[Lldb-commits] [lldb] [lldb][FreeBSDKernel] Supply values for CS/SS registers (PR #192207)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-lldb

Author: Minsoo Choo (mchoo7)

<details>
<summary>Changes</summary>

These two values ensure that CPU was in kernel privilege at the time of crash. This change is from KGDB's `amd64fbsd-kern.c`.

---
Full diff: https://github.com/llvm/llvm-project/pull/192207.diff


1 Files Affected:

- (modified) lldb/source/Plugins/Process/FreeBSD-Kernel-Core/RegisterContextFreeBSDKernelCore_x86_64.cpp (+9-2) 


``````````diff
diff --git a/lldb/source/Plugins/Process/FreeBSD-Kernel-Core/RegisterContextFreeBSDKernelCore_x86_64.cpp b/lldb/source/Plugins/Process/FreeBSD-Kernel-Core/RegisterContextFreeBSDKernelCore_x86_64.cpp
index 8f833aa47e486..a0cb53526d331 100644
--- a/lldb/source/Plugins/Process/FreeBSD-Kernel-Core/RegisterContextFreeBSDKernelCore_x86_64.cpp
+++ b/lldb/source/Plugins/Process/FreeBSD-Kernel-Core/RegisterContextFreeBSDKernelCore_x86_64.cpp
@@ -58,6 +58,9 @@ bool RegisterContextFreeBSDKernelCore_x86_64::ReadRegister(
     llvm::support::ulittle64_t rip;
   } pcb;
 
+  constexpr unsigned short CODE_SEL = 4 << 3;
+  constexpr unsigned short DATA_SEL = 5 << 3;
+
 #if defined(__FreeBSD__) && defined(__amd64__)
   static_assert(offsetof(struct pcb, pcb_r15) == offsetof(decltype(pcb), r15));
   static_assert(offsetof(struct pcb, pcb_r14) == offsetof(decltype(pcb), r14));
@@ -90,9 +93,13 @@ bool RegisterContextFreeBSDKernelCore_x86_64::ReadRegister(
     REG(rsp);
     REG(rbx);
     REG(rip);
-
 #undef REG
-
+  case lldb_cs_x86_64:
+    value.SetUInt(CODE_SEL, reg_info->byte_size);
+    break;
+  case lldb_ss_x86_64:
+    value.SetUInt(DATA_SEL, reg_info->byte_size);
+    break;
   default:
     return false;
   }

``````````

</details>


https://github.com/llvm/llvm-project/pull/192207