cpu-target.c - third_party/qemu - Git at Google

 /*
  * Target-specific parts of the CPU object
  *
  *  Copyright (c) 2003 Fabrice Bellard
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
  */

 #include "qemu/osdep.h"
 #include "qapi/error.h"

 #include "exec/target_page.h"
 #include "hw/qdev-core.h"
 #include "hw/qdev-properties.h"
 #include "qemu/error-report.h"
 #include "qemu/qemu-print.h"
 #include "migration/vmstate.h"
 #ifdef CONFIG_USER_ONLY
 #include "qemu.h"
 #else
 #include "hw/core/sysemu-cpu-ops.h"
 #include "exec/address-spaces.h"
 #include "exec/memory.h"
 #endif
 #include "sysemu/cpus.h"
 #include "sysemu/tcg.h"
 #include "exec/replay-core.h"
 #include "exec/cpu-common.h"
 #include "exec/exec-all.h"
 #include "exec/tb-flush.h"
 #include "exec/translate-all.h"
 #include "exec/log.h"
 #include "hw/core/accel-cpu.h"
 #include "trace/trace-root.h"
 #include "qemu/accel.h"

 #ifndef CONFIG_USER_ONLY
 static int cpu_common_post_load(void *opaque, int version_id)
 {
     CPUState *cpu = opaque;

     /* 0x01 was CPU_INTERRUPT_EXIT. This line can be removed when the
        version_id is increased. */
     cpu->interrupt_request &= ~0x01;
     tlb_flush(cpu);

     /* loadvm has just updated the content of RAM, bypassing the
      * usual mechanisms that ensure we flush TBs for writes to
      * memory we've translated code from. So we must flush all TBs,
      * which will now be stale.
      */
     tb_flush(cpu);

     return 0;
 }

 static int cpu_common_pre_load(void *opaque)
 {
     CPUState *cpu = opaque;

     cpu->exception_index = -1;

     return 0;
 }

 static bool cpu_common_exception_index_needed(void *opaque)
 {
     CPUState *cpu = opaque;

     return tcg_enabled() && cpu->exception_index != -1;
 }

 static const VMStateDescription vmstate_cpu_common_exception_index = {
     .name = "cpu_common/exception_index",
     .version_id = 1,
     .minimum_version_id = 1,
     .needed = cpu_common_exception_index_needed,
     .fields = (const VMStateField[]) {
         VMSTATE_INT32(exception_index, CPUState),
         VMSTATE_END_OF_LIST()
     }
 };

 static bool cpu_common_crash_occurred_needed(void *opaque)
 {
     CPUState *cpu = opaque;

     return cpu->crash_occurred;
 }

 static const VMStateDescription vmstate_cpu_common_crash_occurred = {
     .name = "cpu_common/crash_occurred",
     .version_id = 1,
     .minimum_version_id = 1,
     .needed = cpu_common_crash_occurred_needed,
     .fields = (const VMStateField[]) {
         VMSTATE_BOOL(crash_occurred, CPUState),
         VMSTATE_END_OF_LIST()
     }
 };

 const VMStateDescription vmstate_cpu_common = {
     .name = "cpu_common",
     .version_id = 1,
     .minimum_version_id = 1,
     .pre_load = cpu_common_pre_load,
     .post_load = cpu_common_post_load,
     .fields = (const VMStateField[]) {
         VMSTATE_UINT32(halted, CPUState),
         VMSTATE_UINT32(interrupt_request, CPUState),
         VMSTATE_END_OF_LIST()
     },
     .subsections = (const VMStateDescription * const []) {
         &vmstate_cpu_common_exception_index,
         &vmstate_cpu_common_crash_occurred,
         NULL
     }
 };
 #endif

 bool cpu_exec_realizefn(CPUState *cpu, Error **errp)
 {
     /* cache the cpu class for the hotpath */
     cpu->cc = CPU_GET_CLASS(cpu);

     if (!accel_cpu_common_realize(cpu, errp)) {
         return false;
     }

     /* Wait until cpu initialization complete before exposing cpu. */
     cpu_list_add(cpu);

 #ifdef CONFIG_USER_ONLY
     assert(qdev_get_vmsd(DEVICE(cpu)) == NULL ||
            qdev_get_vmsd(DEVICE(cpu))->unmigratable);
 #else
     if (qdev_get_vmsd(DEVICE(cpu)) == NULL) {
         vmstate_register(NULL, cpu->cpu_index, &vmstate_cpu_common, cpu);
     }
     if (cpu->cc->sysemu_ops->legacy_vmsd != NULL) {
         vmstate_register(NULL, cpu->cpu_index, cpu->cc->sysemu_ops->legacy_vmsd, cpu);
     }
 #endif /* CONFIG_USER_ONLY */

     return true;
 }

 void cpu_exec_unrealizefn(CPUState *cpu)
 {
 #ifndef CONFIG_USER_ONLY
     CPUClass *cc = CPU_GET_CLASS(cpu);

     if (cc->sysemu_ops->legacy_vmsd != NULL) {
         vmstate_unregister(NULL, cc->sysemu_ops->legacy_vmsd, cpu);
     }
     if (qdev_get_vmsd(DEVICE(cpu)) == NULL) {
         vmstate_unregister(NULL, &vmstate_cpu_common, cpu);
     }
 #endif

     cpu_list_remove(cpu);
     /*
      * Now that the vCPU has been removed from the RCU list, we can call
      * accel_cpu_common_unrealize, which may free fields using call_rcu.
      */
     accel_cpu_common_unrealize(cpu);
 }

 /*
  * This can't go in hw/core/cpu.c because that file is compiled only
  * once for both user-mode and system builds.
  */
 static Property cpu_common_props[] = {
 #ifdef CONFIG_USER_ONLY
     /*
      * Create a property for the user-only object, so users can
      * adjust prctl(PR_SET_UNALIGN) from the command-line.
      * Has no effect if the target does not support the feature.
      */
     DEFINE_PROP_BOOL("prctl-unalign-sigbus", CPUState,
                      prctl_unalign_sigbus, false),
 #else
     /*
      * Create a memory property for system CPU object, so users can
      * wire up its memory.  The default if no link is set up is to use
      * the system address space.
      */
     DEFINE_PROP_LINK("memory", CPUState, memory, TYPE_MEMORY_REGION,
                      MemoryRegion *),
 #endif
     DEFINE_PROP_END_OF_LIST(),
 };

 #ifndef CONFIG_USER_ONLY
 static bool cpu_get_start_powered_off(Object *obj, Error **errp)
 {
     CPUState *cpu = CPU(obj);
     return cpu->start_powered_off;
 }

 static void cpu_set_start_powered_off(Object *obj, bool value, Error **errp)
 {
     CPUState *cpu = CPU(obj);
     cpu->start_powered_off = value;
 }
 #endif

 void cpu_class_init_props(DeviceClass *dc)
 {
 #ifndef CONFIG_USER_ONLY
     ObjectClass *oc = OBJECT_CLASS(dc);

     /*
      * We can't use DEFINE_PROP_BOOL in the Property array for this
      * property, because we want this to be settable after realize.
      */
     object_class_property_add_bool(oc, "start-powered-off",
                                    cpu_get_start_powered_off,
                                    cpu_set_start_powered_off);
 #endif

     device_class_set_props(dc, cpu_common_props);
 }

 void cpu_exec_initfn(CPUState *cpu)
 {
     cpu->as = NULL;
     cpu->num_ases = 0;

 #ifndef CONFIG_USER_ONLY
     cpu->thread_id = qemu_get_thread_id();
     cpu->memory = get_system_memory();
     object_ref(OBJECT(cpu->memory));
 #endif
 }

 char *cpu_model_from_type(const char *typename)
 {
     const char *suffix = "-" CPU_RESOLVING_TYPE;

     if (!object_class_by_name(typename)) {
         return NULL;
     }

     if (g_str_has_suffix(typename, suffix)) {
         return g_strndup(typename, strlen(typename) - strlen(suffix));
     }

     return g_strdup(typename);
 }

 const char *parse_cpu_option(const char *cpu_option)
 {
     ObjectClass *oc;
     CPUClass *cc;
     gchar **model_pieces;
     const char *cpu_type;

     model_pieces = g_strsplit(cpu_option, ",", 2);
     if (!model_pieces[0]) {
         error_report("-cpu option cannot be empty");
         exit(1);
     }

     oc = cpu_class_by_name(CPU_RESOLVING_TYPE, model_pieces[0]);
     if (oc == NULL) {
         error_report("unable to find CPU model '%s'", model_pieces[0]);
         g_strfreev(model_pieces);
         exit(EXIT_FAILURE);
     }

     cpu_type = object_class_get_name(oc);
     cc = CPU_CLASS(oc);
     cc->parse_features(cpu_type, model_pieces[1], &error_fatal);
     g_strfreev(model_pieces);
     return cpu_type;
 }

 #ifndef cpu_list
 static void cpu_list_entry(gpointer data, gpointer user_data)
 {
     CPUClass *cc = CPU_CLASS(OBJECT_CLASS(data));
     const char *typename = object_class_get_name(OBJECT_CLASS(data));
     g_autofree char *model = cpu_model_from_type(typename);

     if (cc->deprecation_note) {
         qemu_printf("  %s (deprecated)\n", model);
     } else {
         qemu_printf("  %s\n", model);
     }
 }

 static void cpu_list(void)
 {
     GSList *list;

     list = object_class_get_list_sorted(TYPE_CPU, false);
     qemu_printf("Available CPUs:\n");
     g_slist_foreach(list, cpu_list_entry, NULL);
     g_slist_free(list);
 }
 #endif

 void list_cpus(void)
 {
     cpu_list();
 }

 /* enable or disable single step mode. EXCP_DEBUG is returned by the
    CPU loop after each instruction */
 void cpu_single_step(CPUState *cpu, int enabled)
 {
     if (cpu->singlestep_enabled != enabled) {
         cpu->singlestep_enabled = enabled;

 #if !defined(CONFIG_USER_ONLY)
         const AccelOpsClass *ops = cpus_get_accel();
         if (ops->update_guest_debug) {
             ops->update_guest_debug(cpu);
         }
 #endif

         trace_breakpoint_singlestep(cpu->cpu_index, enabled);
     }
 }

 void cpu_abort(CPUState *cpu, const char *fmt, ...)
 {
     va_list ap;
     va_list ap2;

     va_start(ap, fmt);
     va_copy(ap2, ap);
     fprintf(stderr, "qemu: fatal: ");
     vfprintf(stderr, fmt, ap);
     fprintf(stderr, "\n");
     cpu_dump_state(cpu, stderr, CPU_DUMP_FPU | CPU_DUMP_CCOP);
     if (qemu_log_separate()) {
         FILE *logfile = qemu_log_trylock();
         if (logfile) {
             fprintf(logfile, "qemu: fatal: ");
             vfprintf(logfile, fmt, ap2);
             fprintf(logfile, "\n");
             cpu_dump_state(cpu, logfile, CPU_DUMP_FPU | CPU_DUMP_CCOP);
             qemu_log_unlock(logfile);
         }
     }
     va_end(ap2);
     va_end(ap);
     replay_finish();
 #if defined(CONFIG_USER_ONLY)
     {
         struct sigaction act;
         sigfillset(&act.sa_mask);
         act.sa_handler = SIG_DFL;
         act.sa_flags = 0;
         sigaction(SIGABRT, &act, NULL);
     }
 #endif
     abort();
 }

 /* physical memory access (slow version, mainly for debug) */
 #if defined(CONFIG_USER_ONLY)
 int cpu_memory_rw_debug(CPUState *cpu, vaddr addr,
                         void *ptr, size_t len, bool is_write)
 {
     int flags;
     vaddr l, page;
     void * p;
     uint8_t *buf = ptr;
     ssize_t written;
     int ret = -1;
     int fd = -1;

     while (len > 0) {
         page = addr & TARGET_PAGE_MASK;
         l = (page + TARGET_PAGE_SIZE) - addr;
         if (l > len)
             l = len;
         flags = page_get_flags(page);
         if (!(flags & PAGE_VALID)) {
             goto out_close;
         }
         if (is_write) {
             if (flags & PAGE_WRITE) {
                 /* XXX: this code should not depend on lock_user */
                 p = lock_user(VERIFY_WRITE, addr, l, 0);
                 if (!p) {
                     goto out_close;
                 }
                 memcpy(p, buf, l);
                 unlock_user(p, addr, l);
             } else {
                 /* Bypass the host page protection using ptrace. */
                 if (fd == -1) {
                     fd = open("/proc/self/mem", O_WRONLY);
                     if (fd == -1) {
                         goto out;
                     }
                 }
                 /*
                  * If there is a TranslationBlock and we weren't bypassing the
                  * host page protection, the memcpy() above would SEGV,
                  * ultimately leading to page_unprotect(). So invalidate the
                  * translations manually. Both invalidation and pwrite() must
                  * be under mmap_lock() in order to prevent the creation of
                  * another TranslationBlock in between.
                  */
                 mmap_lock();
                 tb_invalidate_phys_range(addr, addr + l - 1);
                 written = pwrite(fd, buf, l,
                                  (off_t)(uintptr_t)g2h_untagged(addr));
                 mmap_unlock();
                 if (written != l) {
                     goto out_close;
                 }
             }
         } else if (flags & PAGE_READ) {
             /* XXX: this code should not depend on lock_user */
             p = lock_user(VERIFY_READ, addr, l, 1);
             if (!p) {
                 goto out_close;
             }
             memcpy(buf, p, l);
             unlock_user(p, addr, 0);
         } else {
             /* Bypass the host page protection using ptrace. */
             if (fd == -1) {
                 fd = open("/proc/self/mem", O_RDONLY);
                 if (fd == -1) {
                     goto out;
                 }
             }
             if (pread(fd, buf, l,
                       (off_t)(uintptr_t)g2h_untagged(addr)) != l) {
                 goto out_close;
             }
         }
         len -= l;
         buf += l;
         addr += l;
     }
     ret = 0;
 out_close:
     if (fd != -1) {
         close(fd);
     }
 out:
     return ret;
 }
 #endif

 bool target_words_bigendian(void)
 {
     return TARGET_BIG_ENDIAN;
 }

 const char *target_name(void)
 {
     return TARGET_NAME;
 }
	/*
	* Target-specific parts of the CPU object
	*
	* Copyright (c) 2003 Fabrice Bellard
	*
	* This library is free software; you can redistribute it and/or
	* modify it under the terms of the GNU Lesser General Public
	* License as published by the Free Software Foundation; either
	* version 2 of the License, or (at your option) any later version.
	*
	* This library is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	* Lesser General Public License for more details.
	*
	* You should have received a copy of the GNU Lesser General Public
	* License along with this library; if not, see <http://www.gnu.org/licenses/>.
	*/

	#include "qemu/osdep.h"
	#include "qapi/error.h"

	#include "exec/target_page.h"
	#include "hw/qdev-core.h"
	#include "hw/qdev-properties.h"
	#include "qemu/error-report.h"
	#include "qemu/qemu-print.h"
	#include "migration/vmstate.h"
	#ifdef CONFIG_USER_ONLY
	#include "qemu.h"
	#else
	#include "hw/core/sysemu-cpu-ops.h"
	#include "exec/address-spaces.h"
	#include "exec/memory.h"
	#endif
	#include "sysemu/cpus.h"
	#include "sysemu/tcg.h"
	#include "exec/replay-core.h"
	#include "exec/cpu-common.h"
	#include "exec/exec-all.h"
	#include "exec/tb-flush.h"
	#include "exec/translate-all.h"
	#include "exec/log.h"
	#include "hw/core/accel-cpu.h"
	#include "trace/trace-root.h"
	#include "qemu/accel.h"

	#ifndef CONFIG_USER_ONLY
	static int cpu_common_post_load(void *opaque, int version_id)
	{
	CPUState *cpu = opaque;

	/* 0x01 was CPU_INTERRUPT_EXIT. This line can be removed when the
	version_id is increased. */
	cpu->interrupt_request &= ~0x01;
	tlb_flush(cpu);

	/* loadvm has just updated the content of RAM, bypassing the
	* usual mechanisms that ensure we flush TBs for writes to
	* memory we've translated code from. So we must flush all TBs,
	* which will now be stale.
	*/
	tb_flush(cpu);

	return 0;
	}

	static int cpu_common_pre_load(void *opaque)
	{
	CPUState *cpu = opaque;

	cpu->exception_index = -1;

	return 0;
	}

	static bool cpu_common_exception_index_needed(void *opaque)
	{
	CPUState *cpu = opaque;

	return tcg_enabled() && cpu->exception_index != -1;
	}

	static const VMStateDescription vmstate_cpu_common_exception_index = {
	.name = "cpu_common/exception_index",
	.version_id = 1,
	.minimum_version_id = 1,
	.needed = cpu_common_exception_index_needed,
	.fields = (const VMStateField[]) {
	VMSTATE_INT32(exception_index, CPUState),
	VMSTATE_END_OF_LIST()
	}
	};

	static bool cpu_common_crash_occurred_needed(void *opaque)
	{
	CPUState *cpu = opaque;

	return cpu->crash_occurred;
	}

	static const VMStateDescription vmstate_cpu_common_crash_occurred = {
	.name = "cpu_common/crash_occurred",
	.version_id = 1,
	.minimum_version_id = 1,
	.needed = cpu_common_crash_occurred_needed,
	.fields = (const VMStateField[]) {
	VMSTATE_BOOL(crash_occurred, CPUState),
	VMSTATE_END_OF_LIST()
	}
	};

	const VMStateDescription vmstate_cpu_common = {
	.name = "cpu_common",
	.version_id = 1,
	.minimum_version_id = 1,
	.pre_load = cpu_common_pre_load,
	.post_load = cpu_common_post_load,
	.fields = (const VMStateField[]) {
	VMSTATE_UINT32(halted, CPUState),
	VMSTATE_UINT32(interrupt_request, CPUState),
	VMSTATE_END_OF_LIST()
	},
	.subsections = (const VMStateDescription * const []) {
	&vmstate_cpu_common_exception_index,
	&vmstate_cpu_common_crash_occurred,
	NULL
	}
	};
	#endif

	bool cpu_exec_realizefn(CPUState cpu, Error *errp)
	{
	/* cache the cpu class for the hotpath */
	cpu->cc = CPU_GET_CLASS(cpu);

	if (!accel_cpu_common_realize(cpu, errp)) {
	return false;
	}

	/* Wait until cpu initialization complete before exposing cpu. */
	cpu_list_add(cpu);

	#ifdef CONFIG_USER_ONLY
	assert(qdev_get_vmsd(DEVICE(cpu)) == NULL \|\|
	qdev_get_vmsd(DEVICE(cpu))->unmigratable);
	#else
	if (qdev_get_vmsd(DEVICE(cpu)) == NULL) {
	vmstate_register(NULL, cpu->cpu_index, &vmstate_cpu_common, cpu);
	}
	if (cpu->cc->sysemu_ops->legacy_vmsd != NULL) {
	vmstate_register(NULL, cpu->cpu_index, cpu->cc->sysemu_ops->legacy_vmsd, cpu);
	}
	#endif /* CONFIG_USER_ONLY */

	return true;
	}

	void cpu_exec_unrealizefn(CPUState *cpu)
	{
	#ifndef CONFIG_USER_ONLY
	CPUClass *cc = CPU_GET_CLASS(cpu);

	if (cc->sysemu_ops->legacy_vmsd != NULL) {
	vmstate_unregister(NULL, cc->sysemu_ops->legacy_vmsd, cpu);
	}
	if (qdev_get_vmsd(DEVICE(cpu)) == NULL) {
	vmstate_unregister(NULL, &vmstate_cpu_common, cpu);
	}
	#endif

	cpu_list_remove(cpu);
	/*
	* Now that the vCPU has been removed from the RCU list, we can call
	* accel_cpu_common_unrealize, which may free fields using call_rcu.
	*/
	accel_cpu_common_unrealize(cpu);
	}

	/*
	* This can't go in hw/core/cpu.c because that file is compiled only
	* once for both user-mode and system builds.
	*/
	static Property cpu_common_props[] = {
	#ifdef CONFIG_USER_ONLY
	/*
	* Create a property for the user-only object, so users can
	* adjust prctl(PR_SET_UNALIGN) from the command-line.
	* Has no effect if the target does not support the feature.
	*/
	DEFINE_PROP_BOOL("prctl-unalign-sigbus", CPUState,
	prctl_unalign_sigbus, false),
	#else
	/*
	* Create a memory property for system CPU object, so users can
	* wire up its memory. The default if no link is set up is to use
	* the system address space.
	*/
	DEFINE_PROP_LINK("memory", CPUState, memory, TYPE_MEMORY_REGION,
	MemoryRegion *),
	#endif
	DEFINE_PROP_END_OF_LIST(),
	};

	#ifndef CONFIG_USER_ONLY
	static bool cpu_get_start_powered_off(Object obj, Error *errp)
	{
	CPUState *cpu = CPU(obj);
	return cpu->start_powered_off;
	}

	static void cpu_set_start_powered_off(Object obj, bool value, Error *errp)
	{
	CPUState *cpu = CPU(obj);
	cpu->start_powered_off = value;
	}
	#endif

	void cpu_class_init_props(DeviceClass *dc)
	{
	#ifndef CONFIG_USER_ONLY
	ObjectClass *oc = OBJECT_CLASS(dc);

	/*
	* We can't use DEFINE_PROP_BOOL in the Property array for this
	* property, because we want this to be settable after realize.
	*/
	object_class_property_add_bool(oc, "start-powered-off",
	cpu_get_start_powered_off,
	cpu_set_start_powered_off);
	#endif

	device_class_set_props(dc, cpu_common_props);
	}

	void cpu_exec_initfn(CPUState *cpu)
	{
	cpu->as = NULL;
	cpu->num_ases = 0;

	#ifndef CONFIG_USER_ONLY
	cpu->thread_id = qemu_get_thread_id();
	cpu->memory = get_system_memory();
	object_ref(OBJECT(cpu->memory));
	#endif
	}

	char cpu_model_from_type(const char typename)
	{
	const char *suffix = "-" CPU_RESOLVING_TYPE;

	if (!object_class_by_name(typename)) {
	return NULL;
	}

	if (g_str_has_suffix(typename, suffix)) {
	return g_strndup(typename, strlen(typename) - strlen(suffix));
	}

	return g_strdup(typename);
	}

	const char parse_cpu_option(const char cpu_option)
	{
	ObjectClass *oc;
	CPUClass *cc;
	gchar **model_pieces;
	const char *cpu_type;

	model_pieces = g_strsplit(cpu_option, ",", 2);
	if (!model_pieces[0]) {
	error_report("-cpu option cannot be empty");
	exit(1);
	}

	oc = cpu_class_by_name(CPU_RESOLVING_TYPE, model_pieces[0]);
	if (oc == NULL) {
	error_report("unable to find CPU model '%s'", model_pieces[0]);
	g_strfreev(model_pieces);
	exit(EXIT_FAILURE);
	}

	cpu_type = object_class_get_name(oc);
	cc = CPU_CLASS(oc);
	cc->parse_features(cpu_type, model_pieces[1], &error_fatal);
	g_strfreev(model_pieces);
	return cpu_type;
	}

	#ifndef cpu_list
	static void cpu_list_entry(gpointer data, gpointer user_data)
	{
	CPUClass *cc = CPU_CLASS(OBJECT_CLASS(data));
	const char *typename = object_class_get_name(OBJECT_CLASS(data));
	g_autofree char *model = cpu_model_from_type(typename);

	if (cc->deprecation_note) {
	qemu_printf(" %s (deprecated)\n", model);
	} else {
	qemu_printf(" %s\n", model);
	}
	}

	static void cpu_list(void)
	{
	GSList *list;

	list = object_class_get_list_sorted(TYPE_CPU, false);
	qemu_printf("Available CPUs:\n");
	g_slist_foreach(list, cpu_list_entry, NULL);
	g_slist_free(list);
	}
	#endif

	void list_cpus(void)
	{
	cpu_list();
	}

	/* enable or disable single step mode. EXCP_DEBUG is returned by the
	CPU loop after each instruction */
	void cpu_single_step(CPUState *cpu, int enabled)
	{
	if (cpu->singlestep_enabled != enabled) {
	cpu->singlestep_enabled = enabled;

	#if !defined(CONFIG_USER_ONLY)
	const AccelOpsClass *ops = cpus_get_accel();
	if (ops->update_guest_debug) {
	ops->update_guest_debug(cpu);
	}
	#endif

	trace_breakpoint_singlestep(cpu->cpu_index, enabled);
	}
	}

	void cpu_abort(CPUState cpu, const char fmt, ...)
	{
	va_list ap;
	va_list ap2;

	va_start(ap, fmt);
	va_copy(ap2, ap);
	fprintf(stderr, "qemu: fatal: ");
	vfprintf(stderr, fmt, ap);
	fprintf(stderr, "\n");
	cpu_dump_state(cpu, stderr, CPU_DUMP_FPU \| CPU_DUMP_CCOP);
	if (qemu_log_separate()) {
	FILE *logfile = qemu_log_trylock();
	if (logfile) {
	fprintf(logfile, "qemu: fatal: ");
	vfprintf(logfile, fmt, ap2);
	fprintf(logfile, "\n");
	cpu_dump_state(cpu, logfile, CPU_DUMP_FPU \| CPU_DUMP_CCOP);
	qemu_log_unlock(logfile);
	}
	}
	va_end(ap2);
	va_end(ap);
	replay_finish();
	#if defined(CONFIG_USER_ONLY)
	{
	struct sigaction act;
	sigfillset(&act.sa_mask);
	act.sa_handler = SIG_DFL;
	act.sa_flags = 0;
	sigaction(SIGABRT, &act, NULL);
	}
	#endif
	abort();
	}

	/* physical memory access (slow version, mainly for debug) */
	#if defined(CONFIG_USER_ONLY)
	int cpu_memory_rw_debug(CPUState *cpu, vaddr addr,
	void *ptr, size_t len, bool is_write)
	{
	int flags;
	vaddr l, page;
	void * p;
	uint8_t *buf = ptr;
	ssize_t written;
	int ret = -1;
	int fd = -1;

	while (len > 0) {
	page = addr & TARGET_PAGE_MASK;
	l = (page + TARGET_PAGE_SIZE) - addr;
	if (l > len)
	l = len;
	flags = page_get_flags(page);
	if (!(flags & PAGE_VALID)) {
	goto out_close;
	}
	if (is_write) {
	if (flags & PAGE_WRITE) {
	/* XXX: this code should not depend on lock_user */
	p = lock_user(VERIFY_WRITE, addr, l, 0);
	if (!p) {
	goto out_close;
	}
	memcpy(p, buf, l);
	unlock_user(p, addr, l);
	} else {
	/* Bypass the host page protection using ptrace. */
	if (fd == -1) {
	fd = open("/proc/self/mem", O_WRONLY);
	if (fd == -1) {
	goto out;
	}
	}
	/*
	* If there is a TranslationBlock and we weren't bypassing the
	* host page protection, the memcpy() above would SEGV,
	* ultimately leading to page_unprotect(). So invalidate the
	* translations manually. Both invalidation and pwrite() must
	* be under mmap_lock() in order to prevent the creation of
	* another TranslationBlock in between.
	*/
	mmap_lock();
	tb_invalidate_phys_range(addr, addr + l - 1);
	written = pwrite(fd, buf, l,
	(off_t)(uintptr_t)g2h_untagged(addr));
	mmap_unlock();
	if (written != l) {
	goto out_close;
	}
	}
	} else if (flags & PAGE_READ) {
	/* XXX: this code should not depend on lock_user */
	p = lock_user(VERIFY_READ, addr, l, 1);
	if (!p) {
	goto out_close;
	}
	memcpy(buf, p, l);
	unlock_user(p, addr, 0);
	} else {
	/* Bypass the host page protection using ptrace. */
	if (fd == -1) {
	fd = open("/proc/self/mem", O_RDONLY);
	if (fd == -1) {
	goto out;
	}
	}
	if (pread(fd, buf, l,
	(off_t)(uintptr_t)g2h_untagged(addr)) != l) {
	goto out_close;
	}
	}
	len -= l;
	buf += l;
	addr += l;
	}
	ret = 0;
	out_close:
	if (fd != -1) {
	close(fd);
	}
	out:
	return ret;
	}
	#endif

	bool target_words_bigendian(void)
	{
	return TARGET_BIG_ENDIAN;
	}

	const char *target_name(void)
	{
	return TARGET_NAME;
	}