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From: Ard Biesheuvel <ardb@kernel.org>
To: Arvind Sankar <nivedita@alum.mit.edu>
Cc: linux-efi <linux-efi@vger.kernel.org>,
	"the arch/x86 maintainers" <x86@kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 5/5] efi/x86: Don't relocate the kernel unless necessary
Date: Wed, 4 Mar 2020 08:30:20 +0100	[thread overview]
Message-ID: <CAKv+Gu9GLik3VZBZg8VQKFBs3GtV+QB7KQSVfiKcCNtyYjW0XQ@mail.gmail.com> (raw)
In-Reply-To: <20200303233457.GA154112@rani.riverdale.lan>

On Wed, 4 Mar 2020 at 00:35, Arvind Sankar <nivedita@alum.mit.edu> wrote:
>
> On Wed, Mar 04, 2020 at 12:08:33AM +0100, Ard Biesheuvel wrote:
> > On Tue, 3 Mar 2020 at 23:12, Arvind Sankar <nivedita@alum.mit.edu> wrote:
> > >
> > > Add alignment slack to the PE image size, so that we can realign the
> > > decompression buffer within the space allocated for the image.
> > >
> > > Only relocate the kernel if it has been loaded at an unsuitable address:
> > > * Below LOAD_PHYSICAL_ADDR, or
> > > * Above 64T for 64-bit and 512MiB for 32-bit
> > >
> > > For 32-bit, the upper limit is conservative, but the exact limit can be
> > > difficult to calculate.
> > >
> >
> > Could we get rid of the call to efi_low_alloc_above() in
> > efi_relocate_kernel(), and just allocate top down with the right
> > alignment? I'd like to get rid of efi_low_alloc() et al if we can.
> >
>
> But we don't have a top-down allocator, do we? ALLOCATE_MAX_ADDRESS
> guarantees the maximum, but it doesn't guarantee that you'll be as high
> as possible.

Good point. We do have a top-down allocator in practice, but it is not
guaranteed by the API.

  reply	other threads:[~2020-03-04  7:30 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-01 23:05 [PATCH 0/5] Minimize the need to move the kernel in the EFI stub Arvind Sankar
2020-03-01 23:05 ` [PATCH 1/5] x86/boot/compressed/32: Save the output address instead of recalculating it Arvind Sankar
2020-03-03 19:10   ` Ard Biesheuvel
2020-03-01 23:05 ` [PATCH 2/5] efi/x86: Decompress at start of PE image load address Arvind Sankar
2020-03-03  6:28   ` Mika Penttilä
2020-03-03 13:45     ` Arvind Sankar
2020-03-03 19:08   ` Ard Biesheuvel
2020-03-01 23:05 ` [PATCH 3/5] efi/x86: Add kernel preferred address to PE header Arvind Sankar
2020-03-03 19:11   ` Ard Biesheuvel
2020-03-01 23:05 ` [PATCH 4/5] efi/x86: Remove extra headroom for setup block Arvind Sankar
2020-03-02  4:21   ` Mika Penttilä
2020-03-03  4:14     ` Arvind Sankar
2020-03-01 23:05 ` [PATCH 5/5] efi/x86: Don't relocate the kernel unless necessary Arvind Sankar
2020-03-03 19:15   ` Ard Biesheuvel
2020-03-03 22:12 ` [PATCH v2 0/5] Minimize the need to move the kernel in the EFI stub Arvind Sankar
2020-03-03 22:12   ` [PATCH v2 1/5] x86/boot/compressed/32: Save the output address instead of recalculating it Arvind Sankar
2020-03-03 22:12   ` [PATCH v2 2/5] efi/x86: Decompress at start of PE image load address Arvind Sankar
2020-03-03 22:12   ` [PATCH v2 3/5] efi/x86: Add kernel preferred address to PE header Arvind Sankar
2020-03-03 22:12   ` [PATCH v2 4/5] efi/x86: Remove extra headroom for setup block Arvind Sankar
2020-05-11 17:01     ` Mike Lothian
2020-05-11 18:36       ` Arvind Sankar
2020-05-11 21:13         ` Ard Biesheuvel
2020-05-11 22:53           ` Arvind Sankar
2020-05-11 22:58             ` [PATCH] x86/boot: Mark global variables as static Arvind Sankar
2020-05-11 23:12               ` Mike Lothian
2020-05-12 11:05                 ` Ard Biesheuvel
2020-05-22 18:30               ` [tip: efi/urgent] " tip-bot2 for Arvind Sankar
2020-03-03 22:12   ` [PATCH v2 5/5] efi/x86: Don't relocate the kernel unless necessary Arvind Sankar
2020-03-03 23:08     ` Ard Biesheuvel
2020-03-03 23:34       ` Arvind Sankar
2020-03-04  7:30         ` Ard Biesheuvel [this message]
2020-03-03 22:26   ` [PATCH v2 0/5] Minimize the need to move the kernel in the EFI stub Ard Biesheuvel

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