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Diffstat (limited to 'tools/testing/selftests/rseq/rseq-abi.h')
| -rw-r--r-- | tools/testing/selftests/rseq/rseq-abi.h | 173 |
1 files changed, 173 insertions, 0 deletions
diff --git a/tools/testing/selftests/rseq/rseq-abi.h b/tools/testing/selftests/rseq/rseq-abi.h new file mode 100644 index 0000000000..fb4ec8a75d --- /dev/null +++ b/tools/testing/selftests/rseq/rseq-abi.h @@ -0,0 +1,173 @@ +/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */ +#ifndef _RSEQ_ABI_H +#define _RSEQ_ABI_H + +/* + * rseq-abi.h + * + * Restartable sequences system call API + * + * Copyright (c) 2015-2022 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> + */ + +#include <linux/types.h> +#include <asm/byteorder.h> + +enum rseq_abi_cpu_id_state { + RSEQ_ABI_CPU_ID_UNINITIALIZED = -1, + RSEQ_ABI_CPU_ID_REGISTRATION_FAILED = -2, +}; + +enum rseq_abi_flags { + RSEQ_ABI_FLAG_UNREGISTER = (1 << 0), +}; + +enum rseq_abi_cs_flags_bit { + RSEQ_ABI_CS_FLAG_NO_RESTART_ON_PREEMPT_BIT = 0, + RSEQ_ABI_CS_FLAG_NO_RESTART_ON_SIGNAL_BIT = 1, + RSEQ_ABI_CS_FLAG_NO_RESTART_ON_MIGRATE_BIT = 2, +}; + +enum rseq_abi_cs_flags { + RSEQ_ABI_CS_FLAG_NO_RESTART_ON_PREEMPT = + (1U << RSEQ_ABI_CS_FLAG_NO_RESTART_ON_PREEMPT_BIT), + RSEQ_ABI_CS_FLAG_NO_RESTART_ON_SIGNAL = + (1U << RSEQ_ABI_CS_FLAG_NO_RESTART_ON_SIGNAL_BIT), + RSEQ_ABI_CS_FLAG_NO_RESTART_ON_MIGRATE = + (1U << RSEQ_ABI_CS_FLAG_NO_RESTART_ON_MIGRATE_BIT), +}; + +/* + * struct rseq_abi_cs is aligned on 4 * 8 bytes to ensure it is always + * contained within a single cache-line. It is usually declared as + * link-time constant data. + */ +struct rseq_abi_cs { + /* Version of this structure. */ + __u32 version; + /* enum rseq_abi_cs_flags */ + __u32 flags; + __u64 start_ip; + /* Offset from start_ip. */ + __u64 post_commit_offset; + __u64 abort_ip; +} __attribute__((aligned(4 * sizeof(__u64)))); + +/* + * struct rseq_abi is aligned on 4 * 8 bytes to ensure it is always + * contained within a single cache-line. + * + * A single struct rseq_abi per thread is allowed. + */ +struct rseq_abi { + /* + * Restartable sequences cpu_id_start field. Updated by the + * kernel. Read by user-space with single-copy atomicity + * semantics. This field should only be read by the thread which + * registered this data structure. Aligned on 32-bit. Always + * contains a value in the range of possible CPUs, although the + * value may not be the actual current CPU (e.g. if rseq is not + * initialized). This CPU number value should always be compared + * against the value of the cpu_id field before performing a rseq + * commit or returning a value read from a data structure indexed + * using the cpu_id_start value. + */ + __u32 cpu_id_start; + /* + * Restartable sequences cpu_id field. Updated by the kernel. + * Read by user-space with single-copy atomicity semantics. This + * field should only be read by the thread which registered this + * data structure. Aligned on 32-bit. Values + * RSEQ_CPU_ID_UNINITIALIZED and RSEQ_CPU_ID_REGISTRATION_FAILED + * have a special semantic: the former means "rseq uninitialized", + * and latter means "rseq initialization failed". This value is + * meant to be read within rseq critical sections and compared + * with the cpu_id_start value previously read, before performing + * the commit instruction, or read and compared with the + * cpu_id_start value before returning a value loaded from a data + * structure indexed using the cpu_id_start value. + */ + __u32 cpu_id; + /* + * Restartable sequences rseq_cs field. + * + * Contains NULL when no critical section is active for the current + * thread, or holds a pointer to the currently active struct rseq_cs. + * + * Updated by user-space, which sets the address of the currently + * active rseq_cs at the beginning of assembly instruction sequence + * block, and set to NULL by the kernel when it restarts an assembly + * instruction sequence block, as well as when the kernel detects that + * it is preempting or delivering a signal outside of the range + * targeted by the rseq_cs. Also needs to be set to NULL by user-space + * before reclaiming memory that contains the targeted struct rseq_cs. + * + * Read and set by the kernel. Set by user-space with single-copy + * atomicity semantics. This field should only be updated by the + * thread which registered this data structure. Aligned on 64-bit. + */ + union { + __u64 ptr64; + + /* + * The "arch" field provides architecture accessor for + * the ptr field based on architecture pointer size and + * endianness. + */ + struct { +#ifdef __LP64__ + __u64 ptr; +#elif defined(__BYTE_ORDER) ? (__BYTE_ORDER == __BIG_ENDIAN) : defined(__BIG_ENDIAN) + __u32 padding; /* Initialized to zero. */ + __u32 ptr; +#else + __u32 ptr; + __u32 padding; /* Initialized to zero. */ +#endif + } arch; + } rseq_cs; + + /* + * Restartable sequences flags field. + * + * This field should only be updated by the thread which + * registered this data structure. Read by the kernel. + * Mainly used for single-stepping through rseq critical sections + * with debuggers. + * + * - RSEQ_ABI_CS_FLAG_NO_RESTART_ON_PREEMPT + * Inhibit instruction sequence block restart on preemption + * for this thread. + * - RSEQ_ABI_CS_FLAG_NO_RESTART_ON_SIGNAL + * Inhibit instruction sequence block restart on signal + * delivery for this thread. + * - RSEQ_ABI_CS_FLAG_NO_RESTART_ON_MIGRATE + * Inhibit instruction sequence block restart on migration for + * this thread. + */ + __u32 flags; + + /* + * Restartable sequences node_id field. Updated by the kernel. Read by + * user-space with single-copy atomicity semantics. This field should + * only be read by the thread which registered this data structure. + * Aligned on 32-bit. Contains the current NUMA node ID. + */ + __u32 node_id; + + /* + * Restartable sequences mm_cid field. Updated by the kernel. Read by + * user-space with single-copy atomicity semantics. This field should + * only be read by the thread which registered this data structure. + * Aligned on 32-bit. Contains the current thread's concurrency ID + * (allocated uniquely within a memory map). + */ + __u32 mm_cid; + + /* + * Flexible array member at end of structure, after last feature field. + */ + char end[]; +} __attribute__((aligned(4 * sizeof(__u64)))); + +#endif /* _RSEQ_ABI_H */ |