Changeset 281720 in webkit

Timestamp:

Aug 27, 2021, 2:16:21 PM (4 years ago)

Author:

mark.lam@apple.com

Message:

Changed ARM64 probe trampoline to do ptr auth the standard way.
​https://bugs.webkit.org/show_bug.cgi?id=229629
rdar://problem/82453220

Reviewed by Saam Barati.

Also fix a comment, and add back 2 lines that I accidentally deleted in r281718.

• assembler/MacroAssemblerARM64.cpp:

Location:

trunk/Source/JavaScriptCore

Files:

• ChangeLog (modified) (1 diff)
• assembler/MacroAssemblerARM64.cpp (modified) (3 diffs)

trunk/Source/JavaScriptCore/ChangeLog

@@ +1 @@
+2021-08-27  Mark Lam  <mark.lam@apple.com>
+
+        Changed ARM64 probe trampoline to do ptr auth the standard way.
+        https://bugs.webkit.org/show_bug.cgi?id=229629
+        rdar://problem/82453220
+
+        Reviewed by Saam Barati.
+
+        Also fix a comment, and add back 2 lines that I accidentally deleted in r281718.
+
+        * assembler/MacroAssemblerARM64.cpp:
+
 2021-08-27  Mark Lam  <mark.lam@apple.com>
 

trunk/Source/JavaScriptCore/assembler/MacroAssemblerARM64.cpp

@@ -501 +501 @@
     // either modify lr or pc, but not both in the same probe invocation. The probe
     // mechanism ensures that we never try to modify both lr and pc with a RELEASE_ASSERT
-    // in Probe::().
+    // in Probe::executeJSCJITProbe().
 
     // Determine if the probe handler changed the pc.
@@ -522 +522 @@
     "movz      x28, #" STRINGIZE_VALUE_OF(JIT_PROBE_PC_PTR_TAG) "\n"
     "autib     x27, x28" "\n"
-    "lsr       x28, x27, #8" "\n"
-    "and       x28, x28, #0xff000000000000" "\n"
-    "orr       x28, x28, x27" "\n"
-    "ldrb      w28, [x28]" "\n"
+    "mov       x28, x27" "\n"
+    "xpaci     x28" "\n"
+    "cmp       x28, x27" "\n"
+    "beq     " LOCAL_LABEL_STRING(ctiMasmProbeTrampolinePCAuthDone) "\n"
+    "brk       #0xc471" "\n"
+    LOCAL_LABEL_STRING(ctiMasmProbeTrampolinePCAuthDone) ":" "\n"
 #endif
     "sub       x27, x27, #" STRINGIZE_VALUE_OF(2 * GPREG_SIZE) "\n" // The return point PC is at 2 instructions before the end of the probe.
@@ -547 +549 @@
     "movz      x27, #" STRINGIZE_VALUE_OF(JIT_PROBE_PC_PTR_TAG) "\n"
     "autib     x28, x27" "\n"
-    "lsr       x27, x28, #8" "\n"
-    "and       x27, x27, #0xff000000000000" "\n"
-    "orr       x27, x27, x28" "\n"
-    "ldrb      w27, [x27]" "\n"
+    "mov       x27, x28" "\n"
+    "xpaci     x27" "\n"
+    "cmp       x27, x28" "\n"
+    "beq     " LOCAL_LABEL_STRING(ctiMasmProbeTrampolinePCAuthDone2) "\n"
+    "brk       #0xc471" "\n"
+    LOCAL_LABEL_STRING(ctiMasmProbeTrampolinePCAuthDone2) ":" "\n"
+    "add       x27, x30, #48" "\n" // Compute sp at return point.
+    "pacib     x28, x27" "\n"
 #endif
     "ldr       x27, [sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_FP_OFFSET) "]" "\n"