From: Ard Biesheuvel <ard.biesheuvel@linaro.org>
To: Mike Rapoport <rppt@linux.ibm.com>
Cc: Chester Lin <clin@suse.com>, Juergen Gross <JGross@suse.com>,
Joey Lee <JLee@suse.com>,
"linux-efi@vger.kernel.org" <linux-efi@vger.kernel.org>,
"guillaume.gardet@arm.com" <guillaume.gardet@arm.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Russell King - ARM Linux admin <linux@armlinux.org.uk>,
"geert@linux-m68k.org" <geert@linux-m68k.org>,
"ren_guo@c-sky.com" <ren_guo@c-sky.com>, Gary Lin <GLin@suse.com>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"mingo@kernel.org" <mingo@kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH] efi/arm: fix allocation failure when reserving the kernel base
Date: Wed, 21 Aug 2019 12:42:56 +0300 [thread overview]
Message-ID: <CAKv+Gu91d3NrcEGsz6yapVnf3NV=F-cGeftdPo=H-cNTXCC2EA@mail.gmail.com> (raw)
In-Reply-To: <20190821082927.GC26713@rapoport-lnx>
On Wed, 21 Aug 2019 at 11:29, Mike Rapoport <rppt@linux.ibm.com> wrote:
>
> On Wed, Aug 21, 2019 at 10:29:37AM +0300, Ard Biesheuvel wrote:
> > On Wed, 21 Aug 2019 at 10:11, Mike Rapoport <rppt@linux.ibm.com> wrote:
> > >
...
> > > I think the only missing part here is to ensure that non-reserved memory in
> > > bank 0 starts from a PMD-aligned address. I believe this could be done if
> > > EFI stub, but I'm not really familiar with it so this just a semi-educated
> > > guess :)
> > >
> >
> > Given that it is the ARM arch code that imposes this requirement, how
> > about adding something like this to adjust_lowmem_bounds():
> >
> > if (memblock_start_of_DRAM() % PMD_SIZE)
> > memblock_mark_nomap(memblock_start_of_DRAM(),
> > PMD_SIZE - (memblock_start_of_DRAM() % PMD_SIZE));
>
> memblock_start_of_DRAM() won't work here, as it returns the actual start of
> the DRAM including NOMAP regions. Moreover, as we cannot mark a region
> NOMAP inside for_each_memblock() this should be done beforehand.
>
> I think something like this could work:
>
> diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
> index 2f0f07e..f2b635b 100644
> --- a/arch/arm/mm/mmu.c
> +++ b/arch/arm/mm/mmu.c
> @@ -1178,6 +1178,19 @@ void __init adjust_lowmem_bounds(void)
> */
> vmalloc_limit = (u64)(uintptr_t)vmalloc_min - PAGE_OFFSET + PHYS_OFFSET;
>
> + /*
> + * The first usable region must be PMD aligned. Mark its start
> + * as MEMBLOCK_NOMAP if it isn't
> + */
> + for_each_memblock(memory, reg) {
> + if (!memblock_is_nomap(reg) && (reg->base % PMD_SIZE)) {
> + phys_addr_t size = PMD_SIZE - (reg->base % PMD_SIZE);
> +
> + memblock_mark_nomap(reg->base, size);
> + break;
We should break on the first !NOMAP memblock, even if it is already
PMD aligned, but beyond that, this looks ok to me.
prev parent reply other threads:[~2019-08-21 9:43 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-02 5:38 [PATCH] efi/arm: fix allocation failure when reserving the kernel base Chester Lin
2019-08-04 7:57 ` Ard Biesheuvel
2019-08-14 7:58 ` Guillaume Gardet
2019-08-15 7:59 ` Ard Biesheuvel
2019-08-15 11:16 ` Chester Lin
2019-08-15 11:32 ` Ard Biesheuvel
2019-08-15 13:37 ` Mike Rapoport
2019-08-19 7:56 ` Chester Lin
2019-08-19 14:56 ` Ard Biesheuvel
2019-08-20 7:33 ` Chester Lin
2019-08-20 7:49 ` Mike Rapoport
2019-08-20 10:29 ` Chester Lin
2019-08-20 11:00 ` Ard Biesheuvel
2019-08-20 11:54 ` Russell King - ARM Linux admin
2019-08-20 12:27 ` Ard Biesheuvel
2019-08-20 11:56 ` Russell King - ARM Linux admin
2019-08-20 12:28 ` Ard Biesheuvel
2019-08-21 6:10 ` Chester Lin
2019-08-21 6:35 ` Ard Biesheuvel
2019-08-21 7:11 ` Mike Rapoport
2019-08-21 7:22 ` Chester Lin
2019-08-21 7:29 ` Ard Biesheuvel
2019-08-21 8:29 ` Mike Rapoport
2019-08-21 9:42 ` Ard Biesheuvel [this message]
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