mirror of
https://github.com/AsahiLinux/u-boot
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f2e4b9d3c2
Eliminating the C extension on application processors is under
discussion.
Support emitting a compressed instruction. This will lead to an
illegal instruction exception if the C extension is not implemented.
For testing build qemu-riscv64_defconfig with CONFIG_RISCV_ISA_C=n
and run with
qemu-system-riscv64 -M virt -bios u-boot -nographic -cpu rv64,c=false
=> exception compressed
Unhandled exception: Illegal instruction
EPC: 0000000087731708 RA: 000000008773fe44 TVAL: 0000000000004501
EPC: 000000008001b708 RA: 0000000080029e44 reloc adjusted
Code: 0b93 0000 0493 0000 0993 0000 f06f ccdf (4501)
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>
66 lines
1.6 KiB
C
66 lines
1.6 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 <common.h>
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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_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(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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static char exception_help_text[] =
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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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" undefined - illegal instruction\n"
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" unaligned - load address misaligned\n"
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;
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#include <exception.h>
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