From: Ard Biesheuvel <ardb@kernel.org>
To: Marc Zyngier <maz@kernel.org>
Cc: kexec@lists.infradead.org,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
James Morse <james.morse@arm.com>,
Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
Hanjun Guo <guohanjun@huawei.com>,
Sudeep Holla <sudeep.holla@arm.com>,
Eric Biederman <ebiederm@xmission.com>,
Bhupesh SHARMA <bhupesh.sharma@linaro.org>,
AKASHI Takahiro <takahiro.akashi@linaro.org>,
Dave Young <dyoung@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Moritz Fischer <mdf@kernel.org>,
Android Kernel Team <kernel-team@android.com>,
"# 3.4.x" <stable@vger.kernel.org>
Subject: Re: [PATCH v2 1/5] arm64: kexec_file: Forbid non-crash kernels
Date: Mon, 31 May 2021 21:37:49 +0200 [thread overview]
Message-ID: <CAMj1kXFNUAtXPzO+EbMzZQPxgst4BMEUuYbrWwYer3P9trYdLQ@mail.gmail.com> (raw)
In-Reply-To: <20210531095720.77469-2-maz@kernel.org>
On Mon, 31 May 2021 at 11:57, Marc Zyngier <maz@kernel.org> wrote:
>
> It has been reported that kexec_file doesn't really work on arm64.
> It completely ignores any of the existing reservations, which results
> in the secondary kernel being loaded where the GICv3 LPI tables live,
> or even corrupting the ACPI tables.
>
> Since only crash kernels are imune to this as they use a reserved
> memory region, disable the non-crash kernel use case. Further
> patches will try and restore the functionality.
>
> Reported-by: Moritz Fischer <mdf@kernel.org>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> Cc: stable@vger.kernel.org # 5.10
Acked-by: Ard Biesheuvel <ardb@kernel.org>
... but do we really only need this in 5.10 and not earlier?
> ---
> arch/arm64/kernel/kexec_image.c | 20 ++++++++++++++++++++
> 1 file changed, 20 insertions(+)
>
> diff --git a/arch/arm64/kernel/kexec_image.c b/arch/arm64/kernel/kexec_image.c
> index 9ec34690e255..acf9cd251307 100644
> --- a/arch/arm64/kernel/kexec_image.c
> +++ b/arch/arm64/kernel/kexec_image.c
> @@ -145,3 +145,23 @@ const struct kexec_file_ops kexec_image_ops = {
> .verify_sig = image_verify_sig,
> #endif
> };
> +
> +/**
> + * arch_kexec_locate_mem_hole - Find free memory to place the segments.
> + * @kbuf: Parameters for the memory search.
> + *
> + * On success, kbuf->mem will have the start address of the memory region found.
> + *
> + * Return: 0 on success, negative errno on error.
> + */
> +int arch_kexec_locate_mem_hole(struct kexec_buf *kbuf)
> +{
> + /*
> + * For the time being, kexec_file_load isn't reliable except
> + * for crash kernel. Say sorry to the user.
> + */
> + if (kbuf->image->type != KEXEC_TYPE_CRASH)
> + return -EADDRNOTAVAIL;
> +
> + return kexec_locate_mem_hole(kbuf);
> +}
> --
> 2.30.2
>
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next prev parent reply other threads:[~2021-05-31 19:39 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-31 9:57 [PATCH v2 0/5] arm64: Make kexec_file_load honor iomem reservations Marc Zyngier
2021-05-31 9:57 ` [PATCH v2 1/5] arm64: kexec_file: Forbid non-crash kernels Marc Zyngier
2021-05-31 19:37 ` Ard Biesheuvel [this message]
2021-06-01 8:36 ` Marc Zyngier
2021-06-04 16:20 ` James Morse
2021-05-31 9:57 ` [PATCH v2 2/5] kexec_file: Make locate_mem_hole_callback global Marc Zyngier
2021-05-31 9:57 ` [PATCH v2 3/5] kernel/resource: Allow find_next_iomem_res() to exclude overlapping child resources Marc Zyngier
2021-05-31 9:57 ` [PATCH v2 4/5] kernel/resource: Introduce walk_system_ram_excluding_child_res() Marc Zyngier
2021-05-31 9:57 ` [PATCH v2 5/5] arm64: kexec_image: Restore full kexec functionnality Marc Zyngier
2021-05-31 19:36 ` [PATCH v2 0/5] arm64: Make kexec_file_load honor iomem reservations Ard Biesheuvel
2021-06-04 16:20 ` James Morse
2021-06-09 22:39 ` Moritz Fischer
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