linux-kernel - Re: [PATCH v2 2/2] riscv/purgatory: Omit use of bin2c

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Date:   Mon, 25 Jul 2022 10:52:41 -0700
From:   Nick Desaulniers <ndesaulniers@...gle.com>
To:     Masahiro Yamada <masahiroy@...nel.org>
Cc:     Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        linux-riscv@...ts.infradead.org, Borislav Petkov <bp@...e.de>,
        Helge Deller <deller@....de>,
        Li Zhengyu <lizhengyu3@...wei.com>,
        "Russell King (Oracle)" <rmk+kernel@...linux.org.uk>,
        Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/2] riscv/purgatory: Omit use of bin2c

On Sun, Jul 24, 2022 at 7:22 PM Masahiro Yamada <masahiroy@...nel.org> wrote:
>
> The .incbin assembler directive is much faster than bin2c + $(CC).
>
> Do similar refactoring as in commit 4c0f032d4963 ("s390/purgatory:
> Omit use of bin2c").
>
> Please note the .quad directive matches to size_t in C (both 8 byte)
> because the purgatory is compiled only for the 64-bit kernel.
> (KEXEC_FILE depends on 64BIT).
>
> Signed-off-by: Masahiro Yamada <masahiroy@...nel.org>

Seems fine.  Is the overall goal working towards removing scripts/bin2c?
Acked-by: Nick Desaulniers <ndesaulniers@...gle.com>

> ---
>
> Changes in v2:
>   - Fix a typo (kexec_purgatroy_end -> kexec_purgatory_end)
>
>  arch/riscv/Kconfig                     |  1 -
>  arch/riscv/purgatory/.gitignore        |  1 -
>  arch/riscv/purgatory/Makefile          |  8 +-------
>  arch/riscv/purgatory/kexec-purgatory.S | 14 ++++++++++++++
>  scripts/remove-stale-files             |  2 ++
>  5 files changed, 17 insertions(+), 9 deletions(-)
>  create mode 100644 arch/riscv/purgatory/kexec-purgatory.S
>
> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> index 32ffef9f6e5b..218c2f12b3ef 100644
> --- a/arch/riscv/Kconfig
> +++ b/arch/riscv/Kconfig
> @@ -447,7 +447,6 @@ config KEXEC_FILE
>
>  config ARCH_HAS_KEXEC_PURGATORY
>         def_bool KEXEC_FILE
> -       select BUILD_BIN2C
>         depends on CRYPTO=y
>         depends on CRYPTO_SHA256=y
>
> diff --git a/arch/riscv/purgatory/.gitignore b/arch/riscv/purgatory/.gitignore
> index 38d7d1bda4d7..6e4dfb024ad2 100644
> --- a/arch/riscv/purgatory/.gitignore
> +++ b/arch/riscv/purgatory/.gitignore
> @@ -1,4 +1,3 @@
>  # SPDX-License-Identifier: GPL-2.0-only
>  purgatory.chk
>  purgatory.ro
> -kexec-purgatory.c
> diff --git a/arch/riscv/purgatory/Makefile b/arch/riscv/purgatory/Makefile
> index c2d14e2f345d..dd58e1d99397 100644
> --- a/arch/riscv/purgatory/Makefile
> +++ b/arch/riscv/purgatory/Makefile
> @@ -84,12 +84,6 @@ $(obj)/purgatory.ro: $(PURGATORY_OBJS) FORCE
>  $(obj)/purgatory.chk: $(obj)/purgatory.ro FORCE
>                 $(call if_changed,ld)
>
> -targets += kexec-purgatory.c
> -
> -quiet_cmd_bin2c = BIN2C   $@
> -      cmd_bin2c = $(objtree)/scripts/bin2c kexec_purgatory < $< > $@
> -
> -$(obj)/kexec-purgatory.c: $(obj)/purgatory.ro $(obj)/purgatory.chk FORCE
> -       $(call if_changed,bin2c)
> +$(obj)/kexec-purgatory.o: $(obj)/purgatory.ro $(obj)/purgatory.chk
>
>  obj-y += kexec-purgatory.o
> diff --git a/arch/riscv/purgatory/kexec-purgatory.S b/arch/riscv/purgatory/kexec-purgatory.S
> new file mode 100644
> index 000000000000..32c53581b8f2
> --- /dev/null
> +++ b/arch/riscv/purgatory/kexec-purgatory.S
> @@ -0,0 +1,14 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +
> +       .section .rodata, "a"
> +
> +       .align  8
> +kexec_purgatory:
> +       .globl  kexec_purgatory
> +       .incbin "arch/riscv/purgatory/purgatory.ro"
> +.Lkexec_purgatory_end:
> +
> +       .align  8
> +kexec_purgatory_size:
> +       .globl  kexec_purgatory_size
> +       .quad   .Lkexec_purgatory_end - kexec_purgatory
> diff --git a/scripts/remove-stale-files b/scripts/remove-stale-files
> index 7adab4618035..d75a52199a38 100755
> --- a/scripts/remove-stale-files
> +++ b/scripts/remove-stale-files
> @@ -40,4 +40,6 @@ if [ -n "${building_out_of_srctree}" ]; then
>         done
>  fi
>
> +rm -f arch/riscv/purgatory/kexec-purgatory.c
> +
>  rm -f scripts/extract-cert
> --
> 2.34.1
>


-- 
Thanks,
~Nick Desaulniers