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MemoryTagManager.h
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1 //===-- MemoryTagManager.h --------------------------------------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #ifndef LLDB_TARGET_MEMORYTAGMANAGER_H
10 #define LLDB_TARGET_MEMORYTAGMANAGER_H
11 
13 #include "lldb/Utility/RangeMap.h"
14 #include "lldb/lldb-private.h"
15 #include "llvm/Support/Error.h"
16 
17 namespace lldb_private {
18 
19 // This interface allows high level commands to handle memory tags
20 // in a generic way.
21 //
22 // Definitions:
23 // logical tag - the tag stored in a pointer
24 // allocation tag - the tag stored in hardware
25 // (e.g. special memory, cache line bits)
26 // granule - number of bytes of memory a single tag applies to
27 
29 public:
31 
32  // Extract the logical tag from a pointer
33  // The tag is returned as a plain value, with any shifts removed.
34  // For example if your tags are stored in bits 56-60 then the logical tag
35  // you get will have been shifted down 56 before being returned.
36  virtual lldb::addr_t GetLogicalTag(lldb::addr_t addr) const = 0;
37 
38  // Remove tag bits from a pointer
39  virtual lldb::addr_t RemoveTagBits(lldb::addr_t addr) const = 0;
40 
41  // Return the difference between two addresses, ignoring any logical tags they
42  // have. If your tags are just part of a larger set of ignored bits, this
43  // should ignore all those bits.
44  virtual ptrdiff_t AddressDiff(lldb::addr_t addr1,
45  lldb::addr_t addr2) const = 0;
46 
47  // Return the number of bytes a single tag covers
48  virtual lldb::addr_t GetGranuleSize() const = 0;
49 
50  // Align an address range to granule boundaries.
51  // So that reading memory tags for the new range returns
52  // tags that will cover the original range.
53  //
54  // Say your granules are 16 bytes and you want
55  // tags for 16 bytes of memory starting from address 8.
56  // 1 granule isn't enough because it only covers addresses
57  // 0-16, we want addresses 8-24. So the range must be
58  // expanded to 2 granules.
59  virtual TagRange ExpandToGranule(TagRange range) const = 0;
60 
61  // Given a range addr to end_addr, check that:
62  // * end_addr >= addr (when memory tags are removed)
63  // * the granule aligned range is completely covered by tagged memory
64  // (which may include one or more memory regions)
65  //
66  // If so, return a modified range which will have been expanded
67  // to be granule aligned. Otherwise return an error.
68  //
69  // Tags in the input addresses are ignored and not present
70  // in the returned range.
71  virtual llvm::Expected<TagRange> MakeTaggedRange(
72  lldb::addr_t addr, lldb::addr_t end_addr,
73  const lldb_private::MemoryRegionInfos &memory_regions) const = 0;
74 
75  // Given a range addr to end_addr, check that end_addr >= addr.
76  // If it is not, return an error saying so.
77  // Otherwise, granule align it and return a set of ranges representing
78  // subsections of the aligned range that have memory tagging enabled.
79  //
80  // Basically a sparse version of MakeTaggedRange. Use this when you
81  // want to know which parts of a larger range have memory tagging.
82  //
83  // Regions in memory_regions should be sorted in ascending order and
84  // not overlap. (use Process GetMemoryRegions)
85  //
86  // Tags in the input addresses are ignored and not present
87  // in the returned ranges.
88  virtual llvm::Expected<std::vector<TagRange>> MakeTaggedRanges(
89  lldb::addr_t addr, lldb::addr_t end_addr,
90  const lldb_private::MemoryRegionInfos &memory_regions) const = 0;
91 
92  // Return the type value to use in GDB protocol qMemTags packets to read
93  // allocation tags. This is named "Allocation" specifically because the spec
94  // allows for logical tags to be read the same way, though we do not use that.
95  //
96  // This value is unique within a given architecture. Meaning that different
97  // tagging schemes within the same architecture should use unique values,
98  // but other architectures can overlap those values.
99  virtual int32_t GetAllocationTagType() const = 0;
100 
101  // Return the number of bytes a single tag will be packed into during
102  // transport. For example an MTE tag is 4 bits but occupies 1 byte during
103  // transport.
104  virtual size_t GetTagSizeInBytes() const = 0;
105 
106  // Unpack tags from their stored format (e.g. gdb qMemTags data) into seperate
107  // tags.
108  //
109  // Checks that each tag is within the expected value range and if granules is
110  // set to non-zero, that the number of tags found matches the number of
111  // granules we expected to cover.
112  virtual llvm::Expected<std::vector<lldb::addr_t>>
113  UnpackTagsData(const std::vector<uint8_t> &tags,
114  size_t granules = 0) const = 0;
115 
116  // Unpack tags from a corefile segment containing compressed tags
117  // (compression that may be different from the one used for GDB transport).
118  //
119  // This method asumes that:
120  // * addr and len have been granule aligned by a tag manager
121  // * addr >= tag_segment_virtual_address
122  //
123  // 'reader' will always be a wrapper around a CoreFile in real use
124  // but allows testing without having to mock a CoreFile.
125  typedef std::function<size_t(lldb::offset_t, size_t, void *)> CoreReaderFn;
126  std::vector<lldb::addr_t> virtual UnpackTagsFromCoreFileSegment(
127  CoreReaderFn reader, lldb::addr_t tag_segment_virtual_address,
128  lldb::addr_t tag_segment_data_address, lldb::addr_t addr,
129  size_t len) const = 0;
130 
131  // Pack uncompressed tags into their storage format (e.g. for gdb QMemTags).
132  // Checks that each tag is within the expected value range.
133  // We do not check the number of tags or range they apply to because
134  // it is up to the remote to repeat them as needed.
135  virtual llvm::Expected<std::vector<uint8_t>>
136  PackTags(const std::vector<lldb::addr_t> &tags) const = 0;
137 
138  // Take a set of tags and repeat them as much as needed to cover the given
139  // range. We assume that this range has been previously expanded/aligned to
140  // granules. (this method is used by lldb-server to implement QMemTags
141  // packet handling)
142  //
143  // If the range is empty, zero tags are returned.
144  // If the range is not empty and...
145  // * there are no tags, an error is returned.
146  // * there are fewer tags than granules, the tags are repeated to fill the
147  // range.
148  // * there are more tags than granules, only the tags required to cover
149  // the range are returned.
150  //
151  // When repeating tags it will not always return a multiple of the original
152  // list. For example if your range is 3 granules and your tags are 1 and 2.
153  // You will get tags 1, 2 and 1 returned. Rather than getting 1, 2, 1, 2,
154  // which would be one too many tags for the range.
155  //
156  // A single tag will just be repeated as you'd expected. Tag 1 over 3 granules
157  // would return 1, 1, 1.
158  virtual llvm::Expected<std::vector<lldb::addr_t>>
159  RepeatTagsForRange(const std::vector<lldb::addr_t> &tags,
160  TagRange range) const = 0;
161 
162  virtual ~MemoryTagManager() = default;
163 };
164 
165 } // namespace lldb_private
166 
167 #endif // LLDB_TARGET_MEMORYTAGMANAGER_H
lldb_private::MemoryTagManager::UnpackTagsFromCoreFileSegment
virtual std::vector< lldb::addr_t > UnpackTagsFromCoreFileSegment(CoreReaderFn reader, lldb::addr_t tag_segment_virtual_address, lldb::addr_t tag_segment_data_address, lldb::addr_t addr, size_t len) const =0
lldb::offset_t
uint64_t offset_t
Definition: lldb-types.h:87
lldb_private::MemoryTagManager::MakeTaggedRange
virtual llvm::Expected< TagRange > MakeTaggedRange(lldb::addr_t addr, lldb::addr_t end_addr, const lldb_private::MemoryRegionInfos &memory_regions) const =0
lldb::addr_t
uint64_t addr_t
Definition: lldb-types.h:83
RangeMap.h
lldb_private::MemoryTagManager::GetLogicalTag
virtual lldb::addr_t GetLogicalTag(lldb::addr_t addr) const =0
lldb_private::MemoryTagManager
Definition: MemoryTagManager.h:28
MemoryRegionInfo.h
lldb_private::MemoryRegionInfos
Definition: MemoryRegionInfo.h:172
lldb_private::Range< lldb::addr_t, lldb::addr_t >
lldb_private::MemoryTagManager::UnpackTagsData
virtual llvm::Expected< std::vector< lldb::addr_t > > UnpackTagsData(const std::vector< uint8_t > &tags, size_t granules=0) const =0
lldb_private::MemoryTagManager::MakeTaggedRanges
virtual llvm::Expected< std::vector< TagRange > > MakeTaggedRanges(lldb::addr_t addr, lldb::addr_t end_addr, const lldb_private::MemoryRegionInfos &memory_regions) const =0
lldb_private::MemoryTagManager::GetAllocationTagType
virtual int32_t GetAllocationTagType() const =0
lldb_private::MemoryTagManager::RemoveTagBits
virtual lldb::addr_t RemoveTagBits(lldb::addr_t addr) const =0
lldb-private.h
lldb_private::MemoryTagManager::GetTagSizeInBytes
virtual size_t GetTagSizeInBytes() const =0
lldb_private::MemoryTagManager::CoreReaderFn
std::function< size_t(lldb::offset_t, size_t, void *)> CoreReaderFn
Definition: MemoryTagManager.h:125
lldb_private::MemoryTagManager::GetGranuleSize
virtual lldb::addr_t GetGranuleSize() const =0
lldb_private
A class that represents a running process on the host machine.
Definition: SBCommandInterpreterRunOptions.h:16
lldb_private::MemoryTagManager::PackTags
virtual llvm::Expected< std::vector< uint8_t > > PackTags(const std::vector< lldb::addr_t > &tags) const =0
lldb_private::MemoryTagManager::AddressDiff
virtual ptrdiff_t AddressDiff(lldb::addr_t addr1, lldb::addr_t addr2) const =0
lldb_private::MemoryTagManager::RepeatTagsForRange
virtual llvm::Expected< std::vector< lldb::addr_t > > RepeatTagsForRange(const std::vector< lldb::addr_t > &tags, TagRange range) const =0
lldb_private::MemoryTagManager::ExpandToGranule
virtual TagRange ExpandToGranule(TagRange range) const =0
lldb_private::MemoryTagManager::~MemoryTagManager
virtual ~MemoryTagManager()=default
lldb_private::MemoryTagManager::TagRange
Range< lldb::addr_t, lldb::addr_t > TagRange
Definition: MemoryTagManager.h:30