From: matt@codeblueprint•co.uk (Matt Fleming)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v2 1/2] efi: esrt: use memremap not ioremap to access ESRT table in memory
Date: Thu, 18 Feb 2016 13:43:24 +0000 [thread overview]
Message-ID: <20160218134324.GG2651@codeblueprint.co.uk> (raw)
In-Reply-To: <CAKv+Gu-s1pzYBzuDG-Z7s3gyo8dPOfeidZQ+rim-uAWZCBcKQQ@mail.gmail.com>
On Thu, 18 Feb, at 02:29:32PM, Ard Biesheuvel wrote:
> On 18 February 2016 at 14:28, Matt Fleming <matt@codeblueprint•co.uk> wrote:
> > On Thu, 18 Feb, at 01:16:05PM, Ard Biesheuvel wrote:
> >> On 18 February 2016 at 11:44, Matt Fleming <matt@codeblueprint•co.uk> wrote:
> >> > On Mon, 15 Feb, at 12:32:32PM, Ard Biesheuvel wrote:
> >> >> On ARM and arm64, ioremap() and memremap() are not interchangeable like
> >> >> on x86, and the use of ioremap() on ordinary RAM is typically flagged
> >> >> as an error if the memory region being mapped is also covered by the
> >> >> linear mapping, since that would lead to aliases with conflicting
> >> >> cacheability attributes.
> >> >>
> >> >> Since what we are dealing with is not an I/O region with side effects,
> >> >> using ioremap() here is arguably incorrect anyway, so let's replace
> >> >> it with memremap instead. Also add a missing unmap on the success path,
> >> >> and drop a memblock_remove() call which does not belong here, this far
> >> >> into the boot sequence.
> >> >>
> >> >> Cc: Peter Jones <pjones@redhat•com>
> >> >> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro•org>
> >> >> ---
> >> >> drivers/firmware/efi/esrt.c | 16 ++++++++--------
> >> >> 1 file changed, 8 insertions(+), 8 deletions(-)
> >> >>
> >> >
> >> > [...]
> >> >
> >> >> @@ -432,8 +434,6 @@ static int __init esrt_sysfs_init(void)
> >> >> if (error)
> >> >> goto err_cleanup_list;
> >> >>
> >> >> - memblock_remove(esrt_data, esrt_data_size);
> >> >> -
> >> >> pr_debug("esrt-sysfs: loaded.\n");
> >> >>
> >> >> return 0;
> >> >
> >> > Shouldn't we be replacing memblock_remove() with free_bootmem_late()?
> >> > The original ESRT region is still reserved at this point, so we should
> >> > do our best to release it to the page allocator.
> >>
> >> I'd rather we keep it reserved. That way, the config table entry still
> >> points to something valid, which could be useful for kexec(), I think?
> >> At least, that is how I intended to handle config tables on ARM ...
> >
> > If we're going to reserve it why do we need to copy the data out at
> > all in esrt_sysfs_init()?
>
> Excellent question. I don't think there is any point to doing that.
... Unless the data is contained in an EFI Boot Services region ;-)
Peter?
next prev parent reply other threads:[~2016-02-18 13:43 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-15 11:32 [PATCH v2 0/2] efi: ARM/arm64: wire up ESRT table Ard Biesheuvel
2016-02-15 11:32 ` [PATCH v2 1/2] efi: esrt: use memremap not ioremap to access ESRT table in memory Ard Biesheuvel
2016-02-15 15:45 ` Peter Jones
2016-02-16 19:19 ` Baicar, Tyler
2016-02-18 10:44 ` Matt Fleming
2016-02-18 12:16 ` Ard Biesheuvel
2016-02-18 13:28 ` Matt Fleming
2016-02-18 13:29 ` Ard Biesheuvel
2016-02-18 13:43 ` Matt Fleming [this message]
2016-02-18 13:44 ` Ard Biesheuvel
2016-02-18 14:15 ` Matt Fleming
2016-02-18 14:21 ` Ard Biesheuvel
2016-02-18 14:38 ` Matt Fleming
2016-02-19 9:27 ` Dave Young
2016-02-18 19:16 ` Peter Jones
2016-02-26 14:41 ` Matt Fleming
2016-03-01 23:30 ` Matt Fleming
2016-03-01 23:31 ` Matt Fleming
2016-03-02 1:16 ` Dave Young
2016-03-02 10:23 ` Matt Fleming
2016-03-04 6:25 ` Dave Young
2016-05-18 8:36 ` Ard Biesheuvel
2016-05-18 8:53 ` Matt Fleming
2016-06-16 13:47 ` Ard Biesheuvel
2016-06-20 11:49 ` Matt Fleming
2016-02-15 11:32 ` [PATCH v2 2/2] arm64/efi: esrt: add missing call to efi_esrt_init() Ard Biesheuvel
2016-02-15 15:46 ` Peter Jones
2016-02-16 20:25 ` Baicar, Tyler
2016-02-17 8:32 ` Ard Biesheuvel
2016-05-17 20:36 ` Christopher Covington
-- strict thread matches above, loose matches on Subject: below --
2016-07-11 19:00 [PATCH v2 0/2] efi/arm*: wire up ESRT table Ard Biesheuvel
2016-07-11 19:00 ` [PATCH v2 1/2] efi: esrt: use memremap not ioremap to access ESRT table in memory Ard Biesheuvel
2016-07-15 15:05 ` Matt Fleming
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