haswell: adjust CAR usage

It was found that the Haswell reference code was smashing through the
stack into the reference code's heap implementation. The reason for this
is because our current CAR allocation is too small. Moreover there are
quite a few things to coordinate between 2 code bases to get correct.
This commit separates the CAR into 2 parts:
  1. MRC CAR usage.
  2. Coreboot CAR usage.
Pointers from one region can be passed between the 2 modules, but one
should not be able to affect the others as checking has been put into
place in both modules.

The CAR size has effectively been doubled from 0x20000 (128 KiB) to
0x40000 (256KiB). Not all of that increase was needed, but enforcing
a power of 2 size only utilizes 1 MTRR.

Old CAR layout with a single contiguous stack with the region starting
at CONFIG_DCACHE_RAM_BASE:

+---------------------------------------+ Offset CONFIG_DCACHE_RAM_SIZE
|  MRC global variables                 |
|  CONFIG_DCACHE_RAM_MRC_VAR_SIZE bytes |
+---------------------------------------+
|  ROM stage stack                      |
|                                       |
|                                       |
+---------------------------------------+
|  MRC Heap 30000 bytes                 |
+---------------------------------------+
|  ROM stage console                    |
|  CONFIG_CONSOLE_CAR_BUFFER_SIZE bytes |
+---------------------------------------+
|  ROM stage CAR_GLOBAL variables       |
+---------------------------------------+ Offset 0

There was some hard coded offsets in the reference code wrapper to start
the heap past the console buffer. Even with this commit the console
can smash into the following region depending on what size
CONFIG_CONSOLE_CAR_BUFFER_SIZE is.

As noted above This change splits the CAR region into 2 parts starting
at CONFIG_DCACHE_RAM_BASE:

+---------------------------------------+
|  MRC Region                           |
|  CONFIG_DCACHE_RAM_MRC_VAR_SIZE bytes |
+---------------------------------------+ Offset CONFIG_DCACHE_RAM_SIZE
|  ROM stage stack                      |
|                                       |
|                                       |
+---------------------------------------+
|  ROM stage console                    |
|  CONFIG_CONSOLE_CAR_BUFFER_SIZE bytes |
+---------------------------------------+
|  ROM stage CAR_GLOBAL variables       |
+---------------------------------------+ Offset 0

Another variable was add, CONFIG_DCACHE_RAM_ROMSTAGE_STACK_SIZE,
which represents the expected stack usage for the romstage. A marker
is checked at the base of the stack to determine if either the stack
was smashed or the console encroached on the stack.

Change-Id: Id76f2fe4a5cf1c776c8f0019f406593f68e443a7
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/2752
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>

4 files changed, 66 insertions, 4 deletions

diff --git a/src/cpu/intel/haswell/Makefile.inc b/src/cpu/intel/haswell/Makefile.inc
index 67b095433e..b2116f2dfe 100644
--- a/src/cpu/intel/haswell/Makefile.inc
+++ b/src/cpu/intel/haswell/Makefile.inc
@@ -1,5 +1,6 @@
 ramstage-y += haswell_init.c
 subdirs-y += ../../x86/name
+romstage-y += romstage.c
 
 ramstage-$(CONFIG_GENERATE_ACPI_TABLES) += acpi.c
 ramstage-$(CONFIG_HAVE_SMI_HANDLER) += smmrelocate.c
diff --git a/src/cpu/intel/haswell/cache_as_ram.inc b/src/cpu/intel/haswell/cache_as_ram.inc
index f5ee82e2d2..72b49589d4 100644
--- a/src/cpu/intel/haswell/cache_as_ram.inc
+++ b/src/cpu/intel/haswell/cache_as_ram.inc
@@ -24,7 +24,11 @@
 #include <cpu/x86/post_code.h>
 #include <cbmem.h>
 
-#define CACHE_AS_RAM_SIZE CONFIG_DCACHE_RAM_SIZE
+/* The full cache-as-ram size includes the cache-as-ram portion from coreboot
+ * and the space used by the reference code. These 2 values combined should
+ * be a power of 2 because the MTRR setup assumes that. */
+#define CACHE_AS_RAM_SIZE \
+	(CONFIG_DCACHE_RAM_SIZE + CONFIG_DCACHE_RAM_MRC_VAR_SIZE)
 #define CACHE_AS_RAM_BASE CONFIG_DCACHE_RAM_BASE
 
 /* Cache 4GB - MRC_SIZE_KB for MRC */
@@ -166,9 +170,8 @@ clear_mtrrs:
 	andl	$(~(CR0_CacheDisable | CR0_NoWriteThrough)), %eax
 	movl	%eax, %cr0
 
-	/* Set up the stack pointer below MRC variable space. */
-	movl	$(CACHE_AS_RAM_SIZE + CACHE_AS_RAM_BASE - \
-		  CONFIG_DCACHE_RAM_MRC_VAR_SIZE - 4), %eax
+	/* Setup the stack. */
+	movl	$(CONFIG_DCACHE_RAM_BASE + CONFIG_DCACHE_RAM_SIZE), %eax
 	movl	%eax, %esp
 
 	/* Restore the BIST result. */
diff --git a/src/cpu/intel/haswell/haswell.h b/src/cpu/intel/haswell/haswell.h
index cb85078db4..8d91dbaf02 100644
--- a/src/cpu/intel/haswell/haswell.h
+++ b/src/cpu/intel/haswell/haswell.h
@@ -101,6 +101,11 @@
 #define PSS_LATENCY_BUSMASTER		10
 
 #ifndef __ROMCC__
+
+#if defined(__PRE_RAM__)
+void romstage_main(unsigned long bist);
+#endif
+
 #ifdef __SMM__
 /* Lock MSRs */
 void intel_cpu_haswell_finalize_smm(void);
diff --git a/src/cpu/intel/haswell/romstage.c b/src/cpu/intel/haswell/romstage.c
new file mode 100644
index 0000000000..f954b91dca
--- /dev/null
+++ b/src/cpu/intel/haswell/romstage.c
@@ -0,0 +1,53 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2012 ChromeOS Authors
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+ */
+
+#include <stdint.h>
+#include <cbmem.h>
+#include <console/console.h>
+
+/* Mainboard needs to supply this symbol. */
+extern void romstage_main(unsigned long bist);
+
+void main(unsigned long bist)
+{
+	int i;
+	const int num_guards = 4;
+	const u32 stack_guard = 0xdeadbeef;
+	u32 *stack_base = (void *)(CONFIG_DCACHE_RAM_BASE +
+	                           CONFIG_DCACHE_RAM_SIZE -
+	                           CONFIG_DCACHE_RAM_ROMSTAGE_STACK_SIZE);
+
+	printk(BIOS_DEBUG, "Setting up stack guards.\n");
+	for (i = 0; i < num_guards; i++)
+		stack_base[i] = stack_guard;
+
+	romstage_main(bist);
+
+	/* Check the stack. */
+	for (i = 0; i < num_guards; i++) {
+		if (stack_base[i] == stack_guard)
+			continue;
+		printk(BIOS_DEBUG, "Smashed stack detected in romstage!\n");
+	}
+
+#if CONFIG_CONSOLE_CBMEM
+	/* Keep this the last thing this function does. */
+	cbmemc_reinit();
+#endif
+}