2022-10-31 12:17:27

by Nicholas Piggin

Subject: [PATCH v5 2/2] powerpc/64: Add module check for ELF ABI version

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 <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
[np: split patch, added changelog, adjust to Jessica's proposal]
Signed-off-by: Nicholas Piggin <[email protected]>
---
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
+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;
+}
+#endif
+
static const Elf_Shdr *find_section(const Elf_Ehdr *hdr,
const Elf_Shdr *sechdrs,
const char *name)
--
2.37.2

2022-11-03 08:53:38

by Christophe Leroy

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 <[email protected]>
> Signed-off-by: Michael Ellerman <[email protected]>
> [np: split patch, added changelog, adjust to Jessica's proposal]
> Signed-off-by: Nicholas Piggin <[email protected]>
> ---
> 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)

2022-11-07 13:54:59

by Nicholas Piggin

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

On Thu Nov 3, 2022 at 6:35 PM AEST, Christophe Leroy wrote:
>
>
> 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 <[email protected]>
> > Signed-off-by: Michael Ellerman <[email protected]>
> > [np: split patch, added changelog, adjust to Jessica's proposal]
> > Signed-off-by: Nicholas Piggin <[email protected]>
> > ---
> > 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;

Yes I think both of those can be done. Good suggestions.

Thanks,
Nick