[Lldb-commits] [lldb] [lldb] Add SBProcess methods for get/set/use address masks (PR #83095)
Jason Molenda via lldb-commits
lldb-commits at lists.llvm.org
Mon Feb 26 18:08:25 PST 2024
https://github.com/jasonmolenda created https://github.com/llvm/llvm-project/pull/83095
I'm reviving a patch from phabracator, https://reviews.llvm.org/D155905 which was approved but I wasn't thrilled with all the API I was adding to SBProcess for all of the address mask types / memory regions. In this update, I added enums to control type address mask type (code, data, any) and address space specifiers (low, high, all) with defaulted arguments for the most common case.
This patch is also fixing a bug in the "addressable bits to address mask" calculation I added in AddressableBits::SetProcessMasks. If lldb were told that 64 bits are valid for addressing, this method would overflow the calculation and set an invalid mask. Added tests to check this specific bug while I was adding these APIs.
rdar://123530562
>From dae16776e8c97158e8965e4d0e950cd2ce836f75 Mon Sep 17 00:00:00 2001
From: Jason Molenda <jason at molenda.com>
Date: Mon, 26 Feb 2024 18:05:27 -0800
Subject: [PATCH] [lldb] Add SBProcess methods for get/set/use address masks
I'm reviving a patch from phabracator, https://reviews.llvm.org/D155905
which was approved but I wasn't thrilled with all the API I was
adding to SBProcess for all of the address mask types / memory
regions. In this update, I added enums to control type address mask
type (code, data, any) and address space specifiers (low, high,
all) with defaulted arguments for the most common case.
This patch is also fixing a bug in the "addressable bits to address
mask" calculation I added in AddressableBits::SetProcessMasks.
If lldb were told that 64 bits are valid for addressing, this method
would overflow the calculation and set an invalid mask. Added tests
to check this specific bug while I was adding these APIs.
rdar://123530562
---
lldb/include/lldb/API/SBProcess.h | 123 ++++++++++++++++++
lldb/include/lldb/Utility/AddressableBits.h | 3 +
lldb/include/lldb/lldb-enumerations.h | 14 ++
lldb/source/API/SBProcess.cpp | 89 +++++++++++++
lldb/source/Utility/AddressableBits.cpp | 12 +-
.../python_api/process/address-masks/Makefile | 3 +
.../process/address-masks/TestAddressMasks.py | 64 +++++++++
.../python_api/process/address-masks/main.c | 5 +
8 files changed, 311 insertions(+), 2 deletions(-)
create mode 100644 lldb/test/API/python_api/process/address-masks/Makefile
create mode 100644 lldb/test/API/python_api/process/address-masks/TestAddressMasks.py
create mode 100644 lldb/test/API/python_api/process/address-masks/main.c
diff --git a/lldb/include/lldb/API/SBProcess.h b/lldb/include/lldb/API/SBProcess.h
index 4f92a41f3028a2..7e9ad7d9a274f2 100644
--- a/lldb/include/lldb/API/SBProcess.h
+++ b/lldb/include/lldb/API/SBProcess.h
@@ -407,6 +407,129 @@ class LLDB_API SBProcess {
/// the process isn't loaded from a core file.
lldb::SBFileSpec GetCoreFile();
+ /// Get the current address mask that can be applied to addresses
+ /// before reading from memory.
+ ///
+ /// \param[in] type
+ /// lldb may have different address masks for code and data
+ /// addresses. Either can be requested, or most commonly,
+ /// eAddressMaskTypeAny can be requested and the least specific
+ /// mask will be fetched. e.g. on a target where instructions
+ /// are word aligned, the Code mask might clear the low 2 bits.
+ ///
+ /// \param[in] addr_range
+ /// Specify whether the address mask for high or low address spaces
+ /// is requested.
+ /// It is highly unusual to have different address masks in high
+ /// or low memory, and by default the eAddressMaskRangeLow is the
+ /// only one used for both types of addresses, the default value for
+ /// this argument is the correct one.
+ ///
+ /// On some architectures like AArch64, it is possible to have
+ /// different page table setups for low and high memory, so different
+ /// numbers of bits relevant to addressing, and it is possible to have
+ /// a program running in one half of memory and accessing the other
+ /// as heap, etc. In that case the eAddressMaskRangeLow and
+ /// eAddressMaskRangeHigh will have different masks that must be handled.
+ ///
+ /// \return
+ /// The address mask currently in use. Bits which are not used
+ /// for addressing will be set to 1 in the mask.
+ lldb::addr_t GetAddressMask(
+ lldb::AddressMaskType type,
+ lldb::AddressMaskRange addr_range = lldb::eAddressMaskRangeLow);
+
+ /// Set the current address mask that can be applied to addresses
+ /// before reading from memory.
+ ///
+ /// \param[in] type
+ /// lldb may have different address masks for code and data
+ /// addresses. Either can be set, or most commonly,
+ /// eAddressMaskTypeAll can be set for both types of addresses.
+ /// An example where they could be different is a target where
+ /// instructions are word aligned, so the low 2 bits are always
+ /// zero.
+ ///
+ /// \param[in] mask
+ /// The address mask to set. Bits which are not used for addressing
+ /// should be set to 1 in the mask.
+ ///
+ /// \param[in] addr_range
+ /// Specify whether the address mask for high or low address spaces
+ /// is being set.
+ /// It is highly unusual to have different address masks in high
+ /// or low memory, and by default the eAddressMaskRangeLow is the
+ /// only one used for both types of addresses, the default value for
+ /// this argument is the correct one.
+ ///
+ /// On some architectures like AArch64, it is possible to have
+ /// different page table setups for low and high memory, so different
+ /// numbers of bits relevant to addressing, and it is possible to have
+ /// a program running in one half of memory and accessing the other
+ /// as heap, etc. In that case the eAddressMaskRangeLow and
+ /// eAddressMaskRangeHigh will have different masks that must be
+ /// specified.
+ void SetAddressMask(
+ lldb::AddressMaskType type, lldb::addr_t mask,
+ lldb::AddressMaskRange addr_range = lldb::eAddressMaskRangeLow);
+
+ /// Set the number of bits used for addressing in this Process.
+ ///
+ /// In some environments, the number of bits that are used for addressing
+ /// is the natural representation insted of a mask; this method calculates
+ /// the addressing mask that lldb uses internally from that number.
+ ///
+ /// \param[in] type
+ /// lldb may have different address masks for code and data
+ /// addresses. Either can be set, or most commonly,
+ /// eAddressMaskTypeAll can be set for both types of addresses.
+ /// An example where they could be different is a target where
+ /// instructions are word aligned, so the low 2 bits are always
+ /// zero.
+ ///
+ /// \param[in] num_bits
+ /// Number of bits that are used for addressing. e.g. the low 42
+ /// bits may be the only ones used for addressing, and high bits may
+ /// store metadata and should be ignored by lldb.
+ ///
+ /// \param[in] addr_range
+ /// Specify whether the address mask for high or low address spaces
+ /// is being set.
+ /// It is highly unusual to have different address masks in high
+ /// or low memory, and by default the eAddressMaskRangeLow is the
+ /// only one used for both types of addresses, the default value for
+ /// this argument is the correct one.
+ ///
+ /// On some architectures like AArch64, it is possible to have
+ /// different page table setups for low and high memory, so different
+ /// numbers of bits relevant to addressing, and it is possible to have
+ /// a program running in one half of memory and accessing the other
+ /// as heap, etc. In that case the eAddressMaskRangeLow and
+ /// eAddressMaskRangeHigh will have different masks that must be
+ /// specified.
+ void
+ SetAddressableBits(AddressMaskType type, uint32_t num_bits,
+ AddressMaskRange addr_range = lldb::eAddressMaskRangeLow);
+
+ /// Clear the non-addressable bits of an \a addr value and return a
+ /// virtual address in memory.
+ ///
+ /// Bits that are not used in addressing may be used for other purposes;
+ /// pointer authentication, or metadata in the top byte, or the 0th bit
+ /// of armv7 code addresses to indicate arm/thumb are common examples.
+ ///
+ /// \param[in] addr
+ /// The address that should be cleared of non-addressable bits.
+ ///
+ /// \param[in] type
+ /// If the address is known to be a code address (address of a function,
+ /// for example), eAddressMaskTypeCode may be passed, which may have
+ /// stricter address clearing than data addresses e.g. the low 2 bits
+ /// being unused for code addresses on AArch64.
+ lldb::addr_t
+ FixAddress(lldb::addr_t addr,
+ lldb::AddressMaskType type = lldb::eAddressMaskTypeAny);
+
/// Allocate memory within the process.
///
/// This function will allocate memory in the process's address space.
diff --git a/lldb/include/lldb/Utility/AddressableBits.h b/lldb/include/lldb/Utility/AddressableBits.h
index 13c21329a8c617..75752fcf840a44 100644
--- a/lldb/include/lldb/Utility/AddressableBits.h
+++ b/lldb/include/lldb/Utility/AddressableBits.h
@@ -10,6 +10,7 @@
#define LLDB_UTILITY_ADDRESSABLEBITS_H
#include "lldb/lldb-forward.h"
+#include "lldb/lldb-public.h"
namespace lldb_private {
@@ -33,6 +34,8 @@ class AddressableBits {
void SetHighmemAddressableBits(uint32_t highmem_addressing_bits);
+ static lldb::addr_t AddressableBitToMask(uint32_t addressable_bits);
+
void SetProcessMasks(lldb_private::Process &process);
private:
diff --git a/lldb/include/lldb/lldb-enumerations.h b/lldb/include/lldb/lldb-enumerations.h
index 85769071dae785..853370bf5eb515 100644
--- a/lldb/include/lldb/lldb-enumerations.h
+++ b/lldb/include/lldb/lldb-enumerations.h
@@ -1323,6 +1323,20 @@ enum SymbolDownload {
eSymbolDownloadForeground = 2,
};
+enum AddressMaskType {
+ eAddressMaskTypeCode = 0,
+ eAddressMaskTypeData,
+ eAddressMaskTypeAny,
+ eAddressMaskTypeAll = eAddressMaskTypeAny
+};
+
+enum AddressMaskRange {
+ eAddressMaskRangeLow = 0,
+ eAddressMaskRangeHigh,
+ eAddressMaskRangeAny,
+ eAddressMaskRangeAll = eAddressMaskRangeAny,
+};
+
} // namespace lldb
#endif // LLDB_LLDB_ENUMERATIONS_H
diff --git a/lldb/source/API/SBProcess.cpp b/lldb/source/API/SBProcess.cpp
index a9fe915324683e..7edaa6b84fd7d7 100644
--- a/lldb/source/API/SBProcess.cpp
+++ b/lldb/source/API/SBProcess.cpp
@@ -1255,6 +1255,95 @@ lldb::SBFileSpec SBProcess::GetCoreFile() {
return SBFileSpec(core_file);
}
+addr_t SBProcess::GetAddressMask(AddressMaskType type,
+ AddressMaskRange addr_range) {
+ LLDB_INSTRUMENT_VA(this, type, addr_range);
+ addr_t default_mask = 0;
+ if (ProcessSP process_sp = GetSP()) {
+ switch (type) {
+ case eAddressMaskTypeCode:
+ if (addr_range == eAddressMaskRangeHigh)
+ return process_sp->GetHighmemCodeAddressMask();
+ else
+ return process_sp->GetCodeAddressMask();
+ case eAddressMaskTypeData:
+ if (addr_range == eAddressMaskRangeHigh)
+ return process_sp->GetHighmemDataAddressMask();
+ else
+ return process_sp->GetDataAddressMask();
+ case eAddressMaskTypeAny:
+ if (addr_range == eAddressMaskRangeHigh)
+ return process_sp->GetHighmemDataAddressMask();
+ else
+ return process_sp->GetDataAddressMask();
+ }
+ }
+ return default_mask;
+}
+
+void SBProcess::SetAddressMask(AddressMaskType type, addr_t mask,
+ AddressMaskRange addr_range) {
+ LLDB_INSTRUMENT_VA(this, type, mask, addr_range);
+ if (ProcessSP process_sp = GetSP()) {
+ switch (type) {
+ case eAddressMaskTypeCode:
+ if (addr_range == eAddressMaskRangeAll) {
+ process_sp->SetCodeAddressMask(mask);
+ process_sp->SetHighmemCodeAddressMask(mask);
+ } else if (addr_range == eAddressMaskRangeHigh) {
+ process_sp->SetHighmemCodeAddressMask(mask);
+ } else {
+ process_sp->SetCodeAddressMask(mask);
+ }
+ break;
+ case eAddressMaskTypeData:
+ if (addr_range == eAddressMaskRangeAll) {
+ process_sp->SetDataAddressMask(mask);
+ process_sp->SetHighmemDataAddressMask(mask);
+ } else if (addr_range == eAddressMaskRangeHigh) {
+ process_sp->SetHighmemDataAddressMask(mask);
+ } else {
+ process_sp->SetDataAddressMask(mask);
+ }
+ break;
+ case eAddressMaskTypeAll:
+ if (addr_range == eAddressMaskRangeAll) {
+ process_sp->SetCodeAddressMask(mask);
+ process_sp->SetDataAddressMask(mask);
+ process_sp->SetHighmemCodeAddressMask(mask);
+ process_sp->SetHighmemDataAddressMask(mask);
+ } else if (addr_range == eAddressMaskRangeHigh) {
+ process_sp->SetHighmemCodeAddressMask(mask);
+ process_sp->SetHighmemDataAddressMask(mask);
+ } else {
+ process_sp->SetCodeAddressMask(mask);
+ process_sp->SetDataAddressMask(mask);
+ }
+ break;
+ }
+ }
+}
+
+void SBProcess::SetAddressableBits(AddressMaskType type, uint32_t num_bits,
+ AddressMaskRange addr_range) {
+ LLDB_INSTRUMENT_VA(this, type, num_bits, addr_range);
+ SetAddressMask(type, AddressableBits::AddressableBitToMask(num_bits),
+ addr_range);
+}
+
+addr_t SBProcess::FixAddress(addr_t addr, AddressMaskType type) {
+ LLDB_INSTRUMENT_VA(this, addr, type);
+ if (ProcessSP process_sp = GetSP()) {
+ if (type == eAddressMaskTypeAny)
+ return process_sp->FixAnyAddress(addr);
+ else if (type == eAddressMaskTypeData)
+ return process_sp->FixDataAddress(addr);
+ else if (type == eAddressMaskTypeCode)
+ return process_sp->FixCodeAddress(addr);
+ }
+ return addr;
+}
+
lldb::addr_t SBProcess::AllocateMemory(size_t size, uint32_t permissions,
lldb::SBError &sb_error) {
LLDB_INSTRUMENT_VA(this, size, permissions, sb_error);
diff --git a/lldb/source/Utility/AddressableBits.cpp b/lldb/source/Utility/AddressableBits.cpp
index c6e25f608da73d..7f9d7ec6c1349c 100644
--- a/lldb/source/Utility/AddressableBits.cpp
+++ b/lldb/source/Utility/AddressableBits.cpp
@@ -33,18 +33,26 @@ void AddressableBits::SetHighmemAddressableBits(
m_high_memory_addr_bits = highmem_addressing_bits;
}
+addr_t AddressableBits::AddressableBitToMask(uint32_t addressable_bits) {
+ assert(addressable_bits <= sizeof(addr_t) * 8);
+ if (addressable_bits == 64)
+ return 0; // all bits used for addressing
+ else
+ return ~((1ULL << addressable_bits) - 1);
+}
+
void AddressableBits::SetProcessMasks(Process &process) {
if (m_low_memory_addr_bits == 0 && m_high_memory_addr_bits == 0)
return;
if (m_low_memory_addr_bits != 0) {
- addr_t low_addr_mask = ~((1ULL << m_low_memory_addr_bits) - 1);
+ addr_t low_addr_mask = AddressableBitToMask(m_low_memory_addr_bits);
process.SetCodeAddressMask(low_addr_mask);
process.SetDataAddressMask(low_addr_mask);
}
if (m_high_memory_addr_bits != 0) {
- addr_t hi_addr_mask = ~((1ULL << m_high_memory_addr_bits) - 1);
+ addr_t hi_addr_mask = AddressableBitToMask(m_high_memory_addr_bits);
process.SetHighmemCodeAddressMask(hi_addr_mask);
process.SetHighmemDataAddressMask(hi_addr_mask);
}
diff --git a/lldb/test/API/python_api/process/address-masks/Makefile b/lldb/test/API/python_api/process/address-masks/Makefile
new file mode 100644
index 00000000000000..10495940055b63
--- /dev/null
+++ b/lldb/test/API/python_api/process/address-masks/Makefile
@@ -0,0 +1,3 @@
+C_SOURCES := main.c
+
+include Makefile.rules
diff --git a/lldb/test/API/python_api/process/address-masks/TestAddressMasks.py b/lldb/test/API/python_api/process/address-masks/TestAddressMasks.py
new file mode 100644
index 00000000000000..4a6a737e94f9d9
--- /dev/null
+++ b/lldb/test/API/python_api/process/address-masks/TestAddressMasks.py
@@ -0,0 +1,64 @@
+"""Test Python APIs for setting, getting, and using address masks."""
+
+import os
+import lldb
+from lldbsuite.test.decorators import *
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test import lldbutil
+
+
+class AddressMasksTestCase(TestBase):
+ NO_DEBUG_INFO_TESTCASE = True
+
+ def test_address_masks(self):
+ self.build()
+ (target, process, t, bp) = lldbutil.run_to_source_breakpoint(
+ self, "break here", lldb.SBFileSpec("main.c")
+ )
+
+ process.SetAddressableBits(lldb.eAddressMaskTypeAll, 42)
+ self.assertEqual(0x0000029500003F94, process.FixAddress(0x00265E9500003F94))
+
+ # ~((1ULL<<42)-1) == 0xfffffc0000000000
+ process.SetAddressMask(lldb.eAddressMaskTypeAll, 0xFFFFFC0000000000)
+ self.assertEqual(0x0000029500003F94, process.FixAddress(0x00265E9500003F94))
+
+ # Check that all bits can pass through unmodified
+ process.SetAddressableBits(lldb.eAddressMaskTypeAll, 64)
+ self.assertEqual(0x00265E9500003F94, process.FixAddress(0x00265E9500003F94))
+
+ process.SetAddressableBits(
+ lldb.eAddressMaskTypeAll, 42, lldb.eAddressMaskRangeLow
+ )
+ process.SetAddressableBits(
+ lldb.eAddressMaskTypeAll, 15, lldb.eAddressMaskRangeHigh
+ )
+ self.assertEqual(0x000002950001F694, process.FixAddress(0x00265E950001F694))
+ self.assertEqual(0xFFFFFFFFFFFFF694, process.FixAddress(0xFFA65E950000F694))
+
+ process.SetAddressableBits(
+ lldb.eAddressMaskTypeAll, 42, lldb.eAddressMaskRangeAll
+ )
+ self.assertEqual(0x000002950001F694, process.FixAddress(0x00265E950001F694))
+ self.assertEqual(0xFFFFFE950000F694, process.FixAddress(0xFFA65E950000F694))
+
+ process.SetAddressMask(lldb.eAddressMaskTypeCode, 0xFFFFFC0000000003)
+ self.assertEqual(0x000002950001F697, process.FixAddress(0x00265E950001F697))
+ self.assertEqual(0xFFFFFE950000F697, process.FixAddress(0xFFA65E950000F697))
+ self.assertEqual(
+ 0x000002950001F697,
+ process.FixAddress(0x00265E950001F697, lldb.eAddressMaskTypeData),
+ )
+ self.assertEqual(
+ 0x000002950001F694,
+ process.FixAddress(0x00265E950001F697, lldb.eAddressMaskTypeCode),
+ )
+
+ # The user can override whatever settings the Process thinks should be used.
+ process.SetAddressableBits(
+ lldb.eAddressMaskTypeAll, 42, lldb.eAddressMaskRangeAll
+ )
+ self.runCmd("settings set target.process.virtual-addressable-bits 15")
+ self.runCmd("settings set target.process.highmem-virtual-addressable-bits 15")
+ self.assertEqual(0x0000000000007694, process.FixAddress(0x00265E950001F694))
+ self.assertEqual(0xFFFFFFFFFFFFF694, process.FixAddress(0xFFA65E950000F694))
diff --git a/lldb/test/API/python_api/process/address-masks/main.c b/lldb/test/API/python_api/process/address-masks/main.c
new file mode 100644
index 00000000000000..f21a10a16d5a75
--- /dev/null
+++ b/lldb/test/API/python_api/process/address-masks/main.c
@@ -0,0 +1,5 @@
+#include <stdio.h>
+
+int main(int argc, char const *argv[]) {
+ puts("Hello address masking world"); // break here
+}
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