timestamp: Remove HAS_PRECBMEM_TIMESTAMP_REGION Kconfig

This patch generalizes the approach previously used for ARM32
TTB_SUBTABLES to "auto-detect" whether a certain region was defined in
memlayout.ld. This allows us to get rid of the explicit Kconfig for the
TIMESTAMP region, reducing configuration redundancy and avoiding
confusion when setting up future boards.

(Removing armv4/bootblock_simple.c because it references this Kconfig
and it is a dead file that I just forgot to remove in CL:12076.)

BRANCH=None
BUG=None
TEST=Booted Oak and confirmed that all pre-RAM timestamps are still
there. Built Nyan and Falco.

Change-Id: I557a4b263018511d17baa4177963130a97ea310a
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://review.coreboot.org/13652
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

3 files changed, 2 insertions, 54 deletions

diff --git a/src/arch/arm/armv4/bootblock_simple.c b/src/arch/arm/armv4/bootblock_simple.c
deleted file mode 100644
index 85f486e796..0000000000
--- a/src/arch/arm/armv4/bootblock_simple.c
+++ /dev/null
@@ -1,47 +0,0 @@
-/*
- * This file is part of the coreboot project.
- *
- * Copyright 2010 Google Inc.
- *
- * 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.
- */
-
-#include <arch/exception.h>
-#include <arch/stages.h>
-#include <bootblock_common.h>
-#include <cbfs.h>
-#include <console/console.h>
-#include <delay.h>
-#include <program_loading.h>
-#include <timestamp.h>
-
-__attribute__((weak)) void bootblock_mainboard_early_init(void) { /* no-op */ }
-__attribute__((weak)) void bootblock_soc_init(void) { /* do nothing */ }
-__attribute__((weak)) void bootblock_mainboard_init(void) { /* do nothing */ }
-
-void main(void)
-{
-	init_timer();
-	if (IS_ENABLED(CONFIG_HAS_PRECBMEM_TIMESTAMP_REGION))
-		timestamp_init(timestamp_get());
-
-	bootblock_mainboard_early_init();
-
-	if (CONFIG_BOOTBLOCK_CONSOLE) {
-		console_init();
-		exception_init();
-	}
-
-	bootblock_soc_init();
-	bootblock_mainboard_init();
-
-	run_romstage();
-}
diff --git a/src/arch/arm/armv7/mmu.c b/src/arch/arm/armv7/mmu.c
index 8c2f78c4d0..2cf90e75f7 100644
--- a/src/arch/arm/armv7/mmu.c
+++ b/src/arch/arm/armv7/mmu.c
@@ -118,11 +118,8 @@ typedef uint32_t pte_t;
 
 static pte_t *const ttb_buff = (void *)_ttb;
 
-/* Not all boards want to use subtables and declare them in memlayout.ld. This
- * outputs two 0x00000000 symbols if they don't, making _ttb_subtables_size 0.
- * (I would like to explicitly assign them to 0 here, but that triggers
- * https://sourceware.org/bugzilla/show_bug.cgi?id=1038 in GNU as.) */
-asm (".weak _ttb_subtables, _ettb_subtables");
+/* Not all boards want to use subtables and declare them in memlayout.ld. */
+DECLARE_OPTIONAL_REGION(ttb_subtables);
 
 static struct {
 	pte_t value;
diff --git a/src/arch/x86/car.ld b/src/arch/x86/car.ld
index f29a465784..d19e61300b 100644
--- a/src/arch/x86/car.ld
+++ b/src/arch/x86/car.ld
@@ -42,9 +42,7 @@
 	 * backing store once cbmem comes online. Therefore, this data needs
 	 * to reside in the migrated area (between _car_data_start and
 	 * _car_data_end). */
-#if IS_ENABLED(CONFIG_HAS_PRECBMEM_TIMESTAMP_REGION)
 	TIMESTAMP(., 0x100)
-#endif
 	/* _car_global_start and _car_global_end provide symbols to per-stage
 	 * variables that are not shared like the timestamp and the pre-ram
 	 * cbmem console. This is useful for clearing this area on a per-stage