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/*
* CPU watchpoints
*
* 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 2.1 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 "qemu/main-loop.h"
#include "qemu/error-report.h"
#include "exec/exec-all.h"
#include "exec/translate-all.h"
#include "sysemu/tcg.h"
#include "sysemu/replay.h"
#include "hw/core/tcg-cpu-ops.h"
#include "hw/core/cpu.h"
/* Add a watchpoint. */
int cpu_watchpoint_insert(CPUState *cpu, vaddr addr, vaddr len,
int flags, CPUWatchpoint **watchpoint)
{
CPUWatchpoint *wp;
vaddr in_page;
/* forbid ranges which are empty or run off the end of the address space */
if (len == 0 || (addr + len - 1) < addr) {
error_report("tried to set invalid watchpoint at %"
VADDR_PRIx ", len=%" VADDR_PRIu, addr, len);
return -EINVAL;
}
wp = g_malloc(sizeof(*wp));
wp->vaddr = addr;
wp->len = len;
wp->flags = flags;
/* keep all GDB-injected watchpoints in front */
if (flags & BP_GDB) {
QTAILQ_INSERT_HEAD(&cpu->watchpoints, wp, entry);
} else {
QTAILQ_INSERT_TAIL(&cpu->watchpoints, wp, entry);
}
in_page = -(addr | TARGET_PAGE_MASK);
if (len <= in_page) {
tlb_flush_page(cpu, addr);
} else {
tlb_flush(cpu);
}
if (watchpoint) {
*watchpoint = wp;
}
return 0;
}
/* Remove a specific watchpoint. */
int cpu_watchpoint_remove(CPUState *cpu, vaddr addr, vaddr len,
int flags)
{
CPUWatchpoint *wp;
QTAILQ_FOREACH(wp, &cpu->watchpoints, entry) {
if (addr == wp->vaddr && len == wp->len
&& flags == (wp->flags & ~BP_WATCHPOINT_HIT)) {
cpu_watchpoint_remove_by_ref(cpu, wp);
return 0;
}
}
return -ENOENT;
}
/* Remove a specific watchpoint by reference. */
void cpu_watchpoint_remove_by_ref(CPUState *cpu, CPUWatchpoint *watchpoint)
{
QTAILQ_REMOVE(&cpu->watchpoints, watchpoint, entry);
tlb_flush_page(cpu, watchpoint->vaddr);
g_free(watchpoint);
}
/* Remove all matching watchpoints. */
void cpu_watchpoint_remove_all(CPUState *cpu, int mask)
{
CPUWatchpoint *wp, *next;
QTAILQ_FOREACH_SAFE(wp, &cpu->watchpoints, entry, next) {
if (wp->flags & mask) {
cpu_watchpoint_remove_by_ref(cpu, wp);
}
}
}
#ifdef CONFIG_TCG
/*
* Return true if this watchpoint address matches the specified
* access (ie the address range covered by the watchpoint overlaps
* partially or completely with the address range covered by the
* access).
*/
static inline bool watchpoint_address_matches(CPUWatchpoint *wp,
vaddr addr, vaddr len)
{
/*
* We know the lengths are non-zero, but a little caution is
* required to avoid errors in the case where the range ends
* exactly at the top of the address space and so addr + len
* wraps round to zero.
*/
vaddr wpend = wp->vaddr + wp->len - 1;
vaddr addrend = addr + len - 1;
return !(addr > wpend || wp->vaddr > addrend);
}
/* Return flags for watchpoints that match addr + prot. */
int cpu_watchpoint_address_matches(CPUState *cpu, vaddr addr, vaddr len)
{
CPUWatchpoint *wp;
int ret = 0;
QTAILQ_FOREACH(wp, &cpu->watchpoints, entry) {
if (watchpoint_address_matches(wp, addr, len)) {
ret |= wp->flags;
}
}
return ret;
}
/* Generate a debug exception if a watchpoint has been hit. */
void cpu_check_watchpoint(CPUState *cpu, vaddr addr, vaddr len,
MemTxAttrs attrs, int flags, uintptr_t ra)
{
CPUClass *cc = CPU_GET_CLASS(cpu);
CPUWatchpoint *wp;
assert(tcg_enabled());
if (cpu->watchpoint_hit) {
/*
* We re-entered the check after replacing the TB.
* Now raise the debug interrupt so that it will
* trigger after the current instruction.
*/
qemu_mutex_lock_iothread();
cpu_interrupt(cpu, CPU_INTERRUPT_DEBUG);
qemu_mutex_unlock_iothread();
return;
}
if (cc->tcg_ops->adjust_watchpoint_address) {
/* this is currently used only by ARM BE32 */
addr = cc->tcg_ops->adjust_watchpoint_address(cpu, addr, len);
}
assert((flags & ~BP_MEM_ACCESS) == 0);
QTAILQ_FOREACH(wp, &cpu->watchpoints, entry) {
int hit_flags = wp->flags & flags;
if (hit_flags && watchpoint_address_matches(wp, addr, len)) {
if (replay_running_debug()) {
/*
* replay_breakpoint reads icount.
* Force recompile to succeed, because icount may
* be read only at the end of the block.
*/
if (!cpu->neg.can_do_io) {
/* Force execution of one insn next time. */
cpu->cflags_next_tb = 1 | CF_NOIRQ | curr_cflags(cpu);
cpu_loop_exit_restore(cpu, ra);
}
/*
* Don't process the watchpoints when we are
* in a reverse debugging operation.
*/
replay_breakpoint();
return;
}
wp->flags |= hit_flags << BP_HIT_SHIFT;
wp->hitaddr = MAX(addr, wp->vaddr);
wp->hitattrs = attrs;
if (wp->flags & BP_CPU
&& cc->tcg_ops->debug_check_watchpoint
&& !cc->tcg_ops->debug_check_watchpoint(cpu, wp)) {
wp->flags &= ~BP_WATCHPOINT_HIT;
continue;
}
cpu->watchpoint_hit = wp;
mmap_lock();
/* This call also restores vCPU state */
tb_check_watchpoint(cpu, ra);
if (wp->flags & BP_STOP_BEFORE_ACCESS) {
cpu->exception_index = EXCP_DEBUG;
mmap_unlock();
cpu_loop_exit(cpu);
} else {
/* Force execution of one insn next time. */
cpu->cflags_next_tb = 1 | CF_NOIRQ | curr_cflags(cpu);
mmap_unlock();
cpu_loop_exit_noexc(cpu);
}
} else {
wp->flags &= ~BP_WATCHPOINT_HIT;
}
}
}
#endif /* CONFIG_TCG */
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