| 1 | //===-- SingleStepCheck.h ------------------------------------- -*- C++ -*-===// |
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| 2 | // |
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| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 4 | // See https://llvm.org/LICENSE.txt for license information. |
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| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 6 | // |
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| 7 | //===----------------------------------------------------------------------===// |
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| 8 | |
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| 9 | #ifndef liblldb_SingleStepCheck_H_ |
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| 10 | #define liblldb_SingleStepCheck_H_ |
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| 11 | |
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| 12 | #include <memory> |
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| 13 | #include <sched.h> |
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| 14 | #include <sys/types.h> |
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| 15 | |
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| 16 | namespace lldb_private { |
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| 17 | namespace process_linux { |
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| 18 | |
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| 19 | // arm64 linux had a bug which prevented single-stepping and watchpoints from |
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| 20 | // working on non-boot cpus, due to them being incorrectly initialized after |
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| 21 | // coming out of suspend. This issue is particularly affecting android M, which |
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| 22 | // uses suspend ("doze mode") quite aggressively. This code detects that |
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| 23 | // situation and makes single-stepping work by doing all the step operations on |
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| 24 | // the boot cpu. |
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| 25 | // |
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| 26 | // The underlying issue has been fixed in android N and linux 4.4. This code can |
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| 27 | // be removed once these systems become obsolete. |
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| 28 | |
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| 29 | #if defined(__arm64__) || defined(__aarch64__) |
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| 30 | class SingleStepWorkaround { |
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| 31 | ::pid_t m_tid; |
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| 32 | cpu_set_t m_original_set; |
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| 33 | |
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| 34 | SingleStepWorkaround(const SingleStepWorkaround &) = delete; |
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| 35 | void operator=(const SingleStepWorkaround &) = delete; |
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| 36 | |
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| 37 | public: |
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| 38 | SingleStepWorkaround(::pid_t tid, cpu_set_t original_set) |
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| 39 | : m_tid(tid), m_original_set(original_set) {} |
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| 40 | ~SingleStepWorkaround(); |
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| 41 | |
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| 42 | static std::unique_ptr<SingleStepWorkaround> Get(::pid_t tid); |
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| 43 | }; |
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| 44 | #else |
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| 45 | class SingleStepWorkaround { |
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| 46 | public: |
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| 47 | static std::unique_ptr<SingleStepWorkaround> Get(::pid_t tid) { |
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| 48 | return nullptr; |
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| 49 | } |
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| 50 | }; |
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| 51 | #endif |
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| 52 | |
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| 53 | } // end namespace process_linux |
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| 54 | } // end namespace lldb_private |
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| 55 | |
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| 56 | #endif // #ifndef liblldb_SingleStepCheck_H_ |
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| 57 | |
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