To clear all DRAM on x86_32, add a new method that uses PAE to access
more than 32bit of address space.
Add Documentation as well.
Required for clearing all system memory as part of security API.
Tested on wedge100s:
Takes less than 2 seconds to clear 8GiB of DRAM.
Tested on P8H61M-Pro:
Takes less than 1 second to clear 4GiB of DRAM.
Change-Id: I00f7ecf87b5c9227a9d58a0b61eecc38007e1a57
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/31549
Reviewed-by: Philipp Deppenwiese <zaolin.daisuki@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Add files to introduce a memory clearing framework.
Introduce Kconfig PLATFORM_HAS_DRAM_CLEAR that is to be selected by
platforms, that are able to clear all DRAM.
Introduce Kconfig SECURITY_CLEAR_DRAM_ON_REGULAR_BOOT that is user
selectable to always clear DRAM on non S3 boot.
The function security_clear_dram_request tells the calling platform when
to wipe all DRAM. Will be extended by TEE frameworks.
Add Documentation for the new security API.
Change-Id: Ifba25bfdd1057049f5cbae8968501bd9be487110
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/31548
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Philipp Deppenwiese <zaolin.daisuki@gmail.com>
Reviewed-by: Christian Walter <christian.walter@9elements.com>
Patrick Rudolph