On 4/14/24 20:39, Marek Vasut wrote:
> SoC revision is only accessible via DBUMCU IDC register,
> which requires BSEC.DENABLE DBGSWENABLE bit to be set to
> make the register accessible, otherwise an access to the
> register triggers bus fault. As BSEC.DBGSWENABLE is zero
> in case of an OTP-CLOSED system, do NOT set DBGSWENABLE
> bit as this might open a brief window for timing attacks.
> Instead, report that this system is OTP-CLOSED and do not
> report any SoC revision to avoid confusing users. Use an
> SEC/C abbreviation to avoid growing SOC_NAME_SIZE .
>
> Signed-off-by: Marek Vasut <[email protected]>
> ---
> Cc: Igor Opaniuk <[email protected]>
> Cc: Patrice Chotard <[email protected]>
> Cc: Patrick Delaunay <[email protected]>
> Cc: Simon Glass <[email protected]
> Cc: Simon Glass <[email protected]>
> Cc: Tom Rini <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> ---
> arch/arm/mach-stm32mp/stm32mp1/stm32mp15x.c | 19 +++++++++++++++++--
> 1 file changed, 17 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm/mach-stm32mp/stm32mp1/stm32mp15x.c
> b/arch/arm/mach-stm32mp/stm32mp1/stm32mp15x.c
> index afc56b02eea..dd99150fbc2 100644
> --- a/arch/arm/mach-stm32mp/stm32mp1/stm32mp15x.c
> +++ b/arch/arm/mach-stm32mp/stm32mp1/stm32mp15x.c
> @@ -322,8 +322,23 @@ void get_soc_name(char name[SOC_NAME_SIZE])
>
> get_cpu_string_offsets(&type, &pkg, &rev);
>
> - snprintf(name, SOC_NAME_SIZE, "STM32MP%s%s Rev.%s",
> - soc_type[type], soc_pkg[pkg], soc_rev[rev]);
> + if (bsec_dbgswenable()) {
> + snprintf(name, SOC_NAME_SIZE, "STM32MP%s%s Rev.%s",
> + soc_type[type], soc_pkg[pkg], soc_rev[rev]);
> + } else {
> + /*
> + * SoC revision is only accessible via DBUMCU IDC register,
> + * which requires BSEC.DENABLE DBGSWENABLE bit to be set to
> + * make the register accessible, otherwise an access to the
> + * register triggers bus fault. As BSEC.DBGSWENABLE is zero
> + * in case of an OTP-CLOSED system, do NOT set DBGSWENABLE
> + * bit as this might open a brief window for timing attacks.
> + * Instead, report that this system is OTP-CLOSED and do not
> + * report any SoC revision to avoid confusing users.
> + */
> + snprintf(name, SOC_NAME_SIZE, "STM32MP%s%s SEC/C",
> + soc_type[type], soc_pkg[pkg]);
> + }
> }
>
> static void setup_soc_type_pkg_rev(void)
Reviewed-by: Patrice Chotard <[email protected]>
Thanks
Patrice
