Huacai,
On 12/29/23 at 04:02pm, Huacai Chen wrote:
> In /proc/iomem, sub-regions should be inserted after their parent,
> otherwise the insertion of parent resource fails. But after generic
> crashkernel reservation applied, in both RISC-V and ARM64 (LoongArch
> will also use generic reservation later on), crashkernel resources are
> inserted before their parent, which causes the parent disappear in
> /proc/iomem. So we defer the insertion of crashkernel resources to an
> early_initcall().
>
> 1, Without 'crashkernel' parameter:
>
> 100d0100-100d01ff : LOON0001:00
> 100d0100-100d01ff : LOON0001:00 LOON0001:00
> 100e0000-100e0bff : LOON0002:00
> 100e0000-100e0bff : LOON0002:00 LOON0002:00
> 1fe001e0-1fe001e7 : serial
> 90400000-fa17ffff : System RAM
> f6220000-f622ffff : Reserved
> f9ee0000-f9ee3fff : Reserved
> fa120000-fa17ffff : Reserved
> fa190000-fe0bffff : System RAM
> fa190000-fa1bffff : Reserved
> fe4e0000-47fffffff : System RAM
> 43c000000-441ffffff : Reserved
> 47ff98000-47ffa3fff : Reserved
> 47ffa4000-47ffa7fff : Reserved
> 47ffa8000-47ffabfff : Reserved
> 47ffac000-47ffaffff : Reserved
> 47ffb0000-47ffb3fff : Reserved
>
> 2, With 'crashkernel' parameter, before this patch:
>
> 100d0100-100d01ff : LOON0001:00
> 100d0100-100d01ff : LOON0001:00 LOON0001:00
> 100e0000-100e0bff : LOON0002:00
> 100e0000-100e0bff : LOON0002:00 LOON0002:00
> 1fe001e0-1fe001e7 : serial
> e6200000-f61fffff : Crash kernel
> fa190000-fe0bffff : System RAM
> fa190000-fa1bffff : Reserved
> fe4e0000-47fffffff : System RAM
> 43c000000-441ffffff : Reserved
> 47ff98000-47ffa3fff : Reserved
> 47ffa4000-47ffa7fff : Reserved
> 47ffa8000-47ffabfff : Reserved
> 47ffac000-47ffaffff : Reserved
> 47ffb0000-47ffb3fff : Reserved
>
> 3, With 'crashkernel' parameter, after this patch:
>
> 100d0100-100d01ff : LOON0001:00
> 100d0100-100d01ff : LOON0001:00 LOON0001:00
> 100e0000-100e0bff : LOON0002:00
> 100e0000-100e0bff : LOON0002:00 LOON0002:00
> 1fe001e0-1fe001e7 : serial
> 90400000-fa17ffff : System RAM
> e6200000-f61fffff : Crash kernel
> f6220000-f622ffff : Reserved
> f9ee0000-f9ee3fff : Reserved
> fa120000-fa17ffff : Reserved
> fa190000-fe0bffff : System RAM
> fa190000-fa1bffff : Reserved
> fe4e0000-47fffffff : System RAM
> 43c000000-441ffffff : Reserved
> 47ff98000-47ffa3fff : Reserved
> 47ffa4000-47ffa7fff : Reserved
> 47ffa8000-47ffabfff : Reserved
> 47ffac000-47ffaffff : Reserved
> 47ffb0000-47ffb3fff : Reserved
This looks like a great catch. I am curious where arm64 and loongarch
insert the system RAM range into iomem before crashk_res and
crashk_low_res. On x86, it should be done by pci or acpi init which is
earlier than crashkernel parsing and inserting into iomem, just went\
through codes, haven't adding debugging code to print.
>
> Signed-off-by: Huacai Chen <chenhuacai@xxxxxxxxxxx>
> ---
> kernel/crash_core.c | 14 ++++++++++++--
> 1 file changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/crash_core.c b/kernel/crash_core.c
> index d4313b53837e..755d8d4ef5b0 100644
> --- a/kernel/crash_core.c
> +++ b/kernel/crash_core.c
> @@ -377,7 +377,6 @@ static int __init reserve_crashkernel_low(unsigned long long low_size)
>
> crashk_low_res.start = low_base;
> crashk_low_res.end = low_base + low_size - 1;
> - insert_resource(&iomem_resource, &crashk_low_res);
> #endif
> return 0;
> }
> @@ -459,8 +458,19 @@ void __init reserve_crashkernel_generic(char *cmdline,
>
> crashk_res.start = crash_base;
> crashk_res.end = crash_base + crash_size - 1;
> - insert_resource(&iomem_resource, &crashk_res);
> }
> +
> +static __init int insert_crashkernel_resources(void)
> +{
> + if (crashk_res.start < crashk_res.end)
> + insert_resource(&iomem_resource, &crashk_res);
> +
> + if (crashk_low_res.start < crashk_low_res.end)
> + insert_resource(&iomem_resource, &crashk_low_res);
> +
> + return 0;
> +}
> +early_initcall(insert_crashkernel_resources);
> #endif
>
> int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map,
> --
> 2.39.3
>
>
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