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Message-ID: <CAMuHMdVSuNS4edh-zM0_sbC0i1AAjQ9Y0n_8Mjz=3CALkW4pgg@mail.gmail.com>
Date: Tue, 15 Jun 2021 14:17:59 +0200
From: Geert Uytterhoeven <geert@...ux-m68k.org>
To: Lakshmi Ramasubramanian <nramas@...ux.microsoft.com>,
Rob Herring <robh@...nel.org>
Cc: Mimi Zohar <zohar@...ux.ibm.com>,
Thiago Jung Bauermann <bauerman@...ux.ibm.com>,
AKASHI Takahiro <takahiro.akashi@...aro.org>,
Greg KH <gregkh@...uxfoundation.org>,
Will Deacon <will@...nel.org>, Joe Perches <joe@...ches.com>,
Catalin Marinas <catalin.marinas@....com>,
Michael Ellerman <mpe@...erman.id.au>,
Stephen Rothwell <sfr@...b.auug.org.au>,
James Morse <james.morse@....com>,
Sasha Levin <sashal@...nel.org>,
Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Paul Mackerras <paulus@...ba.org>,
Frank Rowand <frowand.list@...il.com>,
Vincenzo Frascino <vincenzo.frascino@....com>,
Mark Rutland <mark.rutland@....com>, dmitry.kasatkin@...il.com,
James Morris <jmorris@...ei.org>,
"Serge E. Hallyn" <serge@...lyn.com>,
Pavel Tatashin <pasha.tatashin@...een.com>,
Allison Randal <allison@...utok.net>,
Masahiro Yamada <masahiroy@...nel.org>,
Matthias Brugger <mbrugger@...e.com>,
Hsin-Yi Wang <hsinyi@...omium.org>, tao.li@...o.com,
Christophe Leroy <christophe.leroy@....fr>,
prsriva@...ux.microsoft.com, balajib@...ux.microsoft.com,
linux-integrity <linux-integrity@...r.kernel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Linux ARM <linux-arm-kernel@...ts.infradead.org>,
"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
<devicetree@...r.kernel.org>,
linuxppc-dev <linuxppc-dev@...ts.ozlabs.org>
Subject: Re: [PATCH v19 05/13] of: Add a common kexec FDT setup function
Hi Lakshmi and Rob,
On Sun, Feb 21, 2021 at 6:52 PM Lakshmi Ramasubramanian
<nramas@...ux.microsoft.com> wrote:
> From: Rob Herring <robh@...nel.org>
>
> Both arm64 and powerpc do essentially the same FDT /chosen setup for
> kexec. The differences are either omissions that arm64 should have
> or additional properties that will be ignored. The setup code can be
> combined and shared by both powerpc and arm64.
>
> The differences relative to the arm64 version:
> - If /chosen doesn't exist, it will be created (should never happen).
> - Any old dtb and initrd reserved memory will be released.
> - The new initrd and elfcorehdr are marked reserved.
> - "linux,booted-from-kexec" is set.
>
> The differences relative to the powerpc version:
> - "kaslr-seed" and "rng-seed" may be set.
> - "linux,elfcorehdr" is set.
> - Any existing "linux,usable-memory-range" is removed.
>
> Combine the code for setting up the /chosen node in the FDT and updating
> the memory reservation for kexec, for powerpc and arm64, in
> of_kexec_alloc_and_setup_fdt() and move it to "drivers/of/kexec.c".
>
> Signed-off-by: Rob Herring <robh@...nel.org>
> Signed-off-by: Lakshmi Ramasubramanian <nramas@...ux.microsoft.com>
> --- /dev/null
> +++ b/drivers/of/kexec.c
> +/*
> + * 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.
> + * @extra_fdt_size: Additional size for the new FDT buffer.
> + *
> + * 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, 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.
linux/Documentation/arm/uefi.rst says 64-bit,
dt-schema/schemas/chosen.yaml says 32-bit.
> +
> + /*
> + * kexec reserves exact initrd size, while firmware may
> + * reserve a multiple of PAGE_SIZE, so check for both.
> + */
> + tmp_size = tmp_end - tmp_start;
> + ret = fdt_find_and_del_mem_rsv(fdt, tmp_start, tmp_size);
> + if (ret == -ENOENT)
> + ret = fdt_find_and_del_mem_rsv(fdt, tmp_start,
> + round_up(tmp_size, PAGE_SIZE));
> + if (ret == -EINVAL)
> + goto out;
> + }
> +
> + /* add initrd-* */
> + if (initrd_load_addr) {
> + ret = fdt_setprop_u64(fdt, chosen_node, FDT_PROP_INITRD_START,
> + initrd_load_addr);
> + if (ret)
> + goto out;
> +
> + ret = fdt_setprop_u64(fdt, chosen_node, FDT_PROP_INITRD_END,
> + initrd_load_addr + initrd_len);
> + if (ret)
> + goto out;
> +
> + ret = fdt_add_mem_rsv(fdt, initrd_load_addr, initrd_len);
> + if (ret)
> + goto out;
> +
> + } else {
> + ret = fdt_delprop(fdt, chosen_node, FDT_PROP_INITRD_START);
> + if (ret && (ret != -FDT_ERR_NOTFOUND))
> + goto out;
> +
> + ret = fdt_delprop(fdt, chosen_node, FDT_PROP_INITRD_END);
> + if (ret && (ret != -FDT_ERR_NOTFOUND))
> + goto out;
> + }
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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