From: Nicholas Piggin <npiggin@gmail.com>
To: Andrew Morton <akpm@linux-foundation.org>,
Arnd Bergmann <arnd@arndb.de>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Christophe Leroy <christophe.leroy@csgroup.eu>,
Helge Deller <deller@gmx.de>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>,
Kees Cook <keescook@chromium.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Paul Mackerras <paulus@samba.org>
Cc: linux-arch@vger.kernel.org, linux-ia64@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v2 06/13] asm-generic: Use HAVE_FUNCTION_DESCRIPTORS to define associated stubs
Date: Fri, 15 Oct 2021 18:02:00 +1000 [thread overview]
Message-ID: <1634284464.kd8scm0ckz.astroid@bobo.none> (raw)
In-Reply-To: <7523a005-ea69-7c4c-64ad-bc2537921975@csgroup.eu>
Excerpts from Christophe Leroy's message of October 15, 2021 4:24 pm:
>
>
> Le 15/10/2021 à 08:16, Nicholas Piggin a écrit :
>> Excerpts from Christophe Leroy's message of October 14, 2021 3:49 pm:
>>> Replace HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR by
>>> HAVE_FUNCTION_DESCRIPTORS and use it instead of
>>> 'dereference_function_descriptor' macro to know
>>> whether an arch has function descriptors.
>>>
>>> To limit churn in one of the following patches, use
>>> an #ifdef/#else construct with empty first part
>>> instead of an #ifndef in asm-generic/sections.h
>>
>> Is it worth putting this into Kconfig if you're going to
>> change it? In any case
>
> That was what I wanted to do in the begining but how can I do that in
> Kconfig ?
>
> #ifdef __powerpc64__
> #if defined(_CALL_ELF) && _CALL_ELF == 2
> #define PPC64_ELF_ABI_v2
> #else
> #define PPC64_ELF_ABI_v1
> #endif
> #endif /* __powerpc64__ */
>
> #ifdef PPC64_ELF_ABI_v1
> #define HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR 1
We have ELFv2 ABI / function descriptors iff big-endian so you could
just select based on that.
I have a patch that makes the ABI version configurable which cleans
some of this up a bit, but that can be rebased on your series if we
ever merge it. Maybe just add BUILD_BUG_ONs in the above ifdef block
to ensure CONFIG_HAVE_FUNCTION_DESCRIPTORS was set the right way, so
I don't forget.
Thanks,
Nick
next prev parent reply other threads:[~2021-10-15 8:02 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-14 5:49 [PATCH v2 00/13] Fix LKDTM for PPC64/IA64/PARISC Christophe Leroy
2021-10-14 5:49 ` [PATCH v2 01/13] powerpc: Move 'struct ppc64_opd_entry' back into asm/elf.h Christophe Leroy
2021-10-14 21:26 ` Daniel Axtens
2021-10-15 5:57 ` Nicholas Piggin
2021-10-14 5:49 ` [PATCH v2 02/13] powerpc: Rename 'funcaddr' to 'addr' in 'struct ppc64_opd_entry' Christophe Leroy
2021-10-14 21:45 ` Daniel Axtens
2021-10-15 4:59 ` Christophe Leroy
2021-10-15 6:01 ` Nicholas Piggin
2021-10-14 5:49 ` [PATCH v2 03/13] powerpc: Remove func_descr_t Christophe Leroy
2021-10-14 22:17 ` Daniel Axtens
2021-10-15 5:19 ` Christophe Leroy
2021-10-15 6:11 ` Nicholas Piggin
2021-10-14 5:49 ` [PATCH v2 04/13] powerpc: Prepare func_desc_t for refactorisation Christophe Leroy
2021-10-14 5:49 ` [PATCH v2 05/13] ia64: Rename 'ip' to 'addr' in 'struct fdesc' Christophe Leroy
2021-10-14 5:49 ` [PATCH v2 06/13] asm-generic: Use HAVE_FUNCTION_DESCRIPTORS to define associated stubs Christophe Leroy
2021-10-15 6:16 ` Nicholas Piggin
2021-10-15 6:24 ` Christophe Leroy
2021-10-15 8:02 ` Nicholas Piggin [this message]
2021-10-15 11:52 ` Nicholas Piggin
2021-10-14 5:49 ` [PATCH v2 07/13] asm-generic: Define 'func_desc_t' to commonly describe function descriptors Christophe Leroy
2021-10-14 6:52 ` Arnd Bergmann
2021-10-14 5:49 ` [PATCH v2 08/13] asm-generic: Refactor dereference_[kernel]_function_descriptor() Christophe Leroy
2021-10-15 7:00 ` Nicholas Piggin
2021-10-14 5:49 ` [PATCH v2 09/13] lkdtm: Force do_nothing() out of line Christophe Leroy
2021-10-14 5:49 ` [PATCH v2 10/13] lkdtm: Really write into kernel text in WRITE_KERN Christophe Leroy
2021-10-14 5:50 ` [PATCH v2 11/13] lkdtm: Fix lkdtm_EXEC_RODATA() Christophe Leroy
2021-10-15 21:32 ` Kees Cook
2021-10-16 6:41 ` Christophe Leroy
2021-10-17 7:50 ` Christophe Leroy
2021-10-14 5:50 ` [PATCH v2 12/13] lkdtm: Fix execute_[user]_location() Christophe Leroy
2021-10-15 21:31 ` Kees Cook
2021-10-16 6:42 ` Christophe Leroy
2021-11-16 15:07 ` Christophe Leroy
2021-10-14 5:50 ` [PATCH v2 13/13] lkdtm: Add a test for function descriptors protection Christophe Leroy
2021-10-15 21:35 ` Kees Cook
2021-10-16 6:28 ` Christophe Leroy
2021-10-14 21:35 ` [PATCH v2 00/13] Fix LKDTM for PPC64/IA64/PARISC Daniel Axtens
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