diff --git a/arch/riscv64/makecontext.c b/arch/riscv64/makecontext.c new file mode 100644 index 0000000..7325a9a --- /dev/null +++ b/arch/riscv64/makecontext.c @@ -0,0 +1,62 @@ +/* + * Copyright (c) 2018 Ariadne Conill + * + * Permission to use, copy, modify, and/or distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * This software is provided 'as is' and without any warranty, express or + * implied. In no event shall the authors be liable for any damages arising + * from the use of this software. + */ + +#define _GNU_SOURCE +#include +#include +#include +#include +#include +#include +#include "defs.h" + + +extern void __start_context(void); + + +void +__makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...) +{ + greg_t *sp, *regp; + va_list va; + int i; + + /* set up and align the stack. */ + sp = (greg_t *) ((uintptr_t) ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size); + sp -= argc < 8 ? 0 : argc - 8; + sp = (greg_t *) (((uintptr_t) sp & -16L)); + + /* set up the ucontext structure */ + ucp->uc_mcontext.gregs[REG_PC] = (greg_t) __start_context; + ucp->uc_mcontext.gregs[REG_S0] = 0; + ucp->uc_mcontext.gregs[REG_S1] = (greg_t) func; + ucp->uc_mcontext.gregs[REG_S2] = (greg_t) ucp->uc_link; + ucp->uc_mcontext.gregs[REG_SP] = (greg_t) sp; + ucp->uc_mcontext.gregs[REG_PC_SAVE] = 0; + + va_start(va, argc); + + /* first 8 args go in $a0 through $a7. */ + regp = &(ucp->uc_mcontext.gregs[REG_A0]); + + for (i = 0; (i < argc && i < 8); i++) + *regp++ = va_arg (va, greg_t); + + /* remainder overflows into stack */ + for (; i < argc; i++) + *sp++ = va_arg (va, greg_t); + + va_end(va); +} + + +extern __typeof(__makecontext) makecontext __attribute__((weak, __alias__("__makecontext"))); diff --git a/arch/riscv64/startcontext.S b/arch/riscv64/startcontext.S new file mode 100644 index 0000000..9a885c8 --- /dev/null +++ b/arch/riscv64/startcontext.S @@ -0,0 +1,29 @@ +/* + * Copyright (c) 2020 Ariadne Conill + * + * Permission to use, copy, modify, and/or distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * This software is provided 'as is' and without any warranty, express or + * implied. In no event shall the authors be liable for any damages arising + * from the use of this software. + */ + +#include "defs.h" + +FUNC(__start_context) + /* call the function passed to makecontext() */ + jalr s1 + + /* check for linked context */ + beqz s2, no_linked_context + + /* if one is set, invoke it */ + mv a0, s2 + jal __setcontext + + /* otherwise, exit. */ +no_linked_context: + j exit +END(__start_context)