From: t.figa@samsung•com (Tomasz Figa)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 1/2] arm: use generic fixmap.h
Date: Tue, 22 Jul 2014 18:39:51 +0200 [thread overview]
Message-ID: <53CE93D7.5010608@samsung.com> (raw)
In-Reply-To: <1404898792-4201-2-git-send-email-leif.lindholm@linaro.org>
Hi Leif,
On 09.07.2014 11:39, Leif Lindholm wrote:
> From: Mark Salter <msalter@redhat•com>
>
> ARM is different from other architectures in that fixmap pages are
> indexed with a positive offset from FIXADDR_START. Other architectures
> index with a negative offset from FIXADDR_TOP. In order to use the
> generic fixmap.h definitions, this patch redefines FIXADDR_TOP to be
> inclusive of the useable range. That is, FIXADDR_TOP is the virtual
> address of the topmost fixed page. The newly defined FIXADDR_END is
> the first virtual address past the fixed mappings.
>
> The patch also introduces local helper macros in highmem.c to reverse
> the iteration order of fixmap pages.
>
> Signed-off-by: Mark Salter <msalter@redhat•com>
> [Rebased to 3.16-rc4, reverse kmap fixmap traversal]
> Signed-off-by: Leif Lindholm <leif.lindholm@linaro•org>
> ---
> arch/arm/include/asm/fixmap.h | 45 ++++++++++++++++++++++++++---------------
> arch/arm/mm/highmem.c | 13 +++++++-----
> arch/arm/mm/init.c | 2 +-
> 3 files changed, 38 insertions(+), 22 deletions(-)
>
I've tried to use this series to enable earlycon without hardcoded
static mappings, but apparently something is not right yet. Please see
below.
[snip]
> -extern void __this_fixmap_does_not_exist(void);
> +#define FIXMAP_PAGE_NORMAL (L_PTE_MT_WRITEBACK | L_PTE_YOUNG | L_PTE_PRESENT)
> +#define FIXMAP_PAGE_IO (L_PTE_MT_DEV_NONSHARED | L_PTE_YOUNG | L_PTE_PRESENT)
This set of flags gives a read-only mapping on the machine I'm testing
on (Exynos4412, Cortex A9MPcore). If I use the same set of flags as used
in arch/arm/mm/mmu.c for MT_DEVICE_NONSHARED then the mapping works fine.
Best regards,
Tomasz
next prev parent reply other threads:[~2014-07-22 16:39 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-09 9:39 [PATCH 0/2] arm: add early_ioremap support Leif Lindholm
2014-07-09 9:39 ` [PATCH 1/2] arm: use generic fixmap.h Leif Lindholm
2014-07-09 20:49 ` Mark Salter
2014-07-18 14:33 ` Leif Lindholm
2014-07-25 19:56 ` Kees Cook
2014-07-22 16:39 ` Tomasz Figa [this message]
2014-07-09 9:39 ` [PATCH 2/2] arm: add early_ioremap support Leif Lindholm
2014-07-09 9:49 ` Russell King - ARM Linux
2014-07-09 11:48 ` Leif Lindholm
2014-07-22 16:48 ` Tomasz Figa
2014-07-22 17:11 ` Rob Herring
2014-07-22 17:27 ` Tomasz Figa
2014-07-09 9:42 ` [PATCH 0/2] " Russell King - ARM Linux
2014-07-09 9:58 ` Leif Lindholm
2014-07-09 9:47 ` Will Deacon
2014-07-09 10:02 ` Leif Lindholm
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