148 строки
4.8 KiB
C
148 строки
4.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
|
|
#ifndef _UAPI_LINUX_RSEQ_H
|
|
#define _UAPI_LINUX_RSEQ_H
|
|
|
|
/*
|
|
* linux/rseq.h
|
|
*
|
|
* Restartable sequences system call API
|
|
*
|
|
* Copyright (c) 2015-2018 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
|
|
*/
|
|
|
|
#include <linux/types.h>
|
|
#include <asm/byteorder.h>
|
|
|
|
enum rseq_cpu_id_state {
|
|
RSEQ_CPU_ID_UNINITIALIZED = -1,
|
|
RSEQ_CPU_ID_REGISTRATION_FAILED = -2,
|
|
};
|
|
|
|
enum rseq_flags {
|
|
RSEQ_FLAG_UNREGISTER = (1 << 0),
|
|
};
|
|
|
|
enum rseq_cs_flags_bit {
|
|
RSEQ_CS_FLAG_NO_RESTART_ON_PREEMPT_BIT = 0,
|
|
RSEQ_CS_FLAG_NO_RESTART_ON_SIGNAL_BIT = 1,
|
|
RSEQ_CS_FLAG_NO_RESTART_ON_MIGRATE_BIT = 2,
|
|
};
|
|
|
|
enum rseq_cs_flags {
|
|
RSEQ_CS_FLAG_NO_RESTART_ON_PREEMPT =
|
|
(1U << RSEQ_CS_FLAG_NO_RESTART_ON_PREEMPT_BIT),
|
|
RSEQ_CS_FLAG_NO_RESTART_ON_SIGNAL =
|
|
(1U << RSEQ_CS_FLAG_NO_RESTART_ON_SIGNAL_BIT),
|
|
RSEQ_CS_FLAG_NO_RESTART_ON_MIGRATE =
|
|
(1U << RSEQ_CS_FLAG_NO_RESTART_ON_MIGRATE_BIT),
|
|
};
|
|
|
|
/*
|
|
* struct rseq_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_cs {
|
|
/* Version of this structure. */
|
|
__u32 version;
|
|
/* enum rseq_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 is aligned on 4 * 8 bytes to ensure it is always
|
|
* contained within a single cache-line.
|
|
*
|
|
* A single struct rseq per thread is allowed.
|
|
*/
|
|
struct rseq {
|
|
/*
|
|
* 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;
|
|
#ifdef __LP64__
|
|
__u64 ptr;
|
|
#else
|
|
struct {
|
|
#if (defined(__BYTE_ORDER) && (__BYTE_ORDER == __BIG_ENDIAN)) || defined(__BIG_ENDIAN)
|
|
__u32 padding; /* Initialized to zero. */
|
|
__u32 ptr32;
|
|
#else /* LITTLE */
|
|
__u32 ptr32;
|
|
__u32 padding; /* Initialized to zero. */
|
|
#endif /* ENDIAN */
|
|
} ptr;
|
|
#endif
|
|
} 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_CS_FLAG_NO_RESTART_ON_PREEMPT
|
|
* Inhibit instruction sequence block restart on preemption
|
|
* for this thread.
|
|
* - RSEQ_CS_FLAG_NO_RESTART_ON_SIGNAL
|
|
* Inhibit instruction sequence block restart on signal
|
|
* delivery for this thread.
|
|
* - RSEQ_CS_FLAG_NO_RESTART_ON_MIGRATE
|
|
* Inhibit instruction sequence block restart on migration for
|
|
* this thread.
|
|
*/
|
|
__u32 flags;
|
|
} __attribute__((aligned(4 * sizeof(__u64))));
|
|
|
|
#endif /* _UAPI_LINUX_RSEQ_H */
|