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Commit 206a2a73 authored by Steve Capper's avatar Steve Capper Committed by Catalin Marinas
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arm64: mm: Create gigabyte kernel logical mappings where possible 



We have the capability to map 1GB level 1 blocks when using a 4K
granule.

This patch adjusts the create_mapping logic s.t. when mapping physical
memory on boot, we attempt to use a 1GB block if both the VA and PA
start and end are 1GB aligned. This both reduces the levels of lookup
required to resolve a kernel logical address, as well as reduces TLB
pressure on cores that support 1GB TLB entries.

Signed-off-by: default avatarSteve Capper <steve.capper@linaro.org>
Tested-by: default avatarJungseok Lee <jays.lee@samsung.com>
[catalin.marinas@arm.com: s/prot_sect_kernel/PROT_SECT_NORMAL_EXEC/]
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent ba6bf8c8

arch/arm64/include/asm/pgtable-hwdef.h

+2 −0
Original line number Diff line number Diff line
@@ -29,6 +29,8 @@ 
 */



#define PUD_TABLE_BIT		(_AT(pgdval_t, 1) << 1)

#define PUD_TYPE_MASK		(_AT(pgdval_t, 3) << 0)

#define PUD_TYPE_SECT		(_AT(pgdval_t, 1) << 0)



/*

 * Level 2 descriptor (PMD).

arch/arm64/include/asm/pgtable.h

+7 −0
Original line number Diff line number Diff line
@@ -259,6 +259,7 @@ static inline pmd_t pte_pmd(pte_t pte) 
#define mk_pmd(page,prot)	pfn_pmd(page_to_pfn(page),prot)



#define pmd_page(pmd)           pfn_to_page(__phys_to_pfn(pmd_val(pmd) & PHYS_MASK))

#define pud_pfn(pud)		(((pud_val(pud) & PUD_MASK) & PHYS_MASK) >> PAGE_SHIFT)



#define set_pmd_at(mm, addr, pmdp, pmd)	set_pmd(pmdp, pmd)
@@ -292,6 +293,12 @@ extern pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, 
#define pmd_sect(pmd)		((pmd_val(pmd) & PMD_TYPE_MASK) == \

				 PMD_TYPE_SECT)



#ifdef ARM64_64K_PAGES

#define pud_sect(pud)		(0)

#else

#define pud_sect(pud)		((pud_val(pud) & PUD_TYPE_MASK) == \

				 PUD_TYPE_SECT)

#endif



static inline void set_pmd(pmd_t *pmdp, pmd_t pmd)

{

arch/arm64/mm/mmu.c

+27 −1
Original line number Diff line number Diff line
@@ -195,7 +195,30 @@ static void __init alloc_init_pud(pgd_t *pgd, unsigned long addr, 


	do {

		next = pud_addr_end(addr, end);



		/*

		 * For 4K granule only, attempt to put down a 1GB block

		 */

		if ((PAGE_SHIFT == 12) &&

		    ((addr | next | phys) & ~PUD_MASK) == 0) {

			pud_t old_pud = *pud;

			set_pud(pud, __pud(phys | PROT_SECT_NORMAL_EXEC));



			/*

			 * If we have an old value for a pud, it will

			 * be pointing to a pmd table that we no longer

			 * need (from swapper_pg_dir).

			 *

			 * Look up the old pmd table and free it.

			 */

			if (!pud_none(old_pud)) {

				phys_addr_t table = __pa(pmd_offset(&old_pud, 0));

				memblock_free(table, PAGE_SIZE);

				flush_tlb_all();

			}

		} else {

			alloc_init_pmd(pud, addr, next, phys);

		}

		phys += next - addr;

	} while (pud++, addr = next, addr != end);

}
@@ -338,6 +361,9 @@ int kern_addr_valid(unsigned long addr) 
	if (pud_none(*pud))

		return 0;



	if (pud_sect(*pud))

		return pfn_valid(pud_pfn(*pud));



	pmd = pmd_offset(pud, addr);

	if (pmd_none(*pmd))

		return 0;