From: Ard Biesheuvel <ardb@kernel.org>
To: Marc Zyngier <maz@kernel.org>
Cc: Linux ARM <linux-arm-kernel@lists.infradead.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
wnliu@google.com, Moritz Fischer <mdf@kernel.org>,
"# 3.4.x" <stable@vger.kernel.org>,
James Morse <james.morse@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>
Subject: Re: [PATCH v2] firmware/efi: Tell memblock about EFI iomem reservations
Date: Fri, 16 Jul 2021 14:10:14 +0200 [thread overview]
Message-ID: <CAMj1kXEB6eRPOLAaz7gWgUrpn2R6fy6kJ=S8u_54kNfQCbEfqg@mail.gmail.com> (raw)
In-Reply-To: <20210713184326.570923-1-maz@kernel.org>
On Tue, 13 Jul 2021 at 20:43, Marc Zyngier <maz@kernel.org> wrote:
>
> kexec_load_file() relies on the memblock infrastructure to avoid
> stamping over regions of memory that are essential to the survival
> of the system.
>
> However, nobody seems to agree how to flag these regions as reserved,
> and (for example) EFI only publishes its reservations in /proc/iomem
> for the benefit of the traditional, userspace based kexec tool.
>
> On arm64 platforms with GICv3, this can result in the payload being
> placed at the location of the LPI tables. Shock, horror!
>
> Let's augment the EFI reservation code with a memblock_reserve() call,
> protecting our dear tables from the secondary kernel invasion.
>
> Reported-by: Moritz Fischer <mdf@kernel.org>
> Tested-by: Moritz Fischer <mdf@kernel.org>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> Cc: stable@vger.kernel.org
> Cc: Ard Biesheuvel <ardb@kernel.org>
> Cc: James Morse <james.morse@arm.com>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Will Deacon <will@kernel.org>
Thanks, I'll queue this as a fix.
> ---
> drivers/firmware/efi/efi.c | 13 ++++++++++++-
> 1 file changed, 12 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
> index 4b7ee3fa9224..847f33ffc4ae 100644
> --- a/drivers/firmware/efi/efi.c
> +++ b/drivers/firmware/efi/efi.c
> @@ -896,6 +896,7 @@ static int __init efi_memreserve_map_root(void)
> static int efi_mem_reserve_iomem(phys_addr_t addr, u64 size)
> {
> struct resource *res, *parent;
> + int ret;
>
> res = kzalloc(sizeof(struct resource), GFP_ATOMIC);
> if (!res)
> @@ -908,7 +909,17 @@ static int efi_mem_reserve_iomem(phys_addr_t addr, u64 size)
>
> /* we expect a conflict with a 'System RAM' region */
> parent = request_resource_conflict(&iomem_resource, res);
> - return parent ? request_resource(parent, res) : 0;
> + ret = parent ? request_resource(parent, res) : 0;
> +
> + /*
> + * Given that efi_mem_reserve_iomem() can be called at any
> + * time, only call memblock_reserve() if the architecture
> + * keeps the infrastructure around.
> + */
> + if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK) && !ret)
> + memblock_reserve(addr, size);
> +
> + return ret;
> }
>
> int __ref efi_mem_reserve_persistent(phys_addr_t addr, u64 size)
> --
> 2.30.2
>
prev parent reply other threads:[~2021-07-16 12:10 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-13 18:43 [PATCH v2] firmware/efi: Tell memblock about EFI iomem reservations Marc Zyngier
2021-07-16 12:10 ` Ard Biesheuvel [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CAMj1kXEB6eRPOLAaz7gWgUrpn2R6fy6kJ=S8u_54kNfQCbEfqg@mail.gmail.com' \
--to=ardb@kernel.org \
--cc=catalin.marinas@arm.com \
--cc=james.morse@arm.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=maz@kernel.org \
--cc=mdf@kernel.org \
--cc=stable@vger.kernel.org \
--cc=will@kernel.org \
--cc=wnliu@google.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).