selftests/rseq: introduce own copy of rseq uapi header
The Linux kernel rseq uapi header has a broken layout for the rseq_cs.ptr field on 32-bit little endian architectures. The entire rseq_cs.ptr field is planned for removal, leaving only the 64-bit rseq_cs.ptr64 field available. Both glibc and librseq use their own copy of the Linux kernel uapi header, where they introduce proper union fields to access to the 32-bit low order bits of the rseq_cs pointer on 32-bit architectures. Introduce a copy of the Linux kernel uapi headers in the Linux kernel selftests. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20220124171253.22072-2-mathieu.desnoyers@efficios.com
This commit is contained in:
Mathieu Desnoyers
Peter Zijlstra
parent
ec24445306
commit
5c105d55a9
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@ -0,0 +1,151 @@
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/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
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#ifndef _RSEQ_ABI_H
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#define _RSEQ_ABI_H
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/*
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* rseq-abi.h
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*
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* Restartable sequences system call API
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*
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* Copyright (c) 2015-2022 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
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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_abi_cpu_id_state {
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RSEQ_ABI_CPU_ID_UNINITIALIZED = -1,
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RSEQ_ABI_CPU_ID_REGISTRATION_FAILED = -2,
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};
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enum rseq_abi_flags {
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RSEQ_ABI_FLAG_UNREGISTER = (1 << 0),
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};
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enum rseq_abi_cs_flags_bit {
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RSEQ_ABI_CS_FLAG_NO_RESTART_ON_PREEMPT_BIT = 0,
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RSEQ_ABI_CS_FLAG_NO_RESTART_ON_SIGNAL_BIT = 1,
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RSEQ_ABI_CS_FLAG_NO_RESTART_ON_MIGRATE_BIT = 2,
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};
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enum rseq_abi_cs_flags {
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RSEQ_ABI_CS_FLAG_NO_RESTART_ON_PREEMPT =
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(1U << RSEQ_ABI_CS_FLAG_NO_RESTART_ON_PREEMPT_BIT),
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RSEQ_ABI_CS_FLAG_NO_RESTART_ON_SIGNAL =
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(1U << RSEQ_ABI_CS_FLAG_NO_RESTART_ON_SIGNAL_BIT),
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RSEQ_ABI_CS_FLAG_NO_RESTART_ON_MIGRATE =
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(1U << RSEQ_ABI_CS_FLAG_NO_RESTART_ON_MIGRATE_BIT),
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};
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/*
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* struct rseq_abi_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_abi_cs {
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/* Version of this structure. */
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__u32 version;
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/* enum rseq_abi_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_abi 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_abi per thread is allowed.
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*/
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struct rseq_abi {
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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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/*
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* The "arch" field provides architecture accessor for
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* the ptr field based on architecture pointer size and
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* endianness.
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*/
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struct {
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#ifdef __LP64__
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__u64 ptr;
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#elif defined(__BYTE_ORDER) ? (__BYTE_ORDER == __BIG_ENDIAN) : defined(__BIG_ENDIAN)
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__u32 padding; /* Initialized to zero. */
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__u32 ptr;
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#else
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__u32 ptr;
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__u32 padding; /* Initialized to zero. */
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#endif
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} arch;
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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_ABI_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_ABI_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_ABI_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 /* _RSEQ_ABI_H */
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@ -30,8 +30,8 @@
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#include "../kselftest.h"
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#include "rseq.h"
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__thread volatile struct rseq __rseq_abi = {
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.cpu_id = RSEQ_CPU_ID_UNINITIALIZED,
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__thread volatile struct rseq_abi __rseq_abi = {
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.cpu_id = RSEQ_ABI_CPU_ID_UNINITIALIZED,
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};
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/*
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@ -66,7 +66,7 @@ static void signal_restore(sigset_t oldset)
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abort();
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}
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static int sys_rseq(volatile struct rseq *rseq_abi, uint32_t rseq_len,
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static int sys_rseq(volatile struct rseq_abi *rseq_abi, uint32_t rseq_len,
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int flags, uint32_t sig)
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{
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return syscall(__NR_rseq, rseq_abi, rseq_len, flags, sig);
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@ -86,13 +86,13 @@ int rseq_register_current_thread(void)
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}
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if (__rseq_refcount++)
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goto end;
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rc = sys_rseq(&__rseq_abi, sizeof(struct rseq), 0, RSEQ_SIG);
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rc = sys_rseq(&__rseq_abi, sizeof(struct rseq_abi), 0, RSEQ_SIG);
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if (!rc) {
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assert(rseq_current_cpu_raw() >= 0);
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goto end;
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}
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if (errno != EBUSY)
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__rseq_abi.cpu_id = RSEQ_CPU_ID_REGISTRATION_FAILED;
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__rseq_abi.cpu_id = RSEQ_ABI_CPU_ID_REGISTRATION_FAILED;
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ret = -1;
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__rseq_refcount--;
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end:
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@ -114,8 +114,8 @@ int rseq_unregister_current_thread(void)
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}
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if (--__rseq_refcount)
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goto end;
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rc = sys_rseq(&__rseq_abi, sizeof(struct rseq),
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RSEQ_FLAG_UNREGISTER, RSEQ_SIG);
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rc = sys_rseq(&__rseq_abi, sizeof(struct rseq_abi),
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RSEQ_ABI_FLAG_UNREGISTER, RSEQ_SIG);
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if (!rc)
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goto end;
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__rseq_refcount = 1;
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@ -16,7 +16,7 @@
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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 <linux/rseq.h>
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#include "rseq-abi.h"
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/*
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* Empty code injection macros, override when testing.
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@ -43,7 +43,7 @@
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#define RSEQ_INJECT_FAILED
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#endif
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extern __thread volatile struct rseq __rseq_abi;
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extern __thread volatile struct rseq_abi __rseq_abi;
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extern int __rseq_handled;
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#define rseq_likely(x) __builtin_expect(!!(x), 1)
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@ -139,11 +139,7 @@ static inline uint32_t rseq_current_cpu(void)
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static inline void rseq_clear_rseq_cs(void)
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{
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#ifdef __LP64__
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__rseq_abi.rseq_cs.ptr = 0;
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#else
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__rseq_abi.rseq_cs.ptr.ptr32 = 0;
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#endif
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__rseq_abi.rseq_cs.arch.ptr = 0;
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}
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/*
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