1 files changed, 222 insertions, 0 deletions

diff --git a/arch/um/sys-i386/bugs.c b/arch/um/sys-i386/bugs.c
new file mode 100644
index 000000000000..41b0ab2fe830
--- /dev/null
+++ b/arch/um/sys-i386/bugs.c
@@ -0,0 +1,222 @@
+/* 
+ * 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 host_has_cmov = 1;
+int host_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 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);
+}
+
+int cpu_feature(char *what, char *buf, int len)
+{
+        int fd, ret = 0;
+
+        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);
+        }
+
+        if(!find_cpuinfo_line(fd, what, buf, len)){
+                printk("Couldn't find '%s' line in /proc/cpuinfo\n", what);
+                goto out_close;
+        }
+
+        token(fd, buf, len, '\n');
+        ret = 1;
+
+ out_close:
+        os_close_file(fd);
+        return(ret);
+}
+
+static int check_cpu_flag(char *feature, int *have_it)
+{
+        char buf[MAXTOKEN], c;
+        int fd, len = sizeof(buf)/sizeof(buf[0]);
+
+        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, sizeof(buf) / sizeof(buf[0])))
+                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)
+{
+        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);
+}
+#endif
+
+void arch_init_thread(void)
+{
+#if 0
+        disable_lcall();
+#endif
+}
+
+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_flag("cmov", &have_it))
+                host_has_cmov = have_it;
+        if(check_cpu_flag("xmm", &have_it))
+                host_has_xmm = have_it;
+}
+
+int arch_handle_signal(int sig, union 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);
+}
+
+/*
+ * 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:
+ */