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/* Create new context.
Copyright (C) 2022-2023 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 <sys/asm.h>
#include <sys/ucontext.h>
#include <stdarg.h>
#include <assert.h>
void
__makecontext (ucontext_t *ucp, void (*func) (void), int argc, long int a0,
long int a1, long int a2, long int a3, long int a4, ...)
{
extern void __start_context (void) attribute_hidden;
unsigned long int *sp;
_Static_assert(LARCH_REG_NARGS == 8,
"__makecontext assumes 8 argument registers");
/* Set up the stack. */
sp = (unsigned long int *)
(((uintptr_t) ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size) & ALMASK);
/* Set up the register context.
ra = s0 = 0, terminating the stack for backtracing purposes.
s1 = the function we must call.
s2 = the subsequent context to run. */
ucp->uc_mcontext.__gregs[LARCH_REG_RA] = (uintptr_t) 0;
ucp->uc_mcontext.__gregs[LARCH_REG_S0] = (uintptr_t) 0;
ucp->uc_mcontext.__gregs[LARCH_REG_S1] = (uintptr_t) func;
ucp->uc_mcontext.__gregs[LARCH_REG_S2] = (uintptr_t) ucp->uc_link;
ucp->uc_mcontext.__gregs[LARCH_REG_SP] = (uintptr_t) sp;
ucp->uc_mcontext.__pc = (uintptr_t) &__start_context;
/* Put args in a0-a7, then put any remaining args on the stack. */
ucp->uc_mcontext.__gregs[LARCH_REG_A0 + 0] = (uintptr_t) a0;
ucp->uc_mcontext.__gregs[LARCH_REG_A0 + 1] = (uintptr_t) a1;
ucp->uc_mcontext.__gregs[LARCH_REG_A0 + 2] = (uintptr_t) a2;
ucp->uc_mcontext.__gregs[LARCH_REG_A0 + 3] = (uintptr_t) a3;
ucp->uc_mcontext.__gregs[LARCH_REG_A0 + 4] = (uintptr_t) a4;
if (__glibc_unlikely (argc > 5))
{
va_list vl;
va_start (vl, a4);
long int reg_args = argc < LARCH_REG_NARGS ? argc : LARCH_REG_NARGS;
for (long int i = 5; i < reg_args; i++)
ucp->uc_mcontext.__gregs[LARCH_REG_A0 + i] = va_arg (vl, unsigned long int);
long int stack_args = argc - reg_args;
if (stack_args > 0)
{
sp = (unsigned long int *)
(((uintptr_t) sp - stack_args * sizeof (long int)) & ALMASK);
ucp->uc_mcontext.__gregs[LARCH_REG_SP] = (uintptr_t) sp;
for (long int i = 0; i < stack_args; i++)
sp[i] = va_arg (vl, unsigned long int);
}
va_end (vl);
}
}
weak_alias (__makecontext, makecontext)
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