[U-Boot] [PATCH 1/1] cmd: add el command

[Alexander Graf]

On 11.10.18 08:08, Heinrich Schuchardt wrote:
> On 10/11/2018 05:28 AM, Heinrich Schuchardt wrote:
>> The 'el' command displays the current exception level of the processor
>> on the aarch64 architecture.
>>
>> This information is needed to analyze problems in the EFI subsystem.
>>
>> Signed-off-by: Heinrich Schuchardt <xypron.glpk at gmx.de>
>> ---
>>  cmd/Kconfig  |  7 +++++++
>>  cmd/Makefile |  1 +
>>  cmd/el.c     | 25 +++++++++++++++++++++++++
>>  3 files changed, 33 insertions(+)
>>  create mode 100644 cmd/el.c
>>
>> diff --git a/cmd/Kconfig b/cmd/Kconfig
>> index 7ed3c9c3b3..cfad07432e 100644
>> --- a/cmd/Kconfig
>> +++ b/cmd/Kconfig
>> @@ -1373,6 +1373,13 @@ config CMD_DISPLAY
>>  	  displayed on a simple board-specific display. Implement
>>  	  display_putc() to use it.
>>  
>> +config CMD_EL
>> +	bool "el - display processor exception level"
>> +	depends on ARM64
>> +	help
>> +	  Enable the 'el' command which displays the exception level of the
>> +	  processor.
>> +
>>  config CMD_LED
>>  	bool "led"
>>  	default y if LED
>> diff --git a/cmd/Makefile b/cmd/Makefile
>> index d9cdaf6064..63e3afd56b 100644
>> --- a/cmd/Makefile
>> +++ b/cmd/Makefile
>> @@ -47,6 +47,7 @@ endif
>>  obj-$(CONFIG_CMD_DISPLAY) += display.o
>>  obj-$(CONFIG_CMD_DTIMG) += dtimg.o
>>  obj-$(CONFIG_CMD_ECHO) += echo.o
>> +obj-$(CONFIG_CMD_EL) += el.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/el.c b/cmd/el.c
>> new file mode 100644
>> index 0000000000..57081c36f2
>> --- /dev/null
>> +++ b/cmd/el.c
>> @@ -0,0 +1,25 @@
>> +// SPDX-License-Identifier: GPL-2.0+
>> +/*
>> + * The 'el' command prints the current exception level
>> + *
>> + * Copyright (c) 2018, Heinrich Schuchardt <xypron.glpk at gmx.de>
>> + */
>> +#include <common.h>
>> +#include <command.h>
>> +#include <asm/system.h>
>> +
>> +static int do_el(cmd_tbl_t *cmdtp, int flag, int argc,
>> +		 char * const argv[])
>> +{
>> +	printf("processor exception level: EL%d\n", current_el());
>> +	return CMD_RET_SUCCESS;
>> +}
>> +
>> +#ifdef CONFIG_SYS_LONGHELP
>> +static char el_help_text[] = "";
>> +#endif
>> +
>> +U_BOOT_CMD_COMPLETE
>> +	(el, 2, 0, do_el,
>> +	 "display processor exception level",
>> +	 el_help_text, NULL);
>>
> Would it be preferable to include the information about the exception
> level to the bdinfo command?
> 
> An example where the information came in handy is
> https://lists.denx.de/pipermail/u-boot/2018-October/343998.html
> efi_loader: PSCI reset and shutdown for EL1

I think bdinfo is exactly the right spot for it, yes.

The only other good alternative I can think of would be an env variable.
That way you could do something conditionally based on the EL. But I
doubt anyone really needs that - and it'd clutter nvram.


Alex