[PATCH v3] linux-user: Add guest memory layout to exception dump

[Helge Deller <deller@gmx.de>]

When the emulation stops with a hard exception it's very useful for
debugging purposes to dump the current guest memory layout (for an
example see /proc/self/maps) beside the CPU registers.

The open_self_maps() function provides such a memory dump, but since
it's located in the syscall.c file, various changes (add #includes, make
this function externally visible, ...) are needed to be able to call it
from the existing EXCP_DUMP() macro.

This patch takes another approach by re-defining EXCP_DUMP() to call
target_exception_dump(), which is in syscall.c, consolidates the log
print functions and allows to add the call to dump the memory layout.

Beside a reduced code footprint, this approach keeps the changes across
the various callers minimal, and keeps EXCP_DUMP() highlighted as
important macro/function.

Signed-off-by: Helge Deller <deller@gmx.de>
---

v3:
Fix build error in i386/cpu_loop.c

v2:
Based on feedback by Philippe Mathieu-Daudé, renamed the two functions
to excp_dump_file() and target_exception_dump(), and #define'ed
EXCP_DUMP() to target_exception_dump().
I intentionally did not replace all occurences of EXCP_DUMP() by
target_exception_dump() as I think it's unneccesary and not beneficial.
If this is really wished, I will send a v3.


diff --git a/linux-user/cpu_loop-common.h b/linux-user/cpu_loop-common.h
index 36ff5b14f2..e644d2ef90 100644
--- a/linux-user/cpu_loop-common.h
+++ b/linux-user/cpu_loop-common.h
@@ -23,18 +23,9 @@
 #include "exec/log.h"
 #include "special-errno.h"

-#define EXCP_DUMP(env, fmt, ...)                                        \
-do {                                                                    \
-    CPUState *cs = env_cpu(env);                                        \
-    fprintf(stderr, fmt , ## __VA_ARGS__);                              \
-    fprintf(stderr, "Failing executable: %s\n", exec_path);             \
-    cpu_dump_state(cs, stderr, 0);                                      \
-    if (qemu_log_separate()) {                                          \
-        qemu_log(fmt, ## __VA_ARGS__);                                  \
-        qemu_log("Failing executable: %s\n", exec_path);                \
-        log_cpu_state(cs, 0);                                           \
-    }                                                                   \
-} while (0)
+void target_exception_dump(CPUArchState *env, const char *fmt, int code);
+#define EXCP_DUMP(env, fmt, code) \
+    target_exception_dump(env, fmt, code)

 void target_cpu_copy_regs(CPUArchState *env, struct target_pt_regs *regs);
 #endif
diff --git a/linux-user/i386/cpu_loop.c b/linux-user/i386/cpu_loop.c
index 42837399bc..404f6d6634 100644
--- a/linux-user/i386/cpu_loop.c
+++ b/linux-user/i386/cpu_loop.c
@@ -308,8 +308,8 @@ void cpu_loop(CPUX86State *env)
             break;
         default:
             pc = env->segs[R_CS].base + env->eip;
-            EXCP_DUMP(env, "qemu: 0x%08lx: unhandled CPU exception 0x%x - aborting\n",
-                      (long)pc, trapnr);
+            EXCP_DUMP(env, "qemu: unhandled CPU exception 0x%x - aborting\n",
+                      trapnr);
             abort();
         }
         process_pending_signals(env);
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 2e954d8dbd..7d29c4c396 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -158,6 +158,7 @@
 #include "qapi/error.h"
 #include "fd-trans.h"
 #include "tcg/tcg.h"
+#include "cpu_loop-common.h"

 #ifndef CLONE_IO
 #define CLONE_IO                0x80000000      /* Clone io context */
@@ -8144,6 +8145,33 @@ static int is_proc_myself(const char *filename, const char *entry)
     return 0;
 }

+static void excp_dump_file(FILE *logfile, CPUArchState *env,
+                      const char *fmt, int code)
+{
+    if (logfile) {
+        CPUState *cs = env_cpu(env);
+
+        fprintf(logfile, fmt, code);
+        fprintf(logfile, "Failing executable: %s\n", exec_path);
+        cpu_dump_state(cs, logfile, 0);
+        open_self_maps(env, fileno(logfile));
+    }
+}
+
+void target_exception_dump(CPUArchState *env, const char *fmt, int code)
+{
+    /* dump to console */
+    excp_dump_file(stderr, env, fmt, code);
+
+    /* dump to log file */
+    if (qemu_log_separate()) {
+        FILE *logfile = qemu_log_trylock();
+
+        excp_dump_file(logfile, env, fmt, code);
+        qemu_log_unlock(logfile);
+    }
+}
+
 #if HOST_BIG_ENDIAN != TARGET_BIG_ENDIAN || \
     defined(TARGET_SPARC) || defined(TARGET_M68K) || defined(TARGET_HPPA)
 static int is_proc(const char *filename, const char *entry)