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Diffstat (limited to 'arch/um/sys-i386/bugs.c')
-rw-r--r--arch/um/sys-i386/bugs.c201
1 files changed, 39 insertions, 162 deletions
diff --git a/arch/um/sys-i386/bugs.c b/arch/um/sys-i386/bugs.c
index 806895d73bc..a74442d1376 100644
--- a/arch/um/sys-i386/bugs.c
+++ b/arch/um/sys-i386/bugs.c
@@ -3,171 +3,47 @@
* Licensed under the GPL
*/
-#include <errno.h>
#include <signal.h>
-#include <string.h>
#include "kern_constants.h"
-#include "os.h"
+#include "kern_util.h"
+#include "longjmp.h"
#include "task.h"
#include "user.h"
-
-#define MAXTOKEN 64
+#include "sysdep/ptrace.h"
/* Set during early boot */
int host_has_cmov = 1;
-int host_has_xmm = 0;
+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(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;
+ host_has_cmov = 0;
+ longjmp(cmov_test_return, 1);
}
-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)
+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(UM_KERN_ERR "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(UM_KERN_ERR "/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, struct uml_pt_regs *regs)
+void arch_examine_signal(int sig, struct uml_pt_regs *regs)
{
unsigned char tmp[2];
@@ -176,24 +52,25 @@ int arch_handle_signal(int sig, struct uml_pt_regs *regs)
* SIGILL in init.
*/
if ((sig != SIGILL) || (TASK_PID(get_current()) != 1))
- return 0;
+ return;
+
+ 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 (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;
+ return;
if (host_has_cmov == 0)
- panic("SIGILL caused by cmov, which this processor doesn't "
- "implement, boot a filesystem compiled for older "
- "processors");
+ 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)
- 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;
+ 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);
}
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