[PATCH] firmware: Fix fw_rw_offset computation in fw_base.S

[Anup Patel]

Hi Jessica,

On Thu, Jan 26, 2023 at 9:22 PM Anup Patel <apatel at ventanamicro.com> wrote:
>
> From: Jessica Clarke <jrtc27 at jrtc27.com>
>
> It seems BFD just does totally nonsensical things for SHN_ABS symbols
> when producing position-independent outputs (both -pie and -shared)
> for various historical reasons, and so SHN_ABS symbols are still
> subject to relocation as far as BFD is concerned (except AArch64,
> which fixes it in limited cases that don’t apply here...).
>
> The above affects the _fw_rw_offset provided through fw_base.ldS
> linker script which results in OpenSBI firmware failing to boot
> whne loaded at an address different from FW_TEXT_START.
>
> Fixes: c10e3fe5f9a1 ("firmware: Add RW section offset in scratch")
> Signed-off-by: Jessica Clarke <jrtc27 at jrtc27.com>
> Tested-by: Anup Patel <apatel at ventanamicro.com>
> Signed-off-by: Anup Patel <apatel at ventanamicro.com>

Let me know if you are okay with the above commit description ?

Regards,
Anup

> ---
>  firmware/fw_base.S   | 2 +-
>  firmware/fw_base.ldS | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/firmware/fw_base.S b/firmware/fw_base.S
> index e04b683..fb6ac92 100644
> --- a/firmware/fw_base.S
> +++ b/firmware/fw_base.S
> @@ -526,7 +526,7 @@ _link_start:
>  _link_end:
>         RISCV_PTR       _fw_reloc_end
>  __fw_rw_offset:
> -       RISCV_PTR       _fw_rw_offset
> +       RISCV_PTR       _fw_rw_start - _fw_start
>
>         .section .entry, "ax", %progbits
>         .align 3
> diff --git a/firmware/fw_base.ldS b/firmware/fw_base.ldS
> index 9a1304e..3d68484 100644
> --- a/firmware/fw_base.ldS
> +++ b/firmware/fw_base.ldS
> @@ -64,7 +64,7 @@
>         . = ALIGN(1 << LOG2CEIL((SIZEOF(.rodata) + SIZEOF(.text)
>                                 + SIZEOF(.dynsym) + SIZEOF(.rela.dyn))));
>
> -       PROVIDE(_fw_rw_offset = (.  - _fw_start));
> +       PROVIDE(_fw_rw_start = .);
>
>         /* Beginning of the read-write data sections */
>
> --
> 2.34.1
>