From: will.deacon@arm•com (Will Deacon)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v2 1/2] arm64: don't make early_*map() calls post paging_init()
Date: Wed, 7 Jan 2015 19:03:36 +0000 [thread overview]
Message-ID: <20150107190335.GX7485@arm.com> (raw)
In-Reply-To: <20150107133109.GM3827@bivouac.eciton.net>
On Wed, Jan 07, 2015 at 01:31:09PM +0000, Leif Lindholm wrote:
> On Wed, Jan 07, 2015 at 01:13:06PM +0000, Ard Biesheuvel wrote:
> > >> > -void __init efi_idmap_init(void)
> > >> > +void __init efi_memmap_init(void)
> > >> > {
> > >> > + u64 mapsize;
> > >> > +
> > >> > if (!efi_enabled(EFI_BOOT))
> > >> > return;
> > >> >
> > >> > + /* replace early memmap mapping with permanent mapping */
> > >> > + mapsize = memmap.map_end - memmap.map;
> > >> > + memmap.map = (__force void *)ioremap_cache((phys_addr_t)memmap.phys_map,
> > >> > + mapsize);
> > >>
> > >> ioremap_cache() could potententially fail here if the phys_map address
> > >> doesn't have a valid pfn (not in the kernel linear ram mapping) because
> > >> some of the underlying vm support hasn't been initialized yet.
> > >
> > > Can you be more specific about the case you have in mind, please? pfn_valid
> > > uses the memblocks on arm64, and that should all have been sorted out in
> > > paging_init(). What's the issue that you're anticipating?
> >
> > I think Mark's concern is that it is too early to call
> > __get_free_page(), which is what happens if ioremap_cache() finds that
> > the requested address is not covered by the existing linear mapping.
> > Currently, UEFI reserved RAM regions are covered by the linear
> > mapping, but that is something we intend to change in the future.
>
> Which shouldn't be a problem, right? Since this function will be going
> away with your "stable mappings" set, and the remap call bumped down
> to an early initcall in arm64_enter_virtual_mode() (or potential
> future name for that function).
Sounds reasonable to me... Ard?
However, I'd certainly like something in the commit log and/or a comment
in the code with our reasoning.
Will
next prev parent reply other threads:[~2015-01-07 19:03 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-06 13:41 [PATCH v2 0/2] arm64: don't call early_*map() post paging_init() Leif Lindholm
2015-01-06 13:41 ` [PATCH v2 1/2] arm64: don't make early_*map() calls " Leif Lindholm
2015-01-06 20:35 ` Mark Salter
2015-01-07 10:58 ` Will Deacon
2015-01-07 13:13 ` Ard Biesheuvel
2015-01-07 13:31 ` Leif Lindholm
2015-01-07 19:03 ` Will Deacon [this message]
2015-01-06 13:41 ` [PATCH v2 2/2] arm64: call early_ioremap_reset() in paging_init() Leif Lindholm
2015-01-06 13:59 ` [PATCH v2 0/2] arm64: don't call early_*map() post paging_init() Will Deacon
2015-01-06 14:04 ` Ard Biesheuvel
2015-01-06 15:52 ` Leif Lindholm
2015-01-06 15:54 ` Ard Biesheuvel
2015-01-06 16:05 ` Will Deacon
2015-01-06 16:23 ` Ard Biesheuvel
2015-01-06 19:18 ` Will Deacon
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