From mboxrd@z Thu Jan 1 00:00:00 1970 From: acourbot@nvidia.com (Alexandre Courbot) Date: Fri, 7 Feb 2014 13:35:02 +0900 Subject: [PATCH v2 2/6] ARM: trusted_foundations: fallback when TF support is missing In-Reply-To: <1391747706-1847-1-git-send-email-acourbot@nvidia.com> References: <1391747706-1847-1-git-send-email-acourbot@nvidia.com> Message-ID: <1391747706-1847-3-git-send-email-acourbot@nvidia.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org When Trusted Foundations is detected as present on the system, but Trusted Foundations support is not built into the kernel, the kernel used to issue a panic very early during boot, leaving little clue to the user as to what is going wrong. It turns out that even without TF support built-in, the kernel can boot on a TF-enabled system provided that SMP and cpuidle are disabled. This patch does this and continue booting on one CPU, leaving the user with a usable (however degraded) system. Signed-off-by: Alexandre Courbot --- arch/arm/include/asm/trusted_foundations.h | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/arch/arm/include/asm/trusted_foundations.h b/arch/arm/include/asm/trusted_foundations.h index 997862fd5d77..b5f7705abcb0 100644 --- a/arch/arm/include/asm/trusted_foundations.h +++ b/arch/arm/include/asm/trusted_foundations.h @@ -30,6 +30,8 @@ #include #include #include +#include +#include struct trusted_foundations_platform_data { unsigned int version_major; @@ -47,10 +49,13 @@ static inline void register_trusted_foundations( struct trusted_foundations_platform_data *pd) { /* - * If we try to register TF, this means the system needs it to continue. - * Its absence if thus a fatal error. + * If the system requires TF and we cannot provide it, continue booting + * but disable features that cannot be provided. */ - panic("No support for Trusted Foundations, stopping...\n"); + pr_err("No support for Trusted Foundations, continuing in degraded mode.\n"); + pr_err("Secondary processors as well as CPU PM will be disabled.\n"); + setup_max_cpus = 0; + cpu_idle_poll_ctrl(true); } static inline void of_register_trusted_foundations(void) -- 1.8.5.3