/* * 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: */