From: Michael Ellerman <mpe@ellerman.id.au>
To: Rob Herring <robh@kernel.org>, nramas <nramas@linux.microsoft.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>,
Mimi Zohar <zohar@linux.ibm.com>,
Thiago Jung Bauermann <bauerman@linux.ibm.com>,
AKASHI Takahiro <takahiro.akashi@linaro.org>,
Greg KH <gregkh@linuxfoundation.org>,
Will Deacon <will@kernel.org>, Joe Perches <joe@perches.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Stephen Rothwell <sfr@canb.auug.org.au>,
James Morse <james.morse@arm.com>,
Sasha Levin <sashal@kernel.org>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Frank Rowand <frowand.list@gmail.com>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
dmitry.kasatkin@gmail.com, James Morris <jmorris@namei.org>,
"Serge E. Hallyn" <serge@hallyn.com>,
Pavel Tatashin <pasha.tatashin@soleen.com>,
Allison Randal <allison@lohutok.net>,
Masahiro Yamada <masahiroy@kernel.org>,
Matthias Brugger <mbrugger@suse.com>,
Hsin-Yi Wang <hsinyi@chromium.org>,
tao.li@vivo.com, Christophe Leroy <christophe.leroy@c-s.fr>,
Prakhar Srivastava <prsriva@linux.microsoft.com>,
balajib@linux.microsoft.com,
linux-integrity <linux-integrity@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
<devicetree@vger.kernel.org>,
linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Subject: Re: [PATCH v19 05/13] of: Add a common kexec FDT setup function
Date: Wed, 16 Jun 2021 12:23:44 +1000 [thread overview]
Message-ID: <87y2basg27.fsf@mpe.ellerman.id.au> (raw)
In-Reply-To: <CAL_JsqJEucP043eViq0Y1kAeqWNTqP5fLjfjz7+ksYx7QP_V5w@mail.gmail.com>
Rob Herring <robh@kernel.org> writes:
> On Tue, Jun 15, 2021 at 10:13 AM nramas <nramas@linux.microsoft.com> wrote:
>>
>> On Tue, 2021-06-15 at 08:01 -0600, Rob Herring wrote:
>> > On Tue, Jun 15, 2021 at 6:18 AM Geert Uytterhoeven <
>> > geert@linux-m68k.org> wrote:
>> > >
>> > > > +void *of_kexec_alloc_and_setup_fdt(const struct kimage *image,
>> > > > + unsigned long
>> > > > initrd_load_addr,
>> > > > + unsigned long initrd_len,
>> > > > + const char *cmdline, size_t
>> > > > extra_fdt_size)
>> > > > +{
>> > > > + /* Did we boot using an initrd? */
>> > > > + prop = fdt_getprop(fdt, chosen_node, "linux,initrd-
>> > > > start", NULL);
>> > > > + if (prop) {
>> > > > + u64 tmp_start, tmp_end, tmp_size;
>> > > > +
>> > > > + tmp_start = fdt64_to_cpu(*((const fdt64_t *)
>> > > > prop));
>> > > > +
>> > > > + prop = fdt_getprop(fdt, chosen_node,
>> > > > "linux,initrd-end", NULL);
>> > > > + if (!prop) {
>> > > > + ret = -EINVAL;
>> > > > + goto out;
>> > > > + }
>> > > > +
>> > > > + tmp_end = fdt64_to_cpu(*((const fdt64_t *)
>> > > > prop));
>> > >
>> > > Some kernel code assumes "linux,initrd-{start,end}" are 64-bit,
>> > > other code assumes 32-bit.
>> >
>> > It can be either. The above code was a merge of arm64 and powerpc >> > both
>> > of which use 64-bit and still only runs on those arches. It looks >> > like
>> > some powerpc platforms may use 32-bit, but this would have been >> > broken
>> > before.
>> of_kexec_alloc_and_setup_fdt() is called from elf_64.c (in
>> arch/powerpc/kexec) which is for 64-bit powerpc platform only.
>
> 64-bit PPC could be writing 32-bit property values. The architecture
> size doesn't necessarily matter. And if the values came from the
> bootloader, who knows what size it used.
>
> This code is 32-bit powerpc only?:
>
> arch/powerpc/boot/main.c- /* Tell the kernel initrd address via device tree */
> arch/powerpc/boot/main.c: setprop_val(chosen, "linux,initrd-start", (u32)(initrd_addr));
> arch/powerpc/boot/main.c- setprop_val(chosen, "linux,initrd-end", (u32)(initrd_addr+initrd_size));
Historically that code was always built 32-bit, even when used with a
64-bit kernel.
These days it is also built 64-bit (for ppc64le).
It looks like the drivers/of/fdt.c code can handle either 64 or 32-bit,
so I guess that's why it seems to be working.
Although I'm not sure how much testing the 64-bit case gets, because the
distros tend to just use the vmlinux.
cheers
next prev parent reply other threads:[~2021-06-16 2:23 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-21 17:49 [PATCH v19 00/13] Carry forward IMA measurement log on kexec on ARM64 Lakshmi Ramasubramanian
2021-02-21 17:49 ` [PATCH v19 01/13] kexec: Move ELF fields to struct kimage Lakshmi Ramasubramanian
2021-02-24 1:03 ` Thiago Jung Bauermann
2021-02-21 17:49 ` [PATCH v19 02/13] arm64: Use ELF fields defined in 'struct kimage' Lakshmi Ramasubramanian
2021-02-24 1:07 ` Thiago Jung Bauermann
2021-02-21 17:49 ` [PATCH v19 03/13] powerpc: " Lakshmi Ramasubramanian
2021-02-24 1:07 ` Thiago Jung Bauermann
2021-02-21 17:49 ` [PATCH v19 04/13] x86: " Lakshmi Ramasubramanian
2021-02-24 1:08 ` Thiago Jung Bauermann
2021-02-24 1:13 ` Thiago Jung Bauermann
2021-02-21 17:49 ` [PATCH v19 05/13] of: Add a common kexec FDT setup function Lakshmi Ramasubramanian
2021-02-24 1:20 ` Thiago Jung Bauermann
2021-02-24 1:57 ` Lakshmi Ramasubramanian
2021-06-15 12:17 ` Geert Uytterhoeven
2021-06-15 14:01 ` Rob Herring
2021-06-15 16:13 ` nramas
2021-06-15 16:34 ` Rob Herring
2021-06-16 2:23 ` Michael Ellerman [this message]
2021-06-16 15:12 ` Rob Herring
2021-02-21 17:49 ` [PATCH v19 06/13] arm64: Use common of_kexec_alloc_and_setup_fdt() Lakshmi Ramasubramanian
2021-02-21 17:49 ` [PATCH v19 07/13] powerpc: " Lakshmi Ramasubramanian
2021-02-21 17:49 ` [PATCH v19 08/13] powerpc: Move ima buffer fields to struct kimage Lakshmi Ramasubramanian
2021-02-21 17:49 ` [PATCH v19 09/13] powerpc: Enable passing IMA log to next kernel on kexec Lakshmi Ramasubramanian
2021-02-21 17:49 ` [PATCH v19 10/13] powerpc: Move arch independent ima kexec functions to drivers/of/kexec.c Lakshmi Ramasubramanian
2021-02-21 17:49 ` [PATCH v19 11/13] kexec: Use fdt_appendprop_addrrange() to add ima buffer to FDT Lakshmi Ramasubramanian
2021-02-21 17:49 ` [PATCH v19 12/13] powerpc: Delete unused function delete_fdt_mem_rsv() Lakshmi Ramasubramanian
2021-02-21 17:49 ` [PATCH v19 13/13] arm64: Enable passing IMA log to next kernel on kexec Lakshmi Ramasubramanian
2021-03-02 15:06 ` [PATCH v19 00/13] Carry forward IMA measurement log on kexec on ARM64 Rob Herring
2021-03-02 15:25 ` Lakshmi Ramasubramanian
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