[PATCH 1/3 v11] x86/e820, resource: add a new I/O resource descriptor 'IORES_DESC_RESERVED'

[Lianbo Jiang]

When doing kexec_file_load(), the first kernel needs to pass the e820
reserved ranges to the second kernel, because some devices may use it
in kdump kernel, such as PCI devices.

But, the kernel can not exactly match the e820 reserved ranges when
walking through the iomem resources via the 'IORES_DESC_NONE', because
there are several types of e820 that are described as the 'IORES_DESC_NONE'
type. Please refer to the e820_type_to_iores_desc().

Therefore, add a 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: Borislav Petkov <bp@xxxxxxx>
Signed-off-by: Lianbo Jiang <lijiang@xxxxxxxxxx>
---
 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 2879e234e193..16fcde196243 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -1050,10 +1050,10 @@ 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,
 };
 
 /* helpers to define resources */
-- 
2.17.1