riscv: provide a flat image loader

This allows just loading the kernel at a pre-set address without
qemu going bonkers trying to map the ELF file.

Contains a contribution from Aurabindo Jayamohanan to reuse the
PAGE_OFFSET definition.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Anup Patel <anup@brainfault.org>
[paul.walmsley@sifive.com: fixed checkpatch issue; minor commit
 message fix]
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
This commit is contained in:
Christoph Hellwig 2019-10-28 13:10:42 +01:00 committed by Paul Walmsley
parent 6bd33e1ece
commit 405fe7aa0d
4 changed files with 39 additions and 5 deletions

View File

@ -83,13 +83,18 @@ PHONY += vdso_install
vdso_install:
$(Q)$(MAKE) $(build)=arch/riscv/kernel/vdso $@
all: Image.gz
ifeq ($(CONFIG_RISCV_M_MODE),y)
KBUILD_IMAGE := $(boot)/loader
else
KBUILD_IMAGE := $(boot)/Image.gz
endif
BOOT_TARGETS := Image Image.gz loader
Image: vmlinux
$(Q)$(MAKE) $(build)=$(boot) $(boot)/$@
all: $(notdir $(KBUILD_IMAGE))
Image.%: Image
$(BOOT_TARGETS): vmlinux
$(Q)$(MAKE) $(build)=$(boot) $(boot)/$@
@$(kecho) ' Kernel: $(boot)/$@ is ready'
zinstall install:
$(Q)$(MAKE) $(build)=$(boot) $@

View File

@ -16,7 +16,7 @@
OBJCOPYFLAGS_Image :=-O binary -R .note -R .note.gnu.build-id -R .comment -S
targets := Image
targets := Image loader
$(obj)/Image: vmlinux FORCE
$(call if_changed,objcopy)
@ -24,6 +24,11 @@ $(obj)/Image: vmlinux FORCE
$(obj)/Image.gz: $(obj)/Image FORCE
$(call if_changed,gzip)
loader.o: $(src)/loader.S $(obj)/Image
$(obj)/loader: $(obj)/loader.o $(obj)/Image $(obj)/loader.lds FORCE
$(Q)$(LD) -T $(obj)/loader.lds -o $@ $(obj)/loader.o
install:
$(CONFIG_SHELL) $(srctree)/$(src)/install.sh $(KERNELRELEASE) \
$(obj)/Image System.map "$(INSTALL_PATH)"

8
arch/riscv/boot/loader.S Normal file
View File

@ -0,0 +1,8 @@
/* SPDX-License-Identifier: GPL-2.0 */
.align 4
.section .payload, "ax", %progbits
.globl _start
_start:
.incbin "arch/riscv/boot/Image"

View File

@ -0,0 +1,16 @@
/* SPDX-License-Identifier: GPL-2.0 */
#include <asm/page.h>
OUTPUT_ARCH(riscv)
ENTRY(_start)
SECTIONS
{
. = PAGE_OFFSET;
.payload : {
*(.payload)
. = ALIGN(8);
}
}