From: Lakshmi Ramasubramanian <nramas@linux•microsoft.com>
To: Thiago Jung Bauermann <bauerman@linux•ibm.com>
Cc: mark.rutland@arm•com, tao.li@vivo•com, zohar@linux•ibm.com,
paulus@samba•org, vincenzo.frascino@arm•com,
frowand.list@gmail•com, sashal@kernel•org, robh@kernel•org,
masahiroy@kernel•org, jmorris@namei•org,
takahiro.akashi@linaro•org, linux-arm-kernel@lists•infradead.org,
catalin.marinas@arm•com, serge@hallyn•com,
devicetree@vger•kernel.org, pasha.tatashin@soleen•com,
will@kernel•org, prsriva@linux•microsoft.com,
hsinyi@chromium•org, allison@lohutok•net,
christophe.leroy@c-s•fr, mbrugger@suse•com,
balajib@linux•microsoft.com, dmitry.kasatkin@gmail•com,
linux-kernel@vger•kernel.org, james.morse@arm•com,
gregkh@linuxfoundation•org, joe@perches•com,
linux-integrity@vger•kernel.org, linuxppc-dev@lists•ozlabs.org
Subject: Re: [PATCH v17 02/10] of: Add a common kexec FDT setup function
Date: Thu, 11 Feb 2021 17:17:56 -0800 [thread overview]
Message-ID: <8a3aa3d2-2eba-549a-9970-a2b0fe3586c9@linux.microsoft.com> (raw)
In-Reply-To: <87k0reozwh.fsf@manicouagan.localdomain>
On 2/11/21 5:09 PM, Thiago Jung Bauermann wrote:
>
> There's actually a complication that I just noticed and needs to be
> addressed. More below.
>
<...>
>> +
>> +/*
>> + * of_kexec_alloc_and_setup_fdt - Alloc and setup a new Flattened Device Tree
>> + *
>> + * @image: kexec image being loaded.
>> + * @initrd_load_addr: Address where the next initrd will be loaded.
>> + * @initrd_len: Size of the next initrd, or 0 if there will be none.
>> + * @cmdline: Command line for the next kernel, or NULL if there will
>> + * be none.
>> + *
>> + * Return: fdt on success, or NULL errno on error.
>> + */
>> +void *of_kexec_alloc_and_setup_fdt(const struct kimage *image,
>> + unsigned long initrd_load_addr,
>> + unsigned long initrd_len,
>> + const char *cmdline)
>> +{
>> + void *fdt;
>> + int ret, chosen_node;
>> + const void *prop;
>> + unsigned long fdt_size;
>> +
>> + fdt_size = fdt_totalsize(initial_boot_params) +
>> + (cmdline ? strlen(cmdline) : 0) +
>> + FDT_EXTRA_SPACE;
>
> Just adding 4 KB to initial_boot_params won't be enough for crash
> kernels on ppc64. The current powerpc code doubles the size of
> initial_boot_params (which is normally larger than 4 KB) and even that
> isn't enough. A patch was added to powerpc/next today which uses a more
> precise (but arch-specific) formula:
>
> https://lore.kernel.org/linuxppc-dev/161243826811.119001.14083048209224609814.stgit@hbathini/
>
> So I believe we need a hook here where architectures can provide their
> own specific calculation for the size of the fdt. Perhaps a weakly
> defined function providing a default implementation which an
> arch-specific file can override (a la arch_kexec_kernel_image_load())?
>
> Then the powerpc specific hook would be the kexec_fdt_totalsize_ppc64()
> function from the patch I linked above.
>
Do you think it'd better to add "fdt_size" parameter to
of_kexec_alloc_and_setup_fdt() so that the caller can provide the
desired FDT buffer size?
thanks,
-lakshmi
next prev parent reply other threads:[~2021-02-12 1:19 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-09 18:21 [PATCH v17 00/10] Carry forward IMA measurement log on kexec on ARM64 Lakshmi Ramasubramanian
2021-02-09 18:21 ` [PATCH v17 01/10] powerpc: Rename kexec elfcorehdr_addr to elf_headers_mem Lakshmi Ramasubramanian
2021-02-09 18:21 ` [PATCH v17 02/10] of: Add a common kexec FDT setup function Lakshmi Ramasubramanian
2021-02-10 17:23 ` Rob Herring
2021-02-10 17:59 ` Lakshmi Ramasubramanian
2021-02-10 23:24 ` Thiago Jung Bauermann
2021-02-12 1:09 ` Thiago Jung Bauermann
2021-02-12 1:17 ` Lakshmi Ramasubramanian [this message]
2021-02-12 1:39 ` Thiago Jung Bauermann
2021-02-12 14:38 ` Rob Herring
2021-02-12 17:19 ` Lakshmi Ramasubramanian
2021-02-12 18:24 ` Rob Herring
2021-02-12 18:27 ` Lakshmi Ramasubramanian
2021-02-12 19:39 ` Thiago Jung Bauermann
2021-02-09 18:21 ` [PATCH v17 03/10] arm64: Use common of_kexec_alloc_and_setup_fdt() Lakshmi Ramasubramanian
2021-02-10 17:26 ` Will Deacon
2021-02-10 23:30 ` Thiago Jung Bauermann
2021-02-09 18:21 ` [PATCH v17 04/10] powerpc: " Lakshmi Ramasubramanian
2021-02-11 1:42 ` Thiago Jung Bauermann
2021-02-11 1:50 ` Lakshmi Ramasubramanian
2021-02-09 18:21 ` [PATCH v17 05/10] powerpc: Move ima buffer fields to struct kimage Lakshmi Ramasubramanian
2021-02-10 17:20 ` Rob Herring
2021-02-10 18:00 ` Lakshmi Ramasubramanian
2021-02-09 18:21 ` [PATCH v17 06/10] powerpc: Enable passing IMA log to next kernel on kexec Lakshmi Ramasubramanian
2021-02-11 1:51 ` Thiago Jung Bauermann
2021-02-09 18:21 ` [PATCH v17 07/10] powerpc: Move arch independent ima kexec functions to drivers/of/kexec.c Lakshmi Ramasubramanian
2021-02-11 5:07 ` Thiago Jung Bauermann
2021-02-09 18:21 ` [PATCH v17 08/10] kexec: Use fdt_appendprop_addrrange() to add ima buffer to FDT Lakshmi Ramasubramanian
2021-02-09 18:21 ` [PATCH v17 09/10] powerpc: Delete unused function delete_fdt_mem_rsv() Lakshmi Ramasubramanian
2021-02-11 5:11 ` Thiago Jung Bauermann
2021-02-09 18:22 ` [PATCH v17 10/10] arm64: Enable passing IMA log to next kernel on kexec Lakshmi Ramasubramanian
2021-02-11 5:13 ` Thiago Jung Bauermann
2021-02-10 17:15 ` [PATCH v17 00/10] Carry forward IMA measurement log on kexec on ARM64 Rob Herring
2021-02-10 17:33 ` Lakshmi Ramasubramanian
2021-02-10 20:42 ` Rob Herring
2021-02-10 20:55 ` Mimi Zohar
2021-02-10 21:39 ` Mimi Zohar
2021-02-10 22:34 ` Lakshmi Ramasubramanian
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