arm/arm64: Generalize bootblock C entry point

When we first added ARM support to coreboot, it was clear that the
bootblock would need to do vastly different tasks than on x86, so we
moved its main logic under arch/. Now that we have several more
architectures, it turns out (as with so many things lately) that x86 is
really the odd one out, and all the others are trying to do pretty much
the same thing. This has already caused maintenance issues as the ARM32
bootblock developed and less-mature architectures were left behind with
old cruft.

This patch tries to address that problem by centralizing that logic
under lib/ for use by all architectures/SoCs that don't explicitly
opt-out (with the slightly adapted existing BOOTBLOCK_CUSTOM option).
This works great out of the box for ARM32 and ARM64. It could probably
be easily applied to MIPS and RISCV as well, but I don't have any of
those boards to test so I'll mark them as BOOTBLOCK_CUSTOM for now and
leave that for later cleanup.

BRANCH=None
BUG=None
TEST=Built Jerry and Falco, booted Oak.

Change-Id: Ibbf727ad93651e388aef20e76f03f5567f9860cb
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: http://review.coreboot.org/12076
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: build bot (Jenkins)

src/arch/arm/Kconfig

@@ -22,12 +22,6 @@ config ARCH_RAMSTAGE_ARM
 source src/arch/arm/armv4/Kconfig
 source src/arch/arm/armv7/Kconfig
 
-# If a custom bootblock is necessary, this option should be "select"-ed by
-# the thing that needs it, probably the CPU.
-config ARM_BOOTBLOCK_CUSTOM
-	bool
-	default n
-
 config ARM_LPAE
 	bool
 	default n

src/arch/arm/armv4/Makefile.inc

@@ -24,9 +24,8 @@ armv4_flags = -marm -march=armv4t -I$(src)/arch/arm/include/armv4/ \
 
 ifeq ($(CONFIG_ARCH_BOOTBLOCK_ARMV4),y)
 
-ifneq ($(CONFIG_ARM_BOOTBLOCK_CUSTOM),y)
+ifneq ($(CONFIG_BOOTBLOCK_CUSTOM),y)
 bootblock-y += bootblock.S
-bootblock-y += bootblock_simple.c
 endif
 
 bootblock-y += cache.c

src/arch/arm/armv7/Makefile.inc

@@ -31,9 +31,8 @@ ifeq ($(CONFIG_ARCH_BOOTBLOCK_ARMV7),y)
 bootblock-c-ccopts += $(armv7-a_flags)
 bootblock-S-ccopts += $(armv7-a_asm_flags)
 
-ifneq ($(CONFIG_ARM_BOOTBLOCK_CUSTOM),y)
+ifneq ($(CONFIG_BOOTBLOCK_CUSTOM),y)
 bootblock-y += bootblock.S
-bootblock-$(CONFIG_BOOTBLOCK_SIMPLE) += bootblock_simple.c
 endif
 
 bootblock-y += cache.c
@@ -46,9 +45,8 @@ else ifeq ($(CONFIG_ARCH_BOOTBLOCK_ARMV7_M),y)
 bootblock-c-ccopts += $(armv7-m_flags)
 bootblock-S-ccopts += $(armv7-m_asm_flags)
 
-ifneq ($(CONFIG_ARM_BOOTBLOCK_CUSTOM),y)
+ifneq ($(CONFIG_BOOTBLOCK_CUSTOM),y)
 bootblock-y += bootblock_m.S
-bootblock-y += bootblock_simple.c
 endif
 bootblock-y += exception_m.c
 bootblock-y += cache_m.c

src/arch/arm/armv7/bootblock_simple.c

@@ -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 <console/console.h>
-#include <delay.h>
-#include <program_loading.h>
-#include <smp/node.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();
-#endif
-
-	bootblock_soc_init();
-	bootblock_mainboard_init();
-
-	run_romstage();
-}

src/arch/arm/include/bootblock_common.h

@@ -1,24 +0,0 @@
-/*
- * This file is part of the coreboot project.
- *
- * Copyright 2014 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.
- */
-
-#ifndef __ARCH_BOOTBLOCK_COMMON_H
-#define __ARCH_BOOTBLOCK_COMMON_H
-
-/* These are defined as weak no-ops that can be overridden by mainboard/SoC. */
-void bootblock_mainboard_early_init(void);
-void bootblock_mainboard_init(void);
-void bootblock_soc_init(void);
-
-#endif	/* __ARCH_BOOTBLOCK_COMMON_H */

src/arch/arm64/Kconfig

@@ -22,12 +22,6 @@ config ARCH_RAMSTAGE_ARM64
 source src/arch/arm64/armv8/Kconfig
 source src/arch/arm64/cpu/Kconfig
 
-# If a custom bootblock is necessary, this option should be "select"-ed by
-# the thing that needs it, probably the CPU.
-config ARM64_BOOTBLOCK_CUSTOM
-	bool
-	default n
-
 config ARM64_USE_ARM_TRUSTED_FIRMWARE
 	bool
 	default n

src/arch/arm64/armv8/Makefile.inc

@@ -26,10 +26,6 @@ armv8_asm_flags = $(armv8_flags)
 ################################################################################
 ifeq ($(CONFIG_ARCH_BOOTBLOCK_ARMV8_64),y)
 
-ifneq ($(CONFIG_ARM64_BOOTBLOCK_CUSTOM),y)
-bootblock-y += bootblock.S
-bootblock-y += bootblock_simple.c
-endif
 bootblock-y += cache.c
 bootblock-y += cache_helpers.S
 bootblock-y += cpu.S
@@ -38,6 +34,11 @@ bootblock-$(CONFIG_BOOTBLOCK_CONSOLE) += exception.c
 bootblock-c-ccopts += $(armv8_flags)
 bootblock-S-ccopts += $(armv8_asm_flags)
 
+# Required to access unaligned timestamp struct members before MMU is active
+# (TODO: Maybe use explicit unaligned accesses in timestamp code instead, or
+# evaluate redesigning timestamp data structures to avoid misaligned members.)
+bootblock-c-ccopts += -mstrict-align
+
 endif
 
 ################################################################################

src/arch/arm64/armv8/bootblock_simple.c

@@ -1,60 +0,0 @@
-/*
- * This file is part of the coreboot project.
- *
- * Copyright 2014 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 <bootblock_common.h>
-#include <arch/cache.h>
-#include <arch/stages.h>
-#include <arch/exception.h>
-#include <cbfs.h>
-#include <console/console.h>
-#include <program_loading.h>
-
-static int boot_cpu(void)
-{
-	/*
-	 * FIXME: This is a stub for now. All non-boot CPUs should be
-	 * waiting for an interrupt. We could move the chunk of assembly
-	 * which puts them to sleep in here...
-	 */
-	return 1;
-}
-
-void main(void)
-{
-	/* Globally disable MMU, caches, and branch prediction (these should
-	 * be disabled by default on reset) */
-	mmu_disable();
-
-	/*
-	 * Re-enable icache and branch prediction. MMU and dcache will be
-	 * set up later.
-	 *
-	 * Note: If booting from USB, we need to disable branch prediction
-	 * before copying from USB into RAM (FIXME: why?)
-	 */
-
-	if (boot_cpu()) {
-		//bootblock_cpu_init();
-		//bootblock_mainboard_init();
-	}
-
-#if IS_ENABLED(CONFIG_BOOTBLOCK_CONSOLE)
-	console_init();
-	exception_init();
-#endif
-
-	run_romstage();
-}

src/arch/arm64/include/bootblock_common.h

@@ -1,11 +0,0 @@
-#ifdef CONFIG_BOOTBLOCK_CPU_INIT
-#include CONFIG_BOOTBLOCK_CPU_INIT
-#endif
-
-#ifdef CONFIG_BOOTBLOCK_MAINBOARD_INIT
-#include CONFIG_BOOTBLOCK_MAINBOARD_INIT
-#else
-static void bootblock_mainboard_init(void)
-{
-}
-#endif

src/arch/mips/Kconfig

@@ -22,6 +22,7 @@ config ARCH_BOOTBLOCK_MIPS
 	bool
 	default n
 	select ARCH_MIPS
+	select BOOTBLOCK_CUSTOM
 
 config ARCH_VERSTAGE_MIPS
 	bool

src/arch/mips/bootblock_simple.c

@@ -14,7 +14,7 @@
  * GNU General Public License for more details.
  */
 
-#include <bootblock_common.h>
+#include <arch/bootblock_common.h>
 #include <console/console.h>
 #include <halt.h>
 #include <program_loading.h>

src/arch/riscv/Kconfig

@@ -6,6 +6,7 @@ config ARCH_BOOTBLOCK_RISCV
 	bool
 	default n
 	select ARCH_RISCV
+	select BOOTBLOCK_CUSTOM
 
 config ARCH_VERSTAGE_RISCV
 	bool
@@ -18,9 +19,3 @@ config ARCH_ROMSTAGE_RISCV
 config ARCH_RAMSTAGE_RISCV
 	bool
 	default n
-
-# If a custom bootblock is necessary, this option should be "select"-ed by
-# the thing that needs it, probably the CPU.
-config RISCV_BOOTBLOCK_CUSTOM
-	bool
-	default n

src/arch/riscv/bootblock_simple.c

@@ -14,7 +14,6 @@
  * GNU General Public License for more details.
  */
 
-#include <bootblock_common.h>
 #include <arch/cache.h>
 #include <arch/hlt.h>
 #include <arch/stages.h>

src/arch/riscv/include/bootblock_common.h

@@ -1,16 +0,0 @@
-#ifdef CONFIG_BOOTBLOCK_CPU_INIT
-#include CONFIG_BOOTBLOCK_CPU_INIT
-#endif
-
-// I'm disappointed that we let this kind of thing creep in.
-// we null out functions with this kind of stuff, AND weak symbols,
-// AND empty cpp function defines. What's next? Ouija boards?
-#if 0
-#ifdef CONFIG_BOOTBLOCK_MAINBOARD_INIT
-#include CONFIG_BOOTBLOCK_MAINBOARD_INIT
-#else
-static void bootblock_mainboard_init(void)
-{
-}
-#endif
-#endif

src/arch/x86/Kconfig

@@ -24,6 +24,7 @@ config ARCH_BOOTBLOCK_X86_32
 	bool
 	default n
 	select ARCH_X86
+	select BOOTBLOCK_CUSTOM
 
 config ARCH_VERSTAGE_X86_32
 	bool
@@ -43,6 +44,7 @@ config ARCH_BOOTBLOCK_X86_64
 	bool
 	default n
 	select ARCH_X86
+	select BOOTBLOCK_CUSTOM
 
 config ARCH_VERSTAGE_X86_64
 	bool

src/arch/x86/bootblock_normal.c

@@ -1,5 +1,5 @@
 #include <smp/node.h>
-#include <bootblock_common.h>
+#include <arch/bootblock_common.h>
 #include <pc80/mc146818rtc.h>
 #include <halt.h>
 

src/arch/x86/bootblock_simple.c

@@ -1,5 +1,5 @@
 #include <smp/node.h>
-#include <bootblock_common.h>
+#include <arch/bootblock_common.h>
 #include <halt.h>
 
 static void main(unsigned long bist)