cmd/riscv/exception.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * The 'exception' command can be used for testing exception handling.
 *
 * Copyright (c) 2018, Heinrich Schuchardt <xypron.glpk@gmx.de>
 */

#include <command.h>

static int do_compressed(struct cmd_tbl *cmdtp, int flag, int argc,
			 char *const argv[])
{
	/* c.li a0, 0; c.li a0, 0 */
	asm volatile (".long 0x45014501\n");
	printf("The system supports compressed instructions.\n");
	return CMD_RET_SUCCESS;
}

static int do_ebreak(struct cmd_tbl *cmdtp, int flag, int argc,
			char *const argv[])
{
	asm volatile ("ebreak\n");
	return CMD_RET_FAILURE;
}

static int do_ialign16(struct cmd_tbl *cmdtp, int flag, int argc,
		       char *const argv[])
{
	asm volatile (
		/* jump skipping 2 bytes */
		".long 0x0060006f\n"
		".long 0x006f0000\n"
		".long 0x00000060\n"
	);
	printf("The system supports 16 bit aligned instructions.\n");
	return CMD_RET_SUCCESS;
}

static int do_rdcycle(struct cmd_tbl *cmdtp, int flag, int argc,
		      char *const argv[])
{
	printf("cycle = 0x%lx\n", csr_read(CSR_CYCLE));

	return CMD_RET_SUCCESS;
}

static int do_unaligned(struct cmd_tbl *cmdtp, int flag, int argc,
			char *const argv[])
{
	asm volatile (
		"auipc a1, 0\n"
		"ori   a1, a1, 3\n"
		"lw    a2, (0)(a1)\n"
	);
	printf("The system supports unaligned access.\n");
	return CMD_RET_SUCCESS;
}

static int do_undefined(struct cmd_tbl *cmdtp, int flag, int argc,
			char *const argv[])
{
	asm volatile (".word 0xffffffff\n");
	return CMD_RET_FAILURE;
}

static struct cmd_tbl cmd_sub[] = {
	U_BOOT_CMD_MKENT(compressed, CONFIG_SYS_MAXARGS, 1, do_compressed,
			 "", ""),
	U_BOOT_CMD_MKENT(ebreak, CONFIG_SYS_MAXARGS, 1, do_ebreak,
			 "", ""),
	U_BOOT_CMD_MKENT(ialign16, CONFIG_SYS_MAXARGS, 1, do_ialign16,
			 "", ""),
	U_BOOT_CMD_MKENT(rdcycle, CONFIG_SYS_MAXARGS, 1, do_rdcycle,
			 "", ""),
	U_BOOT_CMD_MKENT(unaligned, CONFIG_SYS_MAXARGS, 1, do_unaligned,
			 "", ""),
	U_BOOT_CMD_MKENT(undefined, CONFIG_SYS_MAXARGS, 1, do_undefined,
			 "", ""),
};

U_BOOT_LONGHELP(exception,
	"<ex>\n"
	"  The following exceptions are available:\n"
	"  compressed - compressed instruction\n"
	"  ebreak     - breakpoint\n"
	"  ialign16   - 16 bit aligned instruction\n"
	"  rdcycle    - read cycle CSR\n"
	"  unaligned  - load address misaligned\n"
	"  undefined  - illegal instruction\n");

#include <exception.h>