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or1k: Linux Syscall Interface

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Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
This commit is contained in:
Stafford Horne
2021-10-20 06:51:52 +09:00
parent 9a47b9660b
commit 1871c95f2b
6 changed files with 738 additions and 0 deletions
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89
sysdeps/unix/sysv/linux/or1k/or1k_clone.S Normal file
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/* clone helper __or1k_clone for OpenRISC.
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, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <sysdep.h>
#include <tls.h>
#define __ASSEMBLY__
#include <linux/sched.h>
.text
ENTRY (__or1k_clone)
/* To handle GCC varargs we need to use our __clone wrapper to pop
everything from the stack for us.
Now everything is placed in the registers which saves us a lot
of trouble.
The userland implementation is:
int clone (int (*fn)(void *), void *child_stack,
int flags, void *arg, pid_t *ptid,
struct user_desc *tls, pid_t *ctid);
The kernel entry is:
int clone (long flags, void *child_stack, int *parent_tid,
int *child_tid, struct void *tls)
NB: tls isn't really an argument, it is read from r7 directly. */
/* First, align the stack to 4 bytes. */
l.xori r11, r0, -4
l.and r4, r4, r11
/* Put 'fn', 'arg' and 'flags' on the child stack. */
l.addi r4, r4, -12
l.sw 8(r4), r3
l.sw 4(r4), r6
l.sw 0(r4), r5
l.ori r3, r5, 0
/* The child_stack is already in r4. */
l.ori r5, r7, 0
l.lwz r6, 0(r1)
l.ori r7, r8, 0
DO_CALL (clone)
l.sfgeui r11, 0xf001
l.bf L(error)
l.nop
/* If we are not the child, return the pid. */
l.sfeqi r11, 0
l.bf L(thread_start)
l.nop
l.jr r9
l.nop
L(thread_start):
/* Load function from stack. */
l.lwz r11, 8(r1)
l.jalr r11
l.lwz r3, 4(r1)
/* Exit the child thread. */
l.ori r3, r11, 0
DO_CALL (exit)
L(error):
l.j SYSCALL_ERROR_NAME
l.ori r3, r11, 0
END (__or1k_clone)