Re: [PATCH v9 1/8] riscv: build crash_mem ranges from memblock instead of resource tree

[Jinjie Ruan <ruanjinjie@huawei.com>]

在 2026/10/21 16:30, Wandun Chen 写道:
> From: Wandun Chen <chenwandun@lixiang.com>
> 
> Replace walk_system_ram_res() with for_each_mem_range(). A later patch
> introduces MEMBLOCK_NODUMP in memblock, the reserved-memory regions
> marked with MEMBLOCK_NODUMP can be excluded from the vmcore by walking
> memblock.
> 
> for_each_mem_range() iterates memblock.memory, which is freed after
> init unless ARCH_KEEP_MEMBLOCK is selected. riscv needs ARCH_KEEP_MEMBLOCK
> to filter reserved memory from the vmcore, so extend its condition
> (ACPI || KEXEC) with CRASH_DUMP. arm64 and loongarch already select
> ARCH_KEEP_MEMBLOCK unconditionally.
> 
> Signed-off-by: Wandun Chen <chenwandun@lixiang.com>
> Tested-by: Meijing Zhao <zhaomeijing@lixiang.com>
> Acked-by: Baoquan He <baoquan.he@linux.dev>
> ---
>  arch/riscv/Kconfig                     |  2 +-
>  arch/riscv/kernel/machine_kexec_file.c | 31 ++++++++++----------------
>  2 files changed, 13 insertions(+), 20 deletions(-)
> 
> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> index e7891a2a89da..e21d0bab77ee 100644
> --- a/arch/riscv/Kconfig
> +++ b/arch/riscv/Kconfig
> @@ -58,7 +58,7 @@ config RISCV
>  	select ARCH_HAS_UBSAN
>  	select ARCH_HAS_VDSO_ARCH_DATA
>  	select ARCH_HAVE_NMI_SAFE_CMPXCHG
> -	select ARCH_KEEP_MEMBLOCK if ACPI || KEXEC
> +	select ARCH_KEEP_MEMBLOCK if ACPI || KEXEC || CRASH_DUMP
>  	select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE	if 64BIT && MMU
>  	select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX
>  	select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
> diff --git a/arch/riscv/kernel/machine_kexec_file.c b/arch/riscv/kernel/machine_kexec_file.c
> index 26cd2a8bd0cd..808e872f4063 100644
> --- a/arch/riscv/kernel/machine_kexec_file.c
> +++ b/arch/riscv/kernel/machine_kexec_file.c
> @@ -37,39 +37,32 @@ int arch_kimage_file_post_load_cleanup(struct kimage *image)
>  }
>  
>  #ifdef CONFIG_CRASH_DUMP
> -static int get_nr_ram_ranges_callback(struct resource *res, void *arg)
> -{
> -	unsigned int *nr_ranges = arg;
> -
> -	(*nr_ranges)++;
> -	return 0;
> -}
> -
>  unsigned int arch_get_system_nr_ranges(void)
>  {
>  	unsigned int nr_ranges = 2 + crashk_cma_cnt; /* For exclusion of crashkernel region */
> +	u64 i;
> +	phys_addr_t start, end;

The kernel prefers the reverse Christmas tree layout for local variables.

>  
> -	walk_system_ram_res(0, -1, &nr_ranges, get_nr_ram_ranges_callback);
> +	for_each_mem_range(i, &start, &end)
> +		nr_ranges++;
>  
>  	return nr_ranges;
>  }
>  
> -static int prepare_elf64_ram_headers_callback(struct resource *res, void *arg)
> +int arch_crash_populate_cmem(struct crash_mem *cmem)
>  {
> -	struct crash_mem *cmem = arg;
> +	u64 i;
> +	phys_addr_t start, end;
>  
> -	cmem->ranges[cmem->nr_ranges].start = res->start;
> -	cmem->ranges[cmem->nr_ranges].end = res->end;
> -	cmem->nr_ranges++;
> +	for_each_mem_range(i, &start, &end) {
> +		cmem->ranges[cmem->nr_ranges].start = start;
> +		cmem->ranges[cmem->nr_ranges].end = end - 1;
> +		cmem->nr_ranges++;
> +	}
>  
>  	return 0;
>  }
>  
> -int arch_crash_populate_cmem(struct crash_mem *cmem)
> -{
> -	return walk_system_ram_res(0, -1, cmem, prepare_elf64_ram_headers_callback);
> -}
> -
>  static char *setup_kdump_cmdline(struct kimage *image, char *cmdline,
>  				 unsigned long cmdline_len)
>  {

-- 
Best regards,
Jinjie