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soc/intel/car: Add support for bootguard CAR

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Bootguard sets up CAR/NEM on its own so the only thing needed is to
find free MTRRs for our own CAR region and clear that area to fill in
cache lines.

TESTED on prodrive/hermes with bootguard enabled.

Change-Id: Ifac5267f8f4b820a61519fb4a497e2ce7075cc40
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/36682
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Michael Niewöhner <foss@mniewoehner.de>
Reviewed-by: Patrick Rudolph <siro@das-labor.org>
This commit is contained in:
Arthur Heymans 2019-11-08 17:05:04 +01:00 • committed by Patrick Georgi
commit 481c52ddd5
2 changed files with 31 additions and 0 deletions
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28
src/soc/intel/common/block/cpu/car/cache_as_ram.S
View file

@ -1,6 +1,7 @@
/* SPDX-License-Identifier: GPL-2.0-only */
#include <commonlib/helpers.h>
#include <cpu/intel/msr.h>
#include <cpu/x86/cache.h>
#include <cpu/x86/cr.h>
#include <cpu/x86/msr.h>
@ -63,6 +64,22 @@ bootblock_pre_c_entry:
post_code(0x20)
/* Bootguard sets up its own CAR and needs separate handling */
check_boot_guard:
movl $MSR_BOOT_GUARD_SACM_INFO, %ecx
rdmsr
andl $B_BOOT_GUARD_SACM_INFO_NEM_ENABLED, %eax
jz no_bootguard
/* Disable PBE timer */
movl $MSR_BC_PBEC, %ecx
movl $B_STOP_PBET, %eax
xorl %edx, %edx
wrmsr
jmp setup_car_mtrr
no_bootguard:
movl $no_reset, %esp /* return address */
jmp check_mtrr /* Check if CPU properly reset */
@ -108,6 +125,7 @@ clear_var_mtrr:
MTRR_DEF_TYPE_FIX_EN), %eax
wrmsr
setup_car_mtrr:
/* Configure MTRR_PHYS_MASK_HIGH for proper addressing above 4GB
* based on the physical address size supported for this processor
* This is based on read from CPUID EAX = 080000008h, EAX bits [7:0]
@ -186,6 +204,16 @@ clear_var_mtrr:
#endif
post_code(0x25)
movl $MSR_BOOT_GUARD_SACM_INFO, %ecx
rdmsr
andl $B_BOOT_GUARD_SACM_INFO_NEM_ENABLED, %eax
jz no_bootguard_car_continue
clear_car
jmp car_init_done
no_bootguard_car_continue:
/* Enable variable MTRRs */
mov $MTRR_DEF_TYPE_MSR, %ecx
rdmsr