Re: [PATCH v4 09/10] riscv: kdump: exclude non-dumpable reserved memory regions from vmcore

From: Pratyush Yadav <pratyush@kernel.org>
To: Wandun Chen <chenwandun1@gmail.com>
Cc: chenhuacai@kernel.org,  kernel@xen0n.name,  pjw@kernel.org,
	palmer@dabbelt.com,  aou@eecs.berkeley.edu,  robh@kernel.org,
	saravanak@kernel.org,  bhe@redhat.com,  rppt@kernel.org,
	linux-arm-kernel@lists.infradead.org,
	 linux-kernel@vger.kernel.org, loongarch@lists.linux.dev,
	 linux-riscv@lists.infradead.org, devicetree@vger.kernel.org,
	 kexec@lists.infradead.org, iommu@lists.linux.dev,
	 zhaomeijing@lixiang.com, catalin.marinas@arm.com,
	 will@kernel.org,  alex@ghiti.fr, akpm@linux-foundation.org,
	 pasha.tatashin@soleen.com, pratyush@kernel.org,
	 ruirui.yang@linux.dev,  m.szyprowski@samsung.com,
	robin.murphy@arm.com
Subject: Re: [PATCH v4 09/10] riscv: kdump: exclude non-dumpable reserved memory regions from vmcore
Date: Tue, 30 Jun 2026 13:12:31 +0200	[thread overview]
Message-ID: <2vxzechoi8o0.fsf@kernel.org> (raw)
In-Reply-To: <20260630074715.4126796-10-chenwandun1@gmail.com> (Wandun Chen's message of "Tue, 30 Jun 2026 15:47:13 +0800")

On Tue, Jun 30 2026, Wandun Chen wrote:

> From: Wandun Chen <chenwandun@lixiang.com>
>
> Apply the same non-dumpable reserved memory filtering to RISC-V kdump
> as was done for arm64. Use of_reserved_mem_kdump_exclude() to drop
> flagged regions from the elfcorehdr PT_LOAD segments, and
> of_reserved_mem_kdump_nr_ranges() to pre-size the crash_mem array.
>
> Signed-off-by: Wandun Chen <chenwandun@lixiang.com>
> ---
>  arch/riscv/kernel/machine_kexec_file.c | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/arch/riscv/kernel/machine_kexec_file.c b/arch/riscv/kernel/machine_kexec_file.c
> index 59d4bbc848a8..25359d583bc3 100644
> --- a/arch/riscv/kernel/machine_kexec_file.c
> +++ b/arch/riscv/kernel/machine_kexec_file.c
> @@ -10,6 +10,7 @@
>  #include <linux/elf.h>
>  #include <linux/slab.h>
>  #include <linux/of.h>
> +#include <linux/of_reserved_mem.h>
>  #include <linux/libfdt.h>
>  #include <linux/types.h>
>  #include <linux/memblock.h>
> @@ -64,6 +65,7 @@ static int prepare_elf_headers(void **addr, unsigned long *sz)
>  
>  	nr_ranges = 1; /* For exclusion of crashkernel region */
>  	walk_system_ram_res(0, -1, &nr_ranges, get_nr_ram_ranges_callback);
> +	nr_ranges += of_reserved_mem_kdump_nr_ranges();
>  
>  	cmem = kmalloc_flex(*cmem, ranges, nr_ranges);
>  	if (!cmem)
> @@ -77,6 +79,8 @@ static int prepare_elf_headers(void **addr, unsigned long *sz)
>  
>  	/* Exclude crashkernel region */
>  	ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
> +	if (!ret)
> +		ret = of_reserved_mem_kdump_exclude(cmem);
>  	if (!ret)
>  		ret = crash_prepare_elf64_headers(cmem, true, addr, sz);

Nit: can you do the usual pattern of if (err) goto err; instead?

So this would look like:

	/* Exclude crashkernel region */
	ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
	if (ret)
		goto out;

	ret = of_reserved_mem_kdump_exclude(cmem);
	if (ret)
		goto out;

	ret = crash_prepare_elf64_headers(cmem, true, addr, sz);
out:
	...

With this,

Acked-by: Pratyush Yadav <pratyush@kernel.org>

-- 
Regards,
Pratyush Yadav