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arm64: mm: add param to force create_pgd_mapping() to use page mappings
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Add a bool parameter 'allow_block_mappings' to create_pgd_mapping() and
the various helper functions that it descends into, to give the caller
control over whether block entries may be used to create the mapping.

The UEFI runtime mapping routines will use this to avoid creating block
entries that would need to split up into page entries when applying the
permissions listed in the Memory Attributes firmware table.

This also replaces the block_mappings_allowed() helper function that was
added for DEBUG_PAGEALLOC functionality, but the resulting code is
functionally equivalent (given that debug_page_alloc does not operate on
EFI page table entries anyway)

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Ard Biesheuvel authored and Catalin Marinas committed Jul 1, 2016
1 parent 7dd01ae commit 53e1b32
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Showing 3 changed files with 29 additions and 42 deletions.
2 changes: 1 addition & 1 deletion arch/arm64/include/asm/mmu.h
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Original file line number Diff line number Diff line change
Expand Up @@ -34,7 +34,7 @@ extern void __iomem *early_io_map(phys_addr_t phys, unsigned long virt);
extern void init_mem_pgprot(void);
extern void create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys,
unsigned long virt, phys_addr_t size,
pgprot_t prot);
pgprot_t prot, bool allow_block_mappings);
extern void *fixmap_remap_fdt(phys_addr_t dt_phys);

#endif
2 changes: 1 addition & 1 deletion arch/arm64/kernel/efi.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -65,7 +65,7 @@ int __init efi_create_mapping(struct mm_struct *mm, efi_memory_desc_t *md)

create_pgd_mapping(mm, md->phys_addr, md->virt_addr,
md->num_pages << EFI_PAGE_SHIFT,
__pgprot(prot_val | PTE_NG));
__pgprot(prot_val | PTE_NG), true);
return 0;
}

Expand Down
67 changes: 27 additions & 40 deletions arch/arm64/mm/mmu.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -155,29 +155,10 @@ static void split_pud(pud_t *old_pud, pmd_t *pmd)
} while (pmd++, i++, i < PTRS_PER_PMD);
}

#ifdef CONFIG_DEBUG_PAGEALLOC
static bool block_mappings_allowed(phys_addr_t (*pgtable_alloc)(void))
{

/*
* If debug_page_alloc is enabled we must map the linear map
* using pages. However, other mappings created by
* create_mapping_noalloc must use sections in some cases. Allow
* sections to be used in those cases, where no pgtable_alloc
* function is provided.
*/
return !pgtable_alloc || !debug_pagealloc_enabled();
}
#else
static bool block_mappings_allowed(phys_addr_t (*pgtable_alloc)(void))
{
return true;
}
#endif

static void alloc_init_pmd(pud_t *pud, unsigned long addr, unsigned long end,
phys_addr_t phys, pgprot_t prot,
phys_addr_t (*pgtable_alloc)(void))
phys_addr_t (*pgtable_alloc)(void),
bool allow_block_mappings)
{
pmd_t *pmd;
unsigned long next;
Expand Down Expand Up @@ -208,7 +189,7 @@ static void alloc_init_pmd(pud_t *pud, unsigned long addr, unsigned long end,
next = pmd_addr_end(addr, end);
/* try section mapping first */
if (((addr | next | phys) & ~SECTION_MASK) == 0 &&
block_mappings_allowed(pgtable_alloc)) {
allow_block_mappings) {
pmd_t old_pmd =*pmd;
pmd_set_huge(pmd, phys, prot);
/*
Expand Down Expand Up @@ -247,7 +228,8 @@ static inline bool use_1G_block(unsigned long addr, unsigned long next,

static void alloc_init_pud(pgd_t *pgd, unsigned long addr, unsigned long end,
phys_addr_t phys, pgprot_t prot,
phys_addr_t (*pgtable_alloc)(void))
phys_addr_t (*pgtable_alloc)(void),
bool allow_block_mappings)
{
pud_t *pud;
unsigned long next;
Expand All @@ -267,8 +249,7 @@ static void alloc_init_pud(pgd_t *pgd, unsigned long addr, unsigned long end,
/*
* For 4K granule only, attempt to put down a 1GB block
*/
if (use_1G_block(addr, next, phys) &&
block_mappings_allowed(pgtable_alloc)) {
if (use_1G_block(addr, next, phys) && allow_block_mappings) {
pud_t old_pud = *pud;
pud_set_huge(pud, phys, prot);

Expand All @@ -289,7 +270,7 @@ static void alloc_init_pud(pgd_t *pgd, unsigned long addr, unsigned long end,
}
} else {
alloc_init_pmd(pud, addr, next, phys, prot,
pgtable_alloc);
pgtable_alloc, allow_block_mappings);
}
phys += next - addr;
} while (pud++, addr = next, addr != end);
Expand All @@ -303,7 +284,8 @@ static void alloc_init_pud(pgd_t *pgd, unsigned long addr, unsigned long end,
*/
static void init_pgd(pgd_t *pgd, phys_addr_t phys, unsigned long virt,
phys_addr_t size, pgprot_t prot,
phys_addr_t (*pgtable_alloc)(void))
phys_addr_t (*pgtable_alloc)(void),
bool allow_block_mappings)
{
unsigned long addr, length, end, next;

Expand All @@ -321,7 +303,8 @@ static void init_pgd(pgd_t *pgd, phys_addr_t phys, unsigned long virt,
end = addr + length;
do {
next = pgd_addr_end(addr, end);
alloc_init_pud(pgd, addr, next, phys, prot, pgtable_alloc);
alloc_init_pud(pgd, addr, next, phys, prot, pgtable_alloc,
allow_block_mappings);
phys += next - addr;
} while (pgd++, addr = next, addr != end);
}
Expand All @@ -339,9 +322,11 @@ static phys_addr_t late_pgtable_alloc(void)
static void __create_pgd_mapping(pgd_t *pgdir, phys_addr_t phys,
unsigned long virt, phys_addr_t size,
pgprot_t prot,
phys_addr_t (*alloc)(void))
phys_addr_t (*alloc)(void),
bool allow_block_mappings)
{
init_pgd(pgd_offset_raw(pgdir, virt), phys, virt, size, prot, alloc);
init_pgd(pgd_offset_raw(pgdir, virt), phys, virt, size, prot, alloc,
allow_block_mappings);
}

/*
Expand All @@ -357,16 +342,15 @@ static void __init create_mapping_noalloc(phys_addr_t phys, unsigned long virt,
&phys, virt);
return;
}
__create_pgd_mapping(init_mm.pgd, phys, virt, size, prot,
NULL);
__create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL, true);
}

void __init create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys,
unsigned long virt, phys_addr_t size,
pgprot_t prot)
pgprot_t prot, bool allow_block_mappings)
{
__create_pgd_mapping(mm->pgd, phys, virt, size, prot,
late_pgtable_alloc);
late_pgtable_alloc, allow_block_mappings);
}

static void create_mapping_late(phys_addr_t phys, unsigned long virt,
Expand All @@ -379,7 +363,7 @@ static void create_mapping_late(phys_addr_t phys, unsigned long virt,
}

__create_pgd_mapping(init_mm.pgd, phys, virt, size, prot,
late_pgtable_alloc);
late_pgtable_alloc, !debug_pagealloc_enabled());
}

static void __init __map_memblock(pgd_t *pgd, phys_addr_t start, phys_addr_t end)
Expand All @@ -396,7 +380,8 @@ static void __init __map_memblock(pgd_t *pgd, phys_addr_t start, phys_addr_t end
if (end < kernel_start || start >= kernel_end) {
__create_pgd_mapping(pgd, start, __phys_to_virt(start),
end - start, PAGE_KERNEL,
early_pgtable_alloc);
early_pgtable_alloc,
!debug_pagealloc_enabled());
return;
}

Expand All @@ -408,12 +393,14 @@ static void __init __map_memblock(pgd_t *pgd, phys_addr_t start, phys_addr_t end
__create_pgd_mapping(pgd, start,
__phys_to_virt(start),
kernel_start - start, PAGE_KERNEL,
early_pgtable_alloc);
early_pgtable_alloc,
!debug_pagealloc_enabled());
if (kernel_end < end)
__create_pgd_mapping(pgd, kernel_end,
__phys_to_virt(kernel_end),
end - kernel_end, PAGE_KERNEL,
early_pgtable_alloc);
early_pgtable_alloc,
!debug_pagealloc_enabled());

/*
* Map the linear alias of the [_text, __init_begin) interval as
Expand All @@ -423,7 +410,7 @@ static void __init __map_memblock(pgd_t *pgd, phys_addr_t start, phys_addr_t end
*/
__create_pgd_mapping(pgd, kernel_start, __phys_to_virt(kernel_start),
kernel_end - kernel_start, PAGE_KERNEL_RO,
early_pgtable_alloc);
early_pgtable_alloc, !debug_pagealloc_enabled());
}

static void __init map_mem(pgd_t *pgd)
Expand Down Expand Up @@ -480,7 +467,7 @@ static void __init map_kernel_segment(pgd_t *pgd, void *va_start, void *va_end,
BUG_ON(!PAGE_ALIGNED(size));

__create_pgd_mapping(pgd, pa_start, (unsigned long)va_start, size, prot,
early_pgtable_alloc);
early_pgtable_alloc, !debug_pagealloc_enabled());

vma->addr = va_start;
vma->phys_addr = pa_start;
Expand Down

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