[Lldb-commits] [lldb] [llvm] [lldb][Process/FreeBSDKernel] Add arm support (PR #180674)
Minsoo Choo via lldb-commits
lldb-commits at lists.llvm.org
Thu Feb 12 07:25:47 PST 2026
https://github.com/mchoo7 updated https://github.com/llvm/llvm-project/pull/180674
>From bc4b272d4e20510d016542dea0a0c69ccee83594 Mon Sep 17 00:00:00 2001
From: Minsoo Choo <minsoochoo0122 at proton.me>
Date: Mon, 9 Feb 2026 23:33:16 -0500
Subject: [PATCH 1/4] [lldb][Process/FreeBSDKernel] Add arm support
Signed-off-by: Minsoo Choo <minsoochoo0122 at proton.me>
---
lldb/docs/index.rst | 2 +-
.../Process/FreeBSDKernel/CMakeLists.txt | 1 +
.../RegisterContextFreeBSDKernel_arm.cpp | 101 ++++++++++++++++++
.../RegisterContextFreeBSDKernel_arm.h | 41 +++++++
.../FreeBSDKernel/ThreadFreeBSDKernel.cpp | 6 ++
llvm/docs/ReleaseNotes.md | 1 +
6 files changed, 151 insertions(+), 1 deletion(-)
create mode 100644 lldb/source/Plugins/Process/FreeBSDKernel/RegisterContextFreeBSDKernel_arm.cpp
create mode 100644 lldb/source/Plugins/Process/FreeBSDKernel/RegisterContextFreeBSDKernel_arm.h
diff --git a/lldb/docs/index.rst b/lldb/docs/index.rst
index 10683c7593b01..fb5d5341b2f31 100644
--- a/lldb/docs/index.rst
+++ b/lldb/docs/index.rst
@@ -74,7 +74,7 @@ are welcome:
* iOS, tvOS, and watchOS device debugging on ARM and AArch64
* Linux user-space debugging for i386, x86_64, ARM, AArch64, PPC64le, s390x
* FreeBSD user-space debugging for i386, x86_64, ARM, AArch64, PPC
-* FreeBSD kernel debugging for i386, x86_64, AArch64
+* FreeBSD kernel debugging for i386, x86_64, ARM, AArch64
* NetBSD user-space debugging for i386 and x86_64
* Windows user-space debugging for i386, x86_64, ARM and AArch64 (*)
diff --git a/lldb/source/Plugins/Process/FreeBSDKernel/CMakeLists.txt b/lldb/source/Plugins/Process/FreeBSDKernel/CMakeLists.txt
index c35b4def24e25..8a970a2b5dee5 100644
--- a/lldb/source/Plugins/Process/FreeBSDKernel/CMakeLists.txt
+++ b/lldb/source/Plugins/Process/FreeBSDKernel/CMakeLists.txt
@@ -13,6 +13,7 @@ endif()
add_lldb_library(lldbPluginProcessFreeBSDKernel PLUGIN
ProcessFreeBSDKernel.cpp
+ RegisterContextFreeBSDKernel_arm.cpp
RegisterContextFreeBSDKernel_arm64.cpp
RegisterContextFreeBSDKernel_i386.cpp
RegisterContextFreeBSDKernel_x86_64.cpp
diff --git a/lldb/source/Plugins/Process/FreeBSDKernel/RegisterContextFreeBSDKernel_arm.cpp b/lldb/source/Plugins/Process/FreeBSDKernel/RegisterContextFreeBSDKernel_arm.cpp
new file mode 100644
index 0000000000000..9db4fecb9936c
--- /dev/null
+++ b/lldb/source/Plugins/Process/FreeBSDKernel/RegisterContextFreeBSDKernel_arm.cpp
@@ -0,0 +1,101 @@
+//===-- RegisterContextFreeBSDKernel_arm.cpp ------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "RegisterContextFreeBSDKernel_arm.h"
+#include "Plugins/Process/Utility/lldb-arm-register-enums.h"
+
+#include "lldb/Target/Process.h"
+#include "lldb/Target/Thread.h"
+#include "lldb/Utility/RegisterValue.h"
+#include "llvm/Support/Endian.h"
+
+using namespace lldb;
+using namespace lldb_private;
+
+RegisterContextFreeBSDKernel_arm::RegisterContextFreeBSDKernel_arm(
+ Thread &thread, std::unique_ptr<RegisterInfoPOSIX_arm> register_info_up,
+ lldb::addr_t pcb_addr)
+ : RegisterContextPOSIX_arm(thread, std::move(register_info_up)),
+ m_pcb_addr(pcb_addr) {}
+
+bool RegisterContextFreeBSDKernel_arm::ReadGPR() { return true; }
+
+bool RegisterContextFreeBSDKernel_arm::ReadFPR() { return true; }
+
+bool RegisterContextFreeBSDKernel_arm::WriteGPR() {
+ assert(0);
+ return false;
+}
+
+bool RegisterContextFreeBSDKernel_arm::WriteFPR() {
+ assert(0);
+ return false;
+}
+
+bool RegisterContextFreeBSDKernel_arm::ReadRegister(
+ const RegisterInfo *reg_info, RegisterValue &value) {
+ if (m_pcb_addr == LLDB_INVALID_ADDRESS)
+ return false;
+
+ // https://cgit.freebsd.org/src/tree/sys/arm/include/frame.h
+ // struct pcb's first field is struct switchframe which is the only field used
+ // by debugger should be aligned by 8 bytes
+ struct {
+ llvm::support::ulittle32_t r4;
+ llvm::support::ulittle32_t r5;
+ llvm::support::ulittle32_t r6;
+ llvm::support::ulittle32_t r7;
+ llvm::support::ulittle32_t r8;
+ llvm::support::ulittle32_t r9;
+ llvm::support::ulittle32_t r10;
+ llvm::support::ulittle64_t r11;
+ llvm::support::ulittle64_t r12;
+ llvm::support::ulittle64_t sp;
+ llvm::support::ulittle64_t lr;
+ llvm::support::ulittle64_t pc;
+ } pcb;
+
+ Status error;
+ size_t rd =
+ m_thread.GetProcess()->ReadMemory(m_pcb_addr, &pcb, sizeof(pcb), error);
+ if (rd != sizeof(pcb))
+ return false;
+
+ uint32_t reg = reg_info->kinds[lldb::eRegisterKindLLDB];
+ switch (reg) {
+
+#define REG(x) \
+ case gpr_##x##_arm: \
+ value = pcb.x; \
+ break;
+
+ REG(r4);
+ REG(r5);
+ REG(r6);
+ REG(r7);
+ REG(r8);
+ REG(r9);
+ REG(r10);
+ REG(r11);
+ REG(r12);
+ REG(sp);
+ REG(lr);
+ REG(pc);
+
+#undef REG
+
+ default:
+ return false;
+ }
+ return true;
+}
+
+bool RegisterContextFreeBSDKernel_arm::WriteRegister(
+ const RegisterInfo *reg_info, const RegisterValue &value) {
+ return false;
+}
diff --git a/lldb/source/Plugins/Process/FreeBSDKernel/RegisterContextFreeBSDKernel_arm.h b/lldb/source/Plugins/Process/FreeBSDKernel/RegisterContextFreeBSDKernel_arm.h
new file mode 100644
index 0000000000000..bad5688d58df3
--- /dev/null
+++ b/lldb/source/Plugins/Process/FreeBSDKernel/RegisterContextFreeBSDKernel_arm.h
@@ -0,0 +1,41 @@
+//===-- RegisterContextFreeBSDKernel_arm.h ----------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLDB_SOURCE_PLUGINS_PROCESS_FREEBSDKERNEL_REGISTERCONTEXTFREEBSDKERNEL_ARM_H
+#define LLDB_SOURCE_PLUGINS_PROCESS_FREEBSDKERNEL_REGISTERCONTEXTFREEBSDKERNEL_ARM_H
+
+#include "Plugins/Process/Utility/RegisterContextPOSIX_arm.h"
+#include "Plugins/Process/elf-core/RegisterUtilities.h"
+
+class RegisterContextFreeBSDKernel_arm : public RegisterContextPOSIX_arm {
+public:
+ RegisterContextFreeBSDKernel_arm(
+ lldb_private::Thread &thread,
+ std::unique_ptr<RegisterInfoPOSIX_arm> register_info_up,
+ lldb::addr_t pcb_addr);
+
+ bool ReadRegister(const lldb_private::RegisterInfo *reg_info,
+ lldb_private::RegisterValue &value) override;
+
+ bool WriteRegister(const lldb_private::RegisterInfo *reg_info,
+ const lldb_private::RegisterValue &value) override;
+
+protected:
+ bool ReadGPR() override;
+
+ bool ReadFPR() override;
+
+ bool WriteGPR() override;
+
+ bool WriteFPR() override;
+
+private:
+ lldb::addr_t m_pcb_addr;
+};
+
+#endif // LLDB_SOURCE_PLUGINS_PROCESS_FREEBSDKERNEL_REGISTERCONTEXTFREEBSDKERNEL_ARM_H
diff --git a/lldb/source/Plugins/Process/FreeBSDKernel/ThreadFreeBSDKernel.cpp b/lldb/source/Plugins/Process/FreeBSDKernel/ThreadFreeBSDKernel.cpp
index dd1ed52719749..98e215146c110 100644
--- a/lldb/source/Plugins/Process/FreeBSDKernel/ThreadFreeBSDKernel.cpp
+++ b/lldb/source/Plugins/Process/FreeBSDKernel/ThreadFreeBSDKernel.cpp
@@ -14,8 +14,10 @@
#include "Plugins/Process/Utility/RegisterContextFreeBSD_i386.h"
#include "Plugins/Process/Utility/RegisterContextFreeBSD_x86_64.h"
+#include "Plugins/Process/Utility/RegisterInfoPOSIX_arm.h"
#include "Plugins/Process/Utility/RegisterInfoPOSIX_arm64.h"
#include "ProcessFreeBSDKernel.h"
+#include "RegisterContextFreeBSDKernel_arm.h"
#include "RegisterContextFreeBSDKernel_arm64.h"
#include "RegisterContextFreeBSDKernel_i386.h"
#include "RegisterContextFreeBSDKernel_x86_64.h"
@@ -62,6 +64,10 @@ ThreadFreeBSDKernel::CreateRegisterContextForFrame(StackFrame *frame) {
*this, std::make_unique<RegisterInfoPOSIX_arm64>(arch, 0),
m_pcb_addr);
break;
+ case llvm::Triple::arm:
+ m_thread_reg_ctx_sp = std::make_shared<RegisterContextFreeBSDKernel_arm>(
+ *this, std::make_unique<RegisterInfoPOSIX_arm>(arch), m_pcb_addr);
+ break;
case llvm::Triple::x86:
m_thread_reg_ctx_sp = std::make_shared<RegisterContextFreeBSDKernel_i386>(
*this, new RegisterContextFreeBSD_i386(arch), m_pcb_addr);
diff --git a/llvm/docs/ReleaseNotes.md b/llvm/docs/ReleaseNotes.md
index 30e74acf973ed..a245f3deb1812 100644
--- a/llvm/docs/ReleaseNotes.md
+++ b/llvm/docs/ReleaseNotes.md
@@ -182,6 +182,7 @@ Changes to LLDB
* Support for FreeBSD on MIPS64 has been removed.
* The minimum assumed version of FreeBSD is now 14. The effect of which is that watchpoints are
assumed to be supported.
+* Kernel debugging support for ARM on FreeBSD has been added.
Changes to BOLT
---------------
>From f5b6f148df804c8e6cf2df9cf955f6cd37187751 Mon Sep 17 00:00:00 2001
From: Minsoo Choo <minsoochoo0122 at proton.me>
Date: Tue, 10 Feb 2026 12:35:17 -0500
Subject: [PATCH 2/4] fixup! [lldb][Process/FreeBSDKernel] Add arm support
Signed-off-by: Minsoo Choo <minsoochoo0122 at proton.me>
---
.../FreeBSDKernel/RegisterContextFreeBSDKernel_arm.cpp | 10 ++++++++--
.../FreeBSDKernel/RegisterContextFreeBSDKernel_arm.h | 8 +++++++-
2 files changed, 15 insertions(+), 3 deletions(-)
diff --git a/lldb/source/Plugins/Process/FreeBSDKernel/RegisterContextFreeBSDKernel_arm.cpp b/lldb/source/Plugins/Process/FreeBSDKernel/RegisterContextFreeBSDKernel_arm.cpp
index 9db4fecb9936c..6aebd97bb2de2 100644
--- a/lldb/source/Plugins/Process/FreeBSDKernel/RegisterContextFreeBSDKernel_arm.cpp
+++ b/lldb/source/Plugins/Process/FreeBSDKernel/RegisterContextFreeBSDKernel_arm.cpp
@@ -1,10 +1,16 @@
-//===-- RegisterContextFreeBSDKernel_arm.cpp ------------------------------===//
+//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file contains the definition of the RegisterContextFreeBSDKernel_arm
+/// class, which is used for reading registers from PCB on arm kernel dump.
+///
+//===----------------------------------------------------------------------===//
#include "RegisterContextFreeBSDKernel_arm.h"
#include "Plugins/Process/Utility/lldb-arm-register-enums.h"
@@ -44,7 +50,7 @@ bool RegisterContextFreeBSDKernel_arm::ReadRegister(
// https://cgit.freebsd.org/src/tree/sys/arm/include/frame.h
// struct pcb's first field is struct switchframe which is the only field used
- // by debugger should be aligned by 8 bytes
+ // by debugger and should be aligned by 8 bytes.
struct {
llvm::support::ulittle32_t r4;
llvm::support::ulittle32_t r5;
diff --git a/lldb/source/Plugins/Process/FreeBSDKernel/RegisterContextFreeBSDKernel_arm.h b/lldb/source/Plugins/Process/FreeBSDKernel/RegisterContextFreeBSDKernel_arm.h
index bad5688d58df3..9b4445e16be79 100644
--- a/lldb/source/Plugins/Process/FreeBSDKernel/RegisterContextFreeBSDKernel_arm.h
+++ b/lldb/source/Plugins/Process/FreeBSDKernel/RegisterContextFreeBSDKernel_arm.h
@@ -1,10 +1,16 @@
-//===-- RegisterContextFreeBSDKernel_arm.h ----------------------*- C++ -*-===//
+//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file contains the declaration of the RegisterContextFreeBSDKernel_arm
+/// class, which is used for reading registers from PCB on arm kernel dump.
+///
+//===----------------------------------------------------------------------===//
#ifndef LLDB_SOURCE_PLUGINS_PROCESS_FREEBSDKERNEL_REGISTERCONTEXTFREEBSDKERNEL_ARM_H
#define LLDB_SOURCE_PLUGINS_PROCESS_FREEBSDKERNEL_REGISTERCONTEXTFREEBSDKERNEL_ARM_H
>From d8b3086e826b735ad3639379166042a84dad0423 Mon Sep 17 00:00:00 2001
From: Minsoo Choo <minsoochoo0122 at proton.me>
Date: Wed, 11 Feb 2026 14:11:17 -0500
Subject: [PATCH 3/4] fixup! [lldb][Process/FreeBSDKernel] Add arm support
Signed-off-by: Minsoo Choo <minsoochoo0122 at proton.me>
---
.../RegisterContextFreeBSDKernel_arm.cpp | 12 ++++++------
.../FreeBSDKernel/RegisterContextFreeBSDKernel_arm.h | 2 +-
llvm/docs/ReleaseNotes.md | 2 +-
3 files changed, 8 insertions(+), 8 deletions(-)
diff --git a/lldb/source/Plugins/Process/FreeBSDKernel/RegisterContextFreeBSDKernel_arm.cpp b/lldb/source/Plugins/Process/FreeBSDKernel/RegisterContextFreeBSDKernel_arm.cpp
index 6aebd97bb2de2..71da0ed99dffa 100644
--- a/lldb/source/Plugins/Process/FreeBSDKernel/RegisterContextFreeBSDKernel_arm.cpp
+++ b/lldb/source/Plugins/Process/FreeBSDKernel/RegisterContextFreeBSDKernel_arm.cpp
@@ -8,7 +8,7 @@
///
/// \file
/// This file contains the definition of the RegisterContextFreeBSDKernel_arm
-/// class, which is used for reading registers from PCB on arm kernel dump.
+/// class, which is used for reading registers from PCB in arm kernel dump.
///
//===----------------------------------------------------------------------===//
@@ -59,11 +59,11 @@ bool RegisterContextFreeBSDKernel_arm::ReadRegister(
llvm::support::ulittle32_t r8;
llvm::support::ulittle32_t r9;
llvm::support::ulittle32_t r10;
- llvm::support::ulittle64_t r11;
- llvm::support::ulittle64_t r12;
- llvm::support::ulittle64_t sp;
- llvm::support::ulittle64_t lr;
- llvm::support::ulittle64_t pc;
+ llvm::support::ulittle32_t r11;
+ llvm::support::ulittle32_t r12;
+ llvm::support::ulittle32_t sp;
+ llvm::support::ulittle32_t lr;
+ llvm::support::ulittle32_t pc;
} pcb;
Status error;
diff --git a/lldb/source/Plugins/Process/FreeBSDKernel/RegisterContextFreeBSDKernel_arm.h b/lldb/source/Plugins/Process/FreeBSDKernel/RegisterContextFreeBSDKernel_arm.h
index 9b4445e16be79..61bd34206a51b 100644
--- a/lldb/source/Plugins/Process/FreeBSDKernel/RegisterContextFreeBSDKernel_arm.h
+++ b/lldb/source/Plugins/Process/FreeBSDKernel/RegisterContextFreeBSDKernel_arm.h
@@ -8,7 +8,7 @@
///
/// \file
/// This file contains the declaration of the RegisterContextFreeBSDKernel_arm
-/// class, which is used for reading registers from PCB on arm kernel dump.
+/// class, which is used for reading registers from PCB in arm kernel dump.
///
//===----------------------------------------------------------------------===//
diff --git a/llvm/docs/ReleaseNotes.md b/llvm/docs/ReleaseNotes.md
index a245f3deb1812..24d56e8e75f47 100644
--- a/llvm/docs/ReleaseNotes.md
+++ b/llvm/docs/ReleaseNotes.md
@@ -182,7 +182,7 @@ Changes to LLDB
* Support for FreeBSD on MIPS64 has been removed.
* The minimum assumed version of FreeBSD is now 14. The effect of which is that watchpoints are
assumed to be supported.
-* Kernel debugging support for ARM on FreeBSD has been added.
+* Kernel debugging support for FreeBSD on ARM has been added.
Changes to BOLT
---------------
>From 5ccef640a90d1df18f191a3dc411c066fe40628b Mon Sep 17 00:00:00 2001
From: Minsoo Choo <minsoochoo0122 at proton.me>
Date: Thu, 12 Feb 2026 10:24:42 -0500
Subject: [PATCH 4/4] fixup! [lldb][Process/FreeBSDKernel] Add arm support
Signed-off-by: Minsoo Choo <minsoochoo0122 at proton.me>
---
.../Process/FreeBSDKernel/RegisterContextFreeBSDKernel_arm.cpp | 1 +
llvm/docs/ReleaseNotes.md | 2 +-
2 files changed, 2 insertions(+), 1 deletion(-)
diff --git a/lldb/source/Plugins/Process/FreeBSDKernel/RegisterContextFreeBSDKernel_arm.cpp b/lldb/source/Plugins/Process/FreeBSDKernel/RegisterContextFreeBSDKernel_arm.cpp
index 71da0ed99dffa..6794778cd4399 100644
--- a/lldb/source/Plugins/Process/FreeBSDKernel/RegisterContextFreeBSDKernel_arm.cpp
+++ b/lldb/source/Plugins/Process/FreeBSDKernel/RegisterContextFreeBSDKernel_arm.cpp
@@ -52,6 +52,7 @@ bool RegisterContextFreeBSDKernel_arm::ReadRegister(
// struct pcb's first field is struct switchframe which is the only field used
// by debugger and should be aligned by 8 bytes.
struct {
+ // Aka switchframe.sf_r4 to switchframe.sf_pc.
llvm::support::ulittle32_t r4;
llvm::support::ulittle32_t r5;
llvm::support::ulittle32_t r6;
diff --git a/llvm/docs/ReleaseNotes.md b/llvm/docs/ReleaseNotes.md
index 3dbec77b8fee0..9111bacd550af 100644
--- a/llvm/docs/ReleaseNotes.md
+++ b/llvm/docs/ReleaseNotes.md
@@ -186,10 +186,10 @@ Changes to LLDB
#### Userspace Debugging
+* Support for ARM has been added.
* Support for MIPS64 has been removed.
* The minimum assumed FreeBSD version is now 14. The effect of which is that watchpoints are
assumed to be supported.
-* Kernel debugging support for FreeBSD on ARM has been added.
#### Kernel Debugging
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