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

Commit Message

Helge Deller Sept. 24, 2022, 2:18 p.m. UTC

When the emulation stops with a hard exception it's very useful for
debugging purposes to dump the current guest memory layout (like
/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 call it from the
existing EXCP_DUMP() macro.

This patch takes another approach by un-macronizing EXCP_DUMP() and turn
it into a function inside syscall.c.
Beside a reduced code footprint this approach allows to use the same
functions to print to console and log file.

This patch applies on top of my previous patch series.

Signed-off-by: Helge Deller <[e-mail]>

Patch

diff --git a/linux-user/cpu_loop-common.h b/linux-user/cpu_loop-common.h
index 36ff5b14f2..0b26b56915 100644
--- a/linux-user/cpu_loop-common.h
+++ b/linux-user/cpu_loop-common.h
@@ -23,18 +23,7 @@ 
 #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 EXCP_DUMP(CPUArchState *env, const char *fmt, int code);

 void target_cpu_copy_regs(CPUArchState *env, struct target_pt_regs *regs);
 #endif
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index d17f5d1c66..00861e9351 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 */
@@ -8177,6 +8178,33 @@  static int is_proc_myself(const char *filename, const char *entry)
     return 0;
 }

+static void excp_dump(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 EXCP_DUMP(CPUArchState *env, const char *fmt, int code)
+{
+    /* dump to console */
+    excp_dump(stderr, env, fmt, code);
+
+    /* dump to log file */
+    if (qemu_log_separate()) {
+        FILE *logfile = qemu_log_trylock();
+
+        excp_dump(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)