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MIPS: Add 48-bit VA space (and 4-level page tables) for 4K pages.

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Some users must have 4K pages while needing a 48-bit VA space size.
The cleanest way do do this is to go to a 4-level page table for this
case.  Each page table level using order-0 pages adds 9 bits to the
VA size (at 4K pages, so for four levels we get 9 * 4 + 12 == 48-bits.

For the 4K page size case only we add support functions for the PUD
level of the page table tree, also the TLB exception handlers get an
extra level of tree walk.

[david.daney@cavium.com: Forward port to v4.10.]
[david.daney@cavium.com: Forward port to v4.11.]

Signed-off-by: Alex Belits <alex.belits@cavium.com>
Signed-off-by: David Daney <david.daney@cavium.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Alex Belits <alex.belits@cavium.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/15312/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Alex Belits 2017-02-16 17:27:34 -08:00 • committed by Ralf Baechle
parent dfa32261fa
commit 3377e227af
6 changed files with 173 additions and 14 deletions
Download patch file Download diff file Expand all files Collapse all files

33
arch/mips/mm/pgtable-64.c
View file

@ -19,10 +19,12 @@ void pgd_init(unsigned long page)
unsigned long *p, *end;
unsigned long entry;
#ifdef __PAGETABLE_PMD_FOLDED
entry = (unsigned long)invalid_pte_table;
#else
#if !defined(__PAGETABLE_PUD_FOLDED)
entry = (unsigned long)invalid_pud_table;
#elif !defined(__PAGETABLE_PMD_FOLDED)
entry = (unsigned long)invalid_pmd_table;
#else
entry = (unsigned long)invalid_pte_table;
#endif
p = (unsigned long *) page;
@ -64,6 +66,28 @@ void pmd_init(unsigned long addr, unsigned long pagetable)
EXPORT_SYMBOL_GPL(pmd_init);
#endif
#ifndef __PAGETABLE_PUD_FOLDED
void pud_init(unsigned long addr, unsigned long pagetable)
{
unsigned long *p, *end;
p = (unsigned long *)addr;
end = p + PTRS_PER_PUD;
do {
p[0] = pagetable;
p[1] = pagetable;
p[2] = pagetable;
p[3] = pagetable;
p[4] = pagetable;
p += 8;
p[-3] = pagetable;
p[-2] = pagetable;
p[-1] = pagetable;
} while (p != end);
}
#endif
pmd_t mk_pmd(struct page *page, pgprot_t prot)
{
pmd_t pmd;
@ -87,6 +111,9 @@ void __init pagetable_init(void)
/* Initialize the entire pgd. */
pgd_init((unsigned long)swapper_pg_dir);
#ifndef __PAGETABLE_PUD_FOLDED
pud_init((unsigned long)invalid_pud_table, (unsigned long)invalid_pmd_table);
#endif
#ifndef __PAGETABLE_PMD_FOLDED
pmd_init((unsigned long)invalid_pmd_table, (unsigned long)invalid_pte_table);
#endif