Changeset 250406 in webkit

Timestamp:

Sep 26, 2019, 6:54:08 PM (6 years ago)

Author:

Alan Coon

Message:

Cherry-pick r250383. rdar://problem/55673084

We need to initialize the Gigacage first in setJITEnabled() when disabling the JIT.
​https://bugs.webkit.org/show_bug.cgi?id=202257

Reviewed by Saam Barati.

Because of an OS quirk, even after the JIT region has been unmapped, the OS thinks
that region is reserved, and as such, can cause Gigacage allocation to fail. We
work around this by initializing the Gigacage first.

Note: when called, setJITEnabled() is always called extra early in the process
bootstrap. Under normal operation (when setJITEnabled() isn't called at all), we
will naturally initialize the Gigacage before we allocate the JIT region.
Hence, this workaround is merely ensuring the same behavior of allocation ordering.

This patch only applies to iOS.

• jit/ExecutableAllocator.cpp: (JSC::ExecutableAllocator::setJITEnabled):

git-svn-id: ​https://svn.webkit.org/repository/webkit/trunk@250383 268f45cc-cd09-0410-ab3c-d52691b4dbfc

Location:

tags/Safari-609.1.5/Source/JavaScriptCore

Files:

• ChangeLog (modified) (1 diff)
• jit/ExecutableAllocator.cpp (modified) (1 diff)

tags/Safari-609.1.5/Source/JavaScriptCore/ChangeLog

@@ +1 @@
+2019-09-26  Kocsen Chung  <kocsen_chung@apple.com>
+
+        Cherry-pick r250383. rdar://problem/55673084
+
+    We need to initialize the Gigacage first in setJITEnabled() when disabling the JIT.
+    https://bugs.webkit.org/show_bug.cgi?id=202257
+    
+    Reviewed by Saam Barati.
+    
+    Because of an OS quirk, even after the JIT region has been unmapped, the OS thinks
+    that region is reserved, and as such, can cause Gigacage allocation to fail.  We
+    work around this by initializing the Gigacage first.
+    
+    Note: when called, setJITEnabled() is always called extra early in the process
+    bootstrap.  Under normal operation (when setJITEnabled() isn't called at all), we
+    will naturally initialize the Gigacage before we allocate the JIT region.
+    Hence, this workaround is merely ensuring the same behavior of allocation ordering.
+    
+    This patch only applies to iOS.
+    
+    * jit/ExecutableAllocator.cpp:
+    (JSC::ExecutableAllocator::setJITEnabled):
+    
+    
+    git-svn-id: https://svn.webkit.org/repository/webkit/trunk@250383 268f45cc-cd09-0410-ab3c-d52691b4dbfc
+
+    2019-09-26  Mark Lam  <mark.lam@apple.com>
+
+            We need to initialize the Gigacage first in setJITEnabled() when disabling the JIT.
+            https://bugs.webkit.org/show_bug.cgi?id=202257
+
+            Reviewed by Saam Barati.
+
+            Because of an OS quirk, even after the JIT region has been unmapped, the OS thinks
+            that region is reserved, and as such, can cause Gigacage allocation to fail.  We
+            work around this by initializing the Gigacage first.
+
+            Note: when called, setJITEnabled() is always called extra early in the process
+            bootstrap.  Under normal operation (when setJITEnabled() isn't called at all), we
+            will naturally initialize the Gigacage before we allocate the JIT region.
+            Hence, this workaround is merely ensuring the same behavior of allocation ordering.
+
+            This patch only applies to iOS.
+
+            * jit/ExecutableAllocator.cpp:
+            (JSC::ExecutableAllocator::setJITEnabled):
+
 2019-09-24  Christopher Reid  <chris.reid@sony.com>
 

tags/Safari-609.1.5/Source/JavaScriptCore/jit/ExecutableAllocator.cpp

@@ -131 +131 @@
 #if PLATFORM(IOS_FAMILY) && (CPU(ARM64) || CPU(ARM))
     if (!enabled) {
+        // Because of an OS quirk, even after the JIT region has been unmapped,
+        // the OS thinks that region is reserved, and as such, can cause Gigacage
+        // allocation to fail. We work around this by initializing the Gigacage
+        // first.
+        // Note: when called, setJITEnabled() is always called extra early in the
+        // process bootstrap. Under normal operation (when setJITEnabled() isn't
+        // called at all), we will naturally initialize the Gigacage before we
+        // allocate the JIT region. Hence, this workaround is merely ensuring the
+        // same behavior of allocation ordering.
+        Gigacage::ensureGigacage();
+
         constexpr size_t size = 1;
         constexpr int protection = PROT_READ | PROT_WRITE | PROT_EXEC;