Commit 7b80ba55 authored by Ingo Molnar's avatar Ingo Molnar
Browse files

x86/boot/e820: Clean up and improve comments in asm/e820/types.h 



Do some common-sense cleanups:

 - standardize on the kernel coding style consistently

 - tabulate definitions consistently

 - extend and clarify various descriptions

 - fix speling

 - update the header guard name according to the new position

 - etc.

No change in functionality.

Cc: Alex Thorlton <athorlton@sgi.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Huang, Ying <ying.huang@intel.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Jackson <pj@sgi.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 70a9d818

arch/x86/include/asm/e820/types.h

+53 −31
Original line number Diff line number Diff line 
#ifndef _UAPI_ASM_X86_E820_H

#define _UAPI_ASM_X86_E820_H

#define E820MAP	0x2d0		/* our map */

#define E820MAX	128		/* number of entries in E820MAP */

#ifndef _ASM_E820_TYPES_H

#define _ASM_E820_TYPES_H



/* Our map: */

#define E820MAP			0x2d0



/* The maximum number of entries in E820MAP: */

#define E820MAX			128



/*

 * Legacy E820 BIOS limits us to 128 (E820MAX) nodes due to the

 * constrained space in the zeropage.  If we have more nodes than

 * that, and if we've booted off EFI firmware, then the EFI tables

 * passed us from the EFI firmware can list more nodes.  Size our

 * internal memory map tables to have room for these additional

 * nodes, based on up to three entries per node for which the

 * kernel was built: MAX_NUMNODES == (1 << CONFIG_NODES_SHIFT),

 * plus E820MAX, allowing space for the possible duplicate E820

 * entries that might need room in the same arrays, prior to the

 * The legacy E820 BIOS limits us to 128 (E820MAX) nodes due to the

 * constrained space in the zeropage.

 *

 * On large systems we can easily have thousands of nodes with RAM,

 * which cannot be fit into so few entries - so we have a mechanism

 * to extend the e820 table size at build-time, via the E820_X_MAX

 * define below.

 *

 * ( Those extra entries are enumerated via the EFI memory map, not

 *   via the legacy zeropage mechanism. )

 *

 * Size our internal memory map tables to have room for these additional

 * entries, based on a heuristic calculation: up to three entries per

 * NUMA node, plus E820MAX for some extra space.

 *

 * This allows for bootstrap/firmware quirks such as possible duplicate

 * E820 entries that might need room in the same arrays, prior to the

 * call to sanitize_e820_map() to remove duplicates.  The allowance

 * of three memory map entries per node is "enough" entries for

 * the initial hardware platform motivating this mechanism to make
@@ -20,12 +32,12 @@ 
 * to allow more than three entries per node or otherwise refine

 * this size.

 */



#ifndef __KERNEL__

# define E820_X_MAX		E820MAX

#endif



#define E820NR	0x1e8		/* # entries in E820MAP */

/* Number of entries in E820MAP: */

#define E820NR			0x1e8



#define E820_RAM		1

#define E820_RESERVED		2
@@ -55,19 +67,30 @@ 


#ifndef __ASSEMBLY__

#include <linux/types.h>



/*

 * A single E820 map entry, describing a memory range of [addr...addr+size-1],

 * of 'type' memory type:

 */

struct e820entry {

	__u64 addr;	/* start of memory segment */

	__u64 size;	/* size of memory segment */

	__u32 type;	/* type of memory segment */

	__u64 addr;

	__u64 size;

	__u32 type;

} __attribute__((packed));



/*

 * The whole array of E820 entries:

 */

struct e820map {

	__u32 nr_map;

	struct e820entry map[E820_X_MAX];

};



#define ISA_START_ADDRESS	0xa0000

#define ISA_END_ADDRESS		0x100000

/*

 * Various legacy ranges in physical memory:

 */

#define ISA_START_ADDRESS	0x000a0000

#define ISA_END_ADDRESS		0x00100000



#define BIOS_BEGIN		0x000a0000

#define BIOS_END		0x00100000
@@ -77,5 +100,4 @@ struct e820map { 


#endif /* __ASSEMBLY__ */





#endif /* _UAPI_ASM_X86_E820_H */
 
#endif /* _ASM_E820_TYPES_H */