/*
- * Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
+ * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
* Licensed under the GPL
*/
-#include <unistd.h>
-#include <errno.h>
-#include <string.h>
-#include <sys/signal.h>
-#include <asm/ldt.h>
+#include <signal.h>
+#include "kern_constants.h"
#include "kern_util.h"
+#include "longjmp.h"
+#include "task.h"
#include "user.h"
#include "sysdep/ptrace.h"
-#include "task.h"
-#include "os.h"
-#include "user_util.h"
-
-#define MAXTOKEN 64
/* Set during early boot */
-int host_has_cmov = 1;
-int host_has_xmm = 0;
+static int host_has_cmov = 1;
+static jmp_buf cmov_test_return;
-static char token(int fd, char *buf, int len, char stop)
+static void cmov_sigill_test_handler(int sig)
{
- 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;
+ host_has_cmov = 0;
+ longjmp(cmov_test_return, 1);
}
-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("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("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("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;
- 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("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)
+void arch_check_bugs(void)
{
- struct modify_ldt_ldt_s ldt;
- int err;
+ struct sigaction old, new;
- 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);
-}
-#endif
+ printk(UM_KERN_INFO "Checking for host processor cmov support...");
+ new.sa_handler = cmov_sigill_test_handler;
-void arch_init_thread(void)
-{
-#if 0
- disable_lcall();
-#endif
-}
+ /* Make sure that SIGILL is enabled after the handler longjmps back */
+ new.sa_flags = SA_NODEFER;
+ sigemptyset(&new.sa_mask);
+ sigaction(SIGILL, &new, &old);
-void arch_check_bugs(void)
-{
- int have_it;
+ 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");
- if(os_access("/proc/cpuinfo", OS_ACC_R_OK) < 0){
- printk("/proc/cpuinfo not available - skipping CPU capability "
- "checks\n");
- return;
- }
- if(check_cpu_flag("cmov", &have_it))
- host_has_cmov = have_it;
- if(check_cpu_flag("xmm", &have_it))
- host_has_xmm = have_it;
+ sigaction(SIGILL, &old, &new);
}
-int arch_handle_signal(int sig, union uml_pt_regs *regs)
+void arch_examine_signal(int sig, struct uml_pt_regs *regs)
{
unsigned char tmp[2];
- /* This is testing for a cmov (0x0f 0x4x) instruction causing a
+ /*
+ * 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 ((sig != SIGILL) || (TASK_PID(get_current()) != 1))
+ return;
- 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 (copy_from_user_proc(tmp, (void *) UPT_IP(regs), 2)) {
+ printk(UM_KERN_ERR "SIGILL in init, could not read "
+ "instructions!\n");
+ return;
+ }
+
+ if ((tmp[0] != 0x0f) || ((tmp[1] & 0xf0) != 0x40))
+ return;
- 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;
+ if (host_has_cmov == 0)
+ printk(UM_KERN_ERR "SIGILL caused by cmov, which this "
+ "processor doesn't implement. Boot a filesystem "
+ "compiled for older processors");
+ else if (host_has_cmov == 1)
+ printk(UM_KERN_ERR "SIGILL caused by cmov, which this "
+ "processor claims to implement");
+ else
+ printk(UM_KERN_ERR "Bad value for host_has_cmov (%d)",
+ host_has_cmov);
}
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff