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147 lines
4.8 KiB
147 lines
4.8 KiB
/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */ |
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#ifndef _UAPI_LINUX_RSEQ_H |
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#define _UAPI_LINUX_RSEQ_H |
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/* |
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* linux/rseq.h |
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* |
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* Restartable sequences system call API |
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* |
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* Copyright (c) 2015-2018 Mathieu Desnoyers <[email protected]> |
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*/ |
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#include <linux/types.h> |
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#include <asm/byteorder.h> |
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enum rseq_cpu_id_state { |
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RSEQ_CPU_ID_UNINITIALIZED = -1, |
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RSEQ_CPU_ID_REGISTRATION_FAILED = -2, |
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}; |
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enum rseq_flags { |
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RSEQ_FLAG_UNREGISTER = (1 << 0), |
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}; |
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enum rseq_cs_flags_bit { |
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RSEQ_CS_FLAG_NO_RESTART_ON_PREEMPT_BIT = 0, |
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RSEQ_CS_FLAG_NO_RESTART_ON_SIGNAL_BIT = 1, |
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RSEQ_CS_FLAG_NO_RESTART_ON_MIGRATE_BIT = 2, |
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}; |
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enum rseq_cs_flags { |
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RSEQ_CS_FLAG_NO_RESTART_ON_PREEMPT = |
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(1U << RSEQ_CS_FLAG_NO_RESTART_ON_PREEMPT_BIT), |
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RSEQ_CS_FLAG_NO_RESTART_ON_SIGNAL = |
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(1U << RSEQ_CS_FLAG_NO_RESTART_ON_SIGNAL_BIT), |
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RSEQ_CS_FLAG_NO_RESTART_ON_MIGRATE = |
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(1U << RSEQ_CS_FLAG_NO_RESTART_ON_MIGRATE_BIT), |
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}; |
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/* |
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* struct rseq_cs is aligned on 4 * 8 bytes to ensure it is always |
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* contained within a single cache-line. It is usually declared as |
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* link-time constant data. |
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*/ |
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struct rseq_cs { |
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/* Version of this structure. */ |
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__u32 version; |
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/* enum rseq_cs_flags */ |
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__u32 flags; |
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__u64 start_ip; |
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/* Offset from start_ip. */ |
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__u64 post_commit_offset; |
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__u64 abort_ip; |
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} __attribute__((aligned(4 * sizeof(__u64)))); |
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/* |
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* struct rseq is aligned on 4 * 8 bytes to ensure it is always |
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* contained within a single cache-line. |
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* |
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* A single struct rseq per thread is allowed. |
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*/ |
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struct rseq { |
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/* |
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* Restartable sequences cpu_id_start field. Updated by the |
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* kernel. Read by user-space with single-copy atomicity |
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* semantics. This field should only be read by the thread which |
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* registered this data structure. Aligned on 32-bit. Always |
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* contains a value in the range of possible CPUs, although the |
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* value may not be the actual current CPU (e.g. if rseq is not |
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* initialized). This CPU number value should always be compared |
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* against the value of the cpu_id field before performing a rseq |
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* commit or returning a value read from a data structure indexed |
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* using the cpu_id_start value. |
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*/ |
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__u32 cpu_id_start; |
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/* |
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* Restartable sequences cpu_id field. Updated by the kernel. |
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* Read by user-space with single-copy atomicity semantics. This |
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* field should only be read by the thread which registered this |
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* data structure. Aligned on 32-bit. Values |
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* RSEQ_CPU_ID_UNINITIALIZED and RSEQ_CPU_ID_REGISTRATION_FAILED |
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* have a special semantic: the former means "rseq uninitialized", |
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* and latter means "rseq initialization failed". This value is |
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* meant to be read within rseq critical sections and compared |
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* with the cpu_id_start value previously read, before performing |
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* the commit instruction, or read and compared with the |
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* cpu_id_start value before returning a value loaded from a data |
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* structure indexed using the cpu_id_start value. |
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*/ |
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__u32 cpu_id; |
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/* |
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* Restartable sequences rseq_cs field. |
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* |
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* Contains NULL when no critical section is active for the current |
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* thread, or holds a pointer to the currently active struct rseq_cs. |
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* |
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* Updated by user-space, which sets the address of the currently |
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* active rseq_cs at the beginning of assembly instruction sequence |
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* block, and set to NULL by the kernel when it restarts an assembly |
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* instruction sequence block, as well as when the kernel detects that |
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* it is preempting or delivering a signal outside of the range |
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* targeted by the rseq_cs. Also needs to be set to NULL by user-space |
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* before reclaiming memory that contains the targeted struct rseq_cs. |
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* |
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* Read and set by the kernel. Set by user-space with single-copy |
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* atomicity semantics. This field should only be updated by the |
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* thread which registered this data structure. Aligned on 64-bit. |
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*/ |
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union { |
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__u64 ptr64; |
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#ifdef __LP64__ |
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__u64 ptr; |
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#else |
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struct { |
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#if (defined(__BYTE_ORDER) && (__BYTE_ORDER == __BIG_ENDIAN)) || defined(__BIG_ENDIAN) |
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__u32 padding; /* Initialized to zero. */ |
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__u32 ptr32; |
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#else /* LITTLE */ |
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__u32 ptr32; |
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__u32 padding; /* Initialized to zero. */ |
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#endif /* ENDIAN */ |
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} ptr; |
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#endif |
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} rseq_cs; |
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/* |
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* Restartable sequences flags field. |
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* |
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* This field should only be updated by the thread which |
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* registered this data structure. Read by the kernel. |
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* Mainly used for single-stepping through rseq critical sections |
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* with debuggers. |
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* |
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* - RSEQ_CS_FLAG_NO_RESTART_ON_PREEMPT |
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* Inhibit instruction sequence block restart on preemption |
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* for this thread. |
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* - RSEQ_CS_FLAG_NO_RESTART_ON_SIGNAL |
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* Inhibit instruction sequence block restart on signal |
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* delivery for this thread. |
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* - RSEQ_CS_FLAG_NO_RESTART_ON_MIGRATE |
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* Inhibit instruction sequence block restart on migration for |
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* this thread. |
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*/ |
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__u32 flags; |
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} __attribute__((aligned(4 * sizeof(__u64)))); |
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#endif /* _UAPI_LINUX_RSEQ_H */
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