385 lines
10 KiB
C
385 lines
10 KiB
C
/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
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/*
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* rseq.h
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*
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* (C) Copyright 2016-2018 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
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*/
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#ifndef RSEQ_H
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#define RSEQ_H
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#include <stdint.h>
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#include <stdbool.h>
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#include <pthread.h>
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#include <signal.h>
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#include <sched.h>
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#include <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <stddef.h>
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#include "rseq-abi.h"
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#include "compiler.h"
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#ifndef rseq_sizeof_field
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#define rseq_sizeof_field(TYPE, MEMBER) sizeof((((TYPE *)0)->MEMBER))
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#endif
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#ifndef rseq_offsetofend
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#define rseq_offsetofend(TYPE, MEMBER) \
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(offsetof(TYPE, MEMBER) + rseq_sizeof_field(TYPE, MEMBER))
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#endif
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/*
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* Empty code injection macros, override when testing.
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* It is important to consider that the ASM injection macros need to be
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* fully reentrant (e.g. do not modify the stack).
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*/
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#ifndef RSEQ_INJECT_ASM
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#define RSEQ_INJECT_ASM(n)
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#endif
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#ifndef RSEQ_INJECT_C
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#define RSEQ_INJECT_C(n)
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#endif
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#ifndef RSEQ_INJECT_INPUT
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#define RSEQ_INJECT_INPUT
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#endif
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#ifndef RSEQ_INJECT_CLOBBER
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#define RSEQ_INJECT_CLOBBER
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#endif
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#ifndef RSEQ_INJECT_FAILED
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#define RSEQ_INJECT_FAILED
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#endif
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#include "rseq-thread-pointer.h"
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/* Offset from the thread pointer to the rseq area. */
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extern ptrdiff_t rseq_offset;
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/*
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* Size of the registered rseq area. 0 if the registration was
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* unsuccessful.
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*/
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extern unsigned int rseq_size;
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/* Flags used during rseq registration. */
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extern unsigned int rseq_flags;
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/*
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* rseq feature size supported by the kernel. 0 if the registration was
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* unsuccessful.
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*/
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extern unsigned int rseq_feature_size;
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enum rseq_mo {
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RSEQ_MO_RELAXED = 0,
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RSEQ_MO_CONSUME = 1, /* Unused */
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RSEQ_MO_ACQUIRE = 2, /* Unused */
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RSEQ_MO_RELEASE = 3,
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RSEQ_MO_ACQ_REL = 4, /* Unused */
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RSEQ_MO_SEQ_CST = 5, /* Unused */
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};
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enum rseq_percpu_mode {
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RSEQ_PERCPU_CPU_ID = 0,
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RSEQ_PERCPU_MM_CID = 1,
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};
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static inline struct rseq_abi *rseq_get_abi(void)
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{
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return (struct rseq_abi *) ((uintptr_t) rseq_thread_pointer() + rseq_offset);
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}
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#define rseq_likely(x) __builtin_expect(!!(x), 1)
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#define rseq_unlikely(x) __builtin_expect(!!(x), 0)
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#define rseq_barrier() __asm__ __volatile__("" : : : "memory")
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#define RSEQ_ACCESS_ONCE(x) (*(__volatile__ __typeof__(x) *)&(x))
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#define RSEQ_WRITE_ONCE(x, v) __extension__ ({ RSEQ_ACCESS_ONCE(x) = (v); })
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#define RSEQ_READ_ONCE(x) RSEQ_ACCESS_ONCE(x)
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#define __rseq_str_1(x) #x
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#define __rseq_str(x) __rseq_str_1(x)
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#define rseq_log(fmt, args...) \
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fprintf(stderr, fmt "(in %s() at " __FILE__ ":" __rseq_str(__LINE__)"\n", \
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## args, __func__)
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#define rseq_bug(fmt, args...) \
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do { \
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rseq_log(fmt, ##args); \
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abort(); \
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} while (0)
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#if defined(__x86_64__) || defined(__i386__)
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#include <rseq-x86.h>
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#elif defined(__ARMEL__)
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#include <rseq-arm.h>
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#elif defined (__AARCH64EL__)
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#include <rseq-arm64.h>
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#elif defined(__PPC__)
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#include <rseq-ppc.h>
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#elif defined(__mips__)
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#include <rseq-mips.h>
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#elif defined(__s390__)
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#include <rseq-s390.h>
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#elif defined(__riscv)
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#include <rseq-riscv.h>
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#else
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#error unsupported target
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#endif
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/*
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* Register rseq for the current thread. This needs to be called once
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* by any thread which uses restartable sequences, before they start
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* using restartable sequences, to ensure restartable sequences
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* succeed. A restartable sequence executed from a non-registered
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* thread will always fail.
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*/
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int rseq_register_current_thread(void);
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/*
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* Unregister rseq for current thread.
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*/
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int rseq_unregister_current_thread(void);
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/*
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* Restartable sequence fallback for reading the current CPU number.
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*/
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int32_t rseq_fallback_current_cpu(void);
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/*
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* Restartable sequence fallback for reading the current node number.
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*/
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int32_t rseq_fallback_current_node(void);
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/*
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* Values returned can be either the current CPU number, -1 (rseq is
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* uninitialized), or -2 (rseq initialization has failed).
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*/
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static inline int32_t rseq_current_cpu_raw(void)
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{
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return RSEQ_ACCESS_ONCE(rseq_get_abi()->cpu_id);
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}
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/*
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* Returns a possible CPU number, which is typically the current CPU.
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* The returned CPU number can be used to prepare for an rseq critical
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* section, which will confirm whether the cpu number is indeed the
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* current one, and whether rseq is initialized.
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*
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* The CPU number returned by rseq_cpu_start should always be validated
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* by passing it to a rseq asm sequence, or by comparing it to the
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* return value of rseq_current_cpu_raw() if the rseq asm sequence
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* does not need to be invoked.
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*/
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static inline uint32_t rseq_cpu_start(void)
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{
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return RSEQ_ACCESS_ONCE(rseq_get_abi()->cpu_id_start);
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}
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static inline uint32_t rseq_current_cpu(void)
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{
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int32_t cpu;
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cpu = rseq_current_cpu_raw();
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if (rseq_unlikely(cpu < 0))
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cpu = rseq_fallback_current_cpu();
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return cpu;
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}
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static inline bool rseq_node_id_available(void)
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{
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return (int) rseq_feature_size >= rseq_offsetofend(struct rseq_abi, node_id);
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}
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/*
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* Current NUMA node number.
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*/
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static inline uint32_t rseq_current_node_id(void)
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{
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assert(rseq_node_id_available());
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return RSEQ_ACCESS_ONCE(rseq_get_abi()->node_id);
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}
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static inline bool rseq_mm_cid_available(void)
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{
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return (int) rseq_feature_size >= rseq_offsetofend(struct rseq_abi, mm_cid);
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}
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static inline uint32_t rseq_current_mm_cid(void)
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{
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return RSEQ_ACCESS_ONCE(rseq_get_abi()->mm_cid);
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}
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static inline void rseq_clear_rseq_cs(void)
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{
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RSEQ_WRITE_ONCE(rseq_get_abi()->rseq_cs.arch.ptr, 0);
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}
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/*
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* rseq_prepare_unload() should be invoked by each thread executing a rseq
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* critical section at least once between their last critical section and
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* library unload of the library defining the rseq critical section (struct
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* rseq_cs) or the code referred to by the struct rseq_cs start_ip and
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* post_commit_offset fields. This also applies to use of rseq in code
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* generated by JIT: rseq_prepare_unload() should be invoked at least once by
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* each thread executing a rseq critical section before reclaim of the memory
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* holding the struct rseq_cs or reclaim of the code pointed to by struct
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* rseq_cs start_ip and post_commit_offset fields.
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*/
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static inline void rseq_prepare_unload(void)
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{
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rseq_clear_rseq_cs();
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}
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static inline __attribute__((always_inline))
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int rseq_cmpeqv_storev(enum rseq_mo rseq_mo, enum rseq_percpu_mode percpu_mode,
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intptr_t *v, intptr_t expect,
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intptr_t newv, int cpu)
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{
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if (rseq_mo != RSEQ_MO_RELAXED)
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return -1;
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switch (percpu_mode) {
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case RSEQ_PERCPU_CPU_ID:
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return rseq_cmpeqv_storev_relaxed_cpu_id(v, expect, newv, cpu);
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case RSEQ_PERCPU_MM_CID:
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return rseq_cmpeqv_storev_relaxed_mm_cid(v, expect, newv, cpu);
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}
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return -1;
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}
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/*
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* Compare @v against @expectnot. When it does _not_ match, load @v
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* into @load, and store the content of *@v + voffp into @v.
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*/
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static inline __attribute__((always_inline))
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int rseq_cmpnev_storeoffp_load(enum rseq_mo rseq_mo, enum rseq_percpu_mode percpu_mode,
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intptr_t *v, intptr_t expectnot, long voffp, intptr_t *load,
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int cpu)
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{
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if (rseq_mo != RSEQ_MO_RELAXED)
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return -1;
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switch (percpu_mode) {
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case RSEQ_PERCPU_CPU_ID:
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return rseq_cmpnev_storeoffp_load_relaxed_cpu_id(v, expectnot, voffp, load, cpu);
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case RSEQ_PERCPU_MM_CID:
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return rseq_cmpnev_storeoffp_load_relaxed_mm_cid(v, expectnot, voffp, load, cpu);
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}
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return -1;
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}
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static inline __attribute__((always_inline))
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int rseq_addv(enum rseq_mo rseq_mo, enum rseq_percpu_mode percpu_mode,
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intptr_t *v, intptr_t count, int cpu)
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{
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if (rseq_mo != RSEQ_MO_RELAXED)
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return -1;
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switch (percpu_mode) {
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case RSEQ_PERCPU_CPU_ID:
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return rseq_addv_relaxed_cpu_id(v, count, cpu);
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case RSEQ_PERCPU_MM_CID:
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return rseq_addv_relaxed_mm_cid(v, count, cpu);
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}
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return -1;
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}
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#ifdef RSEQ_ARCH_HAS_OFFSET_DEREF_ADDV
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/*
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* pval = *(ptr+off)
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* *pval += inc;
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*/
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static inline __attribute__((always_inline))
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int rseq_offset_deref_addv(enum rseq_mo rseq_mo, enum rseq_percpu_mode percpu_mode,
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intptr_t *ptr, long off, intptr_t inc, int cpu)
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{
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if (rseq_mo != RSEQ_MO_RELAXED)
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return -1;
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switch (percpu_mode) {
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case RSEQ_PERCPU_CPU_ID:
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return rseq_offset_deref_addv_relaxed_cpu_id(ptr, off, inc, cpu);
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case RSEQ_PERCPU_MM_CID:
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return rseq_offset_deref_addv_relaxed_mm_cid(ptr, off, inc, cpu);
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}
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return -1;
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}
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#endif
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static inline __attribute__((always_inline))
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int rseq_cmpeqv_trystorev_storev(enum rseq_mo rseq_mo, enum rseq_percpu_mode percpu_mode,
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intptr_t *v, intptr_t expect,
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intptr_t *v2, intptr_t newv2,
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intptr_t newv, int cpu)
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{
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switch (rseq_mo) {
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case RSEQ_MO_RELAXED:
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switch (percpu_mode) {
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case RSEQ_PERCPU_CPU_ID:
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return rseq_cmpeqv_trystorev_storev_relaxed_cpu_id(v, expect, v2, newv2, newv, cpu);
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case RSEQ_PERCPU_MM_CID:
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return rseq_cmpeqv_trystorev_storev_relaxed_mm_cid(v, expect, v2, newv2, newv, cpu);
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}
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return -1;
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case RSEQ_MO_RELEASE:
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switch (percpu_mode) {
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case RSEQ_PERCPU_CPU_ID:
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return rseq_cmpeqv_trystorev_storev_release_cpu_id(v, expect, v2, newv2, newv, cpu);
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case RSEQ_PERCPU_MM_CID:
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return rseq_cmpeqv_trystorev_storev_release_mm_cid(v, expect, v2, newv2, newv, cpu);
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}
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return -1;
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default:
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return -1;
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}
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}
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static inline __attribute__((always_inline))
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int rseq_cmpeqv_cmpeqv_storev(enum rseq_mo rseq_mo, enum rseq_percpu_mode percpu_mode,
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intptr_t *v, intptr_t expect,
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intptr_t *v2, intptr_t expect2,
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intptr_t newv, int cpu)
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{
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if (rseq_mo != RSEQ_MO_RELAXED)
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return -1;
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switch (percpu_mode) {
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case RSEQ_PERCPU_CPU_ID:
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return rseq_cmpeqv_cmpeqv_storev_relaxed_cpu_id(v, expect, v2, expect2, newv, cpu);
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case RSEQ_PERCPU_MM_CID:
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return rseq_cmpeqv_cmpeqv_storev_relaxed_mm_cid(v, expect, v2, expect2, newv, cpu);
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}
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return -1;
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}
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static inline __attribute__((always_inline))
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int rseq_cmpeqv_trymemcpy_storev(enum rseq_mo rseq_mo, enum rseq_percpu_mode percpu_mode,
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intptr_t *v, intptr_t expect,
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void *dst, void *src, size_t len,
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intptr_t newv, int cpu)
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{
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switch (rseq_mo) {
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case RSEQ_MO_RELAXED:
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switch (percpu_mode) {
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case RSEQ_PERCPU_CPU_ID:
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return rseq_cmpeqv_trymemcpy_storev_relaxed_cpu_id(v, expect, dst, src, len, newv, cpu);
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case RSEQ_PERCPU_MM_CID:
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return rseq_cmpeqv_trymemcpy_storev_relaxed_mm_cid(v, expect, dst, src, len, newv, cpu);
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}
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return -1;
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case RSEQ_MO_RELEASE:
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switch (percpu_mode) {
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case RSEQ_PERCPU_CPU_ID:
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return rseq_cmpeqv_trymemcpy_storev_release_cpu_id(v, expect, dst, src, len, newv, cpu);
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case RSEQ_PERCPU_MM_CID:
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return rseq_cmpeqv_trymemcpy_storev_release_mm_cid(v, expect, dst, src, len, newv, cpu);
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}
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return -1;
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default:
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return -1;
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}
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}
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#endif /* RSEQ_H_ */
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