90 lines
2.5 KiB
C
90 lines
2.5 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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#include <linux/bitops.h>
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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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/*
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* Instructions starting with the upper 16 bits all 0 are permanently
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* undefined. The lower 16 bits can be used for some kind of immediate.
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* --- ARMv8 ARM (ARM DDI 0487G.a C6.2.339: "UDF")
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*/
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asm volatile (".word 0x00001234\n");
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return CMD_RET_FAILURE;
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}
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/*
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* The ID_AA64MMFR2_EL1 register name is only know to binutils for ARMv8.2
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* and later architecture revisions. However the register is valid regardless
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* of binutils architecture support or the core the code is running on, so
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* just use the generic encoding.
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*/
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#define ID_AA64MMFR2_EL1 "S3_0_C0_C7_2"
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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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uint64_t reg;
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/*
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* The unaligned LDAR access below is only guaranteed to generate an
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* alignment fault on cores not implementing FEAT_LSE2. To avoid false
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* negatives, check this condition before we exectute LDAR.
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*/
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asm ("mrs %0, "ID_AA64MMFR2_EL1"\n" : "=r" (reg));
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if (reg & GENMASK(35, 32)) {
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printf("unaligned access check only supported on pre-v8.4 cores\n");
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return CMD_RET_FAILURE;
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}
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/*
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* The load acquire instruction requires the data source to be
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* naturally aligned, and will fault even if strict alignment fault
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* checking is disabled (but only without FEAT_LSE2).
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* --- ARMv8 ARM (ARM DDI 0487G.a B2.5.2: "Alignment of data accesses")
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*/
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asm volatile (
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"mov x1, sp\n\t"
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"orr x1, x1, #3\n\t"
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"ldar x0, [x1]\n"
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::: "x0", "x1" );
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return CMD_RET_FAILURE;
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}
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static int do_breakpoint(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 ("brk #123\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(breakpoint, CONFIG_SYS_MAXARGS, 1, do_breakpoint,
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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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" breakpoint - breakpoint instruction exception\n"
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" unaligned - unaligned LDAR data abort\n"
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" undefined - undefined instruction exception\n"
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;
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#include <exception.h>
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