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arm64: mm: use fixmap when creating page tables 

As a preparatory step to allow us to allocate early page tables from
unmapped memory using memblock_alloc, modify the __create_mapping
callees to map and unmap the tables they modify using fixmap entries.

All but the top-level pgd initialisation is performed via the fixmap.
Subsequent patches will inject the pgd physical address, and migrate to
using the FIX_PGD slot.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: Jeremy Linton <jeremy.linton@arm.com>
Cc: Laura Abbott <labbott@fedoraproject.org>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Mark Rutland 2016-01-25 11:45:08 +00:00 committed by Catalin Marinas
parent 961faac114
commit f471044545
1 changed files with 41 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

61
arch/arm64/mm/mmu.c
View File

@ -63,19 +63,30 @@ pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
}
EXPORT_SYMBOL(phys_mem_access_prot);
static void __init *early_pgtable_alloc(void)
static phys_addr_t __init early_pgtable_alloc(void)
{
phys_addr_t phys;
void *ptr;
phys = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
BUG_ON(!phys);
ptr = __va(phys);
/*
* The FIX_{PGD,PUD,PMD} slots may be in active use, but the FIX_PTE
* slot will be free, so we can (ab)use the FIX_PTE slot to initialise
* any level of table.
*/
ptr = pte_set_fixmap(phys);
memset(ptr, 0, PAGE_SIZE);
/* Ensure the zeroed page is visible to the page table walker */
dsb(ishst);
return ptr;
/*
* Implicit barriers also ensure the zeroed page is visible to the page
* table walker
*/
pte_clear_fixmap();
return phys;
}
/*
@ -99,24 +110,28 @@ static void split_pmd(pmd_t *pmd, pte_t *pte)
static void alloc_init_pte(pmd_t *pmd, unsigned long addr,
unsigned long end, unsigned long pfn,
pgprot_t prot,
void *(*pgtable_alloc)(void))
phys_addr_t (*pgtable_alloc)(void))
{
pte_t *pte;
if (pmd_none(*pmd) || pmd_sect(*pmd)) {
pte = pgtable_alloc();
phys_addr_t pte_phys = pgtable_alloc();
pte = pte_set_fixmap(pte_phys);
if (pmd_sect(*pmd))
split_pmd(pmd, pte);
__pmd_populate(pmd, __pa(pte), PMD_TYPE_TABLE);
__pmd_populate(pmd, pte_phys, PMD_TYPE_TABLE);
flush_tlb_all();
pte_clear_fixmap();
}
BUG_ON(pmd_bad(*pmd));
pte = pte_offset_kernel(pmd, addr);
pte = pte_set_fixmap_offset(pmd, addr);
do {
set_pte(pte, pfn_pte(pfn, prot));
pfn++;
} while (pte++, addr += PAGE_SIZE, addr != end);
pte_clear_fixmap();
}
static void split_pud(pud_t *old_pud, pmd_t *pmd)
@ -134,7 +149,7 @@ static void split_pud(pud_t *old_pud, pmd_t *pmd)
static void alloc_init_pmd(struct mm_struct *mm, pud_t *pud,
unsigned long addr, unsigned long end,
phys_addr_t phys, pgprot_t prot,
void *(*pgtable_alloc)(void))
phys_addr_t (*pgtable_alloc)(void))
{
pmd_t *pmd;
unsigned long next;
@ -143,7 +158,8 @@ static void alloc_init_pmd(struct mm_struct *mm, pud_t *pud,
* Check for initial section mappings in the pgd/pud and remove them.
*/
if (pud_none(*pud) || pud_sect(*pud)) {
pmd = pgtable_alloc();
phys_addr_t pmd_phys = pgtable_alloc();
pmd = pmd_set_fixmap(pmd_phys);
if (pud_sect(*pud)) {
/*
* need to have the 1G of mappings continue to be
@ -151,12 +167,13 @@ static void alloc_init_pmd(struct mm_struct *mm, pud_t *pud,
*/
split_pud(pud, pmd);
}
pud_populate(mm, pud, pmd);
__pud_populate(pud, pmd_phys, PUD_TYPE_TABLE);
flush_tlb_all();
pmd_clear_fixmap();
}
BUG_ON(pud_bad(*pud));
pmd = pmd_offset(pud, addr);
pmd = pmd_set_fixmap_offset(pud, addr);
do {
next = pmd_addr_end(addr, end);
/* try section mapping first */
@ -182,6 +199,8 @@ static void alloc_init_pmd(struct mm_struct *mm, pud_t *pud,
}
phys += next - addr;
} while (pmd++, addr = next, addr != end);
pmd_clear_fixmap();
}
static inline bool use_1G_block(unsigned long addr, unsigned long next,
@ -199,18 +218,18 @@ static inline bool use_1G_block(unsigned long addr, unsigned long next,
static void alloc_init_pud(struct mm_struct *mm, pgd_t *pgd,
unsigned long addr, unsigned long end,
phys_addr_t phys, pgprot_t prot,
void *(*pgtable_alloc)(void))
phys_addr_t (*pgtable_alloc)(void))
{
pud_t *pud;
unsigned long next;
if (pgd_none(*pgd)) {
pud = pgtable_alloc();
pgd_populate(mm, pgd, pud);
phys_addr_t pud_phys = pgtable_alloc();
__pgd_populate(pgd, pud_phys, PUD_TYPE_TABLE);
}
BUG_ON(pgd_bad(*pgd));
pud = pud_offset(pgd, addr);
pud = pud_set_fixmap_offset(pgd, addr);
do {
next = pud_addr_end(addr, end);
@ -243,6 +262,8 @@ static void alloc_init_pud(struct mm_struct *mm, pgd_t *pgd,
}
phys += next - addr;
} while (pud++, addr = next, addr != end);
pud_clear_fixmap();
}
/*
@ -252,7 +273,7 @@ static void alloc_init_pud(struct mm_struct *mm, pgd_t *pgd,
static void __create_mapping(struct mm_struct *mm, pgd_t *pgd,
phys_addr_t phys, unsigned long virt,
phys_addr_t size, pgprot_t prot,
void *(*pgtable_alloc)(void))
phys_addr_t (*pgtable_alloc)(void))
{
unsigned long addr, length, end, next;
@ -275,14 +296,14 @@ static void __create_mapping(struct mm_struct *mm, pgd_t *pgd,
} while (pgd++, addr = next, addr != end);
}
static void *late_pgtable_alloc(void)
static phys_addr_t late_pgtable_alloc(void)
{
void *ptr = (void *)__get_free_page(PGALLOC_GFP);
BUG_ON(!ptr);
/* Ensure the zeroed page is visible to the page table walker */
dsb(ishst);
return ptr;
return __pa(ptr);
}
static void __init create_mapping(phys_addr_t phys, unsigned long virt,