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/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Page table support for the Hexagon architecture
*
* Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
*/
#ifndef _ASM_PGALLOC_H
#define _ASM_PGALLOC_H
#include <asm/mem-layout.h>
#include <asm/atomic.h>
#include <asm-generic/pgalloc.h> /* for pte_{alloc,free}_one */
extern unsigned long long kmap_generation;
/*
* Page table creation interface
*/
static inline pgd_t *pgd_alloc(struct mm_struct *mm)
{
pgd_t *pgd;
pgd = (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
/*
* There may be better ways to do this, but to ensure
* that new address spaces always contain the kernel
* base mapping, and to ensure that the user area is
* initially marked invalid, initialize the new map
* map with a copy of the kernel's persistent map.
*/
memcpy(pgd, swapper_pg_dir, PTRS_PER_PGD*sizeof(pgd_t));
mm->context.generation = kmap_generation;
/* Physical version is what is passed to virtual machine on switch */
mm->context.ptbase = __pa(pgd);
return pgd;
}
static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
{
free_page((unsigned long) pgd);
}
static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd,
pgtable_t pte)
{
/*
* Conveniently, zero in 3 LSB means indirect 4K page table.
* Not so convenient when you're trying to vary the page size.
*/
set_pmd(pmd, __pmd(((unsigned long)page_to_pfn(pte) << PAGE_SHIFT) |
HEXAGON_L1_PTE_SIZE));
}
/*
* Other architectures seem to have ways of making all processes
* share the same pmd's for their kernel mappings, but the v0.3
* Hexagon VM spec has a "monolithic" L1 table for user and kernel
* segments. We track "generations" of the kernel map to minimize
* overhead, and update the "slave" copies of the kernel mappings
* as part of switch_mm. However, we still need to update the
* kernel map of the active thread who's calling pmd_populate_kernel...
*/
static inline void pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd,
pte_t *pte)
{
extern spinlock_t kmap_gen_lock;
pmd_t *ppmd;
int pmdindex;
spin_lock(&kmap_gen_lock);
kmap_generation++;
mm->context.generation = kmap_generation;
current->active_mm->context.generation = kmap_generation;
spin_unlock(&kmap_gen_lock);
set_pmd(pmd, __pmd(((unsigned long)__pa(pte)) | HEXAGON_L1_PTE_SIZE));
/*
* Now the "slave" copy of the current thread.
* This is pointer arithmetic, not byte addresses!
*/
pmdindex = (pgd_t *)pmd - mm->pgd;
ppmd = (pmd_t *)current->active_mm->pgd + pmdindex;
set_pmd(ppmd, __pmd(((unsigned long)__pa(pte)) | HEXAGON_L1_PTE_SIZE));
if (pmdindex > max_kernel_seg)
max_kernel_seg = pmdindex;
}
#define __pte_free_tlb(tlb, pte, addr) \
do { \
pgtable_page_dtor((pte)); \
tlb_remove_page((tlb), (pte)); \
} while (0)
#endif
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