[PATCH] D55732: ELF: AArch64: Fix errata patch address calculation.

[Peter Collingbourne via Phabricator via llvm-commits]

pcc created this revision.
pcc added reviewers: ruiu, peter.smith.
Herald added subscribers: kristof.beyls, arichardson, javed.absar, emaste.
Herald added a reviewer: espindola.

The code here wants the output section offset of the instruction
requiring the errata patch, not the virtual address. Without this
change we can end up placing a patch out of range if the virtual
address of the code section is large enough.


Repository:
  rL LLVM

https://reviews.llvm.org/D55732

Files:
  lld/ELF/AArch64ErrataFix.cpp
  lld/test/ELF/aarch64-cortex-a53-843419-large2.s


Index: lld/test/ELF/aarch64-cortex-a53-843419-large2.s
===================================================================
--- /dev/null
+++ lld/test/ELF/aarch64-cortex-a53-843419-large2.s
@@ -0,0 +1,19 @@
+// REQUIRES: aarch64
+// RUN: llvm-mc -filetype=obj -triple=aarch64-none-linux %s -o %t.o
+// RUN: ld.lld --fix-cortex-a53-843419 -Ttext=0x8000000 %t.o -o %t2
+// RUN: llvm-objdump -d --start-address=0x8001000 --stop-address=0x8001004 %t2 | FileCheck %s
+
+.section .text.01, "ax", %progbits
+.balign 4096
+.space 4096 - 8
+adrp x0, thunk
+ldr x1, [x1, #0]
+// CHECK: thunk:
+// CHECK-NEXT: b #67108872 <__CortexA53843419_8001000>
+thunk:
+ldr x0, [x0, :got_lo12:thunk]
+ret
+.space 64 * 1024 * 1024
+
+.section .text.02, "ax", %progbits
+.space 64 * 1024 * 1024
Index: lld/ELF/AArch64ErrataFix.cpp
===================================================================
--- lld/ELF/AArch64ErrataFix.cpp
+++ lld/ELF/AArch64ErrataFix.cpp
@@ -488,6 +488,7 @@
   uint64_t ISLimit;
   uint64_t PrevISLimit = ISD.Sections.front()->OutSecOff;
   uint64_t PatchUpperBound = PrevISLimit + Target->getThunkSectionSpacing();
+  uint64_t OutSecAddr = ISD.Sections.front()->getParent()->Addr;
 
   // Set the OutSecOff of patches to the place where we want to insert them.
   // We use a similar strategy to Thunk placement. Place patches roughly
@@ -498,7 +499,7 @@
     ISLimit = IS->OutSecOff + IS->getSize();
     if (ISLimit > PatchUpperBound) {
       while (PatchIt != PatchEnd) {
-        if ((*PatchIt)->getLDSTAddr() >= PrevISLimit)
+        if ((*PatchIt)->getLDSTAddr() - OutSecAddr >= PrevISLimit)
           break;
         (*PatchIt)->OutSecOff = PrevISLimit;
         ++PatchIt;


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D55732.178337.patch
Type: text/x-patch
Size: 1686 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20181215/7845a6d0/attachment.bin>