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