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Commit d29eff7b authored by Andy Whitcroft's avatar Andy Whitcroft Committed by Linus Torvalds
Browse files

ppc64: SPARSEMEM_VMEMMAP support 



Enable virtual memmap support for SPARSEMEM on PPC64 systems.  Slice a 16th
off the end of the linear mapping space and use that to hold the vmemmap.
Uses the same size mapping as uses in the linear 1:1 kernel mapping.

[pbadari@gmail.com: fix warning]
Signed-off-by: default avatarAndy Whitcroft <apw@shadowen.org>
Acked-by: default avatarMel Gorman <mel@csn.ul.ie>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: default avatarBadari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 46644c24

arch/powerpc/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -295,6 +295,7 @@ config ARCH_FLATMEM_ENABLE 
config ARCH_SPARSEMEM_ENABLE

	def_bool y

	depends on PPC64

	select SPARSEMEM_VMEMMAP_ENABLE



config ARCH_SPARSEMEM_DEFAULT

	def_bool y

arch/powerpc/mm/init_64.c

+67 −0
Original line number Diff line number Diff line
@@ -183,3 +183,70 @@ void pgtable_cache_init(void) 
						     zero_ctor);

	}

}



#ifdef CONFIG_SPARSEMEM_VMEMMAP

/*

 * Given an address within the vmemmap, determine the pfn of the page that

 * represents the start of the section it is within.  Note that we have to

 * do this by hand as the proffered address may not be correctly aligned.

 * Subtraction of non-aligned pointers produces undefined results.

 */

unsigned long __meminit vmemmap_section_start(unsigned long page)

{

	unsigned long offset = page - ((unsigned long)(vmemmap));



	/* Return the pfn of the start of the section. */

	return (offset / sizeof(struct page)) & PAGE_SECTION_MASK;

}



/*

 * Check if this vmemmap page is already initialised.  If any section

 * which overlaps this vmemmap page is initialised then this page is

 * initialised already.

 */

int __meminit vmemmap_populated(unsigned long start, int page_size)

{

	unsigned long end = start + page_size;



	for (; start < end; start += (PAGES_PER_SECTION * sizeof(struct page)))

		if (pfn_valid(vmemmap_section_start(start)))

			return 1;



	return 0;

}



int __meminit vmemmap_populate(struct page *start_page,

					unsigned long nr_pages, int node)

{

	unsigned long mode_rw;

	unsigned long start = (unsigned long)start_page;

	unsigned long end = (unsigned long)(start_page + nr_pages);

	unsigned long page_size = 1 << mmu_psize_defs[mmu_linear_psize].shift;



	mode_rw = _PAGE_ACCESSED | _PAGE_DIRTY | _PAGE_COHERENT | PP_RWXX;



	/* Align to the page size of the linear mapping. */

	start = _ALIGN_DOWN(start, page_size);



	for (; start < end; start += page_size) {

		int mapped;

		void *p;



		if (vmemmap_populated(start, page_size))

			continue;



		p = vmemmap_alloc_block(page_size, node);

		if (!p)

			return -ENOMEM;



		printk(KERN_WARNING "vmemmap %08lx allocated at %p, "

					"physical %p.\n", start, p, __pa(p));



		mapped = htab_bolt_mapping(start, start + page_size,

					__pa(p), mode_rw, mmu_linear_psize);

		BUG_ON(mapped < 0);

	}



	return 0;

}

#endif

include/asm-powerpc/pgtable-ppc64.h

+8 −0
Original line number Diff line number Diff line
@@ -67,6 +67,14 @@ 
#define KERNEL_REGION_ID	(REGION_ID(PAGE_OFFSET))

#define USER_REGION_ID		(0UL)



/*

 * Defines the address of the vmemap area, in the top 16th of the

 * kernel region.

 */

#define VMEMMAP_BASE (ASM_CONST(CONFIG_KERNEL_START) + \

					(0xfUL << (REGION_SHIFT - 4)))

#define vmemmap ((struct page *)VMEMMAP_BASE)



/*

 * Common bits in a linux-style PTE.  These match the bits in the

 * (hardware-defined) PowerPC PTE as closely as possible. Additional