diff mbox series

[v19,05/13] of: Add a common kexec FDT setup function

Message ID 20210221174930.27324-6-nramas@linux.microsoft.com (mailing list archive)
State New
Headers show
Series Carry forward IMA measurement log on kexec on ARM64 | expand

Commit Message

Lakshmi Ramasubramanian Feb. 21, 2021, 5:49 p.m. UTC
From: Rob Herring <robh@kernel.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@kernel.org>
Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Fixes: 33488dc4d61f ("of: Add a common kexec FDT setup function")
Reported-by: kernel test robot <lkp@intel.com>
---
 drivers/of/Makefile |   6 +
 drivers/of/kexec.c  | 265 ++++++++++++++++++++++++++++++++++++++++++++
 include/linux/of.h  |   5 +
 3 files changed, 276 insertions(+)
 create mode 100644 drivers/of/kexec.c

Comments

Thiago Jung Bauermann Feb. 24, 2021, 1:20 a.m. UTC | #1
Lakshmi Ramasubramanian <nramas@linux.microsoft.com> writes:

> From: Rob Herring <robh@kernel.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@kernel.org>
> Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
> Fixes: 33488dc4d61f ("of: Add a common kexec FDT setup function")

A patch cannot fix itself. The world would be a much better place if it
could. :-)

> Reported-by: kernel test robot <lkp@intel.com>
> ---
>  drivers/of/Makefile |   6 +
>  drivers/of/kexec.c  | 265 ++++++++++++++++++++++++++++++++++++++++++++
>  include/linux/of.h  |   5 +
>  3 files changed, 276 insertions(+)
>  create mode 100644 drivers/of/kexec.c

With that fixed:

Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Lakshmi Ramasubramanian Feb. 24, 2021, 1:57 a.m. UTC | #2
On 2/23/21 5:20 PM, Thiago Jung Bauermann wrote:
> 
> Lakshmi Ramasubramanian <nramas@linux.microsoft.com> writes:
> 
>> From: Rob Herring <robh@kernel.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@kernel.org>
>> Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
>> Fixes: 33488dc4d61f ("of: Add a common kexec FDT setup function")
> 
> A patch cannot fix itself. The world would be a much better place if it
> could. :-)

:)

> 
>> Reported-by: kernel test robot <lkp@intel.com>
>> ---
>>   drivers/of/Makefile |   6 +
>>   drivers/of/kexec.c  | 265 ++++++++++++++++++++++++++++++++++++++++++++
>>   include/linux/of.h  |   5 +
>>   3 files changed, 276 insertions(+)
>>   create mode 100644 drivers/of/kexec.c
> 
> With that fixed:
> 
> Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>

Thanks for reviewing the patches Thiago.

  -lakshmi
Geert Uytterhoeven June 15, 2021, 12:17 p.m. UTC | #3
Hi Lakshmi and Rob,

On Sun, Feb 21, 2021 at 6:52 PM Lakshmi Ramasubramanian
<nramas@linux.microsoft.com> wrote:
> From: Rob Herring <robh@kernel.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@kernel.org>
> Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.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
Rob Herring June 15, 2021, 2:01 p.m. UTC | #4
On Tue, Jun 15, 2021 at 6:18 AM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
>
> Hi Lakshmi and Rob,
>
> On Sun, Feb 21, 2021 at 6:52 PM Lakshmi Ramasubramanian
> <nramas@linux.microsoft.com> wrote:
> > From: Rob Herring <robh@kernel.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@kernel.org>
> > Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.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.

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.

The code in drivers/of/fdt.c handles either case. We should probably
refactor early_init_dt_check_for_initrd() and this function to use a
common routine.

> linux/Documentation/arm/uefi.rst says 64-bit,
> dt-schema/schemas/chosen.yaml says 32-bit.

We should fix that.

Rob
Lakshmi Ramasubramanian June 15, 2021, 4:13 p.m. UTC | #5
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.

thanks,
 -lakshmi

> 
> The code in drivers/of/fdt.c handles either case. We should probably
> refactor early_init_dt_check_for_initrd() and this function to use a
> common routine.
> 
> > linux/Documentation/arm/uefi.rst says 64-bit,
> > dt-schema/schemas/chosen.yaml says 32-bit.
> 
> We should fix that.
> 
> Rob
Rob Herring June 15, 2021, 4:34 p.m. UTC | #6
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));

Rob
Michael Ellerman June 16, 2021, 2:23 a.m. UTC | #7
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
Rob Herring June 16, 2021, 3:12 p.m. UTC | #8
On Tue, Jun 15, 2021 at 8:23 PM Michael Ellerman <mpe@ellerman.id.au> wrote:
>
> 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).

How it is built is immaterial. It's always writing a 32-bit value due
to the u32 cast.

> 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.

Yes, that works, but that's not the issue. The question is does the
main.c code run in combination with kexec. The kexec code above
(copied straight from PPC code) would not work if linux,initrd-* are
written by the main.c code.

Rob
diff mbox series

Patch

diff --git a/drivers/of/Makefile b/drivers/of/Makefile
index 6e1e5212f058..c13b982084a3 100644
--- a/drivers/of/Makefile
+++ b/drivers/of/Makefile
@@ -14,4 +14,10 @@  obj-$(CONFIG_OF_RESOLVE)  += resolver.o
 obj-$(CONFIG_OF_OVERLAY) += overlay.o
 obj-$(CONFIG_OF_NUMA) += of_numa.o
 
+ifdef CONFIG_KEXEC_FILE
+ifdef CONFIG_OF_FLATTREE
+obj-y	+= kexec.o
+endif
+endif
+
 obj-$(CONFIG_OF_UNITTEST) += unittest-data/
diff --git a/drivers/of/kexec.c b/drivers/of/kexec.c
new file mode 100644
index 000000000000..8fa8946cda42
--- /dev/null
+++ b/drivers/of/kexec.c
@@ -0,0 +1,265 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2020 Arm Limited
+ *
+ * Based on arch/arm64/kernel/machine_kexec_file.c:
+ *  Copyright (C) 2018 Linaro Limited
+ *
+ * And arch/powerpc/kexec/file_load.c:
+ *  Copyright (C) 2016  IBM Corporation
+ */
+
+#include <linux/kernel.h>
+#include <linux/kexec.h>
+#include <linux/libfdt.h>
+#include <linux/of.h>
+#include <linux/of_fdt.h>
+#include <linux/random.h>
+#include <linux/types.h>
+
+/* relevant device tree properties */
+#define FDT_PROP_KEXEC_ELFHDR	"linux,elfcorehdr"
+#define FDT_PROP_MEM_RANGE	"linux,usable-memory-range"
+#define FDT_PROP_INITRD_START	"linux,initrd-start"
+#define FDT_PROP_INITRD_END	"linux,initrd-end"
+#define FDT_PROP_BOOTARGS	"bootargs"
+#define FDT_PROP_KASLR_SEED	"kaslr-seed"
+#define FDT_PROP_RNG_SEED	"rng-seed"
+#define RNG_SEED_SIZE		128
+
+/*
+ * Additional space needed for the FDT buffer so that we can add initrd,
+ * bootargs, kaslr-seed, rng-seed, useable-memory-range and elfcorehdr.
+ */
+#define FDT_EXTRA_SPACE 0x1000
+
+/**
+ * fdt_find_and_del_mem_rsv - delete memory reservation with given address and size
+ *
+ * @fdt:	Flattened device tree for the current kernel.
+ * @start:	Starting address of the reserved memory.
+ * @size:	Size of the reserved memory.
+ *
+ * Return: 0 on success, or negative errno on error.
+ */
+static int fdt_find_and_del_mem_rsv(void *fdt, unsigned long start, unsigned long size)
+{
+	int i, ret, num_rsvs = fdt_num_mem_rsv(fdt);
+
+	for (i = 0; i < num_rsvs; i++) {
+		u64 rsv_start, rsv_size;
+
+		ret = fdt_get_mem_rsv(fdt, i, &rsv_start, &rsv_size);
+		if (ret) {
+			pr_err("Malformed device tree.\n");
+			return -EINVAL;
+		}
+
+		if (rsv_start == start && rsv_size == size) {
+			ret = fdt_del_mem_rsv(fdt, i);
+			if (ret) {
+				pr_err("Error deleting device tree reservation.\n");
+				return -EINVAL;
+			}
+
+			return 0;
+		}
+	}
+
+	return -ENOENT;
+}
+
+/*
+ * 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)
+{
+	void *fdt;
+	int ret, chosen_node;
+	const void *prop;
+	size_t fdt_size;
+
+	fdt_size = fdt_totalsize(initial_boot_params) +
+		   (cmdline ? strlen(cmdline) : 0) +
+		   FDT_EXTRA_SPACE +
+		   extra_fdt_size;
+	fdt = kvmalloc(fdt_size, GFP_KERNEL);
+	if (!fdt)
+		return NULL;
+
+	ret = fdt_open_into(initial_boot_params, fdt, fdt_size);
+	if (ret < 0) {
+		pr_err("Error %d setting up the new device tree.\n", ret);
+		goto out;
+	}
+
+	/* Remove memory reservation for the current device tree. */
+	ret = fdt_find_and_del_mem_rsv(fdt, __pa(initial_boot_params),
+				       fdt_totalsize(initial_boot_params));
+	if (ret == -EINVAL) {
+		pr_err("Error removing memory reservation.\n");
+		goto out;
+	}
+
+	chosen_node = fdt_path_offset(fdt, "/chosen");
+	if (chosen_node == -FDT_ERR_NOTFOUND)
+		chosen_node = fdt_add_subnode(fdt, fdt_path_offset(fdt, "/"),
+					      "chosen");
+	if (chosen_node < 0) {
+		ret = chosen_node;
+		goto out;
+	}
+
+	ret = fdt_delprop(fdt, chosen_node, FDT_PROP_KEXEC_ELFHDR);
+	if (ret && ret != -FDT_ERR_NOTFOUND)
+		goto out;
+	ret = fdt_delprop(fdt, chosen_node, FDT_PROP_MEM_RANGE);
+	if (ret && ret != -FDT_ERR_NOTFOUND)
+		goto out;
+
+	/* 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));
+
+		/*
+		 * 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;
+	}
+
+	if (image->type == KEXEC_TYPE_CRASH) {
+		/* add linux,elfcorehdr */
+		ret = fdt_appendprop_addrrange(fdt, 0, chosen_node,
+				FDT_PROP_KEXEC_ELFHDR,
+				image->elf_load_addr,
+				image->elf_headers_sz);
+		if (ret)
+			goto out;
+
+		/*
+		 * Avoid elfcorehdr from being stomped on in kdump kernel by
+		 * setting up memory reserve map.
+		 */
+		ret = fdt_add_mem_rsv(fdt, image->elf_load_addr,
+				      image->elf_headers_sz);
+		if (ret)
+			goto out;
+
+		/* add linux,usable-memory-range */
+		ret = fdt_appendprop_addrrange(fdt, 0, chosen_node,
+				FDT_PROP_MEM_RANGE,
+				crashk_res.start,
+				crashk_res.end - crashk_res.start + 1);
+		if (ret)
+			goto out;
+	}
+
+	/* add bootargs */
+	if (cmdline) {
+		ret = fdt_setprop_string(fdt, chosen_node, FDT_PROP_BOOTARGS, cmdline);
+		if (ret)
+			goto out;
+	} else {
+		ret = fdt_delprop(fdt, chosen_node, FDT_PROP_BOOTARGS);
+		if (ret && (ret != -FDT_ERR_NOTFOUND))
+			goto out;
+	}
+
+	/* add kaslr-seed */
+	ret = fdt_delprop(fdt, chosen_node, FDT_PROP_KASLR_SEED);
+	if (ret == -FDT_ERR_NOTFOUND)
+		ret = 0;
+	else if (ret)
+		goto out;
+
+	if (rng_is_initialized()) {
+		u64 seed = get_random_u64();
+
+		ret = fdt_setprop_u64(fdt, chosen_node, FDT_PROP_KASLR_SEED, seed);
+		if (ret)
+			goto out;
+	} else {
+		pr_notice("RNG is not initialised: omitting \"%s\" property\n",
+				FDT_PROP_KASLR_SEED);
+	}
+
+	/* add rng-seed */
+	if (rng_is_initialized()) {
+		void *rng_seed;
+
+		ret = fdt_setprop_placeholder(fdt, chosen_node, FDT_PROP_RNG_SEED,
+				RNG_SEED_SIZE, &rng_seed);
+		if (ret)
+			goto out;
+		get_random_bytes(rng_seed, RNG_SEED_SIZE);
+	} else {
+		pr_notice("RNG is not initialised: omitting \"%s\" property\n",
+				FDT_PROP_RNG_SEED);
+	}
+
+	ret = fdt_setprop(fdt, chosen_node, "linux,booted-from-kexec", NULL, 0);
+
+out:
+	if (ret) {
+		kvfree(fdt);
+		fdt = NULL;
+	}
+
+	return fdt;
+}
diff --git a/include/linux/of.h b/include/linux/of.h
index 4b27c9a27df3..d66c915df910 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -560,6 +560,11 @@  int of_map_id(struct device_node *np, u32 id,
 
 phys_addr_t of_dma_get_max_cpu_address(struct device_node *np);
 
+struct kimage;
+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);
 #else /* CONFIG_OF */
 
 static inline void of_core_init(void)