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) -- 2.43.0
