From 5cb24d4522d489db52d98b2abd365053b1007c20 Mon Sep 17 00:00:00 2001 From: Arthur Heymans <arthur@aheymans.xyz> Date: Wed, 23 Jun 2021 13:17:33 +0200 Subject: soc/intel/cache_as_ram.S: Fix CAR issues with Bootguard It looks like the 'clear_car' code does not properly fill the required cachelines so add code to fill cachelines explicitly. Change-Id: Id5d77295f6d24f9d2bc23f39f8772fd172ac8910 Signed-off-by: Arthur Heymans <arthur@aheymans.xyz> Reviewed-on: https://review.coreboot.org/c/coreboot/+/55791 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Christopher Meis <christopher.meis@9elements.com> Reviewed-by: Patrick Rudolph <siro@das-labor.org> Reviewed-by: Christian Walter <christian.walter@9elements.com> Reviewed-by: Angel Pons <th3fanbus@gmail.com> --- src/soc/intel/common/block/cpu/car/cache_as_ram.S | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) (limited to 'src/soc') diff --git a/src/soc/intel/common/block/cpu/car/cache_as_ram.S b/src/soc/intel/common/block/cpu/car/cache_as_ram.S index 29bd3fe87f..74957aba9f 100644 --- a/src/soc/intel/common/block/cpu/car/cache_as_ram.S +++ b/src/soc/intel/common/block/cpu/car/cache_as_ram.S @@ -221,6 +221,23 @@ setup_car_mtrr: is_bootguard_nem jz no_bootguard_car_continue + /* + * With Bootguard some RO caching of the flash is already set up by + * the ACM. It looks like in such a setup 'clear_car' will not properly fill + * the cachelines. Fill all the CAR cachelines explicitly using sfence. + * This assumes 64 bytes cachelines. + */ + movl $CONFIG_DCACHE_RAM_BASE, %edi + movl $CONFIG_DCACHE_RAM_SIZE, %ecx + shr $0x06, %ecx + xor %eax, %eax + +1: + movl %eax, (%edi) + sfence + add $64, %edi + loop 1b + clear_car jmp car_init_done -- cgit v1.2.3