New patch to review for coreboot: AMD k8 fam10: Separate romstage ramstack (WIP)

[Kyösti Mälkki]

Kyösti Mälkki ([e-mail]) just uploaded a new patch set to gerrit, which you can find at https://review.coreboot.org/15473

-gerrit

commit 6ffef315076ed7841d71844d6d8f2d3f64b55e6f
Author: Kyösti Mälkki 
Date:   Mon Jun 27 19:45:19 2016 +0300

AMD k8 fam10: Separate romstage ramstack (WIP)

Romstage ram stack was placed below RAMTOP. This is vulnerable
    location as a large ramstage could overwrite it. Location also
    prevents optimizing S3 resume path since all low memory between
    RAMBASE..RAMTOP has to be backed to CBMEM.

When possible, place ram stack high.

Change-Id: I4106e91ed3256aca5d0d115d4aa7e46b75b27eec
    Signed-off-by: Kyösti Mälkki 
---
 src/cpu/amd/car/post_cache_as_ram.c | 35 +++++++----------------------------
 1 file changed, 7 insertions(+), 28 deletions(-)

diff --git a/src/cpu/amd/car/post_cache_as_ram.c b/src/cpu/amd/car/post_cache_as_ram.c
index dba2a06..0ec58cd 100644
--- a/src/cpu/amd/car/post_cache_as_ram.c
+++ b/src/cpu/amd/car/post_cache_as_ram.c
@@ -23,6 +23,7 @@
 #include <cpu/amd/mtrr.h>
 #include <cpu/amd/car.h>
 #include <arch/acpi.h>
+#include <program_loading.h>
 #include <romstage_handoff.h>
 #include "cbmem.h"
 #include "cpu/amd/car/disable_cache_as_ram.c"
@@ -37,12 +38,6 @@
 #define print_car_debug(format, arg...)
 #endif

-static size_t backup_size(void)
-{
-	size_t car_size = car_data_size();
-	return ALIGN(car_size + 1024, 1024);
-}
-
 static void memcpy_(void *d, const void *s, size_t len)
 {
    print_car_debug(" Copy [%08x-%08x] to [%08x - %08x] ...",
@@ -63,35 +58,18 @@ static int memcmp_(void *d, const void *s, size_t len)
    return memcmp(d, s, len);
 }

-static void prepare_romstage_ramstack(int s3resume)
-{
-	size_t backup_top = backup_size();
-	print_car_debug("Prepare CAR migration and stack regions...");
-
-	if (s3resume) {
-		void *resume_backup_memory = acpi_backup_container();
-		if (resume_backup_memory)
-			memcpy_(resume_backup_memory + HIGH_MEMORY_SAVE - backup_top,
-				(void *)(CONFIG_RAMTOP - backup_top), backup_top);
-	}
-	memset_((void *)(CONFIG_RAMTOP - backup_top), 0, backup_top);
-
-	print_car_debug(" Done\n");
-}
-
 static void prepare_ramstage_region(int s3resume)
 {
-	size_t backup_top = backup_size();
    print_car_debug("Prepare ramstage memory region...");

if (s3resume) {
    	void *resume_backup_memory = acpi_backup_container();
    	if (resume_backup_memory)
    		memcpy_(resume_backup_memory, (void *) CONFIG_RAMBASE,
-				HIGH_MEMORY_SAVE - backup_top);
-		memset_((void*) CONFIG_RAMBASE, 0, HIGH_MEMORY_SAVE - backup_top);
+				HIGH_MEMORY_SAVE);
+		memset_((void*) CONFIG_RAMBASE, 0, HIGH_MEMORY_SAVE);
    } else {
-		memset_((void*)0, 0, CONFIG_RAMTOP - backup_top);
+		memset_((void*)0, 0, CONFIG_RAMTOP);
    }

#if IS_ENABLED(CONFIG_HAVE_ROMSTAGE_CONSOLE_SPINLOCK)
@@ -138,7 +116,8 @@ void post_cache_as_ram(void)
    if (IS_ENABLED(CONFIG_EARLY_CBMEM_INIT) || s3resume)
    	cbmem_recovery(s3resume);

-	prepare_romstage_ramstack(s3resume);
+	/* FIXME: CBMEM stack is not wb-cacheable yet. */
+	uintptr_t ramtop = romstage_ram_stack_maybe_low(!s3resume);

if (IS_ENABLED(CONFIG_EARLY_CBMEM_INIT)) {
    	struct romstage_handoff *handoff;
@@ -156,7 +135,7 @@ void post_cache_as_ram(void)
    }

size_t car_size = car_data_size();
-	void *migrated_car = (void *)(CONFIG_RAMTOP - car_size);
+	void *migrated_car = (void *)(ramtop - car_size);

print_car_debug("Copying data from cache to RAM...");
    memcpy_(migrated_car, _car_relocatable_data_start, car_size);