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// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/arch/arm/mm/pgd.c
*
* Copyright (C) 1998-2005 Russell King
*/
#include <linux/mm.h>
#include <linux/gfp.h>
#include <linux/highmem.h>
#include <linux/slab.h>
#include <asm/cp15.h>
#include <asm/pgalloc.h>
#include <asm/page.h>
#include <asm/tlbflush.h>
#include "mm.h"
#ifdef CONFIG_ARM_LPAE
#define __pgd_alloc() kmalloc_array(PTRS_PER_PGD, sizeof(pgd_t), GFP_KERNEL)
#define __pgd_free(pgd) kfree(pgd)
#else
#define __pgd_alloc() (pgd_t *)__get_free_pages(GFP_KERNEL, 2)
#define __pgd_free(pgd) free_pages((unsigned long)pgd, 2)
#endif
/*
* need to get a 16k page for level 1
*/
pgd_t *pgd_alloc(struct mm_struct *mm)
{
pgd_t *new_pgd, *init_pgd;
p4d_t *new_p4d, *init_p4d;
pud_t *new_pud, *init_pud;
pmd_t *new_pmd, *init_pmd;
pte_t *new_pte, *init_pte;
new_pgd = __pgd_alloc();
if (!new_pgd)
goto no_pgd;
memset(new_pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t));
/*
* Copy over the kernel and IO PGD entries
*/
init_pgd = pgd_offset_k(0);
memcpy(new_pgd + USER_PTRS_PER_PGD, init_pgd + USER_PTRS_PER_PGD,
(PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
clean_dcache_area(new_pgd, PTRS_PER_PGD * sizeof(pgd_t));
#ifdef CONFIG_ARM_LPAE
/*
* Allocate PMD table for modules and pkmap mappings.
*/
new_p4d = p4d_alloc(mm, new_pgd + pgd_index(MODULES_VADDR),
MODULES_VADDR);
if (!new_p4d)
goto no_p4d;
new_pud = pud_alloc(mm, new_p4d, MODULES_VADDR);
if (!new_pud)
goto no_pud;
new_pmd = pmd_alloc(mm, new_pud, 0);
if (!new_pmd)
goto no_pmd;
#ifdef CONFIG_KASAN
/*
* Copy PMD table for KASAN shadow mappings.
*/
init_pgd = pgd_offset_k(TASK_SIZE);
init_p4d = p4d_offset(init_pgd, TASK_SIZE);
init_pud = pud_offset(init_p4d, TASK_SIZE);
init_pmd = pmd_offset(init_pud, TASK_SIZE);
new_pmd = pmd_offset(new_pud, TASK_SIZE);
memcpy(new_pmd, init_pmd,
(pmd_index(MODULES_VADDR) - pmd_index(TASK_SIZE))
* sizeof(pmd_t));
clean_dcache_area(new_pmd, PTRS_PER_PMD * sizeof(pmd_t));
#endif /* CONFIG_KASAN */
#endif /* CONFIG_LPAE */
if (!vectors_high()) {
/*
* On ARM, first page must always be allocated since it
* contains the machine vectors. The vectors are always high
* with LPAE.
*/
new_p4d = p4d_alloc(mm, new_pgd, 0);
if (!new_p4d)
goto no_p4d;
new_pud = pud_alloc(mm, new_p4d, 0);
if (!new_pud)
goto no_pud;
new_pmd = pmd_alloc(mm, new_pud, 0);
if (!new_pmd)
goto no_pmd;
new_pte = pte_alloc_map(mm, new_pmd, 0);
if (!new_pte)
goto no_pte;
#ifndef CONFIG_ARM_LPAE
/*
* Modify the PTE pointer to have the correct domain. This
* needs to be the vectors domain to avoid the low vectors
* being unmapped.
*/
pmd_val(*new_pmd) &= ~PMD_DOMAIN_MASK;
pmd_val(*new_pmd) |= PMD_DOMAIN(DOMAIN_VECTORS);
#endif
init_p4d = p4d_offset(init_pgd, 0);
init_pud = pud_offset(init_p4d, 0);
init_pmd = pmd_offset(init_pud, 0);
init_pte = pte_offset_map(init_pmd, 0);
set_pte_ext(new_pte + 0, init_pte[0], 0);
set_pte_ext(new_pte + 1, init_pte[1], 0);
pte_unmap(init_pte);
pte_unmap(new_pte);
}
return new_pgd;
no_pte:
pmd_free(mm, new_pmd);
mm_dec_nr_pmds(mm);
no_pmd:
pud_free(mm, new_pud);
no_pud:
p4d_free(mm, new_p4d);
no_p4d:
__pgd_free(new_pgd);
no_pgd:
return NULL;
}
void pgd_free(struct mm_struct *mm, pgd_t *pgd_base)
{
pgd_t *pgd;
p4d_t *p4d;
pud_t *pud;
pmd_t *pmd;
pgtable_t pte;
if (!pgd_base)
return;
pgd = pgd_base + pgd_index(0);
if (pgd_none_or_clear_bad(pgd))
goto no_pgd;
p4d = p4d_offset(pgd, 0);
if (p4d_none_or_clear_bad(p4d))
goto no_p4d;
pud = pud_offset(p4d, 0);
if (pud_none_or_clear_bad(pud))
goto no_pud;
pmd = pmd_offset(pud, 0);
if (pmd_none_or_clear_bad(pmd))
goto no_pmd;
pte = pmd_pgtable(*pmd);
pmd_clear(pmd);
pte_free(mm, pte);
mm_dec_nr_ptes(mm);
no_pmd:
pud_clear(pud);
pmd_free(mm, pmd);
mm_dec_nr_pmds(mm);
no_pud:
p4d_clear(p4d);
pud_free(mm, pud);
no_p4d:
pgd_clear(pgd);
p4d_free(mm, p4d);
no_pgd:
#ifdef CONFIG_ARM_LPAE
/*
* Free modules/pkmap or identity pmd tables.
*/
for (pgd = pgd_base; pgd < pgd_base + PTRS_PER_PGD; pgd++) {
if (pgd_none_or_clear_bad(pgd))
continue;
if (pgd_val(*pgd) & L_PGD_SWAPPER)
continue;
p4d = p4d_offset(pgd, 0);
if (p4d_none_or_clear_bad(p4d))
continue;
pud = pud_offset(p4d, 0);
if (pud_none_or_clear_bad(pud))
continue;
pmd = pmd_offset(pud, 0);
pud_clear(pud);
pmd_free(mm, pmd);
mm_dec_nr_pmds(mm);
p4d_clear(p4d);
pud_free(mm, pud);
mm_dec_nr_puds(mm);
pgd_clear(pgd);
p4d_free(mm, p4d);
}
#endif
__pgd_free(pgd_base);
}
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