From: Christophe Leroy <christophe.leroy@csgroup.eu>
To: Daniel Axtens <dja@axtens.net>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
kasan-dev@googlegroups.com, elver@google.com,
akpm@linux-foundation.org, andreyknvl@gmail.com
Cc: linuxppc-dev@lists.ozlabs.org, aneesh.kumar@linux.ibm.com,
bsingharora@gmail.com
Subject: Re: [PATCH v14 3/4] mm: define default MAX_PTRS_PER_* in include/pgtable.h
Date: Thu, 17 Jun 2021 09:00:35 +0200 [thread overview]
Message-ID: <cbe77a1d-074d-4bc0-0aad-996249a6bf3a@csgroup.eu> (raw)
In-Reply-To: <20210617063956.94061-4-dja@axtens.net>
Le 17/06/2021 à 08:39, Daniel Axtens a écrit :
> Commit c65e774fb3f6 ("x86/mm: Make PGDIR_SHIFT and PTRS_PER_P4D variable")
> made PTRS_PER_P4D variable on x86 and introduced MAX_PTRS_PER_P4D as a
> constant for cases which need a compile-time constant (e.g. fixed-size
> arrays).
>
> powerpc likewise has boot-time selectable MMU features which can cause
> other mm "constants" to vary. For KASAN, we have some static
> PTE/PMD/PUD/P4D arrays so we need compile-time maximums for all these
> constants. Extend the MAX_PTRS_PER_ idiom, and place default definitions
> in include/pgtable.h. These define MAX_PTRS_PER_x to be PTRS_PER_x unless
> an architecture has defined MAX_PTRS_PER_x in its arch headers.
>
> Clean up pgtable-nop4d.h and s390's MAX_PTRS_PER_P4D definitions while
> we're at it: both can just pick up the default now.
>
> Signed-off-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
>
> ---
>
> s390 was compile tested only.
> ---
> arch/s390/include/asm/pgtable.h | 2 --
> include/asm-generic/pgtable-nop4d.h | 1 -
> include/linux/pgtable.h | 22 ++++++++++++++++++++++
> 3 files changed, 22 insertions(+), 3 deletions(-)
>
> diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
> index 7c66ae5d7e32..cf05954ce013 100644
> --- a/arch/s390/include/asm/pgtable.h
> +++ b/arch/s390/include/asm/pgtable.h
> @@ -342,8 +342,6 @@ static inline int is_module_addr(void *addr)
> #define PTRS_PER_P4D _CRST_ENTRIES
> #define PTRS_PER_PGD _CRST_ENTRIES
>
> -#define MAX_PTRS_PER_P4D PTRS_PER_P4D
> -
> /*
> * Segment table and region3 table entry encoding
> * (R = read-only, I = invalid, y = young bit):
> diff --git a/include/asm-generic/pgtable-nop4d.h b/include/asm-generic/pgtable-nop4d.h
> index ce2cbb3c380f..2f6b1befb129 100644
> --- a/include/asm-generic/pgtable-nop4d.h
> +++ b/include/asm-generic/pgtable-nop4d.h
> @@ -9,7 +9,6 @@
> typedef struct { pgd_t pgd; } p4d_t;
>
> #define P4D_SHIFT PGDIR_SHIFT
> -#define MAX_PTRS_PER_P4D 1
> #define PTRS_PER_P4D 1
> #define P4D_SIZE (1UL << P4D_SHIFT)
> #define P4D_MASK (~(P4D_SIZE-1))
> diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
> index 9e6f71265f72..69700e3e615f 100644
> --- a/include/linux/pgtable.h
> +++ b/include/linux/pgtable.h
> @@ -1625,4 +1625,26 @@ typedef unsigned int pgtbl_mod_mask;
> #define pte_leaf_size(x) PAGE_SIZE
> #endif
>
> +/*
> + * Some architectures have MMUs that are configurable or selectable at boot
> + * time. These lead to variable PTRS_PER_x. For statically allocated arrays it
> + * helps to have a static maximum value.
> + */
> +
> +#ifndef MAX_PTRS_PER_PTE
> +#define MAX_PTRS_PER_PTE PTRS_PER_PTE
> +#endif
> +
> +#ifndef MAX_PTRS_PER_PMD
> +#define MAX_PTRS_PER_PMD PTRS_PER_PMD
> +#endif
> +
> +#ifndef MAX_PTRS_PER_PUD
> +#define MAX_PTRS_PER_PUD PTRS_PER_PUD
> +#endif
> +
> +#ifndef MAX_PTRS_PER_P4D
> +#define MAX_PTRS_PER_P4D PTRS_PER_P4D
> +#endif
> +
> #endif /* _LINUX_PGTABLE_H */
>
next prev parent reply other threads:[~2021-06-17 7:00 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-17 6:39 [PATCH v14 0/4] KASAN core changes for ppc64 radix KASAN Daniel Axtens
2021-06-17 6:39 ` [PATCH v14 1/4] kasan: allow an architecture to disable inline instrumentation Daniel Axtens
2021-06-17 7:06 ` Marco Elver
2021-06-17 6:39 ` [PATCH v14 2/4] kasan: allow architectures to provide an outline readiness check Daniel Axtens
2021-06-17 6:55 ` Christophe Leroy
2021-06-17 6:59 ` Christophe Leroy
2021-06-17 7:06 ` Marco Elver
2021-06-17 6:39 ` [PATCH v14 3/4] mm: define default MAX_PTRS_PER_* in include/pgtable.h Daniel Axtens
2021-06-17 7:00 ` Christophe Leroy [this message]
2021-06-17 7:08 ` Marco Elver
2021-06-17 6:39 ` [PATCH v14 4/4] kasan: use MAX_PTRS_PER_* for early shadow tables Daniel Axtens
2021-06-17 7:09 ` Marco Elver
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=cbe77a1d-074d-4bc0-0aad-996249a6bf3a@csgroup.eu \
--to=christophe.leroy@csgroup.eu \
--cc=akpm@linux-foundation.org \
--cc=andreyknvl@gmail.com \
--cc=aneesh.kumar@linux.ibm.com \
--cc=bsingharora@gmail.com \
--cc=dja@axtens.net \
--cc=elver@google.com \
--cc=kasan-dev@googlegroups.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linuxppc-dev@lists.ozlabs.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).