[4/7] aarch64: Add the clone3 wrapper
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| dj/TryBot-apply_patch |
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Patch applied to master at the time it was sent
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Commit Message
It follow the internal signature:
extern int clone3 (struct clone_args *__cl_args, size_t __size,
int (*__func) (void *__arg), void *__arg);
And x86_64 semantics to return EINVAL if either cl_args or func
is NULL. The stack is 16-byte aligned prior executing func.
Checked on aarch64-linux-gnu.
---
sysdeps/unix/sysv/linux/aarch64/clone3.S | 90 ++++++++++++++++++++++++
sysdeps/unix/sysv/linux/aarch64/sysdep.h | 2 +
2 files changed, 92 insertions(+)
create mode 100644 sysdeps/unix/sysv/linux/aarch64/clone3.S
new file mode 100644
@@ -0,0 +1,90 @@
+/* The clone3 syscall wrapper. Linux/aarch64 version.
+ Copyright (C) 2022 Free Software Foundation, Inc.
+
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+#include <sysdep.h>
+#define _ERRNO_H 1
+#include <bits/errno.h>
+
+/* The userland implementation is:
+ int clone3 (struct clone_args *cl_args, size_t size,
+ int (*func)(void *arg), void *arg);
+
+ the kernel entry is:
+ int clone3 (struct clone_args *cl_args, size_t size);
+
+ The parameters are passed in registers from userland:
+ x0: cl_args
+ x1: size
+ x2: func
+ x3: arg */
+
+ .text
+ENTRY(__clone3)
+ PTR_ARG (0)
+ PTR_ARG (1)
+ PTR_ARG (3)
+ PTR_ARG (4)
+ /* Save args for the child. */
+ mov x10, x0 /* cl_args */
+ mov x11, x2 /* func */
+ mov x12, x3 /* args */
+
+ /* Sanity check args. */
+ mov x0, #-EINVAL
+ cbz x10, .Lsyscall_error /* No NULL cl_args pointer. */
+ cbz x2, .Lsyscall_error /* No NULL function pointer. */
+
+ /* Do the system call, the kernel expects:
+ x8: system call number
+ x0: cl_args
+ x1: size */
+ mov x0, x10
+ mov x8, #SYS_ify(clone3)
+ svc 0x0
+
+ cmp x0, #0
+ beq thread_start
+ blt .Lsyscall_error
+ RET
+PSEUDO_END (__clone3)
+
+ .align 4
+ .type thread_start, %function
+thread_start:
+ cfi_startproc
+ cfi_undefined (x30)
+ mov x29, 0
+
+ /* Align sp. */
+ mov x0, sp
+ and x0, x0, -16
+ mov sp, x0
+
+ /* Pick the function arg and execute. */
+ mov x0, x12
+ blr x11
+
+ /* We are done, pass the return value through x0. */
+ mov x8, #SYS_ify(exit)
+ svc 0x0
+ cfi_endproc
+ .size thread_start, .-thread_start
+
+libc_hidden_def (__clone3)
+weak_alias (__clone3, clone3)
@@ -164,6 +164,8 @@
# define HAVE_CLOCK_GETTIME64_VSYSCALL "__kernel_clock_gettime"
# define HAVE_GETTIMEOFDAY_VSYSCALL "__kernel_gettimeofday"
+# define HAVE_CLONE3_WRAPPER 1
+
# undef INTERNAL_SYSCALL_RAW
# define INTERNAL_SYSCALL_RAW(name, nr, args...) \
({ long _sys_result; \