[llvm] [llvm][llvm-readobj] Add NT_ARM_GCS Linux core note type (PR #117545)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-objectyaml

@llvm/pr-subscribers-llvm-binary-utilities

Author: David Spickett (DavidSpickett)

<details>
<summary>Changes</summary>

The ARM Guarded Control Stack extension (GCS) is similar to existing shadow stack extensions for other architectures.

The core note will include which features of GCS are enabled, which have been locked in their current state, and the stack pointer of the shadow stack.

Note that 0x40f is NT_ARM_POE, FPMR and GCS will be supported by lldb, POE is not at this time.

---
Full diff: https://github.com/llvm/llvm-project/pull/117545.diff


4 Files Affected:

- (modified) llvm/include/llvm/BinaryFormat/ELF.h (+1) 
- (modified) llvm/lib/ObjectYAML/ELFYAML.cpp (+1) 
- (modified) llvm/test/tools/llvm-readobj/ELF/note-core.test (+5) 
- (modified) llvm/tools/llvm-readobj/ELFDumper.cpp (+1) 


``````````diff
diff --git a/llvm/include/llvm/BinaryFormat/ELF.h b/llvm/include/llvm/BinaryFormat/ELF.h
index fd32a6ec19652b..5356843f8ecf1a 100644
--- a/llvm/include/llvm/BinaryFormat/ELF.h
+++ b/llvm/include/llvm/BinaryFormat/ELF.h
@@ -1724,6 +1724,7 @@ enum : unsigned {
   NT_ARM_ZA = 0x40c,
   NT_ARM_ZT = 0x40d,
   NT_ARM_FPMR = 0x40e,
+  NT_ARM_GCS = 0x410,
 
   NT_FILE = 0x46494c45,
   NT_PRXFPREG = 0x46e62b7f,
diff --git a/llvm/lib/ObjectYAML/ELFYAML.cpp b/llvm/lib/ObjectYAML/ELFYAML.cpp
index ca0ea03452d3be..f28e6766f734c0 100644
--- a/llvm/lib/ObjectYAML/ELFYAML.cpp
+++ b/llvm/lib/ObjectYAML/ELFYAML.cpp
@@ -136,6 +136,7 @@ void ScalarEnumerationTraits<ELFYAML::ELF_NT>::enumeration(
   ECase(NT_ARM_ZA);
   ECase(NT_ARM_ZT);
   ECase(NT_ARM_FPMR);
+  ECase(NT_ARM_GCS);
   ECase(NT_FILE);
   ECase(NT_PRXFPREG);
   ECase(NT_SIGINFO);
diff --git a/llvm/test/tools/llvm-readobj/ELF/note-core.test b/llvm/test/tools/llvm-readobj/ELF/note-core.test
index 1196d4b2507241..2c35178a97524b 100644
--- a/llvm/test/tools/llvm-readobj/ELF/note-core.test
+++ b/llvm/test/tools/llvm-readobj/ELF/note-core.test
@@ -265,6 +265,11 @@
 # RUN: llvm-readelf --notes %t_nt_arm_fpmr.o | FileCheck %s --check-prefix=CHECK-GNU  -DDESC="NT_ARM_FPMR (AArch64 Floating Point Mode Register)"
 # RUN: llvm-readobj --notes %t_nt_arm_fpmr.o | FileCheck %s --check-prefix=CHECK-LLVM -DDESC="NT_ARM_FPMR (AArch64 Floating Point Mode Register)"
 
+## Check ELF::NT_ARM_GCS
+# RUN: yaml2obj %s -DTYPE=0x410 -o %t_nt_arm_gcs.o
+# RUN: llvm-readelf --notes %t_nt_arm_gcs.o | FileCheck %s --check-prefix=CHECK-GNU  -DDESC="NT_ARM_GCS (AArch64 Guarded Control Stack state)"
+# RUN: llvm-readobj --notes %t_nt_arm_gcs.o | FileCheck %s --check-prefix=CHECK-LLVM -DDESC="NT_ARM_GCS (AArch64 Guarded Control Stack state)"
+
 ## Check ELF::NT_FILE.
 # RUN: yaml2obj %s -DTYPE=0x46494c45 -o %t_nt_file.o
 # RUN: llvm-readelf --notes %t_nt_file.o | FileCheck %s --check-prefix=CHECK-GNU  -DDESC="NT_FILE (mapped files)"
diff --git a/llvm/tools/llvm-readobj/ELFDumper.cpp b/llvm/tools/llvm-readobj/ELFDumper.cpp
index bb8ec41d87454c..bfca65aad52b44 100644
--- a/llvm/tools/llvm-readobj/ELFDumper.cpp
+++ b/llvm/tools/llvm-readobj/ELFDumper.cpp
@@ -6057,6 +6057,7 @@ const NoteType CoreNoteTypes[] = {
     {ELF::NT_ARM_ZA, "NT_ARM_ZA (AArch64 SME ZA registers)"},
     {ELF::NT_ARM_ZT, "NT_ARM_ZT (AArch64 SME ZT registers)"},
     {ELF::NT_ARM_FPMR, "NT_ARM_FPMR (AArch64 Floating Point Mode Register)"},
+    {ELF::NT_ARM_GCS, "NT_ARM_GCS (AArch64 Guarded Control Stack state)"},
 
     {ELF::NT_FILE, "NT_FILE (mapped files)"},
     {ELF::NT_PRXFPREG, "NT_PRXFPREG (user_xfpregs structure)"},

``````````

</details>


https://github.com/llvm/llvm-project/pull/117545