[Lldb-commits] [PATCH] D147462: Use kernel's global variable indicating how many bits are used in addressing when loading Darwin xnu kernel
Jason Molenda via Phabricator via lldb-commits
lldb-commits at lists.llvm.org
Mon Apr 3 13:35:19 PDT 2023
jasonmolenda updated this revision to Diff 510586.
jasonmolenda added a comment.
Update patch to address some of Jonas' comments. I was adding a check that the ptrsize of the architecture was 64-bit, but we don't work on 32-bit xnu kernels for a few years now; we can assume 64-bit safely. I am still forcing the addressable bits value to 55 globally inside lldb while I read & set the correct value.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D147462/new/
https://reviews.llvm.org/D147462
Files:
lldb/source/Plugins/DynamicLoader/Darwin-Kernel/DynamicLoaderDarwinKernel.cpp
Index: lldb/source/Plugins/DynamicLoader/Darwin-Kernel/DynamicLoaderDarwinKernel.cpp
===================================================================
--- lldb/source/Plugins/DynamicLoader/Darwin-Kernel/DynamicLoaderDarwinKernel.cpp
+++ lldb/source/Plugins/DynamicLoader/Darwin-Kernel/DynamicLoaderDarwinKernel.cpp
@@ -1068,6 +1068,7 @@
if (m_kernel.IsLoaded() && m_kernel.GetModule()) {
static ConstString kext_summary_symbol("gLoadedKextSummaries");
+ static ConstString arm64_T1Sz_value("gT1Sz");
const Symbol *symbol =
m_kernel.GetModule()->FindFirstSymbolWithNameAndType(
kext_summary_symbol, eSymbolTypeData);
@@ -1076,6 +1077,36 @@
// Update all image infos
ReadAllKextSummaries();
}
+ // If the kernel global with the T1Sz setting is available,
+ // update the target.process.virtual-addressable-bits to be correct.
+ symbol = m_kernel.GetModule()->FindFirstSymbolWithNameAndType(
+ arm64_T1Sz_value, eSymbolTypeData);
+ if (symbol) {
+ const uint32_t orig_bits_value = m_process->GetVirtualAddressableBits();
+ // Mark all bits as addressable so we don't strip any from our
+ // memory read below, with an incorrect default value.
+ // b55 is the sign extension bit with PAC, b56:63 are TBI,
+ // don't mark those as addressable.
+ m_process->SetVirtualAddressableBits(55);
+ Status error;
+ // gT1Sz is 8 bytes. We may run on a stripped kernel binary
+ // where we can't get the size accurately. Hardcode it.
+ const size_t sym_bytesize = 8; // size of gT1Sz value
+ uint64_t sym_value =
+ m_process->GetTarget().ReadUnsignedIntegerFromMemory(
+ symbol->GetAddress(), sym_bytesize, 0, error);
+ if (error.Success()) {
+ // 64 - T1Sz is the highest bit used for auth.
+ // The value we pass in to SetVirtualAddressableBits is
+ // the number of bits used for addressing, so if
+ // T1Sz is 25, then 64-25 == 39, bits 0..38 are used for
+ // addressing, bits 39..63 are used for PAC/TBI or whatever.
+ uint32_t virt_addr_bits = 64 - sym_value;
+ m_process->SetVirtualAddressableBits(virt_addr_bits);
+ } else {
+ m_process->SetVirtualAddressableBits(orig_bits_value);
+ }
+ }
} else {
m_kernel.Clear();
}
-------------- next part --------------
A non-text attachment was scrubbed...
Name: D147462.510586.patch
Type: text/x-patch
Size: 2441 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/lldb-commits/attachments/20230403/c7601947/attachment-0001.bin>
More information about the lldb-commits
mailing list