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82 lines
2.9 KiB
C
82 lines
2.9 KiB
C
/* Create new context.
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Copyright (C) 2022 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library. If not, see
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<https://www.gnu.org/licenses/>. */
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#include <sysdep.h>
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#include <sys/asm.h>
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#include <sys/ucontext.h>
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#include <stdarg.h>
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#include <assert.h>
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void
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__makecontext (ucontext_t *ucp, void (*func) (void), int argc, long int a0,
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long int a1, long int a2, long int a3, long int a4, ...)
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{
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extern void __start_context (void) attribute_hidden;
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unsigned long int *sp;
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_Static_assert(LARCH_REG_NARGS == 8,
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"__makecontext assumes 8 argument registers");
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/* Set up the stack. */
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sp = (unsigned long int *)
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(((uintptr_t) ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size) & ALMASK);
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/* Set up the register context.
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ra = s0 = 0, terminating the stack for backtracing purposes.
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s1 = the function we must call.
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s2 = the subsequent context to run. */
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ucp->uc_mcontext.__gregs[LARCH_REG_RA] = (uintptr_t) 0;
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ucp->uc_mcontext.__gregs[LARCH_REG_S0] = (uintptr_t) 0;
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ucp->uc_mcontext.__gregs[LARCH_REG_S1] = (uintptr_t) func;
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ucp->uc_mcontext.__gregs[LARCH_REG_S2] = (uintptr_t) ucp->uc_link;
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ucp->uc_mcontext.__gregs[LARCH_REG_SP] = (uintptr_t) sp;
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ucp->uc_mcontext.__pc = (uintptr_t) &__start_context;
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/* Put args in a0-a7, then put any remaining args on the stack. */
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ucp->uc_mcontext.__gregs[LARCH_REG_A0 + 0] = (uintptr_t) a0;
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ucp->uc_mcontext.__gregs[LARCH_REG_A0 + 1] = (uintptr_t) a1;
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ucp->uc_mcontext.__gregs[LARCH_REG_A0 + 2] = (uintptr_t) a2;
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ucp->uc_mcontext.__gregs[LARCH_REG_A0 + 3] = (uintptr_t) a3;
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ucp->uc_mcontext.__gregs[LARCH_REG_A0 + 4] = (uintptr_t) a4;
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if (__glibc_unlikely (argc > 5))
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{
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va_list vl;
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va_start (vl, a4);
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long int reg_args = argc < LARCH_REG_NARGS ? argc : LARCH_REG_NARGS;
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for (long int i = 5; i < reg_args; i++)
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ucp->uc_mcontext.__gregs[LARCH_REG_A0 + i] = va_arg (vl, unsigned long int);
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long int stack_args = argc - reg_args;
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if (stack_args > 0)
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{
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sp = (unsigned long int *)
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(((uintptr_t) sp - stack_args * sizeof (long int)) & ALMASK);
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ucp->uc_mcontext.__gregs[LARCH_REG_SP] = (uintptr_t) sp;
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for (long int i = 0; i < stack_args; i++)
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sp[i] = va_arg (vl, unsigned long int);
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}
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va_end (vl);
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}
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}
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weak_alias (__makecontext, makecontext)
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