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// Copyright 2020 The gVisor Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// Restartable sequences critical sections.
// Loops continuously until aborted.
//
// void rseq_loop(struct rseq* r, struct rseq_cs* cs)
.text
.globl rseq_loop
.type rseq_loop, @function
rseq_loop:
b begin
// Abort block before the critical section.
// Abort signature.
.byte 0x90, 0x90, 0x90, 0x90
.globl rseq_loop_early_abort
rseq_loop_early_abort:
ret
begin:
// r->rseq_cs = cs
str x1, [x0, #8]
// N.B. rseq_cs will be cleared by any preempt, even outside the critical
// section. Thus it must be set in or immediately before the critical section
// to ensure it is not cleared before the section begins.
.globl rseq_loop_start
rseq_loop_start:
b rseq_loop_start
// "Pre-commit": extra instructions inside the critical section. These are
// used as the abort point in TestAbortPreCommit, which is not valid.
.globl rseq_loop_pre_commit
rseq_loop_pre_commit:
// Extra abort signature + nop for TestAbortPostCommit.
.byte 0x90, 0x90, 0x90, 0x90
nop
// "Post-commit": never reached in this case.
.globl rseq_loop_post_commit
rseq_loop_post_commit:
// Abort signature.
.byte 0x90, 0x90, 0x90, 0x90
.globl rseq_loop_abort
rseq_loop_abort:
ret
.size rseq_loop,.-rseq_loop
.section .note.GNU-stack,"",@progbits
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