Re: [PATCH -fixes] riscv: Do not use fortify in early code

[Felix Yan]

On 10/9/24 10:27, Alexandre Ghiti wrote:
> Early code designates the code executed when the MMU is not yet enabled,
> and this comes with some limitations (see
> Documentation/arch/riscv/boot.rst, section "Pre-MMU execution").
>
> FORTIFY_SOURCE must be disabled then since it can trigger kernel panics
> as reported in [1].
>
> Reported-by: Jason Montleon <jmontleo@xxxxxxxxxx>
> Closes: https://lore.kernel.org/linux-riscv/CAJD_bPJes4QhmXY5f63GHV9B9HFkSCoaZjk-qCT2NGS7Q9HODg@xxxxxxxxxxxxxx/ [1]
> Fixes: a35707c3d850 ("riscv: add memory-type errata for T-Head")
> Fixes: 26e7aacb83df ("riscv: Allow to downgrade paging mode from the command line")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Alexandre Ghiti <alexghiti@xxxxxxxxxxxx>
> ---
>   arch/riscv/errata/Makefile    | 6 ++++++
>   arch/riscv/kernel/Makefile    | 5 +++++
>   arch/riscv/kernel/pi/Makefile | 6 +++++-
>   3 files changed, 16 insertions(+), 1 deletion(-)
>
> diff --git a/arch/riscv/errata/Makefile b/arch/riscv/errata/Makefile
> index 8a2739485123..f0da9d7b39c3 100644
> --- a/arch/riscv/errata/Makefile
> +++ b/arch/riscv/errata/Makefile
> @@ -2,6 +2,12 @@ ifdef CONFIG_RELOCATABLE
>   KBUILD_CFLAGS += -fno-pie
>   endif
>   
> +ifdef CONFIG_RISCV_ALTERNATIVE_EARLY
> +ifdef CONFIG_FORTIFY_SOURCE
> +KBUILD_CFLAGS += -D__NO_FORTIFY
> +endif
> +endif
> +
>   obj-$(CONFIG_ERRATA_ANDES) += andes/
>   obj-$(CONFIG_ERRATA_SIFIVE) += sifive/
>   obj-$(CONFIG_ERRATA_THEAD) += thead/
> diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile
> index 7f88cc4931f5..69dc8aaab3fb 100644
> --- a/arch/riscv/kernel/Makefile
> +++ b/arch/riscv/kernel/Makefile
> @@ -36,6 +36,11 @@ KASAN_SANITIZE_alternative.o := n
>   KASAN_SANITIZE_cpufeature.o := n
>   KASAN_SANITIZE_sbi_ecall.o := n
>   endif
> +ifdef CONFIG_FORTIFY_SOURCE
> +CFLAGS_alternative.o += -D__NO_FORTIFY
> +CFLAGS_cpufeature.o += -D__NO_FORTIFY
> +CFLAGS_sbi_ecall.o += -D__NO_FORTIFY
> +endif
>   endif
>   
>   extra-y += vmlinux.lds
> diff --git a/arch/riscv/kernel/pi/Makefile b/arch/riscv/kernel/pi/Makefile
> index d5bf1bc7de62..81d69d45c06c 100644
> --- a/arch/riscv/kernel/pi/Makefile
> +++ b/arch/riscv/kernel/pi/Makefile
> @@ -16,8 +16,12 @@ KBUILD_CFLAGS	:= $(filter-out $(CC_FLAGS_LTO), $(KBUILD_CFLAGS))
>   KBUILD_CFLAGS	+= -mcmodel=medany
>   
>   CFLAGS_cmdline_early.o += -D__NO_FORTIFY
> -CFLAGS_lib-fdt_ro.o += -D__NO_FORTIFY
>   CFLAGS_fdt_early.o += -D__NO_FORTIFY
> +# lib/string.c already defines __NO_FORTIFY
> +CFLAGS_ctype.o += -D__NO_FORTIFY
> +CFLAGS_lib-fdt.o += -D__NO_FORTIFY
> +CFLAGS_lib-fdt_ro.o += -D__NO_FORTIFY
> +CFLAGS_archrandom_early.o += -D__NO_FORTIFY
>   
>   $(obj)/%.pi.o: OBJCOPYFLAGS := --prefix-symbols=__pi_ \
>   			       --remove-section=.note.gnu.property \

I was having similar boot issues with Nezha D1 and this fixes it for me 
as well. Thanks (and thanks Emil for pointing me to this patch)!

Applied in my Arch Linux RISC-V port.

--
Regards,
Felix Yan

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