[PATCH] smbios: Fix BIOS Characteristics Extension Byte 2

[Heinrich Schuchardt]

On 6/9/21 5:14 PM, Ilias Apalodimas wrote:
> We currently define the EFI support of an SMBIOS table as the third bit of
> "BIOS Characteristics Extension Byte 1".  The latest DMTF spec defines it
> on "BIOS Characteristics Extension Byte 2".
>
> Signed-off-by: Ilias Apalodimas <ilias.apalodimas at linaro.org>
> ---
>   include/smbios.h | 2 +-
>   lib/smbios.c     | 5 +++--
>   2 files changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/include/smbios.h b/include/smbios.h
> index ffeefb47372d..fc49fc10b9d7 100644
> --- a/include/smbios.h
> +++ b/include/smbios.h
> @@ -60,7 +60,7 @@ struct __packed smbios_entry {
>   #define BIOS_CHARACTERISTICS_SELECTABLE_BOOT	(1 << 16)
>
>   #define BIOS_CHARACTERISTICS_EXT1_ACPI		(1 << 0)
> -#define BIOS_CHARACTERISTICS_EXT1_UEFI		(1 << 3)
> +#define BIOS_CHARACTERISTICS_EXT2_UEFI		(1 << 3)
>   #define BIOS_CHARACTERISTICS_EXT2_TARGET	(1 << 2)
>
>   struct __packed smbios_type0 {
> diff --git a/lib/smbios.c b/lib/smbios.c
> index 9eb226ec9fbd..abdd157a7084 100644
> --- a/lib/smbios.c
> +++ b/lib/smbios.c
> @@ -214,6 +214,7 @@ static int smbios_write_type0(ulong *current, int handle,
>   		gd->smbios_version = ctx->last_str;
>   	log_debug("smbios_version = %p: '%s'\n", gd->smbios_version,
>   		  gd->smbios_version);
> +	t->bios_characteristics_ext2 = 0;
>   #ifdef LOG_DEBUG
>   	print_buffer((ulong)gd->smbios_version, gd->smbios_version,
>   		     1, strlen(gd->smbios_version) + 1, 0);
> @@ -229,9 +230,9 @@ static int smbios_write_type0(ulong *current, int handle,
>   	t->bios_characteristics_ext1 = BIOS_CHARACTERISTICS_EXT1_ACPI;

This looks fishy. Where is t->bios_characteristics_ext1 initialized if
CONFIG_GENERATE_ACPI_TABLE=n? efi_smbios_register() does not zero out
the memory.

We should initialize the field irrespective of the configuration and
then use a bitwise or here.

>   #endif
>   #ifdef CONFIG_EFI_LOADER
> -	t->bios_characteristics_ext1 |= BIOS_CHARACTERISTICS_EXT1_UEFI;
> +	t->bios_characteristics_ext2 |= BIOS_CHARACTERISTICS_EXT2_UEFI;
>   #endif
> -	t->bios_characteristics_ext2 = BIOS_CHARACTERISTICS_EXT2_TARGET;
> +	t->bios_characteristics_ext2 |= BIOS_CHARACTERISTICS_EXT2_TARGET;

Where is t->bios_characteristics_ext2 initialized?
We don't want random bytes.

@Simon:
The usage of ulong instead of pointers in this module does not make
sense to me. If the sandbox needs to call it, it should map its virtual
addresses. We should not spill those conversion into non-sandbox code.

Best regards

Heinrich

>
>   	/* bios_major_release has only one byte, so drop century */
>   	t->bios_major_release = U_BOOT_VERSION_NUM % 100;
>