Add tests for rseq(2)

Add a decent set of syscall tests for rseq(2). These are a bit awkward because
of issues with library integration. libc may register rseq on thread start
(including before main on the initial thread), precluding much testing. Thus we
run tests in a libc-free subprocess.

Support for rseq(2) in gVisor will come in a later commit.

PiperOrigin-RevId: 284595994

1 files changed, 54 insertions, 0 deletions

diff --git a/test/syscalls/linux/rseq/uapi.h b/test/syscalls/linux/rseq/uapi.h
new file mode 100644
index 000000000..e3ff0579a
--- /dev/null
+++ b/test/syscalls/linux/rseq/uapi.h
@@ -0,0 +1,54 @@
+// Copyright 2019 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.
+
+#ifndef GVISOR_TEST_SYSCALLS_LINUX_RSEQ_UAPI_H_
+#define GVISOR_TEST_SYSCALLS_LINUX_RSEQ_UAPI_H_
+
+// User-kernel ABI for restartable sequences.
+
+// Standard types.
+//
+// N.B. This header will be included in targets that do have the standard
+// library, so we can't shadow the standard type names.
+using __u32 = __UINT32_TYPE__;
+using __u64 = __UINT64_TYPE__;
+
+#ifdef __x86_64__
+// Syscall numbers.
+constexpr int kRseqSyscall = 334;
+#else
+#error "Unknown architecture"
+#endif  // __x86_64__
+
+struct rseq_cs {
+  __u32 version;
+  __u32 flags;
+  __u64 start_ip;
+  __u64 post_commit_offset;
+  __u64 abort_ip;
+} __attribute__((aligned(4 * sizeof(__u64))));
+
+// N.B. alignment is enforced by the kernel.
+struct rseq {
+  __u32 cpu_id_start;
+  __u32 cpu_id;
+  struct rseq_cs* rseq_cs;
+  __u32 flags;
+} __attribute__((aligned(4 * sizeof(__u64))));
+
+constexpr int kRseqFlagUnregister = 1 << 0;
+
+constexpr int kRseqCPUIDUninitialized = -1;
+
+#endif  // GVISOR_TEST_SYSCALLS_LINUX_RSEQ_UAPI_H_