From 9595fb8cd595028bece5174e7eddf660ae3dcc10 Mon Sep 17 00:00:00 2001 From: Waldemar Brodkorb Date: Thu, 31 May 2018 01:04:17 +0200 Subject: risc-v: initial 64 bit port, static only (no TLS/NPTL) Only a simple hello world is tested in qemu system emulation. --- libc/sysdeps/linux/riscv64/clone.S | 80 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 80 insertions(+) create mode 100644 libc/sysdeps/linux/riscv64/clone.S (limited to 'libc/sysdeps/linux/riscv64/clone.S') diff --git a/libc/sysdeps/linux/riscv64/clone.S b/libc/sysdeps/linux/riscv64/clone.S new file mode 100644 index 000000000..f7684c88d --- /dev/null +++ b/libc/sysdeps/linux/riscv64/clone.S @@ -0,0 +1,80 @@ +/* Wrapper around clone system call. RISC-V version. + Copyright (C) 1996-2018 Free Software Foundation, Inc. + + 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 + . */ + +/* clone() is even more special than fork() as it mucks with stacks + and invokes a function in the right context after its all over. */ + +#include +#include +#define _ERRNO_H 1 +#include + +/* int clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg, + void *parent_tidptr, void *tls, void *child_tidptr) */ + + .text +LEAF (clone) + + /* Sanity check arguments. */ + beqz a0,L (invalid) /* No NULL function pointers. */ + beqz a1,L (invalid) /* No NULL stack pointers. */ + + addi a1,a1,-16 /* Reserve argument save space. */ + REG_S a0,0(a1) /* Save function pointer. */ + REG_S a3,SZREG(a1) /* Save argument pointer. */ + + /* The syscall expects the args to be in different slots. */ + mv a0,a2 + mv a2,a4 + mv a3,a5 + mv a4,a6 + + /* Do the system call. */ + li a7,__NR_clone + scall + + bltz a0,L (error) + beqz a0,L (thread_start) + + /* Successful return from the parent. */ + ret + +L (invalid): + li a0, -EINVAL + /* Something bad happened -- no child created. */ +L (error): + j __syscall_error + END (clone) + +/* Load up the arguments to the function. Put this block of code in + its own function so that we can terminate the stack trace with our + debug info. */ + +ENTRY (__thread_start) +L (thread_start): + /* Restore the arg for user's function. */ + REG_L a1,0(sp) /* Function pointer. */ + REG_L a0,SZREG(sp) /* Argument pointer. */ + + /* Call the user's function. */ + jalr a1 + + /* Call exit with the function's return value. */ + li a7, __NR_exit + scall + + END (__thread_start) -- cgit v1.2.3