linux-kernel - Re: [PATCH v5 2/2] powerpc/64: Add module check for ELF ABI version

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Message-ID: <513e1973-a1d4-c698-1441-9c7d0f5205ed@csgroup.eu>
Date:   Thu, 3 Nov 2022 08:35:09 +0000
From:   Christophe Leroy <christophe.leroy@...roup.eu>
To:     Nicholas Piggin <npiggin@...il.com>,
        "linux-modules@...r.kernel.org" <linux-modules@...r.kernel.org>,
        "linuxppc-dev@...ts.ozlabs.org" <linuxppc-dev@...ts.ozlabs.org>
CC:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Michael Ellerman <mpe@...erman.id.au>,
        Jessica Yu <jeyu@...nel.org>,
        Luis Chamberlain <mcgrof@...nel.org>
Subject: Re: [PATCH v5 2/2] powerpc/64: Add module check for ELF ABI version



Le 31/10/2022 à 13:07, Nicholas Piggin a écrit :
> Override the generic module ELF check to provide a check for the ELF ABI
> version. This becomes important if we allow big-endian ELF ABI V2 builds
> but it doesn't hurt to check now.
> 
> Cc: Jessica Yu <jeyu@...nel.org>
> Signed-off-by: Michael Ellerman <mpe@...erman.id.au>
> [np: split patch, added changelog, adjust to Jessica's proposal]
> Signed-off-by: Nicholas Piggin <npiggin@...il.com>
> ---
>   arch/powerpc/kernel/module.c | 17 +++++++++++++++++
>   1 file changed, 17 insertions(+)
> 
> diff --git a/arch/powerpc/kernel/module.c b/arch/powerpc/kernel/module.c
> index f6d6ae0a1692..d46bf9bfda26 100644
> --- a/arch/powerpc/kernel/module.c
> +++ b/arch/powerpc/kernel/module.c
> @@ -19,6 +19,23 @@
>   
>   static LIST_HEAD(module_bug_list);
>   
> +#ifdef CONFIG_PPC64

Can it go in arch/powerpc/kernel/module_64.c instead ?

> +bool module_elf_check_arch(Elf_Ehdr *hdr)
> +{
> +	unsigned long abi_level = hdr->e_flags & 0x3;
> +
> +	if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V2)) {
> +		if (abi_level != 2)
> +			return false;
> +	} else {
> +		if (abi_level >= 2)
> +			return false;
> +	}
> +
> +	return true;

Can be simpler:

	if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V2))
		return abi_level == 2;
	else
		return abi_level < 2;


> +}
> +#endif
> +
>   static const Elf_Shdr *find_section(const Elf_Ehdr *hdr,
>   				    const Elf_Shdr *sechdrs,
>   				    const char *name)