arm: Remove CAR_MIGRATE Kconfig and associated cruft

This is essentially a revert of commit 10bd772d. The CAR_MIGRATE
mechanism is only useful to migrate variables from a special region
(e.g. cache as RAM) into DRAM-backed CBMEM between different parts of
the romstage (it does not persist into ramstage). Since ARM devices use
SRAM for which there is no reason to become inaccessible in later parts
of the romstage, this mechanism isn't useful for them. Removing it makes
the romstage.ld script much simpler, which has the nice side-effect of
putting the BSS at the end of the memory image (so that cbfstool can
actually figure out that it doesn't need to be part of the ROM image).

Old-Change-Id: I50e91d8bd51b5deb19446d9da48699edecbef6ea
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/176761
Reviewed-by: David Hendricks <dhendrix@chromium.org>
(cherry picked from commit ebfd698e57c902e2f39a0cfc1bc2b02665e47ec6)

console: Make cbmem depend on x86.

The cbmem implementation isn't supported on anything other than x86 right now
and actually causes memory corruption on ARM machines. Until that's fixed, this
will prevent people from turning it on and causing hard to track down errors.

Old-Change-Id: I00e8aacf008acfe2f76d4eab82570f7c1cc89cab
Signed-off-by: Gabe Black <gabeblack@google.com>
Reviewed-on: https://chromium-review.googlesource.com/191107
Reviewed-by: Julius Werner <jwerner@chromium.org>
Commit-Queue: Gabe Black <gabeblack@chromium.org>
Tested-by: Gabe Black <gabeblack@chromium.org>
(cherry picked from commit e54f16e346a7f2c66d802fb78a6b24e53b732b83)

Squashed two related commits for cbmem support on arm.

Change-Id: I2be48cea348ee5dc8ca3632d743500aa111bab08
Signed-off-by: Isaac Christensen <isaac.christensen@se-eng.com>
Reviewed-on: http://review.coreboot.org/6888
Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Tested-by: build bot (Jenkins)
diff --git a/src/arch/arm/include/arch/early_variables.h b/src/arch/arm/include/arch/early_variables.h
index cec0a46..041d0ae 100644
--- a/src/arch/arm/include/arch/early_variables.h
+++ b/src/arch/arm/include/arch/early_variables.h
@@ -20,40 +20,13 @@
 #ifndef ARCH_EARLY_VARIABLES_H
 #define ARCH_EARLY_VARIABLES_H
 
-#ifdef __PRE_RAM__
-#define CAR_GLOBAL __attribute__((section(".car.global_data")))
-#define CAR_CBMEM __attribute__((section(".car.cbmem_console")))
-#else
 #define CAR_GLOBAL
 #define CAR_CBMEM
-#endif
 
-#if defined(__PRE_RAM__)
-#define CAR_MIGRATE_ATTR __attribute__ ((used,section (".car.migrate")))
-
-/* Call migrate_fn_() when CAR globals are migrated. */
-#define CAR_MIGRATE(migrate_fn_) \
-	static void (* const migrate_fn_ ## _ptr)(void) CAR_MIGRATE_ATTR = \
-	migrate_fn_;
-
-/* Get the correct pointer for the CAR global variable. */
-void *car_get_var_ptr(void *var);
-
-/* Get and set a primitive type global variable. */
-#define car_get_var(var) \
-	*(typeof(var) *)car_get_var_ptr(&(var))
-#define car_set_var(var, val) \
-	do { car_get_var(var) = (val); } while(0)
-
-/* Migrate the CAR variables to memory. */
-void car_migrate_variables(void);
-
-#else
 #define CAR_MIGRATE(migrate_fn_)
 static inline void *car_get_var_ptr(void *var) { return var; }
 #define car_get_var(var) (var)
 #define car_set_var(var, val) do { (var) = (val); } while (0)
 static inline void car_migrate_variables(void) { }
-#endif
 
 #endif
diff --git a/src/arch/arm/romstage.ld b/src/arch/arm/romstage.ld
index 65b133a..750525b 100644
--- a/src/arch/arm/romstage.ld
+++ b/src/arch/arm/romstage.ld
@@ -35,7 +35,6 @@
 
 SECTIONS
 {
-	/* TODO make this a configurable option (per chipset). */
 	. = CONFIG_ROMSTAGE_BASE;
 
 	.romtext . : {
@@ -50,11 +49,7 @@
 		*(.rodata);
 		*(.machine_param);
 		*(.data);
-		. = ALIGN(16);
-		_car_migrate_start = .;
-		*(.car.migrate);
-		_car_migrate_end = .;
-		. = ALIGN(16);
+		. = ALIGN(8);
 		_erom = .;
 	}
 
@@ -72,32 +67,8 @@
 
 	_ebss = .;
 
-	.car.data . : {
-		. = ALIGN(8);
-		_car_data_start = .;
-		*(.car.global_data);
-		. = ALIGN(8);
-		/* The cbmem_console section comes last to take advantage of
-		 * a zero-sized array to hold the memconsole contents that
-		 * grows to a bound of CONFIG_CONSOLE_CAR_BUFFER_SIZE. However,
-		 * collisions within the cache-as-ram region cannot be
-		 * statically checked because the cache-as-ram region usage is
-		 * cpu/chipset dependent. */
-		*(.car.cbmem_console);
-		_car_data_end = .;
-	}
-
 	_end = .;
 
-	/* TODO: check if we are running out of SRAM. Below check is not good
-	 * enough though because SRAM has different size on different CPUs
-	 * and not all SRAM is available to the romstage. On Exynos, some is
-	 * used for BL1, the bootblock and the stack.
-	 *
-	 * _bogus = ASSERT((_end - _start + EXPECTED_CBMEM_CONSOLE_SIZE <= \
-	 * 				0x54000), "SRAM area is too full");
-	 */
-
 	/* Discard the sections we don't need/want */
 	/DISCARD/ : {
 		*(.comment)
diff --git a/src/console/Kconfig b/src/console/Kconfig
index f5528ed..472ac5c 100644
--- a/src/console/Kconfig
+++ b/src/console/Kconfig
@@ -168,6 +168,7 @@
 	  boundary, qemu needs broader align)
 
 config CONSOLE_CBMEM
+	depends on ARCH_X86
 	bool "Send console output to a CBMEM buffer"
 	default n
 	help
diff --git a/src/cpu/x86/Makefile.inc b/src/cpu/x86/Makefile.inc
index a05c723..418b5d7 100644
--- a/src/cpu/x86/Makefile.inc
+++ b/src/cpu/x86/Makefile.inc
@@ -1,5 +1,7 @@
+ifeq ($(CONFIG_ARCH_ROMSTAGE_X86_32),y)
 romstage-$(CONFIG_EARLY_CBMEM_INIT) += car.c
 romstage-$(CONFIG_BROKEN_CAR_MIGRATE) += car.c
+endif
 
 subdirs-$(CONFIG_PARALLEL_MP) += name
 ramstage-$(CONFIG_PARALLEL_MP) += mp_init.c