Re: [PATCH v17 02/10] of: Add a common kexec FDT setup function

On 2/10/21 9:23 AM, Rob Herring wrote:

On Tue, Feb 09, 2021 at 10:21:52AM -0800, Lakshmi Ramasubramanian wrote:

quoted

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 <redacted>
---
  drivers/of/Makefile |   6 ++
  drivers/of/kexec.c  | 258 ++++++++++++++++++++++++++++++++++++++++++++
  include/linux/of.h  |  13 +++
  3 files changed, 277 insertions(+)
  create mode 100644 drivers/of/kexec.c

quoted

diff --git a/include/linux/of.h b/include/linux/of.h
index 4b27c9a27df3..f0eff5e84353 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h

@@ -560,6 +560,19 @@ int of_map_id(struct device_node *np, u32 id,
  
  phys_addr_t of_dma_get_max_cpu_address(struct device_node *np);
  
+/*
+ * Additional space needed for the buffer to build the new FDT
+ * so that we can add initrd, bootargs, kaslr-seed, rng-seed,
+ * userable-memory-range and elfcorehdr.
+ */
+#define FDT_EXTRA_SPACE 0x1000

No need for this to be public now. Move it to of/kexec.c.

Will do.

  -lakshmi