mirror of
https://gitlab.com/qemu-project/qemu
synced 2024-09-06 18:05:37 +00:00
![Philippe Mathieu-Daudé](/assets/img/avatar_default.png)
CPU watchpoints can be use by non-TCG accelerators. KVM uses them: $ git grep CPUWatchpoint|fgrep kvm target/arm/kvm64.c:1558: CPUWatchpoint *wp = find_hw_watchpoint(cs, debug_exit->far); target/i386/kvm/kvm.c:5216:static CPUWatchpoint hw_watchpoint; target/ppc/kvm.c:443:static CPUWatchpoint hw_watchpoint; target/s390x/kvm/kvm.c:139:static CPUWatchpoint hw_watchpoint; See for example commite4482ab7e3
("target-arm: kvm - add support for HW assisted debug"): This adds basic support for HW assisted debug. The ioctl interface to KVM allows us to pass an implementation defined number of break and watch point registers. [...] This partially reverts commit2609ec2868
. Fixes:2609ec2868
("softmmu: Extract watchpoint API from physmem.c") Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org> Message-Id: <20230328173117.15226-4-philmd@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
227 lines
6.9 KiB
C
227 lines
6.9 KiB
C
/*
|
|
* 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->can_do_io) {
|
|
/* Force execution of one insn next time. */
|
|
cpu->cflags_next_tb = 1 | CF_LAST_IO | 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_LAST_IO | CF_NOIRQ
|
|
| curr_cflags(cpu);
|
|
mmap_unlock();
|
|
cpu_loop_exit_noexc(cpu);
|
|
}
|
|
} else {
|
|
wp->flags &= ~BP_WATCHPOINT_HIT;
|
|
}
|
|
}
|
|
}
|
|
|
|
#endif /* CONFIG_TCG */
|