cmd: add rdcycle test to RISC-V exception command

Some versions of KVM don't allow access to the cycle CSR.

Provide a command 'exception rdcycle' for testing.

If the cycle CSR is accessible, we get an output like:

    => exception rdcycle
    cycle = 0x41f7563de

If the cycle CSR is not accessible, we get an output like:

    => exception rdcycle
    Unhandled exception: Illegal instruction

Put subcommands into alphabetical order in long help.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>

diff --git a/cmd/riscv/exception.c b/cmd/riscv/exception.c
index 2b58b1c449c08d02bef2c0cba477d574258f6505..16e335327f17c6961f62158e030feca0a2fcc5ab 100644 (file)
--- a/cmd/riscv/exception.c
+++ b/cmd/riscv/exception.c
@@ -36,6 +36,14 @@ static int do_ialign16(struct cmd_tbl *cmdtp, int flag, int argc,
        return CMD_RET_SUCCESS;
 }
 
+static int do_rdcycle(struct cmd_tbl *cmdtp, int flag, int argc,
+                     char *const argv[])
+{
+       printf("cycle = 0x%lx\n", csr_read(CSR_CYCLE));
+
+       return CMD_RET_SUCCESS;
+}
+
 static int do_unaligned(struct cmd_tbl *cmdtp, int flag, int argc,
                        char *const argv[])
 {
@@ -62,6 +70,8 @@ static struct cmd_tbl cmd_sub[] = {
                         "", ""),
        U_BOOT_CMD_MKENT(ialign16, CONFIG_SYS_MAXARGS, 1, do_ialign16,
                         "", ""),
+       U_BOOT_CMD_MKENT(rdcycle, CONFIG_SYS_MAXARGS, 1, do_rdcycle,
+                        "", ""),
        U_BOOT_CMD_MKENT(unaligned, CONFIG_SYS_MAXARGS, 1, do_unaligned,
                         "", ""),
        U_BOOT_CMD_MKENT(undefined, CONFIG_SYS_MAXARGS, 1, do_undefined,
@@ -74,7 +84,8 @@ U_BOOT_LONGHELP(exception,
        "  compressed - compressed instruction\n"
        "  ebreak     - breakpoint\n"
        "  ialign16   - 16 bit aligned instruction\n"
-       "  undefined  - illegal instruction\n"
-       "  unaligned  - load address misaligned\n");
+       "  rdcycle    - read cycle CSR\n"
+       "  unaligned  - load address misaligned\n"
+       "  undefined  - illegal instruction\n");
 
 #include <exception.h>