diff options
| -rw-r--r-- | arch/arm/mach-omap2/omap-smp.c | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/arch/arm/mach-omap2/omap-smp.c b/arch/arm/mach-omap2/omap-smp.c index 69df3620eca5..1c73694c871a 100644 --- a/arch/arm/mach-omap2/omap-smp.c +++ b/arch/arm/mach-omap2/omap-smp.c @@ -109,6 +109,45 @@ void omap5_erratum_workaround_801819(void) static inline void omap5_erratum_workaround_801819(void) { } #endif +#ifdef CONFIG_HARDEN_BRANCH_PREDICTOR +/* + * Configure ACR and enable ACTLR[0] (Enable invalidates of BTB with + * ICIALLU) to activate the workaround for secondary Core. + * NOTE: it is assumed that the primary core's configuration is done + * by the boot loader (kernel will detect a misconfiguration and complain + * if this is not done). + * + * In General Purpose(GP) devices, ACR bit settings can only be done + * by ROM code in "secure world" using the smc call and there is no + * option to update the "firmware" on such devices. This also works for + * High security(HS) devices, as a backup option in case the + * "update" is not done in the "security firmware". + */ +static void omap5_secondary_harden_predictor(void) +{ + u32 acr, acr_mask; + + asm volatile ("mrc p15, 0, %0, c1, c0, 1" : "=r" (acr)); + + /* + * ACTLR[0] (Enable invalidates of BTB with ICIALLU) + */ + acr_mask = BIT(0); + + /* Do we already have it done.. if yes, skip expensive smc */ + if ((acr & acr_mask) == acr_mask) + return; + + acr |= acr_mask; + omap_smc1(OMAP5_DRA7_MON_SET_ACR_INDEX, acr); + + pr_debug("%s: ARM ACR setup for CVE_2017_5715 applied on CPU%d\n", + __func__, smp_processor_id()); +} +#else +static inline void omap5_secondary_harden_predictor(void) { } +#endif + static void omap4_secondary_init(unsigned int cpu) { /* @@ -131,6 +170,8 @@ static void omap4_secondary_init(unsigned int cpu) set_cntfreq(); /* Configure ACR to disable streaming WA for 801819 */ omap5_erratum_workaround_801819(); + /* Enable ACR to allow for ICUALLU workaround */ + omap5_secondary_harden_predictor(); } /* |