From f2dc1ef7390c4dd05a54958da1942399e26e3fde Mon Sep 17 00:00:00 2001
From: Erik Verbruggen <erik.verbruggen@digia.com>
Date: Fri, 15 Jan 2016 15:33:00 +0100
Subject: V4 JIT: Switch all platforms to W^X for the ExecutableAllocator.

This also fixes makeWritable, which needs to work in order to add more
c0d3 to used pages. Also finish the WinRT parts.

Change-Id: Idaa4187b1ec256e65c881285a608f3a51fdbeebd
Reviewed-by: Simon Hausmann <simon.hausmann@theqtcompany.com>
---
 src/3rdparty/masm/masm-defs.pri               |  3 +-
 src/3rdparty/masm/stubs/ExecutableAllocator.h | 74 +++++++++++++++++++--------
 2 files changed, 53 insertions(+), 24 deletions(-)

(limited to 'src/3rdparty')

diff --git a/src/3rdparty/masm/masm-defs.pri b/src/3rdparty/masm/masm-defs.pri
index f09a8329c9..c76eeec724 100644
--- a/src/3rdparty/masm/masm-defs.pri
+++ b/src/3rdparty/masm/masm-defs.pri
@@ -1,6 +1,5 @@
-
-
 DEFINES += WTF_EXPORT_PRIVATE="" JS_EXPORT_PRIVATE=""
+DEFINES += ENABLE_ASSEMBLER_WX_EXCLUSIVE=1
 
 # Avoid symbol clashes with QtScript during static linking
 DEFINES += WTFReportAssertionFailure=qmlWTFReportAssertionFailure
diff --git a/src/3rdparty/masm/stubs/ExecutableAllocator.h b/src/3rdparty/masm/stubs/ExecutableAllocator.h
index 5f7d5678ab..578a944bf9 100644
--- a/src/3rdparty/masm/stubs/ExecutableAllocator.h
+++ b/src/3rdparty/masm/stubs/ExecutableAllocator.h
@@ -89,15 +89,34 @@ struct ExecutableAllocator {
         return adoptRef(new ExecutableMemoryHandle(realAllocator, size));
     }
 
-    static void makeWritable(void* addr, int size)
+    static void makeWritable(void* addr, size_t size)
     {
-#if ENABLE(ASSEMBLER_WX_EXCLUSIVE)
-        size_t pageSize = WTF::pageSize();
-        size_t iaddr = reinterpret_cast<size_t>(addr);
-        size_t roundAddr = iaddr & ~(pageSize - static_cast<size_t>(1));
+        quintptr pageSize = WTF::pageSize();
+        quintptr iaddr = reinterpret_cast<quintptr>(addr);
+        quintptr roundAddr = iaddr & ~(pageSize - 1);
+        size = size + (iaddr - roundAddr);
+        addr = reinterpret_cast<void*>(roundAddr);
 
+#if ENABLE(ASSEMBLER_WX_EXCLUSIVE)
+#  if OS(WINDOWS)
+        DWORD oldProtect;
+#    if !OS(WINRT)
+        VirtualProtect(addr, size, PAGE_READWRITE, &oldProtect);
+#    elif _MSC_VER >= 1900
+        bool hr = VirtualProtectFromApp(addr, size, PAGE_READWRITE, &oldProtect);
+        if (!hr) {
+            Q_UNREACHABLE();
+        }
+#    else
+        (void)oldProtect;
+#    endif
+#  else
         int mode = PROT_READ | PROT_WRITE;
-        mprotect(reinterpret_cast<void*>(roundAddr), size + (iaddr - roundAddr), mode);
+        if (mprotect(addr, size, mode) != 0) {
+            perror("mprotect failed in ExecutableAllocator::makeWritable");
+            Q_UNREACHABLE();
+        }
+#  endif
 #else
         // We assume we already have RWX
         (void)addr; // suppress unused parameter warning
@@ -105,25 +124,36 @@ struct ExecutableAllocator {
 #endif
     }
 
-    static void makeExecutable(void* addr, int size)
+    static void makeExecutable(void* addr, size_t size)
     {
-        size_t pageSize = WTF::pageSize();
-        size_t iaddr = reinterpret_cast<size_t>(addr);
-        size_t roundAddr = iaddr & ~(pageSize - static_cast<size_t>(1));
-#if OS(WINDOWS)
-#if !OS(WINRT)
+        quintptr pageSize = WTF::pageSize();
+        quintptr iaddr = reinterpret_cast<quintptr>(addr);
+        quintptr roundAddr = iaddr & ~(pageSize - 1);
+        size = size + (iaddr - roundAddr);
+        addr = reinterpret_cast<void*>(roundAddr);
+
+#if ENABLE(ASSEMBLER_WX_EXCLUSIVE)
+#  if OS(WINDOWS)
         DWORD oldProtect;
-        VirtualProtect(reinterpret_cast<void*>(roundAddr), size + (iaddr - roundAddr), PAGE_EXECUTE_READWRITE, &oldProtect);
-#else
-        (void)size; // suppress unused parameter warning
-        (void)roundAddr; // suppress unused parameter warning
-#endif
-#else
+#    if !OS(WINRT)
+        VirtualProtect(addr, size, PAGE_EXECUTE_READ, &oldProtect);
+#    elif _MSC_VER >= 1900
+        bool hr = VirtualProtectFromApp(addr, size, PAGE_EXECUTE_READ, &oldProtect);
+        if (!hr) {
+            Q_UNREACHABLE();
+        }
+#    else
+        (void)oldProtect;
+#    endif
+#  else
         int mode = PROT_READ | PROT_EXEC;
-#if !ENABLE(ASSEMBLER_WX_EXCLUSIVE)
-        mode |= PROT_WRITE;
-#endif
-        mprotect(reinterpret_cast<void*>(roundAddr), size + (iaddr - roundAddr), mode);
+        if (mprotect(addr, size, mode) != 0) {
+            perror("mprotect failed in ExecutableAllocator::makeExecutable");
+            Q_UNREACHABLE();
+        }
+#  endif
+#else
+#  error "Only W^X is supported"
 #endif
     }
 
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