Commit 0167d7d8 authored by Tang Chen's avatar Tang Chen Committed by Linus Torvalds
Browse files

x86/mm: factor out of top-down direct mapping setup 



Create a new function memory_map_top_down to factor out of the top-down
direct memory mapping pagetable setup.  This is also a preparation for the
following patch, which will introduce the bottom-up memory mapping.  That
said, we will put the two ways of pagetable setup into separate functions,
and choose to use which way in init_mem_mapping, which makes the code more
clear.

Signed-off-by: default avatarTang Chen <tangchen@cn.fujitsu.com>
Signed-off-by: default avatarZhang Yanfei <zhangyanfei@cn.fujitsu.com>
Acked-by: default avatarTejun Heo <tj@kernel.org>
Acked-by: default avatarToshi Kani <toshi.kani@hp.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Thomas Renninger <trenn@suse.de>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Jiang Liu <jiang.liu@huawei.com>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Taku Izumi <izumi.taku@jp.fujitsu.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 79442ed1

arch/x86/mm/init.c

+39 −20
Original line number Diff line number Diff line
@@ -418,27 +418,27 @@ static unsigned long __init get_new_step_size(unsigned long step_size) 
	return step_size << 5;

}



void __init init_mem_mapping(void)

/**

 * memory_map_top_down - Map [map_start, map_end) top down

 * @map_start: start address of the target memory range

 * @map_end: end address of the target memory range

 *

 * This function will setup direct mapping for memory range

 * [map_start, map_end) in top-down. That said, the page tables

 * will be allocated at the end of the memory, and we map the

 * memory in top-down.

 */

static void __init memory_map_top_down(unsigned long map_start,

				       unsigned long map_end)

{

	unsigned long end, real_end, start, last_start;

	unsigned long real_end, start, last_start;

	unsigned long step_size;

	unsigned long addr;

	unsigned long mapped_ram_size = 0;

	unsigned long new_mapped_ram_size;



	probe_page_size_mask();



#ifdef CONFIG_X86_64

	end = max_pfn << PAGE_SHIFT;

#else

	end = max_low_pfn << PAGE_SHIFT;

#endif



	/* the ISA range is always mapped regardless of memory holes */

	init_memory_mapping(0, ISA_END_ADDRESS);



	/* xen has big range in reserved near end of ram, skip it at first.*/

	addr = memblock_find_in_range(ISA_END_ADDRESS, end, PMD_SIZE, PMD_SIZE);

	addr = memblock_find_in_range(map_start, map_end, PMD_SIZE, PMD_SIZE);

	real_end = addr + PMD_SIZE;



	/* step_size need to be small so pgt_buf from BRK could cover it */
@@ -453,13 +453,13 @@ void __init init_mem_mapping(void) 
	 * end of RAM in [min_pfn_mapped, max_pfn_mapped) used as new pages

	 * for page table.

	 */

	while (last_start > ISA_END_ADDRESS) {

	while (last_start > map_start) {

		if (last_start > step_size) {

			start = round_down(last_start - 1, step_size);

			if (start < ISA_END_ADDRESS)

				start = ISA_END_ADDRESS;

			if (start < map_start)

				start = map_start;

		} else

			start = ISA_END_ADDRESS;

			start = map_start;

		new_mapped_ram_size = init_range_memory_mapping(start,

							last_start);

		last_start = start;
@@ -470,8 +470,27 @@ void __init init_mem_mapping(void) 
		mapped_ram_size += new_mapped_ram_size;

	}



	if (real_end < end)

		init_range_memory_mapping(real_end, end);

	if (real_end < map_end)

		init_range_memory_mapping(real_end, map_end);

}



void __init init_mem_mapping(void)

{

	unsigned long end;



	probe_page_size_mask();



#ifdef CONFIG_X86_64

	end = max_pfn << PAGE_SHIFT;

#else

	end = max_low_pfn << PAGE_SHIFT;

#endif



	/* the ISA range is always mapped regardless of memory holes */

	init_memory_mapping(0, ISA_END_ADDRESS);



	/* setup direct mapping for range [ISA_END_ADDRESS, end) in top-down*/

	memory_map_top_down(ISA_END_ADDRESS, end);



#ifdef CONFIG_X86_64

	if (max_pfn > max_low_pfn) {

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