| Message ID | 20210601145516.3553627-3-hjl.tools@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | Add an internal wrapper for clone, clone2 and clone3 | expand |
LGTM, thanks. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> On 01/06/2021 11:55, H.J. Lu wrote: > extern int clone3 (struct clone_args *__cl_args, size_t __size, > int (*__func) (void *__arg), void *__arg); > --- > sysdeps/unix/sysv/linux/x86_64/clone3.S | 92 +++++++++++++++++++++++++ > sysdeps/unix/sysv/linux/x86_64/sysdep.h | 2 + > 2 files changed, 94 insertions(+) > create mode 100644 sysdeps/unix/sysv/linux/x86_64/clone3.S > > diff --git a/sysdeps/unix/sysv/linux/x86_64/clone3.S b/sysdeps/unix/sysv/linux/x86_64/clone3.S > new file mode 100644 > index 0000000000..71caaecc29 > --- /dev/null > +++ b/sysdeps/unix/sysv/linux/x86_64/clone3.S > @@ -0,0 +1,92 @@ > +/* The clone3 syscall wrapper. Linux/x86-64 version. > + Copyright (C) 2021 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/>. */ > + > +/* clone3() is even more special than fork() as it mucks with stacks > + and invokes a function in the right context after its all over. */ > + > +#include <sysdep.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: > + rdi: cl_args > + rsi: size > + rdx: func > + rcx: arg > + > + The kernel expects: > + rax: system call number > + rdi: cl_args > + rsi: size */ > + > + .text > +ENTRY (__clone3) > + /* Sanity check arguments. */ > + movl $-EINVAL, %eax > + test %RDI_LP, %RDI_LP /* No NULL cl_args pointer. */ > + jz SYSCALL_ERROR_LABEL > + test %RDX_LP, %RDX_LP /* No NULL function pointer. */ > + jz SYSCALL_ERROR_LABEL > + > + /* Save the cl_args pointer in R8 which is preserved by the > + syscall. */ > + mov %RCX_LP, %R8_LP > + > + /* Do the system call. */ > + movl $SYS_ify(clone3), %eax > + > + /* End FDE now, because in the child the unwind info will be > + wrong. */ > + cfi_endproc > + syscall > + > + test %RAX_LP, %RAX_LP > + jl SYSCALL_ERROR_LABEL > + jz L(thread_start) > + > + ret > + > +L(thread_start): > + cfi_startproc > + /* Clearing frame pointer is insufficient, use CFI. */ > + cfi_undefined (rip) > + /* Clear the frame pointer. The ABI suggests this be done, to mark > + the outermost frame obviously. */ > + xorl %ebp, %ebp > + > + /* Align stack to 16 bytes per the x86-64 psABI. */ > + and $-16, %RSP_LP > + > + /* Set up arguments for the function call. */ > + mov %R8_LP, %RDI_LP /* Argument. */ > + call *%rdx /* Call function. */ > + /* Call exit with return value from function call. */ > + movq %rax, %rdi > + movl $SYS_ify(exit), %eax > + syscall > + cfi_endproc > + > + cfi_startproc > +PSEUDO_END (__clone3) > + > +libc_hidden_def (__clone3) > +weak_alias (__clone3, clone3) > diff --git a/sysdeps/unix/sysv/linux/x86_64/sysdep.h b/sysdeps/unix/sysv/linux/x86_64/sysdep.h > index dbad2c788a..f26ffc68ae 100644 > --- a/sysdeps/unix/sysv/linux/x86_64/sysdep.h > +++ b/sysdeps/unix/sysv/linux/x86_64/sysdep.h > @@ -377,6 +377,8 @@ > # define HAVE_GETCPU_VSYSCALL "__vdso_getcpu" > # define HAVE_CLOCK_GETRES64_VSYSCALL "__vdso_clock_getres" > > +# define HAVE_CLONE3_WAPPER 1 > + > # define SINGLE_THREAD_BY_GLOBAL 1 > > #endif /* __ASSEMBLER__ */ > Ok.
diff --git a/sysdeps/unix/sysv/linux/x86_64/clone3.S b/sysdeps/unix/sysv/linux/x86_64/clone3.S new file mode 100644 index 0000000000..71caaecc29 --- /dev/null +++ b/sysdeps/unix/sysv/linux/x86_64/clone3.S @@ -0,0 +1,92 @@ +/* The clone3 syscall wrapper. Linux/x86-64 version. + Copyright (C) 2021 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/>. */ + +/* clone3() is even more special than fork() as it mucks with stacks + and invokes a function in the right context after its all over. */ + +#include <sysdep.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: + rdi: cl_args + rsi: size + rdx: func + rcx: arg + + The kernel expects: + rax: system call number + rdi: cl_args + rsi: size */ + + .text +ENTRY (__clone3) + /* Sanity check arguments. */ + movl $-EINVAL, %eax + test %RDI_LP, %RDI_LP /* No NULL cl_args pointer. */ + jz SYSCALL_ERROR_LABEL + test %RDX_LP, %RDX_LP /* No NULL function pointer. */ + jz SYSCALL_ERROR_LABEL + + /* Save the cl_args pointer in R8 which is preserved by the + syscall. */ + mov %RCX_LP, %R8_LP + + /* Do the system call. */ + movl $SYS_ify(clone3), %eax + + /* End FDE now, because in the child the unwind info will be + wrong. */ + cfi_endproc + syscall + + test %RAX_LP, %RAX_LP + jl SYSCALL_ERROR_LABEL + jz L(thread_start) + + ret + +L(thread_start): + cfi_startproc + /* Clearing frame pointer is insufficient, use CFI. */ + cfi_undefined (rip) + /* Clear the frame pointer. The ABI suggests this be done, to mark + the outermost frame obviously. */ + xorl %ebp, %ebp + + /* Align stack to 16 bytes per the x86-64 psABI. */ + and $-16, %RSP_LP + + /* Set up arguments for the function call. */ + mov %R8_LP, %RDI_LP /* Argument. */ + call *%rdx /* Call function. */ + /* Call exit with return value from function call. */ + movq %rax, %rdi + movl $SYS_ify(exit), %eax + syscall + cfi_endproc + + cfi_startproc +PSEUDO_END (__clone3) + +libc_hidden_def (__clone3) +weak_alias (__clone3, clone3) diff --git a/sysdeps/unix/sysv/linux/x86_64/sysdep.h b/sysdeps/unix/sysv/linux/x86_64/sysdep.h index dbad2c788a..f26ffc68ae 100644 --- a/sysdeps/unix/sysv/linux/x86_64/sysdep.h +++ b/sysdeps/unix/sysv/linux/x86_64/sysdep.h @@ -377,6 +377,8 @@ # define HAVE_GETCPU_VSYSCALL "__vdso_getcpu" # define HAVE_CLOCK_GETRES64_VSYSCALL "__vdso_clock_getres" +# define HAVE_CLONE3_WAPPER 1 + # define SINGLE_THREAD_BY_GLOBAL 1 #endif /* __ASSEMBLER__ */