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1da177e4 LT |
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 */ | |
20 | int host_has_cmov = 1; | |
21 | int host_has_xmm = 0; | |
22 | ||
23 | static 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 | ||
51 | static 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 | ||
81 | int 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 | ||
104 | static 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 | */ | |
147 | static 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 | ||
162 | void arch_init_thread(void) | |
163 | { | |
164 | #if 0 | |
165 | disable_lcall(); | |
166 | #endif | |
167 | } | |
168 | ||
169 | void 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 | ||
184 | int 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 | */ |