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sh: pmd rework.

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Remove extra bits from the pmd structure and store a kernel logical
address rather than a physical address. This allows it to be directly
dereferenced. Another piece of wierdness inherited from x86.

Signed-off-by: Stuart Menefy <stuart.menefy@st.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This commit is contained in:
Stuart Menefy 2006-11-21 15:38:05 +09:00 committed by Paul Mundt
parent 6e4662ff49
commit 99a596f93b
4 changed files with 76 additions and 48 deletions
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40
arch/sh/mm/fault.c
View file

@ -46,6 +46,45 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
mm = tsk->mm;
si_code = SEGV_MAPERR;
if (unlikely(address >= TASK_SIZE)) {
/*
* Synchronize this task's top level page-table
* with the 'reference' page table.
*
* Do _not_ use "tsk" here. We might be inside
* an interrupt in the middle of a task switch..
*/
int offset = pgd_index(address);
pgd_t *pgd, *pgd_k;
pud_t *pud, *pud_k;
pmd_t *pmd, *pmd_k;
pgd = get_TTB() + offset;
pgd_k = swapper_pg_dir + offset;
/* This will never happen with the folded page table. */
if (!pgd_present(*pgd)) {
if (!pgd_present(*pgd_k))
goto bad_area_nosemaphore;
set_pgd(pgd, *pgd_k);
return;
}
pud = pud_offset(pgd, address);
pud_k = pud_offset(pgd_k, address);
if (pud_present(*pud) || !pud_present(*pud_k))
goto bad_area_nosemaphore;
set_pud(pud, *pud_k);
pmd = pmd_offset(pud, address);
pmd_k = pmd_offset(pud_k, address);
if (pmd_present(*pmd) || !pmd_present(*pmd_k))
goto bad_area_nosemaphore;
set_pmd(pmd, *pmd_k);
return;
}
/*
* If we're in an interrupt or have no user
* context, we must not take the fault..
@ -109,6 +148,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
bad_area:
up_read(&mm->mmap_sem);
bad_area_nosemaphore:
if (user_mode(regs)) {
info.si_signo = SIGSEGV;
info.si_errno = 0;

18
arch/sh/mm/init.c
View file

@ -84,31 +84,23 @@ static void set_pte_phys(unsigned long addr, unsigned long phys, pgprot_t prot)
pmd_t *pmd;
pte_t *pte;
pgd = swapper_pg_dir + pgd_index(addr);
pgd = pgd_offset_k(addr);
if (pgd_none(*pgd)) {
pgd_ERROR(*pgd);
return;
}
pud = pud_offset(pgd, addr);
if (pud_none(*pud)) {
pmd = (pmd_t *)get_zeroed_page(GFP_ATOMIC);
set_pud(pud, __pud(__pa(pmd) | _PAGE_TABLE));
if (pmd != pmd_offset(pud, 0)) {
pud = pud_alloc(NULL, pgd, addr);
if (unlikely(!pud)) {
pud_ERROR(*pud);
return;
}
}
pmd = pmd_offset(pud, addr);
if (pmd_none(*pmd)) {
pte = (pte_t *)get_zeroed_page(GFP_ATOMIC);
set_pmd(pmd, __pmd(__pa(pte) | _PAGE_TABLE));
if (pte != pte_offset_kernel(pmd, 0)) {
pmd = pmd_alloc(NULL, pud, addr);
if (unlikely(!pmd)) {
pmd_ERROR(*pmd);
return;
}
}
pte = pte_offset_kernel(pmd, addr);
if (!pte_none(*pte)) {

20
include/asm-sh/pgalloc.h
View file

@ -1,13 +1,16 @@
#ifndef __ASM_SH_PGALLOC_H
#define __ASM_SH_PGALLOC_H
#define pmd_populate_kernel(mm, pmd, pte) \
set_pmd(pmd, __pmd(_PAGE_TABLE + __pa(pte)))
static inline void pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd,
pte_t *pte)
{
set_pmd(pmd, __pmd((unsigned long)pte));
}
static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd,
struct page *pte)
{
set_pmd(pmd, __pmd(_PAGE_TABLE + page_to_phys(pte)));
set_pmd(pmd, __pmd((unsigned long)page_address(pte)));
}
/*
@ -15,7 +18,16 @@ static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd,
*/
static inline pgd_t *pgd_alloc(struct mm_struct *mm)
{
return (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_REPEAT | __GFP_ZERO);
pgd_t *pgd = (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_REPEAT);
if (pgd) {
memset(pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t));
memcpy(pgd + USER_PTRS_PER_PGD,
swapper_pg_dir + USER_PTRS_PER_PGD,
(PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
}
return pgd;
}
static inline void pgd_free(pgd_t *pgd)

24
include/asm-sh/pgtable.h
View file

@ -203,14 +203,6 @@ extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
#ifndef __ASSEMBLY__
#if defined(CONFIG_X2TLB) /* SH-X2 TLB */
#define _PAGE_TABLE \
(_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_DIRTY | \
_PAGE_EXT(_PAGE_EXT_USER_READ | _PAGE_EXT_USER_WRITE))
#define _KERNPG_TABLE \
(_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_DIRTY | \
_PAGE_EXT(_PAGE_EXT_KERN_READ | _PAGE_EXT_KERN_WRITE))
#define PAGE_NONE __pgprot(_PAGE_PROTNONE | _PAGE_CACHABLE | \
_PAGE_ACCESSED | _PAGE_FLAGS_HARD)
@ -271,11 +263,6 @@ extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
(type))
#elif defined(CONFIG_MMU) /* SH-X TLB */
#define _PAGE_TABLE \
(_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | _PAGE_ACCESSED | _PAGE_DIRTY)
#define _KERNPG_TABLE \
(_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | _PAGE_DIRTY)
#define PAGE_NONE __pgprot(_PAGE_PROTNONE | _PAGE_CACHABLE | \
_PAGE_ACCESSED | _PAGE_FLAGS_HARD)
@ -390,9 +377,9 @@ static inline void set_pte(pte_t *ptep, pte_t pte)
#define pte_clear(mm,addr,xp) do { set_pte_at(mm, addr, xp, __pte(0)); } while (0)
#define pmd_none(x) (!pmd_val(x))
#define pmd_present(x) (pmd_val(x) & _PAGE_PRESENT)
#define pmd_present(x) (pmd_val(x))
#define pmd_clear(xp) do { set_pmd(xp, __pmd(0)); } while (0)
#define pmd_bad(x) ((pmd_val(x) & (~PAGE_MASK & ~_PAGE_USER)) != _KERNPG_TABLE)
#define pmd_bad(x) (pmd_val(x) & ~PAGE_MASK)
#define pages_to_mb(x) ((x) >> (20-PAGE_SHIFT))
#define pte_page(x) phys_to_page(pte_val(x)&PTE_PHYS_MASK)
@ -477,11 +464,8 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
return pte;
}
#define pmd_page_vaddr(pmd) \
((unsigned long) __va(pmd_val(pmd) & PAGE_MASK))
#define pmd_page(pmd) \
(phys_to_page(pmd_val(pmd)))
#define pmd_page_vaddr(pmd) pmd_val(pmd)
#define pmd_page(pmd) (virt_to_page(pmd_val(pmd)))
/* to find an entry in a page-table-directory. */
#define pgd_index(address) (((address) >> PGDIR_SHIFT) & (PTRS_PER_PGD-1))