Revert^2 "Enable JIT dual data mapping."

We use it for zygote.  Enable it for other cases
as well for consistency, security and testing.

This reverts commit 014c16c3e1ccedbea025111bc79f0a0351ba52d0.

Reason for revert: Reland https://r.android.com/1105362

Test: testrunner.py --host
Change-Id: I147365634ce196c4acc298e36966936f54e181aa

1 files changed, 37 insertions, 37 deletions

diff --git a/runtime/jit/jit_memory_region.cc b/runtime/jit/jit_memory_region.cc
index 7c7496b9e3..09980c8d36 100644
--- a/runtime/jit/jit_memory_region.cc
+++ b/runtime/jit/jit_memory_region.cc
@@ -114,12 +114,14 @@ bool JitMemoryRegion::Initialize(size_t initial_capacity,
     //       +---------------+
     //       | non exec code |\
     //       +---------------+ \
-    //       :               :\ \
-    //       +---------------+.\.+---------------+
-    //       |  exec code    |  \|     code      |
-    //       +---------------+...+---------------+
-    //       |      data     |   |     data      |
-    //       +---------------+...+---------------+
+    //       | writable data |\ \
+    //       +---------------+ \ \
+    //       :               :\ \ \
+    //       +---------------+.\.\.+---------------+
+    //       |  exec code    |  \ \|     code      |
+    //       +---------------+...\.+---------------+
+    //       | readonly data |    \|     data      |
+    //       +---------------+.....+---------------+
     //
     // In this configuration code updates are written to the non-executable view of the code
     // cache, and the executable view of the code cache has fixed RX memory protections.
@@ -132,7 +134,7 @@ bool JitMemoryRegion::Initialize(size_t initial_capacity,
     base_flags = MAP_SHARED;
     data_pages = MemMap::MapFile(
         data_capacity + exec_capacity,
-        is_zygote ? kProtR : kProtRW,
+        kProtR,
         base_flags,
         mem_fd,
         /* start= */ 0,
@@ -214,36 +216,34 @@ bool JitMemoryRegion::Initialize(size_t initial_capacity,
           return false;
         }
       }
-      // For the zygote, create a dual view of the data cache.
-      if (is_zygote) {
-        name = data_cache_name + "-rw";
-        writable_data_pages = MemMap::MapFile(data_capacity,
-                                              kProtRW,
-                                              base_flags,
-                                              mem_fd,
-                                              /* start= */ 0,
-                                              /* low_4GB= */ false,
-                                              name.c_str(),
-                                              &error_str);
-        if (!writable_data_pages.IsValid()) {
-          std::ostringstream oss;
-          oss << "Failed to create dual data view for zygote: " << error_str;
-          *error_msg = oss.str();
-          return false;
-        }
-        if (writable_data_pages.MadviseDontFork() != 0) {
-          *error_msg = "Failed to madvise dont fork the writable data view";
-          return false;
-        }
-        if (non_exec_pages.MadviseDontFork() != 0) {
-          *error_msg = "Failed to madvise dont fork the writable code view";
-          return false;
-        }
-        // Now that we have created the writable and executable mappings, prevent creating any new
-        // ones.
-        if (!ProtectZygoteMemory(mem_fd.get(), error_msg)) {
-          return false;
-        }
+      // Create a dual view of the data cache.
+      name = data_cache_name + "-rw";
+      writable_data_pages = MemMap::MapFile(data_capacity,
+                                            kProtRW,
+                                            base_flags,
+                                            mem_fd,
+                                            /* start= */ 0,
+                                            /* low_4GB= */ false,
+                                            name.c_str(),
+                                            &error_str);
+      if (!writable_data_pages.IsValid()) {
+        std::ostringstream oss;
+        oss << "Failed to create dual data view: " << error_str;
+        *error_msg = oss.str();
+        return false;
+      }
+      if (writable_data_pages.MadviseDontFork() != 0) {
+        *error_msg = "Failed to madvise dont fork the writable data view";
+        return false;
+      }
+      if (non_exec_pages.MadviseDontFork() != 0) {
+        *error_msg = "Failed to madvise dont fork the writable code view";
+        return false;
+      }
+      // Now that we have created the writable and executable mappings, prevent creating any new
+      // ones.
+      if (is_zygote && !ProtectZygoteMemory(mem_fd.get(), error_msg)) {
+        return false;
       }
     }
   } else {