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

From: Wandun <chenwandun1@gmail.com>
To: Pratyush Yadav <pratyush@kernel.org>
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, 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 20:00:16 +0800	[thread overview]
Message-ID: <e6028d44-781f-4d21-bef9-eba0547df03d@gmail.com> (raw)
In-Reply-To: <2vxzechoi8o0.fsf@kernel.org>


On 6/30/26 19:12, Pratyush Yadav wrote:
> 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?
> 
Sure, will fix in the next version.

Best regards,
Wandun

> 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>
> 


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