projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 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 | } |