diff options
Diffstat (limited to 'sysdeps/unix/sysv/linux/or1k/makecontext.c')
-rw-r--r-- | sysdeps/unix/sysv/linux/or1k/makecontext.c | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/or1k/makecontext.c b/sysdeps/unix/sysv/linux/or1k/makecontext.c new file mode 100644 index 0000000000..f0bcadfc74 --- /dev/null +++ b/sysdeps/unix/sysv/linux/or1k/makecontext.c @@ -0,0 +1,77 @@ +/* Create new context. OpenRISC version. + 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, see + <https://www.gnu.org/licenses/>. */ + +#include <sysdep.h> +#include <stdarg.h> +#include <stdint.h> +#include <ucontext.h> + +/* makecontext sets up a stack and the registers for the + user context. The stack looks like this: + + +-----------------------+ + | padding as required | + +-----------------------+ + sp -> | parameters 7 to n | + +-----------------------+ + + The registers are set up like this: + r3-r8 : parameters 1 to 6 + r14 : uc_link + r1 : stack pointer + r2 : frame pointer, set to NULL +*/ +void +__makecontext (ucontext_t *ucp, void (*func) (void), int argc, ...) +{ + extern void __startcontext (void); + unsigned long int *sp; + va_list ap; + int i; + + sp = (unsigned long int *) + ((uintptr_t) ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size); + + /* Allocate stack arguments. */ + sp -= argc < 6 ? 0 : argc - 6; + + /* Keep the stack aligned. */ + sp = (unsigned long int *) (((uintptr_t) sp) & -4L); + + /* Keep uc_link in r14. */ + ucp->uc_mcontext.__gprs[14] = (uintptr_t) ucp->uc_link; + /* Return address points to function __startcontext. */ + ucp->uc_mcontext.__gprs[9] = (uintptr_t) &__startcontext; + /* Frame pointer is null. */ + ucp->uc_mcontext.__gprs[2] = (uintptr_t) 0; + /* Restart in user-space starting at 'func'. */ + ucp->uc_mcontext.__gprs[11] = (uintptr_t) func; + /* Set stack pointer. */ + ucp->uc_mcontext.__gprs[1] = (uintptr_t) sp; + + va_start (ap, argc); + for (i = 0; i < argc; ++i) + if (i < 6) + ucp->uc_mcontext.__gprs[i + 3] = va_arg (ap, unsigned long int); + else + sp[i - 6] = va_arg (ap, unsigned long int); + + va_end (ap); +} + +weak_alias (__makecontext, makecontext) |