75 lines
1.8 KiB
C
75 lines
1.8 KiB
C
/*
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* Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
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* Licensed under the GPL
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*/
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#include <signal.h>
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#include <kern_util.h>
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#include <longjmp.h>
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#include <sysdep/ptrace.h>
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#include <generated/asm-offsets.h>
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/* Set during early boot */
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static int host_has_cmov = 1;
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static jmp_buf cmov_test_return;
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static void cmov_sigill_test_handler(int sig)
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{
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host_has_cmov = 0;
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longjmp(cmov_test_return, 1);
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}
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void arch_check_bugs(void)
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{
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struct sigaction old, new;
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printk(UM_KERN_INFO "Checking for host processor cmov support...");
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new.sa_handler = cmov_sigill_test_handler;
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/* Make sure that SIGILL is enabled after the handler longjmps back */
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new.sa_flags = SA_NODEFER;
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sigemptyset(&new.sa_mask);
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sigaction(SIGILL, &new, &old);
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if (setjmp(cmov_test_return) == 0) {
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unsigned long foo = 0;
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__asm__ __volatile__("cmovz %0, %1" : "=r" (foo) : "0" (foo));
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printk(UM_KERN_CONT "Yes\n");
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} else
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printk(UM_KERN_CONT "No\n");
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sigaction(SIGILL, &old, &new);
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}
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void arch_examine_signal(int sig, struct uml_pt_regs *regs)
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{
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unsigned char tmp[2];
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/*
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* This is testing for a cmov (0x0f 0x4x) instruction causing a
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* SIGILL in init.
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*/
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if ((sig != SIGILL) || (get_current_pid() != 1))
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return;
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if (copy_from_user_proc(tmp, (void *) UPT_IP(regs), 2)) {
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printk(UM_KERN_ERR "SIGILL in init, could not read "
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"instructions!\n");
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return;
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}
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if ((tmp[0] != 0x0f) || ((tmp[1] & 0xf0) != 0x40))
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return;
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if (host_has_cmov == 0)
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printk(UM_KERN_ERR "SIGILL caused by cmov, which this "
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"processor doesn't implement. Boot a filesystem "
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"compiled for older processors");
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else if (host_has_cmov == 1)
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printk(UM_KERN_ERR "SIGILL caused by cmov, which this "
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"processor claims to implement");
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else
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printk(UM_KERN_ERR "Bad value for host_has_cmov (%d)",
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host_has_cmov);
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}
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