CallstackInstr: switch to SBE/EBE callbacks

The old logic would miss many calls if tb_chaining was enabled (which is
is by default). Since this plugin did not disable tb_chaining, many calls
would be missed if a user didn't disable chaining or load another plugin
that disabled chaining.

This commit updates the plugin to use start_block_exec and end_block_exec
which work even with tb_chaining enabled.

panda/plugins/callstack_instr/callstack_instr.cpp

@@ -55,10 +55,8 @@ extern "C" {
 #include "panda/plog.h"
 #include "callstack_instr_int_fns.h"
 
-bool translate_callback(CPUState* cpu, target_ulong pc);
-int exec_callback(CPUState* cpu, target_ulong pc);
-void before_block_exec(CPUState* cpu, TranslationBlock *tb);
-void after_block_exec(CPUState* cpu, TranslationBlock *tb, uint8_t exitCode);
+void start_block_exec(CPUState* cpu, TranslationBlock *tb);
+void end_block_exec(CPUState* cpu, TranslationBlock *tb);
 void after_block_translate(CPUState* cpu, TranslationBlock *tb);
 
 bool init_plugin(void *);
@@ -322,7 +320,7 @@ void after_block_translate(CPUState *cpu, TranslationBlock *tb) {
     return;
 }
 
-void before_block_exec(CPUState *cpu, TranslationBlock *tb) {
+void start_block_exec(CPUState *cpu, TranslationBlock *tb) {
   // if the block a call returns to was interrupted before it completed, this
   // function will be called twice - only want to remove the return value from
   // the stack once
@@ -366,7 +364,7 @@ void before_block_exec(CPUState *cpu, TranslationBlock *tb) {
   }
 }
 
-void after_block_exec(CPUState* cpu, TranslationBlock *tb, uint8_t exitCode) {
+void end_block_exec(CPUState* cpu, TranslationBlock *tb) {
     target_ulong pc = 0x0;
     target_ulong cs_base = 0x0;
     uint32_t flags = 0x0;
@@ -377,35 +375,19 @@ void after_block_exec(CPUState* cpu, TranslationBlock *tb, uint8_t exitCode) {
 
     // sometimes an attempt to run a block is interrupted, but this callback is
     // still made - only update the callstack if the block has run to completion
-    if (exitCode <= TB_EXIT_IDX1) {
-        if (tb_type == INSTR_CALL) {
-            stack_entry se = {tb->pc + tb->size, tb_type};
-            callstacks[curStackid].push_back(se);
-
-            // Also track the function that gets called
-            // This retrieves the pc in an architecture-neutral way
-            cpu_get_tb_cpu_state(env, &pc, &cs_base, &flags);
-            function_stacks[curStackid].push_back(pc);
-
-            PPP_RUN_CB(on_call, cpu, pc);
-        } else if (tb_type == INSTR_RET) {
-            //printf("Just executed a RET in TB " TARGET_FMT_lx "\n", tb->pc);
-            //if (next) printf("Next TB: " TARGET_FMT_lx "\n", next->pc);
-        }
-    }
-    // in case this block is one that a call returns to, need to node that its
-    // execution was interrupted, so don't try to remove it from the callstack
-    // when try (as already removed before this attempt)
-    else {
-        // verbose output is helpful in regression testing
-        if (tb_type == INSTR_CALL) {
-            verbose_log("callstack_instr not adding Stopped caller to stack",
-                    tb, curStackid, true);
-        }
+    if (tb_type == INSTR_CALL) {
+        stack_entry se = {tb->pc + tb->size, tb_type};
+        callstacks[curStackid].push_back(se);
+
+        // Also track the function that gets called
+        // This retrieves the pc in an architecture-neutral way
         cpu_get_tb_cpu_state(env, &pc, &cs_base, &flags);
-        // erase nicely does nothing if key DNE
-        stoppedInfo.erase(curStackid);
-        stoppedInfo[curStackid] = pc;
+        function_stacks[curStackid].push_back(pc);
+
+        PPP_RUN_CB(on_call, cpu, pc);
+    } else if (tb_type == INSTR_RET) {
+        //printf("Just executed a RET in TB " TARGET_FMT_lx "\n", tb->pc);
+        //if (next) printf("Next TB: " TARGET_FMT_lx "\n", next->pc);
     }
 }
 
@@ -611,9 +593,9 @@ bool init_plugin(void *self) {
 
     pcb.after_block_translate = after_block_translate;
     panda_register_callback(self, PANDA_CB_AFTER_BLOCK_TRANSLATE, pcb);
-    pcb.after_block_exec = after_block_exec;
+    pcb.end_block_exec = end_block_exec;
     panda_register_callback(self, PANDA_CB_AFTER_BLOCK_EXEC, pcb);
-    pcb.before_block_exec = before_block_exec;
+    pcb.start_block_exec = start_block_exec;
     panda_register_callback(self, PANDA_CB_BEFORE_BLOCK_EXEC, pcb);
 
     bool setup_ok = true;