AGESA: Disable CAR with empty stack
Calling disable_cache_as_ram() with valuables in stack is not
a stable solution, as per documentation AMD_DISABLE_STACK
should destroy stack in cache.
Change-Id: I986bb7a88f53f7f7a0b05d4edcd5020f5dbeb4b7
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/18626
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
diff --git a/src/cpu/amd/agesa/cache_as_ram.inc b/src/cpu/amd/agesa/cache_as_ram.inc
index 1258d15..857873a 100644
--- a/src/cpu/amd/agesa/cache_as_ram.inc
+++ b/src/cpu/amd/agesa/cache_as_ram.inc
@@ -26,12 +26,8 @@
#include "gcccar.inc"
#include <cpu/x86/cache.h>
-/*
- * XMM map:
- */
-
.code32
-.globl cache_as_ram_setup, disable_cache_as_ram, cache_as_ram_setup_out
+.globl cache_as_ram_setup, cache_as_ram_setup_out
cache_as_ram_setup:
@@ -110,17 +106,13 @@
pushl $0x0
pushl %ebp
call romstage_main
+ movl %eax, %ebx
- /* Should never see this postcode */
- post_code(0xaf)
-stop:
- jmp stop
+/* Register %ebx is new stacktop for remaining of romstage.
+ * It is the only register preserved in AMD_DISABLE_STACK.
+ */
disable_cache_as_ram:
- /* Save return stack */
- movd 0(%esp), %xmm1
- movd %esp, %xmm0
-
/* Disable cache */
movl %cr0, %eax
orl $CR0_CacheDisable, %eax
@@ -132,12 +124,13 @@
movl %cr0, %eax
andl $0x9fffffff, %eax
movl %eax, %cr0
- xorl %eax, %eax
- /* Restore the return stack */
- wbinvd
- movd %xmm0, %esp
- movd %xmm1, (%esp)
- ret
+ movl %ebx, %esp
+ call romstage_after_car
+
+ /* Should never see this postcode */
+ post_code(0xaf)
+stop:
+ jmp stop
cache_as_ram_setup_out: