[PULL 22/25] linux-user: log page table changes under -d page

[Alex Bennée]

The CPU_LOG_PAGE flag is woefully underused and could stand to do
extra duty tracking page changes. If the user doesn't want to see the
details as things change they still have the tracepoints available.

We push the locking into log_page_dump and pass a reason for the
banner text.

Signed-off-by: Alex Bennée <alex.ben...@linaro.org>
Reviewed-by: Richard Henderson <richard.hender...@linaro.org>
Reviewed-by: Laurent Vivier <laur...@vivier.eu>
Message-Id: <20191205122518.10010-5-alex.ben...@linaro.org>

diff --git a/include/exec/log.h b/include/exec/log.h
index 9bd1e4aa20b..fcc7b9e00ba 100644
--- a/include/exec/log.h
+++ b/include/exec/log.h
@@ -69,15 +69,14 @@ static inline void log_disas(void *code, unsigned long size)
 
 #if defined(CONFIG_USER_ONLY)
 /* page_dump() output to the log file: */
-static inline void log_page_dump(void)
+static inline void log_page_dump(const char *operation)
 {
-    QemuLogFile *logfile;
-    rcu_read_lock();
-    logfile = atomic_rcu_read(&qemu_logfile);
+    FILE *logfile = qemu_log_lock();
     if (logfile) {
-        page_dump(logfile->fd);
+        qemu_log("page layout changed following %s\n", operation);
+        page_dump(logfile);
     }
-    rcu_read_unlock();
+    qemu_log_unlock(logfile);
 }
 #endif
 #endif
diff --git a/bsd-user/main.c b/bsd-user/main.c
index 470a8bf79ed..7f4e3cd6271 100644
--- a/bsd-user/main.c
+++ b/bsd-user/main.c
@@ -963,7 +963,7 @@ int main(int argc, char **argv)
 
     if (qemu_loglevel_mask(CPU_LOG_PAGE)) {
         qemu_log("guest_base  0x%lx\n", guest_base);
-        log_page_dump();
+        log_page_dump("binary load");
 
         qemu_log("start_brk   0x" TARGET_ABI_FMT_lx "\n", info->start_brk);
         qemu_log("end_code    0x" TARGET_ABI_FMT_lx "\n", info->end_code);
diff --git a/linux-user/main.c b/linux-user/main.c
index 6ff7851e86f..8718d03ee21 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -826,7 +826,7 @@ int main(int argc, char **argv, char **envp)
 
     if (qemu_loglevel_mask(CPU_LOG_PAGE)) {
         qemu_log("guest_base  0x%lx\n", guest_base);
-        log_page_dump();
+        log_page_dump("binary load");
 
         qemu_log("start_brk   0x" TARGET_ABI_FMT_lx "\n", info->start_brk);
         qemu_log("end_code    0x" TARGET_ABI_FMT_lx "\n", info->end_code);
diff --git a/linux-user/mmap.c b/linux-user/mmap.c
index 0b1b43ac3c0..3d90fa459ca 100644
--- a/linux-user/mmap.c
+++ b/linux-user/mmap.c
@@ -18,6 +18,7 @@
  */
 #include "qemu/osdep.h"
 #include "trace.h"
+#include "exec/log.h"
 #include "qemu.h"
 
 //#define DEBUG_MMAP
@@ -539,10 +540,9 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int 
prot,
     page_set_flags(start, start + len, prot | PAGE_VALID);
  the_end:
     trace_target_mmap_complete(start);
-#ifdef DEBUG_MMAP
-    page_dump(stdout);
-    printf("\n");
-#endif
+    if (qemu_loglevel_mask(CPU_LOG_PAGE)) {
+        log_page_dump(__func__);
+    }
     tb_invalidate_phys_range(start, start + len);
     mmap_unlock();
     return start;
-- 
2.20.1