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From:   Thiago Jung Bauermann <bauerman@linux.ibm.com>
To:     Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Cc:     zohar@linux.ibm.com, robh@kernel.org, takahiro.akashi@linaro.org,
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Subject: Re: [PATCH v17 04/10] powerpc: Use common
 of_kexec_alloc_and_setup_fdt()
In-reply-to: <20210209182200.30606-5-nramas@linux.microsoft.com>
Date:   Wed, 10 Feb 2021 22:42:27 -0300
Message-ID: <87sg63nzwc.fsf@manicouagan.localdomain>
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Lakshmi Ramasubramanian <nramas@linux.microsoft.com> writes:

> From: Rob Herring <robh@kernel.org>
>
> The code for setting up the /chosen node in the device tree
> and updating the memory reservation for the next kernel has been
> moved to of_kexec_alloc_and_setup_fdt() defined in "drivers/of/kexec.c".
>
> Use the common of_kexec_alloc_and_setup_fdt() to setup the device tree
> and update the memory reservation for kexec for powerpc.
>
> Signed-off-by: Rob Herring <robh@kernel.org>
> Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
> ---
>  arch/powerpc/include/asm/kexec.h  |   1 +
>  arch/powerpc/kexec/elf_64.c       |  29 ++++---
>  arch/powerpc/kexec/file_load.c    | 132 +-----------------------------
>  arch/powerpc/kexec/file_load_64.c |   3 +
>  4 files changed, 25 insertions(+), 140 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/kexec.h b/arch/powerpc/include/asm/kexec.h
> index dbf09d2f36d0..bdd0ddb9ac4d 100644
> --- a/arch/powerpc/include/asm/kexec.h
> +++ b/arch/powerpc/include/asm/kexec.h
> @@ -111,6 +111,7 @@ struct kimage_arch {
>  	unsigned long elf_headers_mem;
>  	unsigned long elf_headers_sz;
>  	void *elf_headers;
> +	void *fdt;
>  
>  #ifdef CONFIG_IMA_KEXEC
>  	phys_addr_t ima_buffer_addr;
> diff --git a/arch/powerpc/kexec/elf_64.c b/arch/powerpc/kexec/elf_64.c
> index d0e459bb2f05..bfabd06f99b1 100644
> --- a/arch/powerpc/kexec/elf_64.c
> +++ b/arch/powerpc/kexec/elf_64.c
> @@ -19,6 +19,7 @@
>  #include <linux/kexec.h>
>  #include <linux/libfdt.h>
>  #include <linux/module.h>
> +#include <linux/of.h>
>  #include <linux/of_fdt.h>
>  #include <linux/slab.h>
>  #include <linux/types.h>
> @@ -29,7 +30,6 @@ static void *elf64_load(struct kimage *image, char *kernel_buf,
>  			unsigned long cmdline_len)
>  {
>  	int ret;
> -	unsigned int fdt_size;
>  	unsigned long kernel_load_addr;
>  	unsigned long initrd_load_addr = 0, fdt_load_addr;
>  	void *fdt;
> @@ -102,19 +102,13 @@ static void *elf64_load(struct kimage *image, char *kernel_buf,
>  		pr_debug("Loaded initrd at 0x%lx\n", initrd_load_addr);
>  	}
>  
> -	fdt_size = fdt_totalsize(initial_boot_params) * 2;
> -	fdt = kmalloc(fdt_size, GFP_KERNEL);
> +	fdt = of_kexec_alloc_and_setup_fdt(image, initrd_load_addr,
> +					   initrd_len, cmdline);
>  	if (!fdt) {
>  		pr_err("Not enough memory for the device tree.\n");

This error string can be a bit misleading now, since
of_kexec_alloc_and_setup_fdt() can fail for reasons other than lack of
memory. I suggest changing it to the error string from fdt_open_into()
below:

		pr_err("Error setting up the new device tree.\n");

With this change:

Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>

And also:

Tested-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>

-- 
Thiago Jung Bauermann
IBM Linux Technology Center