Commit 60ec5585 authored by Hugh Dickins's avatar Hugh Dickins Committed by Linus Torvalds
Browse files

[PATCH] mm: i386 sh sh64 ready for split ptlock 



Use pte_offset_map_lock, instead of pte_offset_map (or inappropriate
pte_offset_kernel) and mm-wide page_table_lock, in sundry arch places.

The i386 vm86 mark_screen_rdonly: yes, there was and is an assumption that the
screen fits inside the one page table, as indeed it does.

The sh __do_page_fault: which handles both kernel faults (without lock) and
user mm faults (locked - though it set_pte without locking before).

The sh64 flush_cache_range and helpers: which wrongly thought callers held
page_table_lock before (only its tlb_start_vma did, and no longer does so);
moved the flush loop down, and adjusted the large versus small range decision
to consider a range which spans page tables as large.

Signed-off-by: default avatarHugh Dickins <hugh@veritas.com>
Acked-by: default avatarPaul Mundt <lethal@linux-sh.org>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent deceb6cd

arch/i386/kernel/vm86.c

+7 −10
Original line number Diff line number Diff line
@@ -134,17 +134,16 @@ struct pt_regs * fastcall save_v86_state(struct kernel_vm86_regs * regs) 
	return ret;

}



static void mark_screen_rdonly(struct task_struct * tsk)

static void mark_screen_rdonly(struct mm_struct *mm)

{

	pgd_t *pgd;

	pud_t *pud;

	pmd_t *pmd;

	pte_t *pte, *mapped;

	pte_t *pte;

	spinlock_t *ptl;

	int i;



	preempt_disable();

	spin_lock(&tsk->mm->page_table_lock);

	pgd = pgd_offset(tsk->mm, 0xA0000);

	pgd = pgd_offset(mm, 0xA0000);

	if (pgd_none_or_clear_bad(pgd))

		goto out;

	pud = pud_offset(pgd, 0xA0000);
@@ -153,16 +152,14 @@ static void mark_screen_rdonly(struct task_struct * tsk) 
	pmd = pmd_offset(pud, 0xA0000);

	if (pmd_none_or_clear_bad(pmd))

		goto out;

	pte = mapped = pte_offset_map(pmd, 0xA0000);

	pte = pte_offset_map_lock(mm, pmd, 0xA0000, &ptl);

	for (i = 0; i < 32; i++) {

		if (pte_present(*pte))

			set_pte(pte, pte_wrprotect(*pte));

		pte++;

	}

	pte_unmap(mapped);

	pte_unmap_unlock(pte, ptl);

out:

	spin_unlock(&tsk->mm->page_table_lock);

	preempt_enable();

	flush_tlb();

}
@@ -306,7 +303,7 @@ static void do_sys_vm86(struct kernel_vm86_struct *info, struct task_struct *tsk 


	tsk->thread.screen_bitmap = info->screen_bitmap;

	if (info->flags & VM86_SCREEN_BITMAP)

		mark_screen_rdonly(tsk);

		mark_screen_rdonly(tsk->mm);

	__asm__ __volatile__(

		"xorl %%eax,%%eax; movl %%eax,%%fs; movl %%eax,%%gs\n\t"

		"movl %0,%%esp\n\t"

arch/sh/mm/fault.c

+23 −17
Original line number Diff line number Diff line
@@ -194,10 +194,13 @@ asmlinkage int __do_page_fault(struct pt_regs *regs, unsigned long writeaccess, 
			       unsigned long address)

{

	unsigned long addrmax = P4SEG;

	pgd_t *dir;

	pgd_t *pgd;

	pmd_t *pmd;

	pte_t *pte;

	pte_t entry;

	struct mm_struct *mm;

	spinlock_t *ptl;

	int ret = 1;



#ifdef CONFIG_SH_KGDB

	if (kgdb_nofault && kgdb_bus_err_hook)
@@ -208,28 +211,28 @@ asmlinkage int __do_page_fault(struct pt_regs *regs, unsigned long writeaccess, 
	addrmax = P4SEG_STORE_QUE + 0x04000000;

#endif



	if (address >= P3SEG && address < addrmax)

		dir = pgd_offset_k(address);

	else if (address >= TASK_SIZE)

	if (address >= P3SEG && address < addrmax) {

		pgd = pgd_offset_k(address);

		mm = NULL;

	} else if (address >= TASK_SIZE)

		return 1;

	else if (!current->mm)

	else if (!(mm = current->mm))

		return 1;

	else

		dir = pgd_offset(current->mm, address);

		pgd = pgd_offset(mm, address);



	pmd = pmd_offset(dir, address);

	if (pmd_none(*pmd))

		return 1;

	if (pmd_bad(*pmd)) {

		pmd_ERROR(*pmd);

		pmd_clear(pmd);

	pmd = pmd_offset(pgd, address);

	if (pmd_none_or_clear_bad(pmd))

		return 1;

	}

	if (mm)

		pte = pte_offset_map_lock(mm, pmd, address, &ptl);

	else

		pte = pte_offset_kernel(pmd, address);



	entry = *pte;

	if (pte_none(entry) || pte_not_present(entry)

	    || (writeaccess && !pte_write(entry)))

		return 1;

		goto unlock;



	if (writeaccess)

		entry = pte_mkdirty(entry);
@@ -251,8 +254,11 @@ asmlinkage int __do_page_fault(struct pt_regs *regs, unsigned long writeaccess, 


	set_pte(pte, entry);

	update_mmu_cache(NULL, address, entry);



	return 0;

	ret = 0;

unlock:

	if (mm)

		pte_unmap_unlock(pte, ptl);

	return ret;

}



void flush_tlb_page(struct vm_area_struct *vma, unsigned long page)

arch/sh64/mm/cache.c

+30 −38
Original line number Diff line number Diff line
@@ -584,32 +584,36 @@ static void sh64_dcache_purge_phy_page(unsigned long paddr) 
	}

}



static void sh64_dcache_purge_user_page(struct mm_struct *mm, unsigned long eaddr)

static void sh64_dcache_purge_user_pages(struct mm_struct *mm,

				unsigned long addr, unsigned long end)

{

	pgd_t *pgd;

	pmd_t *pmd;

	pte_t *pte;

	pte_t entry;

	spinlock_t *ptl;

	unsigned long paddr;



	/* NOTE : all the callers of this have mm->page_table_lock held, so the

	   following page table traversal is safe even on SMP/pre-emptible. */

	if (!mm)

		return; /* No way to find physical address of page */



	if (!mm) return; /* No way to find physical address of page */

	pgd = pgd_offset(mm, eaddr);

	if (pgd_bad(*pgd)) return;

	pgd = pgd_offset(mm, addr);

	if (pgd_bad(*pgd))

		return;



	pmd = pmd_offset(pgd, eaddr);

	if (pmd_none(*pmd) || pmd_bad(*pmd)) return;

	pmd = pmd_offset(pgd, addr);

	if (pmd_none(*pmd) || pmd_bad(*pmd))

		return;



	pte = pte_offset_kernel(pmd, eaddr);

	pte = pte_offset_map_lock(mm, pmd, addr, &ptl);

	do {

		entry = *pte;

	if (pte_none(entry) || !pte_present(entry)) return;



		if (pte_none(entry) || !pte_present(entry))

			continue;

		paddr = pte_val(entry) & PAGE_MASK;



	sh64_dcache_purge_coloured_phy_page(paddr, eaddr);



		sh64_dcache_purge_coloured_phy_page(paddr, addr);

	} while (pte++, addr += PAGE_SIZE, addr != end);

	pte_unmap_unlock(pte - 1, ptl);

}

/****************************************************************************/
@@ -668,7 +672,7 @@ static void sh64_dcache_purge_user_range(struct mm_struct *mm, 
	int n_pages;



	n_pages = ((end - start) >> PAGE_SHIFT);

	if (n_pages >= 64) {

	if (n_pages >= 64 || ((start ^ (end - 1)) & PMD_MASK)) {

#if 1

		sh64_dcache_purge_all();

#else
@@ -707,20 +711,10 @@ static void sh64_dcache_purge_user_range(struct mm_struct *mm, 
		}

#endif

	} else {

		/* 'Small' range */

		unsigned long aligned_start;

		unsigned long eaddr;

		unsigned long last_page_start;



		aligned_start = start & PAGE_MASK;

		/* 'end' is 1 byte beyond the end of the range */

		last_page_start = (end - 1) & PAGE_MASK;



		eaddr = aligned_start;

		while (eaddr <= last_page_start) {

			sh64_dcache_purge_user_page(mm, eaddr);

			eaddr += PAGE_SIZE;

		}

		/* Small range, covered by a single page table page */

		start &= PAGE_MASK;	/* should already be so */

		end = PAGE_ALIGN(end);	/* should already be so */

		sh64_dcache_purge_user_pages(mm, start, end);

	}

	return;

}
@@ -880,9 +874,7 @@ void flush_cache_range(struct vm_area_struct *vma, unsigned long start, 
	   addresses from the user address space specified by mm, after writing

	   back any dirty data.



	   Note(1), 'end' is 1 byte beyond the end of the range to flush.



	   Note(2), this is called with mm->page_table_lock held.*/

	   Note, 'end' is 1 byte beyond the end of the range to flush. */



	sh64_dcache_purge_user_range(mm, start, end);

	sh64_icache_inv_user_page_range(mm, start, end);
@@ -898,7 +890,7 @@ void flush_cache_page(struct vm_area_struct *vma, unsigned long eaddr, unsigned 
	   the I-cache must be searched too in case the page in question is

	   both writable and being executed from (e.g. stack trampolines.)



	   Note(1), this is called with mm->page_table_lock held.

	   Note, this is called with pte lock held.

	   */



	sh64_dcache_purge_phy_page(pfn << PAGE_SHIFT);

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