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/*
* Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
* Licensed under the GPL
*/
#include <errno.h>
#include <signal.h>
#include <string.h>
#include "kern_constants.h"
#include "os.h"
#include "task.h"
#include "user.h"
#include "sysdep/archsetjmp.h"
#define MAXTOKEN 64
/* Set during early boot */
int host_has_cmov = 1;
static jmp_buf cmov_test_return;
static void cmov_sigill_test_handler(int sig)
{
host_has_cmov = 0;
longjmp(cmov_test_return, 1);
}
static void test_for_host_cmov(void)
{
struct sigaction old, new;
printk(UM_KERN_INFO "Checking for host processor cmov support...");
new.sa_handler = cmov_sigill_test_handler;
/* Make sure that SIGILL is enabled after the handler longjmps back */
new.sa_flags = SA_NODEFER;
sigemptyset(&new.sa_mask);
sigaction(SIGILL, &new, &old);
if (setjmp(cmov_test_return) == 0) {
unsigned long foo = 0;
__asm__ __volatile__("cmovz %0, %1" : "=r" (foo) : "0" (foo));
printk(UM_KERN_CONT "Yes\n");
} else
printk(UM_KERN_CONT "No\n");
sigaction(SIGILL, &old, &new);
}
static char token(int fd, char *buf, int len, char stop)
{
int n;
char *ptr, *end, c;
ptr = buf;
end = &buf[len];
do {
n = os_read_file(fd, ptr, sizeof(*ptr));
c = *ptr++;
if (n != sizeof(*ptr)) {
if (n == 0)
return 0;
printk(UM_KERN_ERR "Reading /proc/cpuinfo failed, "
"err = %d\n", -n);
if (n < 0)
return n;
else return -EIO;
}
} while ((c != '\n') && (c != stop) && (ptr < end));
if (ptr == end) {
printk(UM_KERN_ERR "Failed to find '%c' in /proc/cpuinfo\n",
stop);
return -1;
}
*(ptr - 1) = '\0';
return c;
}
static int find_cpuinfo_line(int fd, char *key, char *scratch, int len)
{
int n;
char c;
scratch[len - 1] = '\0';
while (1) {
c = token(fd, scratch, len - 1, ':');
if (c <= 0)
return 0;
else if (c != ':') {
printk(UM_KERN_ERR "Failed to find ':' in "
"/proc/cpuinfo\n");
return 0;
}
if (!strncmp(scratch, key, strlen(key)))
return 1;
do {
n = os_read_file(fd, &c, sizeof(c));
if (n != sizeof(c)) {
printk(UM_KERN_ERR "Failed to find newline in "
"/proc/cpuinfo, err = %d\n", -n);
return 0;
}
} while (c != '\n');
}
return 0;
}
static int check_cpu_flag(char *feature, int *have_it)
{
char buf[MAXTOKEN], c;
int fd, len = ARRAY_SIZE(buf);
printk(UM_KERN_INFO "Checking for host processor %s support...",
feature);
fd = os_open_file("/proc/cpuinfo", of_read(OPENFLAGS()), 0);
if (fd < 0) {
printk(UM_KERN_ERR "Couldn't open /proc/cpuinfo, err = %d\n",
-fd);
return 0;
}
*have_it = 0;
if (!find_cpuinfo_line(fd, "flags", buf, ARRAY_SIZE(buf)))
goto out;
c = token(fd, buf, len - 1, ' ');
if (c < 0)
goto out;
else if (c != ' ') {
printk(UM_KERN_ERR "Failed to find ' ' in /proc/cpuinfo\n");
goto out;
}
while (1) {
c = token(fd, buf, len - 1, ' ');
if (c < 0)
goto out;
else if (c == '\n')
break;
if (!strcmp(buf, feature)) {
*have_it = 1;
goto out;
}
}
out:
if (*have_it == 0)
printk("No\n");
else if (*have_it == 1)
printk("Yes\n");
os_close_file(fd);
return 1;
}
#if 0 /*
* This doesn't work in tt mode, plus it's causing compilation problems
* for some people.
*/
static void disable_lcall(void)
{
struct modify_ldt_ldt_s ldt;
int err;
bzero(&ldt, sizeof(ldt));
ldt.entry_number = 7;
ldt.base_addr = 0;
ldt.limit = 0;
err = modify_ldt(1, &ldt, sizeof(ldt));
if (err)
printk(UM_KERN_ERR "Failed to disable lcall7 - errno = %d\n",
errno);
}
#endif
void arch_init_thread(void)
{
#if 0
disable_lcall();
#endif
}
void arch_check_bugs(void)
{
test_for_host_cmov();
}
int arch_handle_signal(int sig, struct uml_pt_regs *regs)
{
unsigned char tmp[2];
/*
* This is testing for a cmov (0x0f 0x4x) instruction causing a
* SIGILL in init.
*/
if ((sig != SIGILL) || (TASK_PID(get_current()) != 1))
return 0;
if (copy_from_user_proc(tmp, (void *) UPT_IP(regs), 2))
panic("SIGILL in init, could not read instructions!\n");
if ((tmp[0] != 0x0f) || ((tmp[1] & 0xf0) != 0x40))
return 0;
if (host_has_cmov == 0)
panic("SIGILL caused by cmov, which this processor doesn't "
"implement, boot a filesystem compiled for older "
"processors");
else if (host_has_cmov == 1)
panic("SIGILL caused by cmov, which this processor claims to "
"implement");
else if (host_has_cmov == -1)
panic("SIGILL caused by cmov, couldn't tell if this processor "
"implements it, boot a filesystem compiled for older "
"processors");
else panic("Bad value for host_has_cmov (%d)", host_has_cmov);
return 0;
}
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