diff options
Diffstat (limited to 'arch/um/sys-i386/bugs.c')
| -rw-r--r-- | arch/um/sys-i386/bugs.c | 222 |
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 00000000000..41b0ab2fe83 --- /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: + */ |