| /* Copyright (C) 1996-2018 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| Contributed by David Huggins-Daines <dhd@debian.org>, 2000. |
| Based on the Alpha version by Richard Henderson <rth@tamu.edu>, 1996. |
| |
| 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 its all over. */ |
| |
| #include <asm/unistd.h> |
| #include <sysdep.h> |
| #define _ERRNO_H 1 |
| #include <bits/errno.h> |
| #include <tcb-offsets.h> |
| |
| /* Non-thread code calls __clone with the following parameters: |
| int clone(int (*fn)(void *arg), |
| void *child_stack, |
| int flags, |
| void *arg) |
| |
| NPTL Code will call __clone with the following parameters: |
| int clone(int (*fn)(void *arg), |
| void *child_stack, |
| int flags, |
| void *arg, |
| int *parent_tidptr, |
| struct user_desc *newtls, |
| int *child_pidptr) |
| |
| The code should not mangle the extra input registers. |
| Syscall expects: Input to __clone: |
| 4(r25) - function pointer (r26, arg0) |
| 0(r25) - argument (r23, arg3) |
| r26 - clone flags. (r24, arg2) |
| r25+64 - user stack pointer. (r25, arg1) |
| r24 - parent tid pointer. (stack - 52) |
| r23 - struct user_desc newtls pointer. (stack - 56) |
| r22 - child tid pointer. (stack - 60) |
| r20 - clone syscall number (constant) |
| |
| Return: |
| |
| On success the thread ID of the child process is returend in |
| the callers context. |
| On error return -1, and set errno to the value returned by |
| the syscall. |
| */ |
| |
| .text |
| ENTRY(__clone) |
| /* Prologue */ |
| stwm %r4, 64(%sp) |
| .cfi_def_cfa_offset -64 |
| .cfi_offset 4, 0 |
| stw %sp, -4(%sp) |
| #ifdef PIC |
| stw %r19, -32(%sp) |
| .cfi_offset 19, 32 |
| #endif |
| |
| /* Sanity check arguments. */ |
| comib,=,n 0, %arg0, .LerrorSanity /* no NULL function pointers */ |
| comib,=,n 0, %arg1, .LerrorSanity /* no NULL stack pointers */ |
| |
| /* Save the function pointer, arg, and flags on the new stack. */ |
| stwm %r26, 64(%r25) |
| stw %r23, -60(%r25) |
| stw %r24, -56(%r25) |
| /* Clone arguments are (int flags, void * child_stack) */ |
| copy %r24, %r26 /* flags are first */ |
| /* User stack pointer is in the correct register already */ |
| |
| /* Load args from stack... */ |
| ldw -116(%sp), %r24 /* Load parent_tidptr */ |
| ldw -120(%sp), %r23 /* Load newtls */ |
| ldw -124(%sp), %r22 /* Load child_tidptr */ |
| |
| /* Save the PIC register. */ |
| #ifdef PIC |
| copy %r19, %r4 /* parent */ |
| #endif |
| |
| /* Do the system call */ |
| ble 0x100(%sr2, %r0) |
| ldi __NR_clone, %r20 |
| |
| ldi -4096, %r1 |
| comclr,>>= %r1, %ret0, %r0 /* Note: unsigned compare. */ |
| b,n .LerrorRest |
| |
| /* Restore the PIC register. */ |
| #ifdef PIC |
| copy %r4, %r19 /* parent */ |
| #endif |
| |
| comib,=,n 0, %ret0, .LthreadStart |
| |
| /* Successful return from the parent |
| No need to restore the PIC register, |
| since we return immediately. */ |
| |
| ldw -84(%sp), %rp |
| bv %r0(%rp) |
| ldwm -64(%sp), %r4 |
| |
| .LerrorRest: |
| /* Something bad happened -- no child created */ |
| bl __syscall_error, %rp |
| sub %r0, %ret0, %arg0 |
| ldw -84(%sp), %rp |
| /* Return after setting errno, ret0 is set to -1 by __syscall_error. */ |
| bv %r0(%rp) |
| ldwm -64(%sp), %r4 |
| |
| .LerrorSanity: |
| /* Sanity checks failed, return -1, and set errno to EINVAL. */ |
| bl __syscall_error, %rp |
| ldi EINVAL, %arg0 |
| ldw -84(%sp), %rp |
| bv %r0(%rp) |
| ldwm -64(%sp), %r4 |
| |
| .LthreadStart: |
| /* Load up the arguments. */ |
| ldw -60(%sp), %arg0 |
| ldw -64(%sp), %r22 |
| |
| /* $$dyncall fixes child's PIC register */ |
| |
| /* Call the user's function */ |
| #ifdef PIC |
| copy %r19, %r4 |
| #endif |
| bl $$dyncall, %r31 |
| copy %r31, %rp |
| #ifdef PIC |
| copy %r4, %r19 |
| #endif |
| copy %r28, %r26 |
| ble 0x100(%sr2, %r0) |
| ldi __NR_exit, %r20 |
| |
| /* We should not return from exit. |
| We do not restore r4, or the stack state. */ |
| iitlbp %r0, (%sr0, %r0) |
| |
| PSEUDO_END(__clone) |
| |
| libc_hidden_def (__clone) |
| weak_alias (__clone, clone) |
