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/* Set up a context to call a function.
Copyright (C) 2002-2024 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
<https://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
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