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Commit 99a596f9 authored by Stuart Menefy's avatar Stuart Menefy Committed by Paul Mundt
Browse files

sh: pmd rework. 



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: default avatarStuart Menefy <stuart.menefy@st.com>
Signed-off-by: default avatarPaul Mundt <lethal@linux-sh.org>
parent 6e4662ff

arch/sh/mm/fault.c

+40 −0
Original line number Diff line number Diff line
@@ -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;

arch/sh/mm/init.c

+9 −17
Original line number Diff line number Diff line
@@ -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)) {

include/asm-sh/pgalloc.h

+16 −4
Original line number Diff line number Diff line 
#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)

include/asm-sh/pgtable.h

+11 −27
Original line number Diff line number Diff line
@@ -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))