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https://github.com/xen-project/xen.git
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Keir Fraser
420820e830
F12 introduces a tool to automatically report bugs when there are core dumps. Since xen-detect relies on fork+waitpid in order to trap a SIGILL from a child, every time someone runs xen-detect on a bare metal kernel a bug is reported into Red Hat's Bugzilla. :-) However, even without this contingent need, leaving core dumps around is not nice. So this patch just traps SIGILL using signal/sentjmp/longjmp, without the need to fork. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Keir Fraser <keir.fraser@citrix.com>
99 lines
3.1 KiB
C
99 lines
3.1 KiB
C
/******************************************************************************
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* xen_detect.c
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*
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* Simple GNU C / POSIX application to detect execution on Xen VMM platform.
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*
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* Copyright (c) 2007, XenSource Inc.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to
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* deal in the Software without restriction, including without limitation the
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* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
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* sell copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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* DEALINGS IN THE SOFTWARE.
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*/
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#include <stdint.h>
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#include <stdio.h>
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#include <string.h>
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#include <setjmp.h>
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#include <signal.h>
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static void cpuid(uint32_t idx,
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uint32_t *eax,
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uint32_t *ebx,
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uint32_t *ecx,
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uint32_t *edx,
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int pv_context)
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{
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asm volatile (
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"test %1,%1 ; jz 1f ; ud2a ; .ascii \"xen\" ; 1: cpuid"
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: "=a" (*eax), "=b" (*ebx), "=c" (*ecx), "=d" (*edx)
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: "0" (idx), "1" (pv_context) );
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}
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static int check_for_xen(int pv_context)
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{
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uint32_t eax, ebx, ecx, edx;
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char signature[13];
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uint32_t base;
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for ( base = 0x40000000; base < 0x40010000; base += 0x100 )
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{
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cpuid(base, &eax, &ebx, &ecx, &edx, pv_context);
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*(uint32_t *)(signature + 0) = ebx;
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*(uint32_t *)(signature + 4) = ecx;
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*(uint32_t *)(signature + 8) = edx;
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signature[12] = '\0';
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if ( !strcmp("XenVMMXenVMM", signature) && (eax >= (base + 2)) )
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goto found;
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}
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return 0;
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found:
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cpuid(base + 1, &eax, &ebx, &ecx, &edx, pv_context);
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printf("Running in %s context on Xen v%d.%d.\n",
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pv_context ? "PV" : "HVM", (uint16_t)(eax >> 16), (uint16_t)eax);
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return 1;
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}
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static jmp_buf sigill_jmp;
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void sigill_handler(int sig)
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{
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longjmp(sigill_jmp, 1);
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}
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int main(void)
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{
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/* Check for execution in HVM context. */
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if ( check_for_xen(0) )
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return 0;
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/*
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* Set up a signal handler to test the paravirtualised CPUID instruction.
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* If executed outside Xen PV context, the extended opcode will fault, we
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* will longjmp via the signal handler, and print "Not running on Xen".
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*/
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if ( !setjmp(sigill_jmp)
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&& (signal(SIGILL, sigill_handler) != SIG_ERR)
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&& check_for_xen(1) )
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return 0;
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printf("Not running on Xen.\n");
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return 0;
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}
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