From a8dc90eaaa5e6474beac828558d969b1aafee4af Mon Sep 17 00:00:00 2001 From: Florian Fainelli Date: Wed, 9 Jan 2013 16:17:21 +0100 Subject: libc: add {get,set,swap,make}context user context manipulation functions Add the obsolescent SUSv3 family of user context manipulating functions for arm, i386, mips, x86_64. Signed-off-by: Timon ter Braak Signed-off-by: Florian Fainelli Signed-off-by: Bernhard Reutner-Fischer Signed-off-by: Natanael Copa Signed-off-by: Bernhard Reutner-Fischer --- libc/sysdeps/linux/arm/makecontext.c | 73 ++++++++++++++++++++++++++++++++++++ 1 file changed, 73 insertions(+) create mode 100644 libc/sysdeps/linux/arm/makecontext.c (limited to 'libc/sysdeps/linux/arm/makecontext.c') diff --git a/libc/sysdeps/linux/arm/makecontext.c b/libc/sysdeps/linux/arm/makecontext.c new file mode 100644 index 000000000..d6ae6f0d7 --- /dev/null +++ b/libc/sysdeps/linux/arm/makecontext.c @@ -0,0 +1,73 @@ +/* Copyright (C) 2012 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 + . */ + +#include +#include + +/* Number of arguments that go in registers. */ +#define NREG_ARGS 4 + +/* Take a context previously prepared via getcontext() and set to + call func() with the given int only args. */ +void +__makecontext (ucontext_t *ucp, void (*func) (void), int argc, ...) +{ + extern void __startcontext (void); + unsigned long *funcstack; + va_list vl; + unsigned long *regptr; + unsigned int reg; + int misaligned; + + /* Start at the top of stack. */ + funcstack = (unsigned long *) (ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size); + + /* Ensure the stack stays eight byte aligned. */ + misaligned = ((unsigned long) funcstack & 4) != 0; + + if ((argc > NREG_ARGS) && (argc & 1) != 0) + misaligned = !misaligned; + + if (misaligned) + funcstack -= 1; + + va_start (vl, argc); + + /* Reserve space for the on-stack arguments. */ + if (argc > NREG_ARGS) + funcstack -= (argc - NREG_ARGS); + + ucp->uc_mcontext.arm_sp = (unsigned long) funcstack; + ucp->uc_mcontext.arm_pc = (unsigned long) func; + + /* Exit to startcontext() with the next context in R4 */ + ucp->uc_mcontext.arm_r4 = (unsigned long) ucp->uc_link; + ucp->uc_mcontext.arm_lr = (unsigned long) __startcontext; + + /* The first four arguments go into registers. */ + regptr = &(ucp->uc_mcontext.arm_r0); + + for (reg = 0; (reg < argc) && (reg < NREG_ARGS); reg++) + *regptr++ = va_arg (vl, unsigned long); + + /* And the remainder on the stack. */ + for (; reg < argc; reg++) + *funcstack++ = va_arg (vl, unsigned long); + + va_end (vl); +} +weak_alias (__makecontext, makecontext) -- cgit v1.2.3