| /* |
| * 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" |
| |
| #define MAXTOKEN 64 |
| |
| /* Set during early boot */ |
| int host_has_cmov = 1; |
| |
| 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) |
| { |
| int have_it; |
| |
| 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; |
| } |
| |
| 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; |
| } |