From d61e832e53029fd135c877514d3d2d38167aafd6 Mon Sep 17 00:00:00 2001 From: Marshall Dawson Date: Wed, 9 Aug 2017 19:59:20 -0600 Subject: soc/amd/stoneyridge: Revert CAR teardown wbinvd Change the cache-as-ram teardown to use invd instead of wbinvd. Save the return and recover the call's return address in chipset_teardown_car. CAR teardown had been modified to use wbinvd to send CAR contents to DRAM backing prior to teardown. This allowed CAR variables, stack, and local variables to be preserved while running the AMD_DISABLE_STACK macro. Using the wbinvd instruction has the side effect of sending all dirty cache contents to DRAM and not only our CAR data. This would likely cause corruption, e.g. during S3 resume. Stoney Ridge now uses a postcar stage and this is no longer a requirement. BUG=b:64768556 Change-Id: I8e6bcb3947f508b1db1a42fd0714bba70074837a Signed-off-by: Marshall Dawson Reviewed-on: https://review.coreboot.org/20967 Reviewed-by: Aaron Durbin Tested-by: build bot (Jenkins) --- src/soc/amd/common/block/cpu/Kconfig | 8 +++--- src/soc/amd/common/block/cpu/car/exit_car.S | 3 ++- src/vendorcode/amd/pi/00670F00/binaryPI/gcccar.inc | 29 ++-------------------- 3 files changed, 9 insertions(+), 31 deletions(-) diff --git a/src/soc/amd/common/block/cpu/Kconfig b/src/soc/amd/common/block/cpu/Kconfig index 86cc77194c..5941599df0 100644 --- a/src/soc/amd/common/block/cpu/Kconfig +++ b/src/soc/amd/common/block/cpu/Kconfig @@ -3,6 +3,8 @@ config SOC_AMD_COMMON_BLOCK_CAR default n help This option allows the SOC to use a standard AMD cache-as-ram (CAR) - implementation. CAR setup is built into bootblock and teardown in - romstage. If it is not used the system must implement these functions - separately. + implementation. CAR setup is built into bootblock and teardown is + in postcar. The teardown procedure does not preserve the stack so + it may not be appropriate for a romstage implementation without + additional consideration. If this option is not used, the SOC must + implement these functions separately. diff --git a/src/soc/amd/common/block/cpu/car/exit_car.S b/src/soc/amd/common/block/cpu/car/exit_car.S index ac36cb0e4f..f9d056e599 100644 --- a/src/soc/amd/common/block/cpu/car/exit_car.S +++ b/src/soc/amd/common/block/cpu/car/exit_car.S @@ -20,6 +20,7 @@ .globl chipset_teardown_car chipset_teardown_car: + pop %esp /* Disable cache */ movl %cr0, %eax @@ -33,4 +34,4 @@ chipset_teardown_car: andl $(~(CR0_CD | CR0_NW)), %eax movl %eax, %cr0 - ret + jmp *%esp diff --git a/src/vendorcode/amd/pi/00670F00/binaryPI/gcccar.inc b/src/vendorcode/amd/pi/00670F00/binaryPI/gcccar.inc index 92fd7e24fb..c744e47a03 100644 --- a/src/vendorcode/amd/pi/00670F00/binaryPI/gcccar.inc +++ b/src/vendorcode/amd/pi/00670F00/binaryPI/gcccar.inc @@ -401,16 +401,6 @@ fam15_enable_stack_hook_exit: * Return any family specific controls to their 'standard' * settings for using cache with main memory. * -* Note: Customized for coreboot: -* A wbinvd is used to send cache to memory. The existing stack is preserved -* at its original location and additional information is preserved (e.g. -* coreboot CAR globals, heap structures, etc.). This implementation should -* NOT be used with S3 resume IF the stack/cache area is not reserved and -* over system memory. -* -* This CPU resume path doesn't use CAR, but be careful if porting to -* other CPUs. -* * Inputs: * ESI - [31:24] flags; [15,8]= Node#; [7,0]= core# * Outputs: @@ -644,12 +634,7 @@ fam15_disable_stack_remote_read_exit: # Begin critical sequence in which EAX, BX, ECX, and EDX must be preserved. #-------------------------------------------------------------------------- - #-------------------------------------------------------------------------- - # Send cache to memory. Preserve stack and coreboot CAR globals. - # This shouldn't be used with S3 resume IF the stack/cache area is - # not reserved and over system memory. - #-------------------------------------------------------------------------- - wbinvd + invd # #.if (bh == 01h) || (bh == 03h) ; Is this TN or KM? # cmp $01, %bh @@ -1289,17 +1274,7 @@ ClearTheStack: # Stack base is in SS, stack pointer is .endm /***************************************************************************** -* AMD_DISABLE_STACK: Implementation is modified for coreboot from -* the original AMD intent. A WBINVD is used in the HOOK -* to send dirty cache contents to DRAM backing before -* disabling cache-as-ram. This is not safe for S3 resume. -* -* todo: -* * rework PI/AGESA source to set DRAM to UC to send -* writes directly to memory -* * move DCACHE_BASE or use postcar stage for teardown -* to eliminate car_migrated problem that will occur -* after wbinvd is changed back to invd +* AMD_DISABLE_STACK: * * In: * none -- cgit v1.2.3