blob: fe4cbdb9b840fe757591c3ee2b14440b0fecd1f9 [file] [log] [blame]
/*
* Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
* Licensed under the GPL
*/
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <sys/signal.h>
#include <asm/ldt.h>
#include "kern_util.h"
#include "user.h"
#include "sysdep/ptrace.h"
#include "task.h"
#include "os.h"
#define MAXTOKEN 64
/* Set during early boot */
int cpu_has_cmov = 1;
int cpu_has_xmm = 0;
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("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("Failed to find '%c' in /proc/cpuinfo\n", stop);
return(-1);
}
*(ptr - 1) = '\0';
return(c);
}
static int check_cpu_feature(char *feature, int *have_it)
{
char buf[MAXTOKEN], c;
int fd, len = sizeof(buf)/sizeof(buf[0]), n;
printk("Checking for host processor %s support...", feature);
fd = os_open_file("/proc/cpuinfo", of_read(OPENFLAGS()), 0);
if(fd < 0){
printk("Couldn't open /proc/cpuinfo, err = %d\n", -fd);
return(0);
}
*have_it = 0;
buf[len - 1] = '\0';
while(1){
c = token(fd, buf, len - 1, ':');
if(c <= 0) goto out;
else if(c != ':'){
printk("Failed to find ':' in /proc/cpuinfo\n");
goto out;
}
if(!strncmp(buf, "flags", strlen("flags"))) break;
do {
n = os_read_file(fd, &c, sizeof(c));
if(n != sizeof(c)){
printk("Failed to find newline in "
"/proc/cpuinfo, err = %d\n", -n);
goto out;
}
} while(c != '\n');
}
c = token(fd, buf, len - 1, ' ');
if(c < 0) goto out;
else if(c != ' '){
printk("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);
}
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("Failed to disable lcall7 - errno = %d\n", errno);
}
void arch_init_thread(void)
{
disable_lcall();
}
void arch_check_bugs(void)
{
int have_it;
if(os_access("/proc/cpuinfo", OS_ACC_R_OK) < 0){
printk("/proc/cpuinfo not available - skipping CPU capability "
"checks\n");
return;
}
if(check_cpu_feature("cmov", &have_it)) cpu_has_cmov = have_it;
if(check_cpu_feature("xmm", &have_it)) cpu_has_xmm = have_it;
}
int arch_handle_signal(int sig, union uml_pt_regs *regs)
{
unsigned long ip;
/* This is testing for a cmov (0x0f 0x4x) instruction causing a
* SIGILL in init.
*/
if((sig != SIGILL) || (TASK_PID(get_current()) != 1)) return(0);
ip = UPT_IP(regs);
if((*((char *) ip) != 0x0f) || ((*((char *) (ip + 1)) & 0xf0) != 0x40))
return(0);
if(cpu_has_cmov == 0)
panic("SIGILL caused by cmov, which this processor doesn't "
"implement, boot a filesystem compiled for older "
"processors");
else if(cpu_has_cmov == 1)
panic("SIGILL caused by cmov, which this processor claims to "
"implement");
else if(cpu_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 cpu_has_cmov (%d)", cpu_has_cmov);
return(0);
}
/*
* Overrides for Emacs so that we follow Linus's tabbing style.
* Emacs will notice this stuff at the end of the file and automatically
* adjust the settings for this buffer only. This must remain at the end
* of the file.
* ---------------------------------------------------------------------------
* Local variables:
* c-file-style: "linux"
* End:
*/