From b5e7c5da8bf3b40bec36295818f0333c5d918630 Mon Sep 17 00:00:00 2001 From: Marek Vasut Date: Sun, 14 Apr 2024 20:39:29 +0200 Subject: [PATCH] ARM: stm32: Report OTP-CLOSED instead of rev.? on closed STM32MP15xx 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 Reviewed-by: Patrice Chotard --- 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 afc56b02ee..dd99150fbc 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) -- 2.39.5