Andrey Petrov (andrey.petrov@intel.com) just uploaded a new patch set to gerrit, which you can find at https://review.coreboot.org/17665
-gerrit
commit 8641788c8a73090581a3b063d5d18d5468ab4df5 Author: Andrey Petrov andrey.petrov@intel.com Date: Wed Nov 30 17:58:38 2016 -0800
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 andrey.petrov@intel.com --- src/soc/intel/apollolake/car.c | 2 +- src/soc/intel/apollolake/cpu.c | 9 +++++++++ src/soc/intel/apollolake/include/soc/cpu.h | 2 ++ 3 files changed, 12 insertions(+), 1 deletion(-)
diff --git a/src/soc/intel/apollolake/car.c b/src/soc/intel/apollolake/car.c index 68bcb31..d58dc0a 100644 --- a/src/soc/intel/apollolake/car.c +++ b/src/soc/intel/apollolake/car.c @@ -28,7 +28,7 @@ static void flush_l1d_to_l2(void) { msr_t msr = rdmsr(MSR_POWER_MISC); - msr.lo |= (1 << 8); + msr.lo |= FLUSH_DL1_L2; wrmsr(MSR_POWER_MISC, msr); }
diff --git a/src/soc/intel/apollolake/cpu.c b/src/soc/intel/apollolake/cpu.c index 9497368..8b8f963 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 = { diff --git a/src/soc/intel/apollolake/include/soc/cpu.h b/src/soc/intel/apollolake/include/soc/cpu.h index 38ce4ff..db9d3dd 100644 --- a/src/soc/intel/apollolake/include/soc/cpu.h +++ b/src/soc/intel/apollolake/include/soc/cpu.h @@ -31,6 +31,8 @@ void set_max_freq(void);
#define MSR_PLATFORM_INFO 0xce #define MSR_POWER_MISC 0x120 +#define ENABLE_IA_UNTRUSTED (1 << 6) +#define FLUSH_DL1_L2 (1 << 8) #define MSR_CORE_THREAD_COUNT 0x35 #define MSR_EVICT_CTL 0x2e0 #define MSR_EMULATE_PM_TMR 0x121