Commit d30e45ee authored by Russell King's avatar Russell King
Browse files

ARM: pgtable: switch order of Linux vs hardware page tables



This switches the ordering of the Linux vs hardware page tables in
each page, thereby eliminating some of the arithmetic in the page
table walks.  As we now place the Linux page table at the beginning
of the page, we can deal with the offset in the pgt by simply masking
it away, along with the other control bits.

This also makes the arithmetic all be positive, rather than a mixture.
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent f6e3354d
......@@ -35,6 +35,11 @@ extern void pgd_free(struct mm_struct *mm, pgd_t *pgd);
#define PGALLOC_GFP (GFP_KERNEL | __GFP_NOTRACK | __GFP_REPEAT | __GFP_ZERO)
static inline void clean_pte_table(pte_t *pte)
{
clean_dcache_area(pte + PTE_HWTABLE_PTRS, PTE_HWTABLE_SIZE);
}
/*
* Allocate one PTE table.
*
......@@ -42,14 +47,14 @@ extern void pgd_free(struct mm_struct *mm, pgd_t *pgd);
* into one table thus:
*
* +------------+
* | h/w pt 0 |
* +------------+
* | h/w pt 1 |
* +------------+
* | Linux pt 0 |
* +------------+
* | Linux pt 1 |
* +------------+
* | h/w pt 0 |
* +------------+
* | h/w pt 1 |
* +------------+
*/
static inline pte_t *
pte_alloc_one_kernel(struct mm_struct *mm, unsigned long addr)
......@@ -57,10 +62,8 @@ pte_alloc_one_kernel(struct mm_struct *mm, unsigned long addr)
pte_t *pte;
pte = (pte_t *)__get_free_page(PGALLOC_GFP);
if (pte) {
clean_dcache_area(pte, sizeof(pte_t) * PTRS_PER_PTE);
pte += PTRS_PER_PTE;
}
if (pte)
clean_pte_table(pte);
return pte;
}
......@@ -76,10 +79,8 @@ pte_alloc_one(struct mm_struct *mm, unsigned long addr)
pte = alloc_pages(PGALLOC_GFP, 0);
#endif
if (pte) {
if (!PageHighMem(pte)) {
void *page = page_address(pte);
clean_dcache_area(page, sizeof(pte_t) * PTRS_PER_PTE);
}
if (!PageHighMem(pte))
clean_pte_table(page_address(pte));
pgtable_page_ctor(pte);
}
......@@ -91,10 +92,8 @@ pte_alloc_one(struct mm_struct *mm, unsigned long addr)
*/
static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
{
if (pte) {
pte -= PTRS_PER_PTE;
if (pte)
free_page((unsigned long)pte);
}
}
static inline void pte_free(struct mm_struct *mm, pgtable_t pte)
......@@ -106,7 +105,7 @@ static inline void pte_free(struct mm_struct *mm, pgtable_t pte)
static inline void __pmd_populate(pmd_t *pmdp, phys_addr_t pte,
unsigned long prot)
{
unsigned long pmdval = pte | prot;
unsigned long pmdval = (pte + PTE_HWTABLE_OFF) | prot;
pmdp[0] = __pmd(pmdval);
pmdp[1] = __pmd(pmdval + 256 * sizeof(pte_t));
flush_pmd_entry(pmdp);
......@@ -121,14 +120,10 @@ static inline void __pmd_populate(pmd_t *pmdp, phys_addr_t pte,
static inline void
pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmdp, pte_t *ptep)
{
unsigned long pte_ptr = (unsigned long)ptep;
/*
* The pmd must be loaded with the physical
* address of the PTE table
* The pmd must be loaded with the physical address of the PTE table
*/
pte_ptr -= PTRS_PER_PTE * sizeof(void *);
__pmd_populate(pmdp, __pa(pte_ptr), _PAGE_KERNEL_TABLE);
__pmd_populate(pmdp, __pa(ptep), _PAGE_KERNEL_TABLE);
}
static inline void
......
......@@ -55,7 +55,7 @@
* Therefore, we tweak the implementation slightly - we tell Linux that we
* have 2048 entries in the first level, each of which is 8 bytes (iow, two
* hardware pointers to the second level.) The second level contains two
* hardware PTE tables arranged contiguously, followed by Linux versions
* hardware PTE tables arranged contiguously, preceded by Linux versions
* which contain the state information Linux needs. We, therefore, end up
* with 512 entries in the "PTE" level.
*
......@@ -63,15 +63,15 @@
*
* pgd pte
* | |
* +--------+ +0
* | |-----> +------------+ +0
* +--------+
* | | +------------+ +0
* +- - - - + | Linux pt 0 |
* | | +------------+ +1024
* +--------+ +0 | Linux pt 1 |
* | |-----> +------------+ +2048
* +- - - - + +4 | h/w pt 0 |
* | |-----> +------------+ +1024
* | |-----> +------------+ +3072
* +--------+ +8 | h/w pt 1 |
* | | +------------+ +2048
* +- - - - + | Linux pt 0 |
* | | +------------+ +3072
* +--------+ | Linux pt 1 |
* | | +------------+ +4096
*
* See L_PTE_xxx below for definitions of bits in the "Linux pt", and
......@@ -103,6 +103,10 @@
#define PTRS_PER_PMD 1
#define PTRS_PER_PGD 2048
#define PTE_HWTABLE_PTRS (PTRS_PER_PTE)
#define PTE_HWTABLE_OFF (PTE_HWTABLE_PTRS * sizeof(pte_t))
#define PTE_HWTABLE_SIZE (PTRS_PER_PTE * sizeof(u32))
/*
* PMD_SHIFT determines the size of the area a second-level page table can map
* PGDIR_SHIFT determines what a third-level page table entry can map
......@@ -323,12 +327,7 @@ extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
static inline pte_t *pmd_page_vaddr(pmd_t pmd)
{
phys_addr_t ptr;
ptr = pmd_val(pmd) & ~(PTRS_PER_PTE * sizeof(void *) - 1);
ptr += PTRS_PER_PTE * sizeof(void *);
return __va(ptr);
return __va(pmd_val(pmd) & PAGE_MASK);
}
#define pmd_page(pmd) pfn_to_page(__phys_to_pfn(pmd_val(pmd)))
......@@ -341,8 +340,8 @@ static inline pte_t *pmd_page_vaddr(pmd_t pmd)
#define __pte_map(pmd) pmd_page_vaddr(*(pmd))
#define __pte_unmap(pte) do { } while (0)
#else
#define __pte_map(pmd) ((pte_t *)kmap_atomic(pmd_page(*(pmd))) + PTRS_PER_PTE)
#define __pte_unmap(pte) kunmap_atomic((pte - PTRS_PER_PTE))
#define __pte_map(pmd) (pte_t *)kmap_atomic(pmd_page(*(pmd)))
#define __pte_unmap(pte) kunmap_atomic(pte)
#endif
#define pte_index(addr) (((addr) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
......
......@@ -108,7 +108,7 @@ void show_pte(struct mm_struct *mm, unsigned long addr)
pte = pte_offset_map(pmd, addr);
printk(", *pte=%08lx", pte_val(*pte));
printk(", *ppte=%08lx", pte_val(pte[-PTRS_PER_PTE]));
printk(", *ppte=%08lx", pte_val(pte[PTE_HWTABLE_PTRS]));
pte_unmap(pte);
} while(0);
......
......@@ -121,7 +121,7 @@
.endm
.macro armv6_set_pte_ext pfx
str r1, [r0], #-2048 @ linux version
str r1, [r0], #2048 @ linux version
bic r3, r1, #0x000003fc
bic r3, r3, #PTE_TYPE_MASK
......@@ -170,7 +170,7 @@
* 1111 0xff r/w r/w
*/
.macro armv3_set_pte_ext wc_disable=1
str r1, [r0], #-2048 @ linux version
str r1, [r0], #2048 @ linux version
eor r3, r1, #L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_WRITE | L_PTE_DIRTY
......@@ -193,7 +193,7 @@
bicne r2, r2, #PTE_BUFFERABLE
#endif
.endif
str r2, [r0] @ hardware version
str r2, [r0] @ hardware version
.endm
......@@ -213,7 +213,7 @@
* 1111 11 r/w r/w
*/
.macro xscale_set_pte_ext_prologue
str r1, [r0], #-2048 @ linux version
str r1, [r0] @ linux version
eor r3, r1, #L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_WRITE | L_PTE_DIRTY
......@@ -232,7 +232,7 @@
tst r3, #L_PTE_PRESENT | L_PTE_YOUNG @ present and young?
movne r2, #0 @ no -> fault
str r2, [r0] @ hardware version
str r2, [r0, #2048]! @ hardware version
mov ip, #0
mcr p15, 0, r0, c7, c10, 1 @ clean L1 D line
mcr p15, 0, ip, c7, c10, 4 @ data write barrier
......
......@@ -124,15 +124,13 @@ ENDPROC(cpu_v7_switch_mm)
* Set a level 2 translation table entry.
*
* - ptep - pointer to level 2 translation table entry
* (hardware version is stored at -1024 bytes)
* (hardware version is stored at +2048 bytes)
* - pte - PTE value to store
* - ext - value for extended PTE bits
*/
ENTRY(cpu_v7_set_pte_ext)
#ifdef CONFIG_MMU
ARM( str r1, [r0], #-2048 ) @ linux version
THUMB( str r1, [r0] ) @ linux version
THUMB( sub r0, r0, #2048 )
str r1, [r0] @ linux version
bic r3, r1, #0x000003f0
bic r3, r3, #PTE_TYPE_MASK
......@@ -158,7 +156,7 @@ ENTRY(cpu_v7_set_pte_ext)
tstne r1, #L_PTE_PRESENT
moveq r3, #0
str r3, [r0]
str r3, [r0, #2048]!
mcr p15, 0, r0, c7, c10, 1 @ flush_pte
#endif
mov pc, lr
......
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