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arm64: mm: Create gigabyte kernel logical mappings where possible

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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: Steve Capper <steve.capper@linaro.org>
Tested-by: Jungseok Lee <jays.lee@samsung.com>
[catalin.marinas@arm.com: s/prot_sect_kernel/PROT_SECT_NORMAL_EXEC/]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Steve Capper 2014-05-06 14:02:27 +01:00 committed by Catalin Marinas
parent ba6bf8c85c
commit 206a2a73a6
3 changed files with 36 additions and 1 deletions
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2
arch/arm64/include/asm/pgtable-hwdef.h
View File

@ -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).

7
arch/arm64/include/asm/pgtable.h
View File

@ -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)
{

28
arch/arm64/mm/mmu.c
View File

@ -195,7 +195,30 @@ static void __init alloc_init_pud(pgd_t *pgd, unsigned long addr,
do {
next = pud_addr_end(addr, end);
alloc_init_pmd(pud, addr, next, phys);
/*
* 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;