On Thu, Oct 17, 2019 at 11:08 PM Christoph Hellwig <h...@lst.de> wrote:
>
> This allows just loading the kernel at a pre-set address without
> qemu going bonkers trying to map the ELF file.
>
> Contains a controbution from Aurabindo Jayamohanan to reuse the
> PAGE_OFFSET definition.
>
> Signed-off-by: Christoph Hellwig <h...@lst.de>
> ---
> arch/riscv/Makefile | 13 +++++++++----
> arch/riscv/boot/Makefile | 7 ++++++-
> arch/riscv/boot/loader.S | 8 ++++++++
> arch/riscv/boot/loader.lds.S | 16 ++++++++++++++++
> 4 files changed, 39 insertions(+), 5 deletions(-)
> create mode 100644 arch/riscv/boot/loader.S
> create mode 100644 arch/riscv/boot/loader.lds.S
>
> diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile
> index f5e914210245..b9009a2fbaf5 100644
> --- a/arch/riscv/Makefile
> +++ b/arch/riscv/Makefile
> @@ -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) $@
> diff --git a/arch/riscv/boot/Makefile b/arch/riscv/boot/Makefile
> index 0990a9fdbe5d..8639e0dd2cdf 100644
> --- a/arch/riscv/boot/Makefile
> +++ b/arch/riscv/boot/Makefile
> @@ -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 $(src)/loader.lds -o $@ $(obj)/loader.o
> +
> install:
> $(CONFIG_SHELL) $(srctree)/$(src)/install.sh $(KERNELRELEASE) \
> $(obj)/Image System.map "$(INSTALL_PATH)"
> diff --git a/arch/riscv/boot/loader.S b/arch/riscv/boot/loader.S
> new file mode 100644
> index 000000000000..5586e2610dbb
> --- /dev/null
> +++ b/arch/riscv/boot/loader.S
> @@ -0,0 +1,8 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> + .align 4
> + .section .payload, "ax", %progbits
> + .globl _start
> +_start:
> + .incbin "arch/riscv/boot/Image"
> +
> diff --git a/arch/riscv/boot/loader.lds.S b/arch/riscv/boot/loader.lds.S
> new file mode 100644
> index 000000000000..47a5003c2e28
> --- /dev/null
> +++ b/arch/riscv/boot/loader.lds.S
> @@ -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);
> + }
> +}
> --
> 2.20.1
>
LGTM.
Reviewed-by: Anup Patel <a...@brainfault.org>
Regards,
Anup
