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Commit 3381959d authored by Alok Kataria's avatar Alok Kataria Committed by Ingo Molnar
Browse files

x86: cleanup e820_setup_gap(), add e820_search_gap(), v2 



This is a preparatory patch for the next patch in series.
Moves some code from e820_setup_gap to a new function e820_search_gap.
This patch is a part of a bug fix where we walk the ACPI table to calculate
a gap for PCI optional devices.

v1->v2: Patch on top of tip/master.
	Fixes a bug introduced in the last patch about the typeof "last".
	Also the new function e820_search_gap now returns if we found a gap in
	e820_map.

Signed-off-by: default avatarAlok N Kataria <akataria@vmware.com>
Cc: lenb@kernel.org
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent c987d12f

arch/x86/kernel/e820.c

+28 −15
Original line number Diff line number Diff line
@@ -488,26 +488,22 @@ void __init update_e820(void) 
}



/*

 * Search for the biggest gap in the low 32 bits of the e820

 * memory space.  We pass this space to PCI to assign MMIO resources

 * for hotplug or unconfigured devices in.

 * Hopefully the BIOS let enough space left.

 * Search for a gap in the e820 memory space from start_addr to 2^32.

 */

__init void e820_setup_gap(void)

__init int e820_search_gap(unsigned long *gapstart, unsigned long *gapsize,

		unsigned long start_addr)

{

	unsigned long gapstart, gapsize, round;

	unsigned long long last;

	int i;

	unsigned long long last = 0x100000000ull;

	int i = e820.nr_map;

	int found = 0;



	last = 0x100000000ull;

	gapstart = 0x10000000;

	gapsize = 0x400000;

	i = e820.nr_map;

	while (--i >= 0) {

		unsigned long long start = e820.map[i].addr;

		unsigned long long end = start + e820.map[i].size;



		if (end < start_addr)

			continue;



		/*

		 * Since "last" is at most 4GB, we know we'll

		 * fit in 32 bits if this condition is true
@@ -515,15 +511,32 @@ __init void e820_setup_gap(void) 
		if (last > end) {

			unsigned long gap = last - end;



			if (gap > gapsize) {

				gapsize = gap;

				gapstart = end;

			if (gap >= *gapsize) {

				*gapsize = gap;

				*gapstart = end;

				found = 1;

			}

		}

		if (start < last)

			last = start;

	}

	return found;

}



/*

 * Search for the biggest gap in the low 32 bits of the e820

 * memory space.  We pass this space to PCI to assign MMIO resources

 * for hotplug or unconfigured devices in.

 * Hopefully the BIOS let enough space left.

 */

__init void e820_setup_gap(void)

{

	unsigned long gapstart, gapsize, round;

	int found;



	gapstart = 0x10000000;

	gapsize = 0x400000;

	found  = e820_search_gap(&gapstart, &gapsize, 0);



#ifdef CONFIG_X86_64

	if (!found) {

include/asm-x86/e820.h

+2 −0
Original line number Diff line number Diff line
@@ -71,6 +71,8 @@ extern u64 e820_remove_range(u64 start, u64 size, unsigned old_type, 
			     int checktype);

extern void update_e820(void);

extern void e820_setup_gap(void);

extern int e820_search_gap(unsigned long *gapstart, unsigned long *gapsize,

				unsigned long start_addr);

struct setup_data;

extern void parse_e820_ext(struct setup_data *data, unsigned long pa_data);