From 3f5e36e15ff340036fc0fa3d93d8e94d9318b71a Mon Sep 17 00:00:00 2001
From: Peter Maydell <peter.maydell@linaro.org>
Date: Thu, 22 Feb 2018 09:37:45 -0500
Subject: [PATCH] qemu-log: Improve the exec TB execution logging

Improve the TB execution logging so that it is easier to identify
what is happening from trace logs:
* move the "Trace" logging of executed TBs into cpu_tb_exec()
so that it is emitted if and only if we actually execute a TB,
and for consistency for the CPU state logging
* log when we link two TBs together via tb_add_jump()
* log when cpu_tb_exec() returns early from a chain of TBs

The new style logging looks like this:

Trace 0x7fb7cc822ca0 [ffffffc0000dce00]
Linking TBs 0x7fb7cc822ca0 [ffffffc0000dce00] index 0 -> 0x7fb7cc823110 [ffffffc0000dce10]
Trace 0x7fb7cc823110 [ffffffc0000dce10]
Trace 0x7fb7cc823420 [ffffffc000302688]
Trace 0x7fb7cc8234a0 [ffffffc000302698]
Trace 0x7fb7cc823520 [ffffffc0003026a4]
Trace 0x7fb7cc823560 [ffffffc0000dce44]
Linking TBs 0x7fb7cc823560 [ffffffc0000dce44] index 1 -> 0x7fb7cc8235d0 [ffffffc0000dce70]
Trace 0x7fb7cc8235d0 [ffffffc0000dce70]
Stopped execution of TB chain before 0x7fb7cc8235d0 [ffffffc0000dce70]
Trace 0x7fb7cc8235d0 [ffffffc0000dce70]
Trace 0x7fb7cc822fd0 [ffffffc0000dd52c]

Backports commit 1a830635229e14c403600167823ea6b3b79d3097 from qemu
---
 qemu/cpu-exec.c              | 18 +++++++++++++-----
 qemu/include/exec/exec-all.h |  3 +++
 2 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/qemu/cpu-exec.c b/qemu/cpu-exec.c
index cf0a9fa1..b52fdcd2 100644
--- a/qemu/cpu-exec.c
+++ b/qemu/cpu-exec.c
@@ -27,7 +27,7 @@
 
 #include "uc_priv.h"
 
-static tcg_target_ulong cpu_tb_exec(CPUState *cpu, uint8_t *tb_ptr);
+static tcg_target_ulong cpu_tb_exec(CPUState *cpu, TranslationBlock *itb);
 static TranslationBlock *tb_find_slow(CPUState *cpu, target_ulong pc,
                                       target_ulong cs_base, uint64_t flags);
 static TranslationBlock *tb_find_fast(CPUState *cpu);
@@ -45,7 +45,6 @@ int cpu_exec(struct uc_struct *uc, CPUState *cpu)
 #endif
     int ret, interrupt_request;
     TranslationBlock *tb;
-    uint8_t *tc_ptr;
     uintptr_t next_tb;
     struct hook *hook;
 
@@ -209,10 +208,9 @@ int cpu_exec(struct uc_struct *uc, CPUState *cpu)
                 }
 
                 if (likely(!cpu->exit_request)) {
-                    tc_ptr = tb->tc_ptr;
                     cpu->current_tb = tb;
                     /* execute the generated code */
-                    next_tb = cpu_tb_exec(cpu, tc_ptr); // UNICORN
+                    next_tb = cpu_tb_exec(cpu, tb);
                     cpu->current_tb = NULL;
 
                     switch (next_tb & TB_EXIT_MASK) {
@@ -278,11 +276,16 @@ int cpu_exec(struct uc_struct *uc, CPUState *cpu)
 }
 
 /* Execute a TB, and fix up the CPU state afterwards if necessary */
-static tcg_target_ulong cpu_tb_exec(CPUState *cpu, uint8_t *tb_ptr)
+static inline tcg_target_ulong cpu_tb_exec(CPUState *cpu, TranslationBlock *itb)
 {
     CPUArchState *env = cpu->env_ptr;
     TCGContext *tcg_ctx = env->uc->tcg_ctx;
     uintptr_t next_tb;
+    uint8_t *tb_ptr = itb->tc_ptr;
+
+    // Unicorn: commented out
+    //qemu_log_mask(CPU_LOG_EXEC, "Trace %p [" TARGET_FMT_lx "] %s\n",
+    //              itb->tc_ptr, itb->pc, lookup_symbol(itb->pc));
 
     next_tb = tcg_qemu_tb_exec(env, tb_ptr);
 
@@ -293,6 +296,11 @@ static tcg_target_ulong cpu_tb_exec(CPUState *cpu, uint8_t *tb_ptr)
          */
         CPUClass *cc = CPU_GET_CLASS(env->uc, cpu);
         TranslationBlock *tb = (TranslationBlock *)(next_tb & ~TB_EXIT_MASK);
+        // Unicorn: commented out
+        //qemu_log_mask(CPU_LOG_EXEC,
+        //              "Stopped execution of TB chain before %p ["
+        //              TARGET_FMT_lx "] %s\n",
+        //              itb->tc_ptr, itb->pc, lookup_symbol(itb->pc));
         if (cc->synchronize_from_tb) {
             // avoid sync twice when helper_uc_tracecode() already did this.
             if (env->uc->emu_counter <= env->uc->emu_count &&
diff --git a/qemu/include/exec/exec-all.h b/qemu/include/exec/exec-all.h
index e22be9e0..d6456202 100644
--- a/qemu/include/exec/exec-all.h
+++ b/qemu/include/exec/exec-all.h
@@ -373,6 +373,9 @@ static inline void tb_add_jump(TranslationBlock *tb, int n,
 {
     /* NOTE: this test is only needed for thread safety */
     if (!tb->jmp_next[n]) {
+        qemu_log_mask(CPU_LOG_EXEC, "Linking TBs %p [" TARGET_FMT_lx
+                      "] index %d -> %p [" TARGET_FMT_lx "]\n",
+                      tb->tc_ptr, tb->pc, n, tb_next->tc_ptr, tb_next->pc);
         /* patch the native jump address */
         tb_set_jmp_target(tb, n, (uintptr_t)tb_next->tc_ptr);