The 'exception' command allows to test exception handling.
This implementation supports ARM, x86, RISC-V and the following exceptions:
* 'breakpoint' - prefetch abort exception (ARM 32bit only)
* 'unaligned' - data abort exception (ARM only)
* 'undefined' - undefined instruction exception
Signed-off-by: Heinrich Schuchardt <xypron.g...@gmx.de>
---
Currently RISC-V 64bit gets into an endless loop when hitting the
undefined instruction.
So it makes sense to have a testing capability.
---
cmd/Kconfig | 6 ++
cmd/Makefile | 1 +
cmd/exception.c | 161 ++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 168 insertions(+)
create mode 100644 cmd/exception.c
diff --git a/cmd/Kconfig b/cmd/Kconfig
index e2973b3c51..9d2b8199b8 100644
--- a/cmd/Kconfig
+++ b/cmd/Kconfig
@@ -1388,6 +1388,12 @@ config CMD_DISPLAY
displayed on a simple board-specific display. Implement
display_putc() to use it.
+config CMD_EXCEPTION
+ bool "exception - raise exception"
+ depends on ARM || RISCV || X86
+ help
+ Enable the 'exception' command which allows to raise an exception.
+
config CMD_LED
bool "led"
default y if LED
diff --git a/cmd/Makefile b/cmd/Makefile
index 0534ddc679..cd67a79170 100644
--- a/cmd/Makefile
+++ b/cmd/Makefile
@@ -46,6 +46,7 @@ endif
obj-$(CONFIG_CMD_DISPLAY) += display.o
obj-$(CONFIG_CMD_DTIMG) += dtimg.o
obj-$(CONFIG_CMD_ECHO) += echo.o
+obj-$(CONFIG_CMD_EXCEPTION) += exception.o
obj-$(CONFIG_ENV_IS_IN_EEPROM) += eeprom.o
obj-$(CONFIG_CMD_EEPROM) += eeprom.o
obj-$(CONFIG_EFI_STUB) += efi.o
diff --git a/cmd/exception.c b/cmd/exception.c
new file mode 100644
index 0000000000..fb6a15573e
--- /dev/null
+++ b/cmd/exception.c
@@ -0,0 +1,161 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * The 'exception' command can be used for testing exception handling.
+ *
+ * Copyright (c) 2018, Heinrich Schuchardt <xypron.g...@gmx.de>
+ */
+#include <common.h>
+#include <command.h>
+
+enum exception {
+ UNDEFINED_INSTRUCTION = 1,
+ DATA_ABORT,
+ BREAKPOINT,
+};
+
+struct exception_str {
+ enum exception id;
+ char *text;
+ void (*func)(void);
+};
+
+#if defined(CONFIG_ARM)
+static void data_abort(void)
+{
+#if defined(CONFIG_ARM64)
+ /*
+ * The LDR instruction requires the data source to be eight byte
+ * aligned.
+ */
+ asm volatile (
+ "MOV x1, sp\n"
+ "ADD x1, x1, 1\n"
+ "LDR x3, [x1]\n");
+#else
+ /*
+ * The LDRD instruction requires the data source to be four byte aligned
+ * even if strict alignment fault checking is disabled in the system
+ * control register.
+ */
+ asm volatile (
+ "MOV r5, sp\n"
+ "ADD r5, #1\n"
+ "LDRD r6, r7, [r5]\n");
+#endif
+}
+
+#if !defined(CONFIG_ARM64)
+static void breakpoint(void)
+{
+ asm volatile ("BKPT #123\n");
+}
+#endif
+#endif
+
+static void undefined_instruction(void)
+{
+#if defined(CONFIG_ARM)
+ /*
+ * 0xe7f...f. is undefined in ARM mode
+ * 0xde.. is undefined in Thumb mode
+ */
+ asm volatile (".word 0xe7f7defb\n");
+#elif defined(CONFIG_RISCV)
+ asm volatile (".word 0xffffffff\n");
+#elif defined(CONFIG_X86)
+ asm volatile (".word 0xffff\n");
+#endif
+}
+
+struct exception_str exceptions[] = {
+#if defined(CONFIG_ARM)
+#if !defined(CONFIG_ARM64)
+ { BREAKPOINT, "breakpoint", breakpoint },
+#endif
+ { DATA_ABORT, "unaligned", data_abort },
+#endif
+ { UNDEFINED_INSTRUCTION, "undefined", undefined_instruction },
+ { 0, NULL, NULL },
+};
+
+static int do_exception(cmd_tbl_t *cmdtp, int flag, int argc,
+ char * const argv[])
+{
+ struct exception_str *ex;
+ enum exception id = 0;
+
+ if (argc != 2)
+ return CMD_RET_USAGE;
+
+ for (ex = exceptions; ex->func ; ++ex) {
+ if (!strcmp(argv[1], ex->text)) {
+ id = ex->id;
+ break;
+ }
+ }
+ switch (id) {
+#if defined(CONFIG_ARM)
+#if !defined(CONFIG_ARM64)
+ case BREAKPOINT:
+ breakpoint();
+ break;
+#endif
+ case DATA_ABORT:
+ data_abort();
+ break;
+#endif
+ case UNDEFINED_INSTRUCTION:
+ undefined_instruction();
+ break;
+ default:
+ return CMD_RET_USAGE;
+ }
+
+ return CMD_RET_FAILURE;
+}
+
+static int exception_complete(int argc, char * const argv[], char last_char,
+ int maxv, char *cmdv[])
+{
+ int len = 0;
+ struct exception_str *ex;
+ int i = 0;
+
+ switch (argc) {
+ case 1:
+ break;
+ case 2:
+ len = strlen(argv[1]);
+ break;
+ default:
+ return 0;
+ }
+ for (ex = exceptions; ex->func ; ++ex) {
+ if (i >= maxv - 1)
+ return i;
+ if (!strncmp(argv[1], ex->text, len))
+ cmdv[i++] = ex->text;
+ }
+ cmdv[i] = NULL;
+ return i;
+}
+
+#ifdef CONFIG_SYS_LONGHELP
+static char exception_help_text[] =
+ "<ex>\n"
+ " The following exceptions are available:\n"
+#if defined(CONFIG_ARM)
+#if !defined(CONFIG_ARM64)
+ " breakpoint - prefetch abort\n"
+#endif
+ " unaligned - data abort\n"
+#endif
+#endif
+ " undefined - undefined instruction\n"
+ ;
+
+U_BOOT_CMD_COMPLETE(
+ exception, 2, 0, do_exception,
+ "Forces an exception to occur",
+ exception_help_text, exception_complete
+);
--
2.19.1
_______________________________________________
U-Boot mailing list
U-Boot@lists.denx.de
https://lists.denx.de/listinfo/u-boot
