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1806fed0ce
Some versions of KVM don't allow access to the cycle CSR.
Provide a command 'exception rdcycle' for testing.
If the cycle CSR is accessible, we get an output like:
=> exception rdcycle
cycle = 0x41f7563de
If the cycle CSR is not accessible, we get an output like:
=> exception rdcycle
Unhandled exception: Illegal instruction
Put subcommands into alphabetical order in long help.
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>
92 lines
2.3 KiB
C
92 lines
2.3 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* The 'exception' command can be used for testing exception handling.
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*
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* Copyright (c) 2018, Heinrich Schuchardt <xypron.glpk@gmx.de>
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*/
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#include <command.h>
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static int do_compressed(struct cmd_tbl *cmdtp, int flag, int argc,
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char *const argv[])
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{
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/* c.li a0, 0; c.li a0, 0 */
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asm volatile (".long 0x45014501\n");
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printf("The system supports compressed instructions.\n");
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return CMD_RET_SUCCESS;
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}
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static int do_ebreak(struct cmd_tbl *cmdtp, int flag, int argc,
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char *const argv[])
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{
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asm volatile ("ebreak\n");
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return CMD_RET_FAILURE;
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}
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static int do_ialign16(struct cmd_tbl *cmdtp, int flag, int argc,
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char *const argv[])
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{
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asm volatile (
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/* jump skipping 2 bytes */
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".long 0x0060006f\n"
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".long 0x006f0000\n"
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".long 0x00000060\n"
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);
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printf("The system supports 16 bit aligned instructions.\n");
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return CMD_RET_SUCCESS;
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}
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static int do_rdcycle(struct cmd_tbl *cmdtp, int flag, int argc,
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char *const argv[])
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{
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printf("cycle = 0x%lx\n", csr_read(CSR_CYCLE));
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return CMD_RET_SUCCESS;
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}
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static int do_unaligned(struct cmd_tbl *cmdtp, int flag, int argc,
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char *const argv[])
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{
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asm volatile (
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"auipc a1, 0\n"
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"ori a1, a1, 3\n"
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"lw a2, (0)(a1)\n"
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);
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printf("The system supports unaligned access.\n");
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return CMD_RET_SUCCESS;
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}
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static int do_undefined(struct cmd_tbl *cmdtp, int flag, int argc,
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char *const argv[])
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{
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asm volatile (".word 0xffffffff\n");
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return CMD_RET_FAILURE;
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}
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static struct cmd_tbl cmd_sub[] = {
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U_BOOT_CMD_MKENT(compressed, CONFIG_SYS_MAXARGS, 1, do_compressed,
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"", ""),
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U_BOOT_CMD_MKENT(ebreak, CONFIG_SYS_MAXARGS, 1, do_ebreak,
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"", ""),
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U_BOOT_CMD_MKENT(ialign16, CONFIG_SYS_MAXARGS, 1, do_ialign16,
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"", ""),
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U_BOOT_CMD_MKENT(rdcycle, CONFIG_SYS_MAXARGS, 1, do_rdcycle,
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"", ""),
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U_BOOT_CMD_MKENT(unaligned, CONFIG_SYS_MAXARGS, 1, do_unaligned,
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"", ""),
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U_BOOT_CMD_MKENT(undefined, CONFIG_SYS_MAXARGS, 1, do_undefined,
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"", ""),
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};
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U_BOOT_LONGHELP(exception,
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"<ex>\n"
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" The following exceptions are available:\n"
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" compressed - compressed instruction\n"
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" ebreak - breakpoint\n"
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" ialign16 - 16 bit aligned instruction\n"
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" rdcycle - read cycle CSR\n"
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" unaligned - load address misaligned\n"
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" undefined - illegal instruction\n");
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#include <exception.h>
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