armv7: add a wrapper for romstage's main() for ARM ISA

This adds a wrapper around main() in romstage which is compiled using
-marm. This assumes that the bootblock branches to romstage in ARM
mode.

The long-term idea is to enforce ABI compatibility when handing off to
the next stage by using shims which are which are compiled in a pre-
determiend manner and leave the main portions of each stage up to
whatever the compiler wants. So it will eventually look like this:
1. bootblock_main (ARM/Thumb)
2. bootblock_exit (ARM)
3. romstage_entry (ARM)
4. romstage_main (ARM/Thumb)

(credit to Gabe Black for writing the patch, I'm just uploading it)

Change-Id: I4fdb8d2c6c2c0a7178bcb9154c378ddce0567309
Signed-off-by: David Hendricks <dhendrix@chromium.org>
Signed-off-by: Gabe Black <gabeblack@chromium.org>
Reviewed-on: http://review.coreboot.org/2175
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
This commit is contained in:
Gabe Black 2013-01-17 22:26:36 -08:00 committed by Ronald G. Minnich
parent fba42a793a
commit 929f9f1719
4 changed files with 42 additions and 4 deletions

View File

@ -265,21 +265,28 @@ endif
################################################################################
# Build the romstage
romstage_main_c = $(src)/arch/armv7/romstage_main.c
romstage_main_o = $(obj)/arch/armv7/romstage_main.o
$(romstage_main_o): $(romstage_main_c)
@printf " CC $(subst $(obj)/,,$(@))\n"
$(CC) -nostdlib -nostartfiles -static -c -o $@ $< -marm
# FIXME(dhendrix): added debug printfs
$(objcbfs)/romstage_null.debug: $$(romstage-objs) $(objgenerated)/romstage_null.ld
$(objcbfs)/romstage_null.debug: $$(romstage-objs) $(romstage_main_o) $(objgenerated)/romstage_null.ld
@printf " LINK $(subst $(obj)/,,$(@))\n"
ifeq ($(CONFIG_COMPILER_LLVM_CLANG),y)
$(LD) -nostdlib -nostartfiles -static -o $@ -L$(obj) $(romstage-objs) -T $(objgenerated)/romstage_null.ld
else
$(CC) -nostdlib -nostartfiles -static -o $@ -L$(obj) -T $(objgenerated)/romstage_null.ld -Wl,--start-group $(romstage-objs) $(LIBGCC_FILE_NAME) -Wl,--end-group
$(CC) -nostdlib -nostartfiles -static -o $@ -L$(obj) -T $(objgenerated)/romstage_null.ld -Wl,--start-group $(romstage-objs) $(romstage_main_o) $(LIBGCC_FILE_NAME) -Wl,--end-group
endif
$(objcbfs)/romstage_xip.debug: $$(romstage-objs) $(objgenerated)/romstage_xip.ld
@printf " LINK $(subst $(obj)/,,$(@))\n"
ifeq ($(CONFIG_COMPILER_LLVM_CLANG),y)
$(LD) -nostdlib -nostartfiles -static -o $@ -L$(obj) $(romstage-objs) -T $(objgenerated)/romstage_xip.ld
$(LD) -nostdlib -nostartfiles -static -o $@ -L$(obj) $(romstage-objs) $(romstage_main_o) -T $(objgenerated)/romstage_xip.ld
else
$(CC) -nostdlib -nostartfiles -static -o $@ -L$(obj) -T $(objgenerated)/romstage_xip.ld -Wl,--start-group $(romstage-objs) $(LIBGCC_FILE_NAME) -Wl,--end-group
$(CC) -nostdlib -nostartfiles -static -o $@ -L$(obj) -T $(objgenerated)/romstage_xip.ld -Wl,--start-group $(romstage-objs) $(romstage_main_o) $(LIBGCC_FILE_NAME) -Wl,--end-group
endif
$(objgenerated)/romstage_null.ld: $$(ldscripts) $(obj)/ldoptions

View File

@ -44,6 +44,7 @@ SECTIONS
.romtext . : {
_rom = .;
_start = .;
*(.text.entry.armv7);
*(.text.startup);
*(.text);
}

View File

@ -0,0 +1,29 @@
/*
* This file is part of the coreboot project.
*
* Copyright (C) 2012 The ChromiumOS Authors. All rights reserved.
*
* 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
*/
void main(void);
/* romstage_main is simply a stub to invoke main(), to handle ARM mode switching
* (ARM/Thumb) properly. */
void romstage_main(void) __attribute__((section(".text.entry.armv7")));
void romstage_main(void)
{
main();
}

View File

@ -26,6 +26,7 @@ static void mmu_setup(void)
dram_bank_mmu_setup(CONFIG_SYS_SDRAM_BASE, CONFIG_DRAM_SIZE_MB * 1024);
}
void main(void);
void main(void)
{
mmu_setup();