diff --git a/src/soc/intel/apollolake/cpu.c b/src/soc/intel/apollolake/cpu.c index a49bf471a9..b8bf39197e 100644 --- a/src/soc/intel/apollolake/cpu.c +++ b/src/soc/intel/apollolake/cpu.c @@ -13,6 +13,7 @@ #include #include #include +#include #include #include #include @@ -279,3 +280,26 @@ void mp_init_cpus(struct bus *cpu_bus) CONFIG(BOOT_DEVICE_SPI_FLASH)) fast_spi_cache_bios_region(); } + +#if CONFIG(SOC_INTEL_GEMINILAKE) +int soc_skip_ucode_update(u32 current_patch_id, u32 new_patch_id) +{ + /* + * If PRMRR/SGX is supported the FIT microcode load will set the msr + * 0x08b with the Patch revision id one less than the id in the + * microcode binary. The PRMRR support is indicated in the MSR + * MTRRCAP[12]. If SGX is not enabled, check and avoid reloading the + * same microcode during CPU initialization. If SGX is enabled, as + * part of SGX BIOS initialization steps, the same microcode needs to + * be reloaded after the core PRMRR MSRs are programmed. + */ + const msr_t mtrr_cap = rdmsr(MTRR_CAP_MSR); + if (mtrr_cap.lo & MTRR_CAP_PRMRR) { + const msr_t prmrr_phys_base = rdmsr(MSR_PRMRR_PHYS_BASE); + if (prmrr_phys_base.raw) { + return 0; + } + } + return current_patch_id == new_patch_id - 1; +} +#endif