[patch] Port of 01-fix-map-pages-on-ia64.patch from Stephan Schreiber on Debian

firefox-10.0.11-fix-map-pages-on-ia64.patch (text/plain), 2.26 KB, created by Émeric Maschino on 2013-05-28 20:22:13 UTC

--- a/js/src/jsgcchunk.cpp	2012-12-15 17:19:27.903779696 +0100
+++ b/js/src/jsgcchunk.cpp	2012-12-15 17:21:29.547785309 +0100
@@ -236,25 +236,58 @@ MapAlignedPages(size_t size, size_t alig
     return p;
 }
 
 # else /* JS_GC_HAS_MAP_ALIGN */
 
 static void *
 MapPages(void *addr, size_t size)
 {
+#if defined(__ia64__)
+    /*
+     * The JS engine assumes that all allocated pointers have their high 17 bits clear,
+     * which ia64's mmap doesn't support directly. However, we can emulate it by passing
+     * mmap an "addr" parameter with those bits clear. The mmap will return that address,
+     * or the nearest available memory above that address, providing a near-guarantee
+     * that those bits are clear. If they are not, we return NULL below to indicate
+     * out-of-memory.
+     * 
+     * The addr is chosen as 0x0000070000000000, which still allows about 120TB of virtual 
+     * address space.
+     * 
+     * See Bug 589735 for more information.
+     */
+#endif
+
     /*
      * We don't use MAP_FIXED here, because it can cause the *replacement*
      * of existing mappings, and we only want to create new mappings.
      */
+#if defined(__ia64__)
+    void *p = mmap(addr ? addr : (void*)0x0000070000000000,
+                   size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON,
+                   -1, 0);
+#else
     void *p = mmap(addr, size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON,
                    -1, 0);
+#endif
     if (p == MAP_FAILED)
         return NULL;
+#if defined(__ia64__)
+    /* 
+     * If the caller requested a specific memory location, verify that's what mmap returned.
+     * Otherwise: If the allocated memory doesn't have its upper 17 bits clear, consider it 
+     * as out of memory.
+     */
+    if (addr && p != addr
+        || !addr && ((long long)p & 0xffff800000000000)) {
+#else
+    /* If the caller requested a specific memory location, verify that's what mmap returned. */
     if (addr && p != addr) {
+#endif
         /* We succeeded in mapping memory, but not in the right place. */
         JS_ALWAYS_TRUE(munmap(p, size) == 0);
         return NULL;
     }
     return p;
 }
 
 # endif /* !JS_GC_HAS_MAP_ALIGN */


Signed-off-by: Stephan Schreiber <[e-mail]>
Based on a work of Jan Horak <[e-mail]>