[PATCH v3] firmware: Move memcpy/memset mapping to fw_base.S

[Anup Patel]

On Thu, Dec 23, 2021 at 5:57 PM Anup Patel <anup.patel at wdc.com> wrote:
>
> Some of the external firmwares using OpenSBI as library are facing
> issues with the weak memcpy() and memset() aliases in libsbi.a so
> we move these to fw_base.S. This way mapping of implicit memcpy()
> or memset() calls to sbi_memcpy() or sbi_memset() will only be done
> for OpenSBI firmwares.
> (Refer, https://github.com/riscv-software-src/opensbi/issues/234)
>
> In addition, we also add memmove() and memcmp() mappings in fw_base.S
> because as-per the GCC documentation the freestanding environment must
> provide memcpy(), memmove(), memset(), and memcmp().
>
> Signed-off-by: Anup Patel <anup.patel at wdc.com>
> Reviewed-by: Atish Patra <atishp at rivosinc.com>

Applied this patch to the riscv/opensbi repo.

Regards,
Anup

> ---
> Changes since v2:
>  - Added mapping for memmove() and memcmp() in fw_base.S
> Changes since v1:
>  - Use "tail" in-place of "j" instruction in fw_base.S
> ---
>  firmware/fw_base.S   | 28 ++++++++++++++++++++++++++++
>  lib/sbi/sbi_string.c |  6 ------
>  2 files changed, 28 insertions(+), 6 deletions(-)
>
> diff --git a/firmware/fw_base.S b/firmware/fw_base.S
> index 1569e60..ab3e1b3 100644
> --- a/firmware/fw_base.S
> +++ b/firmware/fw_base.S
> @@ -561,6 +561,34 @@ fw_platform_init:
>         add     a0, a1, zero
>         ret
>
> +       /* Map implicit memcpy() added by compiler to sbi_memcpy() */
> +       .section .text
> +       .align 3
> +       .globl memcpy
> +memcpy:
> +       tail    sbi_memcpy
> +
> +       /* Map implicit memset() added by compiler to sbi_memset() */
> +       .section .text
> +       .align 3
> +       .globl memset
> +memset:
> +       tail    sbi_memset
> +
> +       /* Map implicit memmove() added by compiler to sbi_memmove() */
> +       .section .text
> +       .align 3
> +       .globl memmove
> +memmove:
> +       tail    sbi_memmove
> +
> +       /* Map implicit memcmp() added by compiler to sbi_memcmp() */
> +       .section .text
> +       .align 3
> +       .globl memcmp
> +memcmp:
> +       tail    sbi_memcmp
> +
>  .macro TRAP_SAVE_AND_SETUP_SP_T0
>         /* Swap TP and MSCRATCH */
>         csrrw   tp, CSR_MSCRATCH, tp
> diff --git a/lib/sbi/sbi_string.c b/lib/sbi/sbi_string.c
> index c67c02e..c87bce9 100644
> --- a/lib/sbi/sbi_string.c
> +++ b/lib/sbi/sbi_string.c
> @@ -122,9 +122,6 @@ void *sbi_memset(void *s, int c, size_t count)
>         return s;
>  }
>
> -void *memset(void *s, int c, size_t count) \
> -__attribute__((weak, alias("sbi_memset")));
> -
>  void *sbi_memcpy(void *dest, const void *src, size_t count)
>  {
>         char *temp1       = dest;
> @@ -138,9 +135,6 @@ void *sbi_memcpy(void *dest, const void *src, size_t count)
>         return dest;
>  }
>
> -void *memcpy(void *dest, const void *src, size_t count) \
> -__attribute__((weak, alias("sbi_memcpy")));
> -
>  void *sbi_memmove(void *dest, const void *src, size_t count)
>  {
>         char *temp1       = (char *)dest;
> --
> 2.25.1
>