https://github.com/jasonmolenda created
https://github.com/llvm/llvm-project/pull/134184
debugserver isn't saving and restoring the SVE/SME register state around
inferior function calls.
Making arbitrary function calls while in Streaming SVE mode is generally a poor
idea because a NEON instruction can be hit and crash the expression execution,
which is how I missed this, but they should be handled correctly if the user
knows it is safe to do.
rdar://146886210
>From 7cc45f1a300b1b0f2cbb529f11a0f9e56c41ffea Mon Sep 17 00:00:00 2001
From: Jason Molenda <jmole...@apple.com>
Date: Wed, 2 Apr 2025 18:05:29 -0700
Subject: [PATCH] [lldb][debugserver] Save and restore the SVE/SME register
state
debugserver isn't saving and restoring the SVE/SME register state
around inferior function calls.
Making arbitrary function calls while in Streaming SVE mode is
generally a poor idea because a NEON instruction can be hit and
crash the expression execution, which is how I missed this, but
they should be handled correctly if the user knows it is safe
to do.
rdar://146886210
---
.../source/MacOSX/arm64/DNBArchImplARM64.cpp | 30 ++++++++++++++++++-
1 file changed, 29 insertions(+), 1 deletion(-)
diff --git a/lldb/tools/debugserver/source/MacOSX/arm64/DNBArchImplARM64.cpp
b/lldb/tools/debugserver/source/MacOSX/arm64/DNBArchImplARM64.cpp
index 34a4ee21f8502..fb23744393d43 100644
--- a/lldb/tools/debugserver/source/MacOSX/arm64/DNBArchImplARM64.cpp
+++ b/lldb/tools/debugserver/source/MacOSX/arm64/DNBArchImplARM64.cpp
@@ -2953,7 +2953,14 @@ kern_return_t DNBArchMachARM64::SetRegisterState(int
set) {
switch (set) {
case e_regSetALL:
- return SetGPRState() | SetVFPState() | SetEXCState() | SetDBGState(false);
+ {
+ kern_return_t ret = SetGPRState() | SetVFPState() | SetEXCState() |
SetDBGState(false);
+ if (CPUHasSME()) {
+ ret |= SetSVEState();
+ ret |= SetSMEState();
+ }
+ return ret;
+ }
case e_regSetGPR:
return SetGPRState();
case e_regSetVFP:
@@ -3122,6 +3129,15 @@ uint32_t DNBArchMachARM64::SaveRegisterState() {
DNBLogThreadedIf(LOG_THREAD, "DNBArchMachARM64::SaveRegisterState () "
"error: %s regs failed to read: %u",
"VFP", kret);
+ } else if (CPUHasSME() && (kret = SetSVEState() != KERN_SUCCESS)) {
+ DNBLogThreadedIf(LOG_THREAD, "DNBArchMachARM64::SaveRegisterState () "
+ "error: %s regs failed to read: %u",
+ "SVE", kret);
+ }
+ else if (CPUHasSME() && (kret = SetSMEState() != KERN_SUCCESS)) {
+ DNBLogThreadedIf(LOG_THREAD, "DNBArchMachARM64::SaveRegisterState () "
+ "error: %s regs failed to read: %u",
+ "SME", kret);
} else {
const uint32_t save_id = GetNextRegisterStateSaveID();
m_saved_register_states[save_id] = m_state.context;
@@ -3149,6 +3165,18 @@ bool DNBArchMachARM64::RestoreRegisterState(uint32_t
save_id) {
"write: %u",
save_id, "VFP", kret);
success = false;
+ } else if ((kret = SetSVEState()) != KERN_SUCCESS) {
+ DNBLogThreadedIf(LOG_THREAD, "DNBArchMachARM64::RestoreRegisterState "
+ "(save_id = %u) error: %s regs failed to "
+ "write: %u",
+ save_id, "SVE", kret);
+ success = false;
+ } else if ((kret = SetSMEState()) != KERN_SUCCESS) {
+ DNBLogThreadedIf(LOG_THREAD, "DNBArchMachARM64::RestoreRegisterState "
+ "(save_id = %u) error: %s regs failed to "
+ "write: %u",
+ save_id, "SME", kret);
+ success = false;
}
m_saved_register_states.erase(pos);
return success;
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