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-rw-r--r--src/vendorcode/amd/pi/00670F00/binaryPI/gcccar.inc35
1 files changed, 28 insertions, 7 deletions
diff --git a/src/vendorcode/amd/pi/00670F00/binaryPI/gcccar.inc b/src/vendorcode/amd/pi/00670F00/binaryPI/gcccar.inc
index d6782a3d29..1dd0724464 100644
--- a/src/vendorcode/amd/pi/00670F00/binaryPI/gcccar.inc
+++ b/src/vendorcode/amd/pi/00670F00/binaryPI/gcccar.inc
@@ -401,6 +401,16 @@ 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:
@@ -634,11 +644,13 @@ fam15_disable_stack_remote_read_exit:
# Begin critical sequence in which EAX, BX, ECX, and EDX must be preserved.
#--------------------------------------------------------------------------
- mov $HWCR, %ecx # MSR:C001_0015h
- _RDMSR
- btr $INVD_WBINVD, %eax # Disable INVD -> WBINVD conversion
- _WRMSR
- wbinvd #bao # Clear the cache tag RAMs
+ #--------------------------------------------------------------------------
+ # 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
+
# #.if (bh == 01h) || (bh == 03h) ; Is this TN or KM?
# cmp $01, %bh
# jz 4f
@@ -1285,8 +1297,17 @@ ClearTheStack: # Stack base is in SS, stack pointer is
.endm
/*****************************************************************************
-* AMD_DISABLE_STACK: Destroy the stack inside the cache. This routine
-* should only be executed on the BSP
+* 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
*
* In:
* none