https://github.com/jasonmolenda created
https://github.com/llvm/llvm-project/pull/155733
Review of diffs from lldb's internal debugserver and llvm.org main found two
orphaned changes that should be upstreamed.
First is in MachTask::ExceptionThread where we want to confirm that a mach
exception messages is from the correct process before we process it.
Second is that we want to run the arm64 register context through
thread_convert_thread_state() after thread_get_state, and before
thread_set_state, to re-sign fp/sp/lr/pc appropriately for ptrauth (arm64e)
processes.
>From 9f6f67403bac881ace1f79327f6cdb612765e478 Mon Sep 17 00:00:00 2001
From: Jason Molenda <jmole...@apple.com>
Date: Wed, 27 Aug 2025 17:54:34 -0700
Subject: [PATCH] [lldb][debugserver] Upstream to debugserver changes
Review of diffs from lldb's internal debugserver and llvm.org main
found two orphaned changes that should be upstreamed.
First is in MachTask::ExceptionThread where we want to confirm that
a mach exception messages is from the correct process before we
process it.
Second is that we want to run the arm64 register context through
thread_convert_thread_state() after thread_get_state, and before
thread_set_state, to re-sign fp/sp/lr/pc appropriately for ptrauth
(arm64e) processes.
---
.../debugserver/source/MacOSX/MachTask.mm | 11 +++
.../source/MacOSX/arm64/DNBArchImplARM64.cpp | 81 ++++++++++++++-----
2 files changed, 72 insertions(+), 20 deletions(-)
diff --git a/lldb/tools/debugserver/source/MacOSX/MachTask.mm
b/lldb/tools/debugserver/source/MacOSX/MachTask.mm
index fd2ac64ac6cf7..8ae9d4df99657 100644
--- a/lldb/tools/debugserver/source/MacOSX/MachTask.mm
+++ b/lldb/tools/debugserver/source/MacOSX/MachTask.mm
@@ -877,6 +877,17 @@ static void
get_threads_profile_data(DNBProfileDataScanType scanType,
if (exception_message.CatchExceptionRaise(task)) {
if (exception_message.state.task_port != task) {
if (exception_message.state.IsValid()) {
+ pid_t new_pid = -1;
+ kern_return_t kr =
+ pid_for_task(exception_message.state.task_port, &new_pid);
+ pid_t old_pid = mach_proc->ProcessID();
+ if (kr == KERN_SUCCESS && old_pid != new_pid) {
+ DNBLogError("Got an exec mach message but the pid of "
+ "the new task and the pid of the old task "
+ "do not match, something is wrong.");
+ // exit the thread.
+ break;
+ }
// We exec'ed and our task port changed on us.
DNBLogThreadedIf(LOG_EXCEPTIONS,
"task port changed from 0x%4.4x to 0x%4.4x",
diff --git a/lldb/tools/debugserver/source/MacOSX/arm64/DNBArchImplARM64.cpp
b/lldb/tools/debugserver/source/MacOSX/arm64/DNBArchImplARM64.cpp
index 6ee1466612ee1..e30e02a911529 100644
--- a/lldb/tools/debugserver/source/MacOSX/arm64/DNBArchImplARM64.cpp
+++ b/lldb/tools/debugserver/source/MacOSX/arm64/DNBArchImplARM64.cpp
@@ -199,6 +199,24 @@ uint64_t DNBArchMachARM64::GetSP(uint64_t failValue) {
return failValue;
}
+static void log_signed_registers(arm_thread_state64_t *gpr, const char *desc) {
+ if (DNBLogEnabledForAny(LOG_THREAD)) {
+ const char *log_str = "%s signed regs "
+ "\n fp=%16.16llx"
+ "\n lr=%16.16llx"
+ "\n sp=%16.16llx"
+ "\n pc=%16.16llx";
+#if defined(DEBUGSERVER_IS_ARM64E)
+ DNBLogThreaded(log_str, desc, reinterpret_cast<uint64_t>(gpr->__opaque_fp),
+ reinterpret_cast<uint64_t>(gpr->__opaque_lr),
+ reinterpret_cast<uint64_t>(gpr->__opaque_sp),
+ reinterpret_cast<uint64_t>(gpr->__opaque_pc));
+#else
+ DNBLogThreaded(log_str, desc, gpr->__fp, gpr->__lr, gpr->__sp, gpr->__pc);
+#endif
+ }
+}
+
kern_return_t DNBArchMachARM64::GetGPRState(bool force) {
int set = e_regSetGPR;
// Check if we have valid cached registers
@@ -210,25 +228,29 @@ kern_return_t DNBArchMachARM64::GetGPRState(bool force) {
kern_return_t kret =
::thread_get_state(m_thread->MachPortNumber(), ARM_THREAD_STATE64,
(thread_state_t)&m_state.context.gpr, &count);
- if (DNBLogEnabledForAny(LOG_THREAD)) {
- uint64_t *x = &m_state.context.gpr.__x[0];
+ log_signed_registers(&m_state.context.gpr, "Values from thread_get_state");
- const char *log_str = "thread_get_state signed regs "
- "\n fp=%16.16llx"
- "\n lr=%16.16llx"
- "\n sp=%16.16llx"
- "\n pc=%16.16llx";
-#if defined(DEBUGSERVER_IS_ARM64E)
- DNBLogThreaded(log_str,
- reinterpret_cast<uint64_t>(m_state.context.gpr.__opaque_fp),
- reinterpret_cast<uint64_t>(m_state.context.gpr.__opaque_lr),
- reinterpret_cast<uint64_t>(m_state.context.gpr.__opaque_sp),
-
reinterpret_cast<uint64_t>(m_state.context.gpr.__opaque_pc));
-#else
- DNBLogThreaded(log_str, m_state.context.gpr.__fp, m_state.context.gpr.__lr,
- m_state.context.gpr.__sp, m_state.context.gpr.__pc);
-#endif
+#if defined(THREAD_CONVERT_THREAD_STATE_TO_SELF) && defined(__LP64__)
+ if (kret == KERN_SUCCESS) {
+ mach_msg_type_number_t newcount = ARM_THREAD_STATE64_COUNT;
+ arm_thread_state64_t new_gpr;
+ kern_return_t convert_kret = thread_convert_thread_state(
+ m_thread->MachPortNumber(), THREAD_CONVERT_THREAD_STATE_TO_SELF,
+ ARM_THREAD_STATE64, (thread_state_t)&m_state.context.gpr, count,
+ (thread_state_t)&new_gpr, &newcount);
+ DNBLogThreadedIf(
+ LOG_THREAD,
+ "converted register values "
+ "to debugserver's keys, return value %d, old count %d new count %d",
+ convert_kret, count, newcount);
+ if (convert_kret == KERN_SUCCESS)
+ memcpy(&m_state.context.gpr, &new_gpr, count * 4);
+ log_signed_registers(&m_state.context.gpr,
+ "Values after thread_convert_thread_state");
+ }
+#endif // THREAD_CONVERT_THREAD_STATE_TO_SELF
+ if (DNBLogEnabledForAny(LOG_THREAD)) {
#if defined(DEBUGSERVER_IS_ARM64E)
uint64_t log_fp = clear_pac_bits(
reinterpret_cast<uint64_t>(m_state.context.gpr.__opaque_fp));
@@ -244,6 +266,7 @@ kern_return_t DNBArchMachARM64::GetGPRState(bool force) {
uint64_t log_sp = m_state.context.gpr.__sp;
uint64_t log_pc = m_state.context.gpr.__pc;
#endif
+ uint64_t *x = &m_state.context.gpr.__x[0];
DNBLogThreaded(
"thread_get_state(0x%4.4x, %u, &gpr, %u) => 0x%8.8x (count = %u) regs"
"\n x0=%16.16llx"
@@ -567,10 +590,28 @@ kern_return_t DNBArchMachARM64::GetSMEState(bool force) {
}
kern_return_t DNBArchMachARM64::SetGPRState() {
+ arm_thread_state64_t *state_to_set = &m_state.context.gpr;
+#if defined(THREAD_CONVERT_THREAD_STATE_FROM_SELF) && defined(__LP64__)
+ mach_msg_type_number_t count = ARM_THREAD_STATE64_COUNT;
+ mach_msg_type_number_t new_count = ARM_THREAD_STATE64_COUNT;
+ arm_thread_state64_t new_gpr;
+ memcpy(&new_gpr, &m_state.context.gpr, count * 4);
+ kern_return_t convert_kret = thread_convert_thread_state(
+ m_thread->MachPortNumber(), THREAD_CONVERT_THREAD_STATE_FROM_SELF,
+ ARM_THREAD_STATE64, (thread_state_t)&m_state.context.gpr, count,
+ (thread_state_t)&new_gpr, &new_count);
+ if (convert_kret == KERN_SUCCESS)
+ state_to_set = &new_gpr;
+ DNBLogThreadedIf(LOG_THREAD,
+ "converted register values "
+ "to inferior's keys, return value %d, count %d",
+ convert_kret, new_count);
+#endif // THREAD_CONVERT_THREAD_STATE_TO_SELF
+
int set = e_regSetGPR;
- kern_return_t kret = ::thread_set_state(
- m_thread->MachPortNumber(), ARM_THREAD_STATE64,
- (thread_state_t)&m_state.context.gpr, e_regSetGPRCount);
+ kern_return_t kret =
+ ::thread_set_state(m_thread->MachPortNumber(), ARM_THREAD_STATE64,
+ (thread_state_t)state_to_set, e_regSetGPRCount);
m_state.SetError(set, Write,
kret); // Set the current write error for this register set
m_state.InvalidateRegisterSetState(set); // Invalidate the current register
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