Run cacheFlush page by page to assure of flushing all the requested r…

…anges

https://bugs.webkit.org/show_bug.cgi?id=77712

Patch by Hojong Han <hojong.han@samsung.com> on 2012-03-14
Reviewed by Geoffrey Garen.

Current MetaAllocator concept, always coalesces adjacent free spaces,
doesn't meet memory management of Linux kernel.
In a certain case Linux kernel doesn't regard contiguous virtual memory areas as one but two.
Therefore cacheFlush page by page guarantees a flush-requested range.

* jit/ExecutableAllocator.h:
(JSC::ExecutableAllocator::cacheFlush):

Canonical link: https://commits.webkit.org/98355@main
git-svn-id: https://svn.webkit.org/repository/webkit/trunk@110792 268f45cc-cd09-0410-ab3c-d52691b4dbfc

Source/JavaScriptCore/ChangeLog

@@ -1,3 +1,18 @@
+2012-03-14  Hojong Han  <hojong.han@samsung.com>
+
+        Run cacheFlush page by page to assure of flushing all the requested ranges
+        https://bugs.webkit.org/show_bug.cgi?id=77712
+
+        Reviewed by Geoffrey Garen.
+
+        Current MetaAllocator concept, always coalesces adjacent free spaces,
+        doesn't meet memory management of Linux kernel.
+        In a certain case Linux kernel doesn't regard contiguous virtual memory areas as one but two.
+        Therefore cacheFlush page by page guarantees a flush-requested range.
+
+        * jit/ExecutableAllocator.h:
+        (JSC::ExecutableAllocator::cacheFlush):
+
 2012-03-14  Oliver Hunt  <oliver@apple.com>
 
         Make ARMv7 work again

Source/JavaScriptCore/jit/ExecutableAllocator.h

@@ -194,18 +194,25 @@ class ExecutableAllocator {
 #elif CPU(ARM_TRADITIONAL) && OS(LINUX) && COMPILER(GCC)
     static void cacheFlush(void* code, size_t size)
     {
-        asm volatile (
-            "push    {r7}\n"
-            "mov     r0, %0\n"
-            "mov     r1, %1\n"
-            "mov     r7, #0xf0000\n"
-            "add     r7, r7, #0x2\n"
-            "mov     r2, #0x0\n"
-            "svc     0x0\n"
-            "pop     {r7}\n"
-            :
-            : "r" (code), "r" (reinterpret_cast<char*>(code) + size)
-            : "r0", "r1", "r2");
+        uintptr_t currentPage = reinterpret_cast<uintptr_t>(code) & ~(pageSize() - 1);
+        uintptr_t lastPage = (reinterpret_cast<uintptr_t>(code) + size) & ~(pageSize() - 1);
+
+        do {
+            asm volatile (
+                "push    {r7}\n"
+                "mov     r0, %0\n"
+                "mov     r1, %1\n"
+                "mov     r7, #0xf0000\n"
+                "add     r7, r7, #0x2\n"
+                "mov     r2, #0x0\n"
+                "svc     0x0\n"
+                "pop     {r7}\n"
+                :
+                : "r" (currentPage), "r" (currentPage + pageSize())
+                : "r0", "r1", "r2");
+            currentPage += pageSize();
+        } while (lastPage >= currentPage);
+     }
     }
 #elif OS(WINCE)
     static void cacheFlush(void* code, size_t size)