On 11/15/18 at 05:55pm, Lianbo Jiang wrote:
> The upstream kernel can not accurately add the e820 reserved type to
> kdump krenel e820 table.
>
> Kdump uses walk_iomem_res_desc() to iterate io resources, then adds
> the matched resource ranges to the e820 table for kdump kernel. But,
> when convert the e820 type into the iores descriptor, several e820
> types are converted to 'IORES_DESC_NONE' in this function e820_type
> _to_iores_desc(). So the walk_iomem_res_desc() will get unnecessary
> types(such as E820_TYPE_RAM/E820_TYPE_UNUSABLE/E820_TYPE_KERN) when
> walk through io resources by the descriptor 'IORES_DESC_NONE'.
>
> This patch adds the new I/O resource descriptor 'IORES_DESC_RESERVED'
> for the iomem resources search interfaces. It is helpful to exactly
> match the reserved resource ranges when walking through iomem resources.
>
> Suggested-by: Dave Young <dyoung@xxxxxxxxxx>
> Signed-off-by: Lianbo Jiang <lijiang@xxxxxxxxxx>
> ---
> Changes since v5:
> 1. Improve the patch log
>
> Changes since v6:
> 1. Modify this patch, and add the new I/O resource descriptor
> 'IORES_DESC_RESERVED' for the iomem resources search interfaces.
> 2. Improve patch log.
>
> arch/x86/kernel/e820.c | 2 +-
> include/linux/ioport.h | 1 +
> 2 files changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
> index 50895c2f937d..57fafdafb860 100644
> --- a/arch/x86/kernel/e820.c
> +++ b/arch/x86/kernel/e820.c
> @@ -1048,10 +1048,10 @@ static unsigned long __init e820_type_to_iores_desc(struct e820_entry *entry)
> case E820_TYPE_NVS: return IORES_DESC_ACPI_NV_STORAGE;
> case E820_TYPE_PMEM: return IORES_DESC_PERSISTENT_MEMORY;
> case E820_TYPE_PRAM: return IORES_DESC_PERSISTENT_MEMORY_LEGACY;
> + case E820_TYPE_RESERVED: return IORES_DESC_RESERVED;
> case E820_TYPE_RESERVED_KERN: /* Fall-through: */
> case E820_TYPE_RAM: /* Fall-through: */
> case E820_TYPE_UNUSABLE: /* Fall-through: */
> - case E820_TYPE_RESERVED: /* Fall-through: */
> default: return IORES_DESC_NONE;
> }
> }
> diff --git a/include/linux/ioport.h b/include/linux/ioport.h
> index da0ebaec25f0..6ed59de48bd5 100644
> --- a/include/linux/ioport.h
> +++ b/include/linux/ioport.h
> @@ -133,6 +133,7 @@ enum {
> IORES_DESC_PERSISTENT_MEMORY_LEGACY = 5,
> IORES_DESC_DEVICE_PRIVATE_MEMORY = 6,
> IORES_DESC_DEVICE_PUBLIC_MEMORY = 7,
> + IORES_DESC_RESERVED = 8,
> };
There more works for a new iores desc. Originally IORES_DESC_NONE
is assumed to include reserved e820 type so all code path relates to
IORES_DESC_NONE should be carefully checked and ensure they still work after
your changes.
>
> /* helpers to define resources */
> --
> 2.17.1
>
>
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Thanks
Dave
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