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/arch/um/sys-i386/bugs.c

https://bitbucket.org/evzijst/gittest
C | 222 lines | 171 code | 31 blank | 20 comment | 59 complexity | 5cab0da9d8759ecca594ace3985ec2c2 MD5 | raw file
  1/* 
  2 * Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
  3 * Licensed under the GPL
  4 */
  5
  6#include <unistd.h>
  7#include <errno.h>
  8#include <string.h>
  9#include <sys/signal.h>
 10#include <asm/ldt.h>
 11#include "kern_util.h"
 12#include "user.h"
 13#include "sysdep/ptrace.h"
 14#include "task.h"
 15#include "os.h"
 16
 17#define MAXTOKEN 64
 18
 19/* Set during early boot */
 20int host_has_cmov = 1;
 21int host_has_xmm = 0;
 22
 23static char token(int fd, char *buf, int len, char stop)
 24{
 25	int n;
 26	char *ptr, *end, c;
 27
 28	ptr = buf;
 29	end = &buf[len];
 30	do {
 31		n = os_read_file(fd, ptr, sizeof(*ptr));
 32		c = *ptr++;
 33		if(n != sizeof(*ptr)){
 34			if(n == 0) return(0);
 35			printk("Reading /proc/cpuinfo failed, err = %d\n", -n);
 36			if(n < 0)
 37				return(n);
 38			else
 39				return(-EIO);
 40		}
 41	} while((c != '\n') && (c != stop) && (ptr < end));
 42
 43	if(ptr == end){
 44		printk("Failed to find '%c' in /proc/cpuinfo\n", stop);
 45		return(-1);
 46	}
 47	*(ptr - 1) = '\0';
 48	return(c);
 49}
 50
 51static int find_cpuinfo_line(int fd, char *key, char *scratch, int len)
 52{
 53	int n;
 54	char c;
 55
 56	scratch[len - 1] = '\0';
 57	while(1){
 58		c = token(fd, scratch, len - 1, ':');
 59		if(c <= 0)
 60			return(0);
 61		else if(c != ':'){
 62			printk("Failed to find ':' in /proc/cpuinfo\n");
 63			return(0);
 64		}
 65
 66		if(!strncmp(scratch, key, strlen(key)))
 67			return(1);
 68
 69		do {
 70			n = os_read_file(fd, &c, sizeof(c));
 71			if(n != sizeof(c)){
 72				printk("Failed to find newline in "
 73				       "/proc/cpuinfo, err = %d\n", -n);
 74				return(0);
 75			}
 76		} while(c != '\n');
 77	}
 78	return(0);
 79}
 80
 81int cpu_feature(char *what, char *buf, int len)
 82{
 83	int fd, ret = 0;
 84
 85	fd = os_open_file("/proc/cpuinfo", of_read(OPENFLAGS()), 0);
 86	if(fd < 0){
 87		printk("Couldn't open /proc/cpuinfo, err = %d\n", -fd);
 88		return(0);
 89	}
 90
 91	if(!find_cpuinfo_line(fd, what, buf, len)){
 92		printk("Couldn't find '%s' line in /proc/cpuinfo\n", what);
 93		goto out_close;
 94	}
 95
 96	token(fd, buf, len, '\n');
 97	ret = 1;
 98
 99 out_close:
100	os_close_file(fd);
101	return(ret);
102}
103
104static int check_cpu_flag(char *feature, int *have_it)
105{
106	char buf[MAXTOKEN], c;
107	int fd, len = sizeof(buf)/sizeof(buf[0]);
108
109	printk("Checking for host processor %s support...", feature);
110	fd = os_open_file("/proc/cpuinfo", of_read(OPENFLAGS()), 0);
111	if(fd < 0){
112		printk("Couldn't open /proc/cpuinfo, err = %d\n", -fd);
113		return(0);
114	}
115
116	*have_it = 0;
117	if(!find_cpuinfo_line(fd, "flags", buf, sizeof(buf) / sizeof(buf[0])))
118		goto out;
119
120	c = token(fd, buf, len - 1, ' ');
121	if(c < 0) goto out;
122	else if(c != ' '){
123		printk("Failed to find ' ' in /proc/cpuinfo\n");
124		goto out;
125	}
126
127	while(1){
128		c = token(fd, buf, len - 1, ' ');
129		if(c < 0) goto out;
130		else if(c == '\n') break;
131
132		if(!strcmp(buf, feature)){
133			*have_it = 1;
134			goto out;
135		}
136	}
137 out:
138	if(*have_it == 0) printk("No\n");
139	else if(*have_it == 1) printk("Yes\n");
140	os_close_file(fd);
141	return(1);
142}
143
144#if 0 /* This doesn't work in tt mode, plus it's causing compilation problems
145       * for some people.
146       */
147static void disable_lcall(void)
148{
149	struct modify_ldt_ldt_s ldt;
150	int err;
151
152	bzero(&ldt, sizeof(ldt));
153	ldt.entry_number = 7;
154	ldt.base_addr = 0;
155	ldt.limit = 0;
156	err = modify_ldt(1, &ldt, sizeof(ldt));
157	if(err)
158		printk("Failed to disable lcall7 - errno = %d\n", errno);
159}
160#endif
161
162void arch_init_thread(void)
163{
164#if 0
165	disable_lcall();
166#endif
167}
168
169void arch_check_bugs(void)
170{
171	int have_it;
172
173	if(os_access("/proc/cpuinfo", OS_ACC_R_OK) < 0){
174		printk("/proc/cpuinfo not available - skipping CPU capability "
175		       "checks\n");
176		return;
177	}
178	if(check_cpu_flag("cmov", &have_it))
179		host_has_cmov = have_it;
180	if(check_cpu_flag("xmm", &have_it))
181		host_has_xmm = have_it;
182}
183
184int arch_handle_signal(int sig, union uml_pt_regs *regs)
185{
186	unsigned char tmp[2];
187
188	/* This is testing for a cmov (0x0f 0x4x) instruction causing a
189	 * SIGILL in init.
190	 */
191	if((sig != SIGILL) || (TASK_PID(get_current()) != 1)) return(0);
192
193	if (copy_from_user_proc(tmp, (void *) UPT_IP(regs), 2))
194		panic("SIGILL in init, could not read instructions!\n");
195	if((tmp[0] != 0x0f) || ((tmp[1] & 0xf0) != 0x40))
196		return(0);
197
198	if(host_has_cmov == 0)
199		panic("SIGILL caused by cmov, which this processor doesn't "
200		      "implement, boot a filesystem compiled for older "
201		      "processors");
202	else if(host_has_cmov == 1)
203		panic("SIGILL caused by cmov, which this processor claims to "
204		      "implement");
205	else if(host_has_cmov == -1)
206		panic("SIGILL caused by cmov, couldn't tell if this processor "
207		      "implements it, boot a filesystem compiled for older "
208		      "processors");
209	else panic("Bad value for host_has_cmov (%d)", host_has_cmov);
210	return(0);
211}
212
213/*
214 * Overrides for Emacs so that we follow Linus's tabbing style.
215 * Emacs will notice this stuff at the end of the file and automatically
216 * adjust the settings for this buffer only.  This must remain at the end
217 * of the file.
218 * ---------------------------------------------------------------------------
219 * Local variables:
220 * c-file-style: "linux"
221 * End:
222 */