[coreboot-gerrit] New patch to review for coreboot: vendorcode/amd/pi/00670F00: cleanup CAR disable

[Marc Jones (marc@marcjonesconsulting.com)]

Marc Jones (marc at marcjonesconsulting.com) just uploaded a new patch set to gerrit, which you can find at https://review.coreboot.org/18492

-gerrit

commit 8b72a5e201f71e5c5cf6647c5892ac74d40501bb
Author: Marc Jones <marcj303 at gmail.com>
Date:   Fri Feb 24 16:40:41 2017 -0700

    vendorcode/amd/pi/00670F00: cleanup CAR disable
    
    Clean up the AMD_DISABLE_STACK_FAMILY_HOOK_F15 to be clear that
    it does a wbinvd to preserve the coreboot stack and CAR globals.
    The Stoney Ridge uses a different S3 architecture, so this is not
    an issue of reserving or relocting the stack on a resume.
    
    Change-Id: I77e53262212e00bce9145b0bc3909ad8651f2328
    Signed-off-by: Marc Jones <marcj303 at gmail.com>
---
 src/vendorcode/amd/pi/00670F00/binaryPI/gcccar.inc | 24 ++++++++++++++--------
 1 file changed, 15 insertions(+), 9 deletions(-)

diff --git a/src/vendorcode/amd/pi/00670F00/binaryPI/gcccar.inc b/src/vendorcode/amd/pi/00670F00/binaryPI/gcccar.inc
index d6782a3..ac15134 100644
--- a/src/vendorcode/amd/pi/00670F00/binaryPI/gcccar.inc
+++ b/src/vendorcode/amd/pi/00670F00/binaryPI/gcccar.inc
@@ -401,6 +401,14 @@ 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 to preserve stack and
+*   coreboot CAR globals. This 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 +642,13 @@ 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                                # Clear the cache tag RAMs
+
 #    #.if (bh == 01h) || (bh == 03h)      ; Is this TN or KM?
 #    cmp   $01, %bh
 #    jz    4f
@@ -659,10 +669,6 @@ fam15_disable_stack_remote_read_exit:
 
 1:  #.endif
     #Do Standard Family 15 work
-    mov     $HWCR, %ecx                    # MSR:C001_0015h
-    _RDMSR
-    bts     $INVD_WBINVD, %eax            # Turn on Conversion of INVD to WBINVD
-    _WRMSR
     #.endif                              # end
     0:
 //