[Qemu-devel] [PATCH 2/6] exec: Factor out core logic of check_watchpoint()

[Richard Henderson <richard.henderson@linaro.org>]

From: David Hildenbrand <david@redhat.com>

We want to perform the same checks in probe_write() to trigger a cpu
exit before doing any modifications. We'll have to pass a PC.

Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20190823100741.9621-9-david@redhat.com>
[rth: Use vaddr for len, like other watchpoint functions;
Move user-only stub to static inline.]
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 include/hw/core/cpu.h |  7 +++++++
 exec.c                | 26 ++++++++++++++++++--------
 2 files changed, 25 insertions(+), 8 deletions(-)

diff --git a/include/hw/core/cpu.h b/include/hw/core/cpu.h
index 6de688059d..7bd8bed5b2 100644
--- a/include/hw/core/cpu.h
+++ b/include/hw/core/cpu.h
@@ -1091,6 +1091,11 @@ static inline void cpu_watchpoint_remove_by_ref(CPUState *cpu,
 static inline void cpu_watchpoint_remove_all(CPUState *cpu, int mask)
 {
 }
+
+static inline void cpu_check_watchpoint(CPUState *cpu, vaddr addr, vaddr len,
+                                        MemTxAttrs atr, int fl, uintptr_t ra)
+{
+}
 #else
 int cpu_watchpoint_insert(CPUState *cpu, vaddr addr, vaddr len,
                           int flags, CPUWatchpoint **watchpoint);
@@ -1098,6 +1103,8 @@ int cpu_watchpoint_remove(CPUState *cpu, vaddr addr,
                           vaddr len, int flags);
 void cpu_watchpoint_remove_by_ref(CPUState *cpu, CPUWatchpoint *watchpoint);
 void cpu_watchpoint_remove_all(CPUState *cpu, int mask);
+void cpu_check_watchpoint(CPUState *cpu, vaddr addr, vaddr len,
+                          MemTxAttrs attrs, int flags, uintptr_t ra);
 #endif
 
 /**
diff --git a/exec.c b/exec.c
index 31fb75901f..cb6f5763dc 100644
--- a/exec.c
+++ b/exec.c
@@ -2789,11 +2789,10 @@ static const MemoryRegionOps notdirty_mem_ops = {
 };
 
 /* Generate a debug exception if a watchpoint has been hit.  */
-static void check_watchpoint(int offset, int len, MemTxAttrs attrs, int flags)
+void cpu_check_watchpoint(CPUState *cpu, vaddr addr, vaddr len,
+                          MemTxAttrs attrs, int flags, uintptr_t ra)
 {
-    CPUState *cpu = current_cpu;
     CPUClass *cc = CPU_GET_CLASS(cpu);
-    target_ulong vaddr;
     CPUWatchpoint *wp;
 
     assert(tcg_enabled());
@@ -2804,17 +2803,17 @@ static void check_watchpoint(int offset, int len, MemTxAttrs attrs, int flags)
         cpu_interrupt(cpu, CPU_INTERRUPT_DEBUG);
         return;
     }
-    vaddr = (cpu->mem_io_vaddr & TARGET_PAGE_MASK) + offset;
-    vaddr = cc->adjust_watchpoint_address(cpu, vaddr, len);
+
+    addr = cc->adjust_watchpoint_address(cpu, addr, len);
     QTAILQ_FOREACH(wp, &cpu->watchpoints, entry) {
-        if (cpu_watchpoint_address_matches(wp, vaddr, len)
+        if (cpu_watchpoint_address_matches(wp, addr, len)
             && (wp->flags & flags)) {
             if (flags == BP_MEM_READ) {
                 wp->flags |= BP_WATCHPOINT_HIT_READ;
             } else {
                 wp->flags |= BP_WATCHPOINT_HIT_WRITE;
             }
-            wp->hitaddr = vaddr;
+            wp->hitaddr = MAX(addr, wp->vaddr);
             wp->hitattrs = attrs;
             if (!cpu->watchpoint_hit) {
                 if (wp->flags & BP_CPU &&
@@ -2829,11 +2828,14 @@ static void check_watchpoint(int offset, int len, MemTxAttrs attrs, int flags)
                 if (wp->flags & BP_STOP_BEFORE_ACCESS) {
                     cpu->exception_index = EXCP_DEBUG;
                     mmap_unlock();
-                    cpu_loop_exit(cpu);
+                    cpu_loop_exit_restore(cpu, ra);
                 } else {
                     /* Force execution of one insn next time.  */
                     cpu->cflags_next_tb = 1 | curr_cflags();
                     mmap_unlock();
+                    if (ra) {
+                        cpu_restore_state(cpu, ra, true);
+                    }
                     cpu_loop_exit_noexc(cpu);
                 }
             }
@@ -2843,6 +2845,14 @@ static void check_watchpoint(int offset, int len, MemTxAttrs attrs, int flags)
     }
 }
 
+static void check_watchpoint(int offset, int len, MemTxAttrs attrs, int flags)
+{
+    CPUState *cpu = current_cpu;
+    vaddr addr = (cpu->mem_io_vaddr & TARGET_PAGE_MASK) + offset;
+
+    cpu_check_watchpoint(cpu, addr, len, attrs, flags, 0);
+}
+
 /* Watchpoint access routines.  Watchpoints are inserted using TLB tricks,
    so these check for a hit then pass through to the normal out-of-line
    phys routines.  */
-- 
2.17.1