system/watchpoint: Move TCG specific code to accel/tcg/

Keep system/watchpoint.c accelerator-agnostic by moving
TCG specific code to accel/tcg/watchpoint.c. Update meson.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20240111162032.43378-1-philmd@linaro.org>

2 files changed, 144 insertions, 0 deletions

diff --git a/accel/tcg/meson.build b/accel/tcg/meson.build
index d25638d..c15ac9a 100644
--- a/accel/tcg/meson.build
+++ b/accel/tcg/meson.build
@@ -24,6 +24,7 @@ specific_ss.add_all(when: 'CONFIG_TCG', if_true: tcg_ss)
 
 specific_ss.add(when: ['CONFIG_SYSTEM_ONLY', 'CONFIG_TCG'], if_true: files(
   'cputlb.c',
+  'watchpoint.c',
 ))
 
 system_ss.add(when: ['CONFIG_TCG'], if_true: files(
diff --git a/accel/tcg/watchpoint.c b/accel/tcg/watchpoint.c
new file mode 100644
index 0000000..d3aab11
--- /dev/null
+++ b/accel/tcg/watchpoint.c
@@ -0,0 +1,143 @@
+/*
+ * 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"
+
+/*
+ * 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.
+         */
+        bql_lock();
+        cpu_interrupt(cpu, CPU_INTERRUPT_DEBUG);
+        bql_unlock();
+        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;
+        }
+    }
+}