[PATCH v2] cmd: exception: unaligned data access on RISC-V

[Heinrich Schuchardt]

The command 'exception' can be used to test the handling of exceptions.

Currently the exception command only allows to create an illegal
instruction exception on RISC-V.

Provide a sub-command 'exception unaligned' to cause a misaligned load
address exception.

Adjust the online help for 'exception undefined'.

Signed-off-by: Heinrich Schuchardt <xypron.g...@gmx.de>
---
v2:
        If unaligned access is support, print success message.
---
 cmd/riscv/exception.c | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/cmd/riscv/exception.c b/cmd/riscv/exception.c
index 3c8dbbec0e..9687cec812 100644
--- a/cmd/riscv/exception.c
+++ b/cmd/riscv/exception.c
@@ -8,6 +8,18 @@
 #include <common.h>
 #include <command.h>

+static int do_unaligned(struct cmd_tbl *cmdtp, int flag, int argc,
+                       char *const argv[])
+{
+       asm volatile (
+               "auipc a1, 0\n"
+               "ori   a1, a1, 3\n"
+               "lw    a2, (0)(a1)\n"
+       );
+       printf("The system supports unaligned access.\n");
+       return CMD_RET_SUCCESS;
+}
+
 static int do_undefined(struct cmd_tbl *cmdtp, int flag, int argc,
                        char *const argv[])
 {
@@ -16,6 +28,8 @@ static int do_undefined(struct cmd_tbl *cmdtp, int flag, int 
argc,
 }

 static struct cmd_tbl cmd_sub[] = {
+       U_BOOT_CMD_MKENT(unaligned, CONFIG_SYS_MAXARGS, 1, do_unaligned,
+                        "", ""),
        U_BOOT_CMD_MKENT(undefined, CONFIG_SYS_MAXARGS, 1, do_undefined,
                         "", ""),
 };
@@ -23,7 +37,8 @@ static struct cmd_tbl cmd_sub[] = {
 static char exception_help_text[] =
        "<ex>\n"
        "  The following exceptions are available:\n"
-       "  undefined  - undefined instruction\n"
+       "  undefined - illegal instruction\n"
+       "  unaligned - load address misaligned\n"
        ;

 #include <exception.h>
--
2.27.0