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Commit 0f60bb25 authored by Paul Mundt's avatar Paul Mundt
Browse files

sh: Tidy up vmalloc fault handling. 



This rewrites the vmalloc fault handling as per x86, which subsequently
allows for easy future tie-in for vmalloc_sync_all().

Signed-off-by: default avatarPaul Mundt <lethal@linux-sh.org>
parent c63c3105

arch/sh/mm/fault_32.c

+97 −56
Original line number Diff line number Diff line
@@ -2,7 +2,7 @@ 
 * Page fault handler for SH with an MMU.

 *

 *  Copyright (C) 1999  Niibe Yutaka

 *  Copyright (C) 2003 - 2008  Paul Mundt

 *  Copyright (C) 2003 - 2009  Paul Mundt

 *

 *  Based on linux/arch/i386/mm/fault.c:

 *   Copyright (C) 1995  Linus Torvalds
@@ -35,6 +35,74 @@ static inline int notify_page_fault(struct pt_regs *regs, int trap) 
	return ret;

}



static inline pmd_t *vmalloc_sync_one(pgd_t *pgd, unsigned long address)

{

	unsigned index = pgd_index(address);

	pgd_t *pgd_k;

	pud_t *pud, *pud_k;

	pmd_t *pmd, *pmd_k;



	pgd += index;

	pgd_k = init_mm.pgd + index;



	if (!pgd_present(*pgd_k))

		return NULL;



	pud = pud_offset(pgd, address);

	pud_k = pud_offset(pgd_k, address);

	if (!pud_present(*pud_k))

		return NULL;



	pmd = pmd_offset(pud, address);

	pmd_k = pmd_offset(pud_k, address);

	if (!pmd_present(*pmd_k))

		return NULL;



	if (!pmd_present(*pmd))

		set_pmd(pmd, *pmd_k);

	else

		BUG_ON(pmd_page(*pmd) != pmd_page(*pmd_k));



	return pmd_k;

}



/*

 * Handle a fault on the vmalloc or module mapping area

 */

static noinline int vmalloc_fault(unsigned long address)

{

	pgd_t *pgd_k;

	pmd_t *pmd_k;

	pte_t *pte_k;



	/* Make sure we are in vmalloc area: */

	if (!(address >= VMALLOC_START && address < VMALLOC_END))

		return -1;



	/*

	 * Synchronize this task's top level page-table

	 * with the 'reference' page table.

	 *

	 * Do _not_ use "current" here. We might be inside

	 * an interrupt in the middle of a task switch..

	 */

	pgd_k = get_TTB();

	pmd_k = vmalloc_sync_one(__va((unsigned long)pgd_k), address);

	if (!pmd_k)

		return -1;



	pte_k = pte_offset_kernel(pmd_k, address);

	if (!pte_present(*pte_k))

		return -1;



	return 0;

}



static int fault_in_kernel_space(unsigned long address)

{

	return address >= TASK_SIZE;

}



/*

 * This routine handles page faults.  It determines the address,

 * and the problem, and then passes it off to one of the appropriate
@@ -44,6 +112,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, 
					unsigned long writeaccess,

					unsigned long address)

{

	unsigned long vec;

	struct task_struct *tsk;

	struct mm_struct *mm;

	struct vm_area_struct * vma;
@@ -51,59 +120,30 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, 
	int fault;

	siginfo_t info;



	/*

	 * We don't bother with any notifier callbacks here, as they are

	 * all handled through the __do_page_fault() fast-path.

	 */



	tsk = current;

	mm = tsk->mm;

	si_code = SEGV_MAPERR;

	vec = lookup_exception_vector();



	if (unlikely(address >= TASK_SIZE)) {

	/*

		 * Synchronize this task's top level page-table

		 * with the 'reference' page table.

	 * We fault-in kernel-space virtual memory on-demand. The

	 * 'reference' page table is init_mm.pgd.

	 *

		 * Do _not_ use "tsk" here. We might be inside

		 * an interrupt in the middle of a task switch..

	 * NOTE! We MUST NOT take any locks for this case. We may

	 * be in an interrupt or a critical region, and should

	 * only copy the information from the master page table,

	 * nothing more.

	 */

		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;



		if (!pgd_present(*pgd)) {

			if (!pgd_present(*pgd_k))

				goto bad_area_nosemaphore;

			set_pgd(pgd, *pgd_k);

	if (unlikely(fault_in_kernel_space(address))) {

		if (vmalloc_fault(address) >= 0)

			return;

		}



		pud = pud_offset(pgd, address);

		pud_k = pud_offset(pgd_k, address);



		if (!pud_present(*pud)) {

			if (!pud_present(*pud_k))

				goto bad_area_nosemaphore;

			set_pud(pud, *pud_k);

		if (notify_page_fault(regs, vec))

			return;

		}



		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;

	}



	mm = tsk->mm;



	if (unlikely(notify_page_fault(regs, lookup_exception_vector())))

	if (unlikely(notify_page_fault(regs, vec)))

		return;



	/* Only enable interrupts if they were on before the fault */
@@ -113,8 +153,8 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, 
	perf_swcounter_event(PERF_COUNT_SW_PAGE_FAULTS, 1, 0, regs, address);



	/*

	 * If we're in an interrupt or have no user

	 * context, we must not take the fault..

	 * If we're in an interrupt, have no user context or are running

	 * in an atomic region then we must not take the fault:

	 */

	if (in_atomic() || !mm)

		goto no_context;
@@ -130,6 +170,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, 
		goto bad_area;

	if (expand_stack(vma, address))

		goto bad_area;



	/*

	 * Ok, we have a good vm_area for this memory access, so

	 * we can handle it..