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Diffstat (limited to 'kernel/arch/riscv/execsp.S')
| -rw-r--r-- | kernel/arch/riscv/execsp.S | 100 |
1 files changed, 100 insertions, 0 deletions
diff --git a/kernel/arch/riscv/execsp.S b/kernel/arch/riscv/execsp.S new file mode 100644 index 000000000000..d045cbf0d3af --- /dev/null +++ b/kernel/arch/riscv/execsp.S @@ -0,0 +1,100 @@ +/* $NetBSD: execsp.S,v 1.1 2025/04/20 22:34:07 riastradh Exp $ */ + +/*- + * Copyright (c) 2025 The NetBSD Foundation, Inc. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS + * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED + * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR + * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS + * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ + +#define _LOCORE + +#include <machine/asm.h> + +RCSID("$NetBSD: execsp.S,v 1.1 2025/04/20 22:34:07 riastradh Exp $") + +/* + * void execsp_start(void (*cleanup@a0)(void), + * struct ps_strings *ps_strings@a1) + * + * ELF entry point. Saves the stack pointer in startsp and defers + * to the usual csu __start routine. + */ +ENTRY(execsp_start) + .option push + .option norelax /* Don't optimize this into `mv gp, gp'! */ + lla gp, __global_pointer$ + .option pop + + PTR_LA t0, _C_LABEL(startsp) /* t0 := &startsp */ + PTR_S sp, 0(t0) /* startsp := sp */ + tail _C_LABEL(__start) /* tail call __start */ +END(execsp_start) + +/* + * void execsp_ctor(void) + * + * ELF constructor. Saves the stack pointer in ctorsp and + * returns. + */ +ENTRY(execsp_ctor) + PTR_LA t0, _C_LABEL(ctorsp) /* t0 := &ctorsp */ + PTR_S sp, 0(t0) /* ctorsp := sp */ + ret +END(execsp_ctor) + + /* Make execsp_ctor a constructor. */ + .section .init_array,"aw" + .p2align PTR_SCALESHIFT + PTR_WORD _C_LABEL(execsp_ctor) + +/* + * int main(int argc@a0, char **argv@a1, ...) + * + * Main function. Saves the stack pointer in mainsp and returns + * zero. We will call execsp_main in execsp_dtor once dtorsp has + * been initialized. + */ +ENTRY(main) + PTR_LA t0, _C_LABEL(mainsp) /* t0 := &mainsp */ + PTR_S sp, 0(t0) /* mainsp := sp */ + li a0, 0 /* return 0 */ + ret +END(main) + +/* + * void execsp_dtor(void) + * + * ELF destructor. Saves the stack pointer in dtorsp and defers + * to the C execsp_main in h_execsp.c to report the stack pointers + * back to the t_signal_and_sp parent. + */ +ENTRY(execsp_dtor) + PTR_LA t0, _C_LABEL(dtorsp) /* t0 := &dtorsp */ + PTR_S sp, 0(t0) /* dtorsp := sp */ + tail _C_LABEL(execsp_main) /* tail call execsp_main */ +END(execsp_dtor) + + /* Make execsp_ctor a destructor. */ + .section .fini_array,"aw" + .p2align PTR_SCALESHIFT + PTR_WORD _C_LABEL(execsp_dtor) |