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Diffstat (limited to 'libc/sysdeps/linux/tile/clone.S')
| -rw-r--r-- | libc/sysdeps/linux/tile/clone.S | 173 |
1 files changed, 173 insertions, 0 deletions
diff --git a/libc/sysdeps/linux/tile/clone.S b/libc/sysdeps/linux/tile/clone.S new file mode 100644 index 000000000..17b9ab1cd --- /dev/null +++ b/libc/sysdeps/linux/tile/clone.S @@ -0,0 +1,173 @@ +/* Copyright (C) 2011-2018 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 + <http://www.gnu.org/licenses/>. */ + +/* clone() is even more special than fork() as it mucks with stacks + and invokes a function in the right context after it's all over. */ + +#include <sysdep.h> +#define _ERRNO_H 1 +#include <bits/errno.h> + +#include <asm/unistd.h> +#include <arch/abi.h> +#include <linux/sched.h> + +/* What we save where in the stack frame; must include all callee-saves. */ +#define FRAME_NEXT_LR (0 * REGSIZE) /* reserved by ABI; not used here */ +#define FRAME_SP (1 * REGSIZE) +#define FRAME_R30 (2 * REGSIZE) +#define FRAME_R31 (3 * REGSIZE) +#define FRAME_R32 (4 * REGSIZE) +#define FRAME_SIZE (5 * REGSIZE) + +/* int clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg, + pid_t *ptid, struct user_desc *tls, pid_t *ctid); */ + + .text +ENTRY (__clone) + /* Create a stack frame so we can pass callee-saves to new task. */ + { + move r10, sp + st sp, lr + ADDI_PTR sp, sp, -FRAME_SIZE + } + cfi_offset (lr, 0) + cfi_def_cfa_offset (FRAME_SIZE) + ADDI_PTR r11, sp, FRAME_SP + { + st r11, r10 + ADDI_PTR r11, sp, FRAME_R30 + } + { + st r11, r30 + ADDI_PTR r11, sp, FRAME_R31 + } + cfi_offset (r30, FRAME_R30 - FRAME_SIZE) + { + st r11, r31 + ADDI_PTR r11, sp, FRAME_R32 + } + cfi_offset (r31, FRAME_R31 - FRAME_SIZE) + st r11, r32 + cfi_offset (r32, FRAME_R32 - FRAME_SIZE) + + /* sanity check arguments */ + beqz r0, .Linvalid + beqz r1, .Linvalid + + /* Make sure child stack is properly aligned, and set up the + top frame so that we can call out of it immediately in the + child. Setting it up here means we fault in the parent if + it's bogus, which is probably cleaner than faulting first + thing in the child. */ + ADDI_PTR r1, r1, -C_ABI_SAVE_AREA_SIZE + andi r1, r1, -C_ABI_SAVE_AREA_SIZE + ADDI_PTR r9, r1, REGSIZE /* sp of this frame on entry, i.e. zero */ + st r9, zero + + /* We need to switch the argument convention around from + libc to kernel: + + libc: + r0 fn + r1 child_stack + r2 flags + r3 arg + r4 ptid + r5 tls + r6 ctid + + kernel: + r0 flags + r1 child_stack [same as libc] + r2 ptid + r3 ctid + r4 tls + + Plus the callee-saves as described at .Lthread_start, below. */ + { + move r32, r0 + move r0, r2 + } + { + move r31, r3 + move r3, r6 + } + { + move r30, r2 + move r2, r4 + } + { + move r4, r5 + moveli TREG_SYSCALL_NR_NAME, __NR_clone + } + swint1 + beqz r0, .Lthread_start /* If in child task. */ + +.Ldone: + /* Restore the callee-saved registers and return. */ + ADDLI_PTR lr, sp, FRAME_SIZE + { + ld lr, lr + ADDLI_PTR r30, sp, FRAME_R30 + } + { + ld r30, r30 + ADDLI_PTR r31, sp, FRAME_R31 + } + { + ld r31, r31 + ADDLI_PTR r32, sp, FRAME_R32 + } + { + ld r32, r32 + ADDI_PTR sp, sp, FRAME_SIZE + } + cfi_def_cfa_offset (0) + + bnez r1, .Lerror + jrp lr + +.Lerror: + j SYSCALL_ERROR_NAME + +.Linvalid: + { + movei r1, EINVAL + j .Ldone + } + +/* This function expects to receive: + + sp: the top of a valid stack area + r30: clone() flags + r31: the argument to pass to the user function + r32: the user function pointer */ + +.Lthread_start: + cfi_def_cfa_offset (FRAME_SIZE) + cfi_undefined (lr) + { + /* Invoke user function with specified argument. */ + move r0, r31 + jalr r32 + } + moveli TREG_SYSCALL_NR_NAME, __NR_exit + swint1 +PSEUDO_END (__clone) + +libc_hidden_def (clone) +weak_alias (__clone, clone) |