From 89e39b5c55cd7612c70cb25d2b2000965cc25539 Mon Sep 17 00:00:00 2001 From: Andrey Petrov Date: Wed, 30 Nov 2016 17:58:38 -0800 Subject: soc/intel/apollolake: Drop privilege level to IA_UNTRUSTED As per guidelines CPU security level should be dropped before OS start, so that certain MSRs are locked out. Drop privilege levels on all logical CPUs. BUG=chrome-os-partner:60454 TEST=iotools rdmsr x 0x120, make sure bit 6 is set, rdmsr x 0x121 results in io error. Change-Id: I67540f6da16f58b822db9160d00b7a5e235188db Signed-off-by: Andrey Petrov Reviewed-on: https://review.coreboot.org/17665 Reviewed-by: Aaron Durbin Tested-by: build bot (Jenkins) --- src/soc/intel/apollolake/cpu.c | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'src/soc/intel/apollolake/cpu.c') diff --git a/src/soc/intel/apollolake/cpu.c b/src/soc/intel/apollolake/cpu.c index 949736821e..8b8f963e4c 100644 --- a/src/soc/intel/apollolake/cpu.c +++ b/src/soc/intel/apollolake/cpu.c @@ -53,6 +53,13 @@ static const struct reg_script core_msr_script[] = { REG_SCRIPT_END }; +static void enable_untrusted_mode(void) +{ + msr_t msr = rdmsr(MSR_POWER_MISC); + msr.lo |= ENABLE_IA_UNTRUSTED; + wrmsr(MSR_POWER_MISC, msr); +} + static void soc_core_init(device_t cpu) { /* Set core MSRs */ @@ -63,6 +70,8 @@ static void soc_core_init(device_t cpu) * implemented in microcode. */ enable_pm_timer_emulation(); + /* Drop privilege level */ + enable_untrusted_mode(); } static struct device_operations cpu_dev_ops = { -- cgit v1.2.3