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#define _GNU_SOURCE
#include <stdio.h>
#include <stdarg.h>
#include <string.h>
#include <stdlib.h>
#include <elf.h>
#include <errno.h>
#include <limits.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <setjmp.h>
#include <signal.h>
#include "kexec.h"
#include "crashdump.h"
#include "kexec-syscall.h"
#include "config.h"
#ifdef HAVE_LIBXENCTRL
#include <xenctrl.h>
#endif
struct crash_note_info {
unsigned long base;
unsigned long length;
};
static int xen_phys_cpus;
static struct crash_note_info *xen_phys_notes;
/* based on code from xen-detect.c */
static int is_dom0;
#if defined(__i386__) || defined(__x86_64__)
static jmp_buf xen_sigill_jmp;
void xen_sigill_handler(int sig)
{
longjmp(xen_sigill_jmp, 1);
}
static void xen_cpuid(uint32_t idx, uint32_t *regs, int pv_context)
{
#ifdef __i386__
/* Use the stack to avoid reg constraint failures with some gcc flags */
asm volatile (
"push %%eax; push %%ebx; push %%ecx; push %%edx\n\t"
"test %1,%1 ; jz 1f ; ud2a ; .ascii \"xen\" ; 1: cpuid\n\t"
"mov %%eax,(%2); mov %%ebx,4(%2)\n\t"
"mov %%ecx,8(%2); mov %%edx,12(%2)\n\t"
"pop %%edx; pop %%ecx; pop %%ebx; pop %%eax\n\t"
: : "a" (idx), "c" (pv_context), "S" (regs) : "memory" );
#else
asm volatile (
"test %5,%5 ; jz 1f ; ud2a ; .ascii \"xen\" ; 1: cpuid\n\t"
: "=a" (regs[0]), "=b" (regs[1]), "=c" (regs[2]), "=d" (regs[3])
: "0" (idx), "1" (pv_context), "2" (0) );
#endif
}
static int check_for_xen(int pv_context)
{
uint32_t regs[4];
char signature[13];
uint32_t base;
for (base = 0x40000000; base < 0x40010000; base += 0x100)
{
xen_cpuid(base, regs, pv_context);
*(uint32_t *)(signature + 0) = regs[1];
*(uint32_t *)(signature + 4) = regs[2];
*(uint32_t *)(signature + 8) = regs[3];
signature[12] = '\0';
if (strcmp("XenVMMXenVMM", signature) == 0 && regs[0] >= (base + 2))
goto found;
}
return 0;
found:
xen_cpuid(base + 1, regs, pv_context);
return regs[0];
}
static int xen_detect_pv_guest(void)
{
struct sigaction act, oldact;
int is_pv = -1;
if (setjmp(xen_sigill_jmp))
return is_pv;
memset(&act, 0, sizeof(act));
act.sa_handler = xen_sigill_handler;
sigemptyset (&act.sa_mask);
if (sigaction(SIGILL, &act, &oldact))
return is_pv;
if (check_for_xen(1))
is_pv = 1;
sigaction(SIGILL, &oldact, NULL);
return is_pv;
}
#else
static int xen_detect_pv_guest(void)
{
return 1;
}
#endif
/*
* Return 1 if its a PV guest.
* This includes dom0, which is the only PV guest where kexec/kdump works.
* HVM guests have to be handled as native hardware.
*/
int xen_present(void)
{
if (!is_dom0) {
if (access("/proc/xen", F_OK) == 0)
is_dom0 = xen_detect_pv_guest();
else
is_dom0 = -1;
}
return is_dom0 > 0;
}
unsigned long xen_architecture(struct crash_elf_info *elf_info)
{
unsigned long machine = elf_info->machine;
#ifdef HAVE_LIBXENCTRL
int rc;
xen_capabilities_info_t capabilities;
#ifdef XENCTRL_HAS_XC_INTERFACE
xc_interface *xc;
#else
int xc;
#endif
if (!xen_present())
goto out;
memset(capabilities, '0', XEN_CAPABILITIES_INFO_LEN);
#ifdef XENCTRL_HAS_XC_INTERFACE
xc = xc_interface_open(NULL, NULL, 0);
if ( !xc ) {
fprintf(stderr, "failed to open xen control interface.\n");
goto out;
}
#else
xc = xc_interface_open();
if ( xc == -1 ) {
fprintf(stderr, "failed to open xen control interface.\n");
goto out;
}
#endif
rc = xc_version(xc, XENVER_capabilities, &capabilities[0]);
if ( rc == -1 ) {
fprintf(stderr, "failed to make Xen version hypercall.\n");
goto out_close;
}
if (strstr(capabilities, "xen-3.0-x86_64"))
machine = EM_X86_64;
else if (strstr(capabilities, "xen-3.0-x86_32"))
machine = EM_386;
out_close:
xc_interface_close(xc);
out:
#endif
return machine;
}
static int xen_crash_note_callback(void *UNUSED(data), int nr,
char *UNUSED(str),
unsigned long base,
unsigned long length)
{
struct crash_note_info *note = xen_phys_notes + nr;
note->base = base;
note->length = length;
return 0;
}
int xen_get_nr_phys_cpus(void)
{
char *match = "Crash note\n";
int cpus, n;
if (xen_phys_cpus)
return xen_phys_cpus;
if ((cpus = kexec_iomem_for_each_line(match, NULL, NULL))) {
n = sizeof(struct crash_note_info) * cpus;
xen_phys_notes = malloc(n);
if (!xen_phys_notes) {
fprintf(stderr, "failed to allocate xen_phys_notes.\n");
return -1;
}
memset(xen_phys_notes, 0, n);
kexec_iomem_for_each_line(match,
xen_crash_note_callback, NULL);
xen_phys_cpus = cpus;
}
return cpus;
}
int xen_get_note(int cpu, uint64_t *addr, uint64_t *len)
{
struct crash_note_info *note;
if (xen_phys_cpus <= 0)
return -1;
note = xen_phys_notes + cpu;
*addr = note->base;
*len = note->length;
return 0;
}
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