/* Set up a context to call a function.

   Copyright (C) 2002-2018 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

   <http://www.gnu.org/licenses/>.  */

#include <sysdep.h>

#include <shlib-compat.h>

#define __ASSEMBLY__

#include <asm/ptrace.h>

#include "ucontext_i.h"

ENTRY(__makecontext)

	/* Set up the first 7 args to the function in its registers */

	lwz	r11,_UC_REGS_PTR(r3)

	stw	r6,_UC_GREGS+(PT_R3*4)(r11)

	stw	r7,_UC_GREGS+(PT_R4*4)(r11)

	stw	r8,_UC_GREGS+(PT_R5*4)(r11)

	stw	r9,_UC_GREGS+(PT_R6*4)(r11)

	stw	r10,_UC_GREGS+(PT_R7*4)(r11)

	lwz	r8,8(r1)

	lwz	r9,12(r1)

	stw	r8,_UC_GREGS+(PT_R8*4)(r11)

	stw	r9,_UC_GREGS+(PT_R9*4)(r11)

	/* Set the NIP to the start of the function */

	stw	r4,_UC_GREGS+(PT_NIP*4)(r11)

	/* Set the function's r31 to ucp->uc_link for the exitcode below. */

	lwz	r7,_UC_LINK(r3)

	stw	r7,_UC_GREGS+(PT_R31*4)(r11)

	/* Set the function's LR to point to the exitcode below. */

#ifdef PIC

	mflr	r0

	cfi_register(lr,r0)

	/* Use this conditional form of branch and link to avoid destroying

	   the cpu link stack used to predict blr return addresses.  */

	bcl	20,31,1f

1:	mflr	r6

	addi	r6,r6,L(exitcode)-1b

	mtlr	r0

	cfi_same_value (lr)

#else

	lis	r6,L(exitcode)@ha

	addi	r6,r6,L(exitcode)@l

#endif

	stw	r6,_UC_GREGS+(PT_LNK*4)(r11)

	/*

	 * Set up the stack frame for the function.

	 * If we have more than 5 args to the function (8 args to makecontext),

	 * there will be some arguments on the stack which have to end up

	 * in registers.  If there are more than 8 args to the function,

	 * we have to copy (argc - 8) args from our stack to the functions'

	 * stack (and allow space for them in the frame).

	 */

	lwz	r4,_UC_STACK_SP(r3)

	lwz	r8,_UC_STACK_SIZE(r3)

	add	r4,r4,r8

	rlwinm	r4,r4,0,0,27	/* round down to 16-byte boundary */

	addi	r7,r4,-16	/* stack frame for fn's caller */

	cmpwi	r5,8

	blt	2f		/* less than 8 args is easy */

	lwz	r10,16(r1)

	stw	r10,_UC_GREGS+(PT_R10*4)(r11)

	beq	2f		/* if exactly 8 args */

	subi	r9,r5,3

	subi	r5,r5,8

	rlwinm	r9,r9,2,0,27

	subf	r7,r9,r4

	mtctr	r5		/* copy the 9th and following args */

	addi	r6,r1,16

	addi	r8,r7,4

3:	lwzu	r10,4(r6)

	stwu	r10,4(r8)

	bdnz	3b

2:	stw	r7,_UC_GREGS+(PT_R1*4)(r11)

	li	r6,0

	stw	r6,0(r7)

	blr

	cfi_endproc

	nop

/*

 * If the function returns, it comes here.  We put ucp->uc_link in

 * r31, which is a callee-saved register.  We have to continue with

 * the context that r31 points to, or exit if it is 0.

 */

L(exitcode):

	mr.	r3,r31

	beq	4f

	bl	__setcontext@local

4:	bl	HIDDEN_JUMPTARGET(exit)

	b	4b

	cfi_startproc

END(__makecontext)

versioned_symbol (libc, __makecontext, makecontext, GLIBC_2_3_4)

#if SHLIB_COMPAT (libc, GLIBC_2_3_3, GLIBC_2_3_4)

	compat_text_section

ENTRY(__novec_makecontext)

	/* Set up the first 7 args to the function in its registers */

	addi	r11,r3,_UC_REG_SPACE

	stw	r11,_UC_REGS_PTR(r3)

	stw	r6,_UC_GREGS+(PT_R3*4)(r11)

	stw	r7,_UC_GREGS+(PT_R4*4)(r11)

	stw	r8,_UC_GREGS+(PT_R5*4)(r11)

	stw	r9,_UC_GREGS+(PT_R6*4)(r11)

	stw	r10,_UC_GREGS+(PT_R7*4)(r11)

	lwz	r8,8(r1)

	lwz	r9,12(r1)

	stw	r8,_UC_GREGS+(PT_R8*4)(r11)

	stw	r9,_UC_GREGS+(PT_R9*4)(r11)

	/* Set the NIP to the start of the function */

	stw	r4,_UC_GREGS+(PT_NIP*4)(r11)

	/* Set the function's r31 to ucp->uc_link for the exitcode below. */

	lwz	r7,_UC_LINK(r3)

	stw	r7,_UC_GREGS+(PT_R31*4)(r11)

	/* Set the function's LR to point to the exitcode below. */

#ifdef PIC

	mflr	r0

	cfi_register(lr,r0)

	/* Use this conditional form of branch and link to avoid destroying

	   the cpu link stack used to predict blr return addresses.  */

	bcl	20,31,1f

1:	mflr	r6

	addi	r6,r6,L(novec_exitcode)-1b

	mtlr	r0

	cfi_same_value (lr)

#else

	lis	r6,L(novec_exitcode)@ha

	addi	r6,r6,L(novec_exitcode)@l

#endif

	stw	r6,_UC_GREGS+(PT_LNK*4)(r11)

	/*

	 * Set up the stack frame for the function.

	 * If we have more than 5 args to the function (8 args to makecontext),

	 * there will be some arguments on the stack which have to end up

	 * in registers.  If there are more than 8 args to the function,

	 * we have to copy (argc - 8) args from our stack to the functions'

	 * stack (and allow space for them in the frame).

	 */

	lwz	r4,_UC_STACK_SP(r3)

	lwz	r8,_UC_STACK_SIZE(r3)

	add	r4,r4,r8

	rlwinm	r4,r4,0,0,27	/* round down to 16-byte boundary */

	addi	r7,r4,-16	/* stack frame for fn's caller */

	cmpwi	r5,8

	blt	2f		/* less than 8 args is easy */

	lwz	r10,16(r1)

	stw	r10,_UC_GREGS+(PT_R10*4)(r11)

	beq	2f		/* if exactly 8 args */

	subi	r9,r5,3

	subi	r5,r5,8

	rlwinm	r9,r9,2,0,27

	subf	r7,r9,r4

	mtctr	r5		/* copy the 9th and following args */

	addi	r6,r1,16

	addi	r8,r7,4

3:	lwzu	r10,4(r6)

	stwu	r10,4(r8)

	bdnz	3b

2:	stw	r7,_UC_GREGS+(PT_R1*4)(r11)

	li	r6,0

	stw	r6,0(r7)

	blr

	cfi_endproc

	nop

/*

 * If the function returns, it comes here.  We put ucp->uc_link in

 * r31, which is a callee-saved register.  We have to continue with

 * the context that r31 points to, or exit if it is 0.

 */

L(novec_exitcode):

	mr.	r3,r31

	beq	4f

	bl	__novec_setcontext@local

4:	bl	HIDDEN_JUMPTARGET(exit)

	b	4b

	cfi_startproc

END(__novec_makecontext)

	.previous

compat_symbol (libc, __novec_makecontext, makecontext, GLIBC_2_3_3)

#endif

#if SHLIB_COMPAT (libc, GLIBC_2_1, GLIBC_2_3_3)

#define _ERRNO_H	1

#include <bits/errno.h>

	compat_text_section

ENTRY (__makecontext_stub)

	li	r3,ENOSYS

	b	__syscall_error@local

END (__makecontext_stub)

	.previous

compat_symbol (libc, __makecontext_stub, makecontext, GLIBC_2_1)

#endif