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Commit | Line | Data |
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a5ed1ffa | 1 | /* |
ba180fd4 | 2 | * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) |
1da177e4 LT |
3 | * Licensed under the GPL |
4 | */ | |
5 | ||
ba180fd4 | 6 | #include <signal.h> |
ba180fd4 | 7 | #include "kern_constants.h" |
edea1385 | 8 | #include "kern_util.h" |
9226b838 | 9 | #include "longjmp.h" |
ba180fd4 JD |
10 | #include "task.h" |
11 | #include "user.h" | |
9226b838 | 12 | #include "sysdep/ptrace.h" |
1da177e4 | 13 | |
1da177e4 LT |
14 | /* Set during early boot */ |
15 | int host_has_cmov = 1; | |
235a6f06 KS |
16 | static jmp_buf cmov_test_return; |
17 | ||
18 | static void cmov_sigill_test_handler(int sig) | |
19 | { | |
20 | host_has_cmov = 0; | |
21 | longjmp(cmov_test_return, 1); | |
22 | } | |
23 | ||
9226b838 | 24 | void arch_check_bugs(void) |
235a6f06 KS |
25 | { |
26 | struct sigaction old, new; | |
27 | ||
28 | printk(UM_KERN_INFO "Checking for host processor cmov support..."); | |
29 | new.sa_handler = cmov_sigill_test_handler; | |
30 | ||
31 | /* Make sure that SIGILL is enabled after the handler longjmps back */ | |
32 | new.sa_flags = SA_NODEFER; | |
33 | sigemptyset(&new.sa_mask); | |
34 | sigaction(SIGILL, &new, &old); | |
35 | ||
36 | if (setjmp(cmov_test_return) == 0) { | |
37 | unsigned long foo = 0; | |
38 | __asm__ __volatile__("cmovz %0, %1" : "=r" (foo) : "0" (foo)); | |
39 | printk(UM_KERN_CONT "Yes\n"); | |
40 | } else | |
41 | printk(UM_KERN_CONT "No\n"); | |
42 | ||
43 | sigaction(SIGILL, &old, &new); | |
44 | } | |
1da177e4 | 45 | |
9226b838 | 46 | void arch_examine_signal(int sig, struct uml_pt_regs *regs) |
1da177e4 LT |
47 | { |
48 | unsigned char tmp[2]; | |
49 | ||
ba180fd4 JD |
50 | /* |
51 | * This is testing for a cmov (0x0f 0x4x) instruction causing a | |
1da177e4 LT |
52 | * SIGILL in init. |
53 | */ | |
ba180fd4 | 54 | if ((sig != SIGILL) || (TASK_PID(get_current()) != 1)) |
9226b838 JD |
55 | return; |
56 | ||
57 | if (copy_from_user_proc(tmp, (void *) UPT_IP(regs), 2)) { | |
58 | printk(UM_KERN_ERR "SIGILL in init, could not read " | |
59 | "instructions!\n"); | |
60 | return; | |
61 | } | |
1da177e4 | 62 | |
ba180fd4 | 63 | if ((tmp[0] != 0x0f) || ((tmp[1] & 0xf0) != 0x40)) |
9226b838 | 64 | return; |
1da177e4 | 65 | |
ba180fd4 | 66 | if (host_has_cmov == 0) |
9226b838 JD |
67 | printk(UM_KERN_ERR "SIGILL caused by cmov, which this " |
68 | "processor doesn't implement. Boot a filesystem " | |
69 | "compiled for older processors"); | |
ba180fd4 | 70 | else if (host_has_cmov == 1) |
9226b838 JD |
71 | printk(UM_KERN_ERR "SIGILL caused by cmov, which this " |
72 | "processor claims to implement"); | |
73 | else | |
74 | printk(UM_KERN_ERR "Bad value for host_has_cmov (%d)", | |
75 | host_has_cmov); | |
1da177e4 | 76 | } |