 1));
}
int checksum(unsigned char *addr)
{
int i, sum;
sum = 0;
for (i = 0; i < pagesize; i++)
sum += addr[i];
return sum;
}
/*
* Older glibc headers don't have the si_addr_lsb field in the siginfo_t
* structure ... ugly hack to get it
*/
struct morebits {
void *addr;
short lsb;
};
char *buf;
unsigned long long phys;
/*
* "Recover" from the error by allocating a new page and mapping
* it at the same virtual address as the page we lost. Fill with
* the same (trivial) contents.
*/
void recover(int sig, siginfo_t *si, void *v)
{
struct morebits *m = (struct morebits *)&si->si_addr;
char *newbuf;
printf("recover: sig=%d si=%p v=%p\n", sig, si, v);
printf("Platform memory error at 0x%p\n", si->si_addr);
printf("addr = %p lsb=%d\n", m->addr, m->lsb);
newbuf = mmap(buf, pagesize, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
if (newbuf == MAP_FAILED) {
fprintf(stderr, "Can't get a single page of memory!\n");
exit(1);
}
if (newbuf != buf) {
fprintf(stderr, "Could not allocate at original virtual address\n");
exit(1);
}
buf = newbuf;
memset(buf, '*', pagesize);
phys = vtop((unsigned long long)buf);
printf("Recovery allocated new page at physical %llx\n", phys);
}
struct sigaction recover_act = {
.sa_sigaction = recover,
.sa_flags = SA_SIGINFO,
};
int main(int argc, char **argv)
{
int i, sum, rightsum;
int iflag = 0;
int tflag = 0;
time_t now;
pagesize = getpagesize();
buf = mmap(NULL, pagesize, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
if (buf == MAP_FAILED) {
fprintf(stderr, "Can't get a single page of memory!\n");
return 1;
}
memset(buf, '*', pagesize);
rightsum = checksum(buf);
phys = vtop((unsigned long long)buf);
printf("vtop(%llx) = %llx\n", (unsigned long long)buf, phys);
fflush(stdout);
sigaction(SIGBUS, &recover_act, NULL);
while (1) {
sum = checksum(buf);
if (sum != rightsum) {
printf("Ooops. Saw bad checksum %d\n", sum);
break;
}
}
return 1;
}
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