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Date:   Mon, 01 May 2023 05:44:26 -0700 (PDT)
Subject:     Re: [PATCH v6 4/4] risc/purgatory: Add linker script
In-Reply-To: <20230321-kexec_clang16-v6-4-a2255e81ab45@chromium.org>
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From:   Palmer Dabbelt <palmer@dabbelt.com>
To:     ribalda@chromium.org
Message-ID: <mhng-6809e805-0a92-401b-af74-fef93eeda1ae@palmer-ri-x1c9a>
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On Mon, 01 May 2023 05:38:22 PDT (-0700), ribalda@chromium.org wrote:
> If PGO is enabled, the purgatory ends up with multiple .text sections.
> This is not supported by kexec and crashes the system.
>
> Cc: stable@vger.kernel.org
> Fixes: 930457057abe ("kernel/kexec_file.c: split up __kexec_load_puragory")
> Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
> ---
>  arch/riscv/purgatory/Makefile | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/arch/riscv/purgatory/Makefile b/arch/riscv/purgatory/Makefile
> index 5730797a6b40..cf3a44121a90 100644
> --- a/arch/riscv/purgatory/Makefile
> +++ b/arch/riscv/purgatory/Makefile
> @@ -35,6 +35,11 @@ CFLAGS_sha256.o := -D__DISABLE_EXPORTS
>  CFLAGS_string.o := -D__DISABLE_EXPORTS
>  CFLAGS_ctype.o := -D__DISABLE_EXPORTS
>
> +# When profile optimization is enabled, llvm emits two different overlapping
> +# text sections, which is not supported by kexec. Remove profile optimization
> +# flags.
> +KBUILD_CFLAGS := $(filter-out -fprofile-sample-use=% -fprofile-use=%,$(KBUILD_CFLAGS))
> +
>  # When linking purgatory.ro with -r unresolved symbols are not checked,
>  # also link a purgatory.chk binary without -r to check for unresolved symbols.
>  PURGATORY_LDFLAGS := -e purgatory_start -z nodefaultlib

Acked-by: Palmer Dabbelt <palmer@rivosinc.com>