arch/xtensa/mm/tlb.c - linux - Git at Google

 /*
  * arch/xtensa/mm/tlb.c
  *
  * Logic that manipulates the Xtensa MMU.  Derived from MIPS.
  *
  * This file is subject to the terms and conditions of the GNU General Public
  * License.  See the file "COPYING" in the main directory of this archive
  * for more details.
  *
  * Copyright (C) 2001 - 2003 Tensilica Inc.
  *
  * Joe Taylor
  * Chris Zankel	<chris@zankel.net>
  * Marc Gauthier
  */

 #include <linux/mm.h>
 #include <asm/processor.h>
 #include <asm/mmu_context.h>
 #include <asm/tlbflush.h>
 #include <asm/cacheflush.h>


 static inline void __flush_itlb_all (void)
 {
 	int w, i;

 	for (w = 0; w < ITLB_ARF_WAYS; w++) {
 		for (i = 0; i < (1 << XCHAL_ITLB_ARF_ENTRIES_LOG2); i++) {
 			int e = w + (i << PAGE_SHIFT);
 			invalidate_itlb_entry_no_isync(e);
 		}
 	}
 	asm volatile ("isync\n");
 }

 static inline void __flush_dtlb_all (void)
 {
 	int w, i;

 	for (w = 0; w < DTLB_ARF_WAYS; w++) {
 		for (i = 0; i < (1 << XCHAL_DTLB_ARF_ENTRIES_LOG2); i++) {
 			int e = w + (i << PAGE_SHIFT);
 			invalidate_dtlb_entry_no_isync(e);
 		}
 	}
 	asm volatile ("isync\n");
 }


 void local_flush_tlb_all(void)
 {
 	__flush_itlb_all();
 	__flush_dtlb_all();
 }

 /* If mm is current, we simply assign the current task a new ASID, thus,
  * invalidating all previous tlb entries. If mm is someone else's user mapping,
  * wie invalidate the context, thus, when that user mapping is swapped in,
  * a new context will be assigned to it.
  */

 void local_flush_tlb_mm(struct mm_struct *mm)
 {
 	int cpu = smp_processor_id();

 	if (mm == current->active_mm) {
 		unsigned long flags;
 		local_irq_save(flags);
 		mm->context.asid[cpu] = NO_CONTEXT;
 		activate_context(mm, cpu);
 		local_irq_restore(flags);
 	} else {
 		mm->context.asid[cpu] = NO_CONTEXT;
 		mm->context.cpu = -1;
 	}
 }


 #define _ITLB_ENTRIES (ITLB_ARF_WAYS << XCHAL_ITLB_ARF_ENTRIES_LOG2)
 #define _DTLB_ENTRIES (DTLB_ARF_WAYS << XCHAL_DTLB_ARF_ENTRIES_LOG2)
 #if _ITLB_ENTRIES > _DTLB_ENTRIES
 # define _TLB_ENTRIES _ITLB_ENTRIES
 #else
 # define _TLB_ENTRIES _DTLB_ENTRIES
 #endif

 void local_flush_tlb_range(struct vm_area_struct *vma,
 		unsigned long start, unsigned long end)
 {
 	int cpu = smp_processor_id();
 	struct mm_struct *mm = vma->vm_mm;
 	unsigned long flags;

 	if (mm->context.asid[cpu] == NO_CONTEXT)
 		return;

 	pr_debug("[tlbrange<%02lx,%08lx,%08lx>]\n",
 		 (unsigned long)mm->context.asid[cpu], start, end);
 	local_irq_save(flags);

 	if (end-start + (PAGE_SIZE-1) <= _TLB_ENTRIES << PAGE_SHIFT) {
 		int oldpid = get_rasid_register();

 		set_rasid_register(ASID_INSERT(mm->context.asid[cpu]));
 		start &= PAGE_MASK;
 		if (vma->vm_flags & VM_EXEC)
 			while(start < end) {
 				invalidate_itlb_mapping(start);
 				invalidate_dtlb_mapping(start);
 				start += PAGE_SIZE;
 			}
 		else
 			while(start < end) {
 				invalidate_dtlb_mapping(start);
 				start += PAGE_SIZE;
 			}

 		set_rasid_register(oldpid);
 	} else {
 		local_flush_tlb_mm(mm);
 	}
 	local_irq_restore(flags);
 }

 void local_flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
 {
 	int cpu = smp_processor_id();
 	struct mm_struct* mm = vma->vm_mm;
 	unsigned long flags;
 	int oldpid;

 	if (mm->context.asid[cpu] == NO_CONTEXT)
 		return;

 	local_irq_save(flags);

 	oldpid = get_rasid_register();
 	set_rasid_register(ASID_INSERT(mm->context.asid[cpu]));

 	if (vma->vm_flags & VM_EXEC)
 		invalidate_itlb_mapping(page);
 	invalidate_dtlb_mapping(page);

 	set_rasid_register(oldpid);

 	local_irq_restore(flags);
 }

 void local_flush_tlb_kernel_range(unsigned long start, unsigned long end)
 {
 	if (end > start && start >= TASK_SIZE && end <= PAGE_OFFSET &&
 	    end - start < _TLB_ENTRIES << PAGE_SHIFT) {
 		start &= PAGE_MASK;
 		while (start < end) {
 			invalidate_itlb_mapping(start);
 			invalidate_dtlb_mapping(start);
 			start += PAGE_SIZE;
 		}
 	} else {
 		local_flush_tlb_all();
 	}
 }

 #ifdef CONFIG_DEBUG_TLB_SANITY

 static unsigned get_pte_for_vaddr(unsigned vaddr)
 {
 	struct task_struct *task = get_current();
 	struct mm_struct *mm = task->mm;
 	pgd_t *pgd;
 	pmd_t *pmd;
 	pte_t *pte;

 	if (!mm)
 		mm = task->active_mm;
 	pgd = pgd_offset(mm, vaddr);
 	if (pgd_none_or_clear_bad(pgd))
 		return 0;
 	pmd = pmd_offset(pgd, vaddr);
 	if (pmd_none_or_clear_bad(pmd))
 		return 0;
 	pte = pte_offset_map(pmd, vaddr);
 	if (!pte)
 		return 0;
 	return pte_val(*pte);
 }

 enum {
 	TLB_SUSPICIOUS	= 1,
 	TLB_INSANE	= 2,
 };

 static void tlb_insane(void)
 {
 	BUG_ON(1);
 }

 static void tlb_suspicious(void)
 {
 	WARN_ON(1);
 }

 /*
  * Check that TLB entries with kernel ASID (1) have kernel VMA (>= TASK_SIZE),
  * and TLB entries with user ASID (>=4) have VMA < TASK_SIZE.
  *
  * Check that valid TLB entries either have the same PA as the PTE, or PTE is
  * marked as non-present. Non-present PTE and the page with non-zero refcount
  * and zero mapcount is normal for batched TLB flush operation. Zero refcount
  * means that the page was freed prematurely. Non-zero mapcount is unusual,
  * but does not necessary means an error, thus marked as suspicious.
  */
 static int check_tlb_entry(unsigned w, unsigned e, bool dtlb)
 {
 	unsigned tlbidx = w | (e << PAGE_SHIFT);
 	unsigned r0 = dtlb ?
 		read_dtlb_virtual(tlbidx) : read_itlb_virtual(tlbidx);
 	unsigned vpn = (r0 & PAGE_MASK) | (e << PAGE_SHIFT);
 	unsigned pte = get_pte_for_vaddr(vpn);
 	unsigned mm_asid = (get_rasid_register() >> 8) & ASID_MASK;
 	unsigned tlb_asid = r0 & ASID_MASK;
 	bool kernel = tlb_asid == 1;
 	int rc = 0;

 	if (tlb_asid > 0 && ((vpn < TASK_SIZE) == kernel)) {
 		pr_err("%cTLB: way: %u, entry: %u, VPN %08x in %s PTE\n",
 				dtlb ? 'D' : 'I', w, e, vpn,
 				kernel ? "kernel" : "user");
 		rc |= TLB_INSANE;
 	}

 	if (tlb_asid == mm_asid) {
 		unsigned r1 = dtlb ? read_dtlb_translation(tlbidx) :
 			read_itlb_translation(tlbidx);
 		if ((pte ^ r1) & PAGE_MASK) {
 			pr_err("%cTLB: way: %u, entry: %u, mapping: %08x->%08x, PTE: %08x\n",
 					dtlb ? 'D' : 'I', w, e, r0, r1, pte);
 			if (pte == 0 || !pte_present(__pte(pte))) {
 				struct page *p = pfn_to_page(r1 >> PAGE_SHIFT);
 				pr_err("page refcount: %d, mapcount: %d\n",
 						page_count(p),
 						page_mapcount(p));
 				if (!page_count(p))
 					rc |= TLB_INSANE;
 				else if (page_mapcount(p))
 					rc |= TLB_SUSPICIOUS;
 			} else {
 				rc |= TLB_INSANE;
 			}
 		}
 	}
 	return rc;
 }

 void check_tlb_sanity(void)
 {
 	unsigned long flags;
 	unsigned w, e;
 	int bug = 0;

 	local_irq_save(flags);
 	for (w = 0; w < DTLB_ARF_WAYS; ++w)
 		for (e = 0; e < (1 << XCHAL_DTLB_ARF_ENTRIES_LOG2); ++e)
 			bug |= check_tlb_entry(w, e, true);
 	for (w = 0; w < ITLB_ARF_WAYS; ++w)
 		for (e = 0; e < (1 << XCHAL_ITLB_ARF_ENTRIES_LOG2); ++e)
 			bug |= check_tlb_entry(w, e, false);
 	if (bug & TLB_INSANE)
 		tlb_insane();
 	if (bug & TLB_SUSPICIOUS)
 		tlb_suspicious();
 	local_irq_restore(flags);
 }

 #endif /* CONFIG_DEBUG_TLB_SANITY */
	/*
	* arch/xtensa/mm/tlb.c
	*
	* Logic that manipulates the Xtensa MMU. Derived from MIPS.
	*
	* This file is subject to the terms and conditions of the GNU General Public
	* License. See the file "COPYING" in the main directory of this archive
	* for more details.
	*
	* Copyright (C) 2001 - 2003 Tensilica Inc.
	*
	* Joe Taylor
	* Chris Zankel <chris@zankel.net>
	* Marc Gauthier
	*/

	#include <linux/mm.h>
	#include <asm/processor.h>
	#include <asm/mmu_context.h>
	#include <asm/tlbflush.h>
	#include <asm/cacheflush.h>


	static inline void __flush_itlb_all (void)
	{
	int w, i;

	for (w = 0; w < ITLB_ARF_WAYS; w++) {
	for (i = 0; i < (1 << XCHAL_ITLB_ARF_ENTRIES_LOG2); i++) {
	int e = w + (i << PAGE_SHIFT);
	invalidate_itlb_entry_no_isync(e);
	}
	}
	asm volatile ("isync\n");
	}

	static inline void __flush_dtlb_all (void)
	{
	int w, i;

	for (w = 0; w < DTLB_ARF_WAYS; w++) {
	for (i = 0; i < (1 << XCHAL_DTLB_ARF_ENTRIES_LOG2); i++) {
	int e = w + (i << PAGE_SHIFT);
	invalidate_dtlb_entry_no_isync(e);
	}
	}
	asm volatile ("isync\n");
	}


	void local_flush_tlb_all(void)
	{
	__flush_itlb_all();
	__flush_dtlb_all();
	}

	/* If mm is current, we simply assign the current task a new ASID, thus,
	* invalidating all previous tlb entries. If mm is someone else's user mapping,
	* wie invalidate the context, thus, when that user mapping is swapped in,
	* a new context will be assigned to it.
	*/

	void local_flush_tlb_mm(struct mm_struct *mm)
	{
	int cpu = smp_processor_id();

	if (mm == current->active_mm) {
	unsigned long flags;
	local_irq_save(flags);
	mm->context.asid[cpu] = NO_CONTEXT;
	activate_context(mm, cpu);
	local_irq_restore(flags);
	} else {
	mm->context.asid[cpu] = NO_CONTEXT;
	mm->context.cpu = -1;
	}
	}


	#define _ITLB_ENTRIES (ITLB_ARF_WAYS << XCHAL_ITLB_ARF_ENTRIES_LOG2)
	#define _DTLB_ENTRIES (DTLB_ARF_WAYS << XCHAL_DTLB_ARF_ENTRIES_LOG2)
	#if _ITLB_ENTRIES > _DTLB_ENTRIES
	# define _TLB_ENTRIES _ITLB_ENTRIES
	#else
	# define _TLB_ENTRIES _DTLB_ENTRIES
	#endif

	void local_flush_tlb_range(struct vm_area_struct *vma,
	unsigned long start, unsigned long end)
	{
	int cpu = smp_processor_id();
	struct mm_struct *mm = vma->vm_mm;
	unsigned long flags;

	if (mm->context.asid[cpu] == NO_CONTEXT)
	return;

	pr_debug("[tlbrange<%02lx,%08lx,%08lx>]\n",
	(unsigned long)mm->context.asid[cpu], start, end);
	local_irq_save(flags);

	if (end-start + (PAGE_SIZE-1) <= _TLB_ENTRIES << PAGE_SHIFT) {
	int oldpid = get_rasid_register();

	set_rasid_register(ASID_INSERT(mm->context.asid[cpu]));
	start &= PAGE_MASK;
	if (vma->vm_flags & VM_EXEC)
	while(start < end) {
	invalidate_itlb_mapping(start);
	invalidate_dtlb_mapping(start);
	start += PAGE_SIZE;
	}
	else
	while(start < end) {
	invalidate_dtlb_mapping(start);
	start += PAGE_SIZE;
	}

	set_rasid_register(oldpid);
	} else {
	local_flush_tlb_mm(mm);
	}
	local_irq_restore(flags);
	}

	void local_flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
	{
	int cpu = smp_processor_id();
	struct mm_struct* mm = vma->vm_mm;
	unsigned long flags;
	int oldpid;

	if (mm->context.asid[cpu] == NO_CONTEXT)
	return;

	local_irq_save(flags);

	oldpid = get_rasid_register();
	set_rasid_register(ASID_INSERT(mm->context.asid[cpu]));

	if (vma->vm_flags & VM_EXEC)
	invalidate_itlb_mapping(page);
	invalidate_dtlb_mapping(page);

	set_rasid_register(oldpid);

	local_irq_restore(flags);
	}

	void local_flush_tlb_kernel_range(unsigned long start, unsigned long end)
	{
	if (end > start && start >= TASK_SIZE && end <= PAGE_OFFSET &&
	end - start < _TLB_ENTRIES << PAGE_SHIFT) {
	start &= PAGE_MASK;
	while (start < end) {
	invalidate_itlb_mapping(start);
	invalidate_dtlb_mapping(start);
	start += PAGE_SIZE;
	}
	} else {
	local_flush_tlb_all();
	}
	}

	#ifdef CONFIG_DEBUG_TLB_SANITY

	static unsigned get_pte_for_vaddr(unsigned vaddr)
	{
	struct task_struct *task = get_current();
	struct mm_struct *mm = task->mm;
	pgd_t *pgd;
	pmd_t *pmd;
	pte_t *pte;

	if (!mm)
	mm = task->active_mm;
	pgd = pgd_offset(mm, vaddr);
	if (pgd_none_or_clear_bad(pgd))
	return 0;
	pmd = pmd_offset(pgd, vaddr);
	if (pmd_none_or_clear_bad(pmd))
	return 0;
	pte = pte_offset_map(pmd, vaddr);
	if (!pte)
	return 0;
	return pte_val(*pte);
	}

	enum {
	TLB_SUSPICIOUS = 1,
	TLB_INSANE = 2,
	};

	static void tlb_insane(void)
	{
	BUG_ON(1);
	}

	static void tlb_suspicious(void)
	{
	WARN_ON(1);
	}

	/*
	* Check that TLB entries with kernel ASID (1) have kernel VMA (>= TASK_SIZE),
	* and TLB entries with user ASID (>=4) have VMA < TASK_SIZE.
	*
	* Check that valid TLB entries either have the same PA as the PTE, or PTE is
	* marked as non-present. Non-present PTE and the page with non-zero refcount
	* and zero mapcount is normal for batched TLB flush operation. Zero refcount
	* means that the page was freed prematurely. Non-zero mapcount is unusual,
	* but does not necessary means an error, thus marked as suspicious.
	*/
	static int check_tlb_entry(unsigned w, unsigned e, bool dtlb)
	{
	unsigned tlbidx = w \| (e << PAGE_SHIFT);
	unsigned r0 = dtlb ?
	read_dtlb_virtual(tlbidx) : read_itlb_virtual(tlbidx);
	unsigned vpn = (r0 & PAGE_MASK) \| (e << PAGE_SHIFT);
	unsigned pte = get_pte_for_vaddr(vpn);
	unsigned mm_asid = (get_rasid_register() >> 8) & ASID_MASK;
	unsigned tlb_asid = r0 & ASID_MASK;
	bool kernel = tlb_asid == 1;
	int rc = 0;

	if (tlb_asid > 0 && ((vpn < TASK_SIZE) == kernel)) {
	pr_err("%cTLB: way: %u, entry: %u, VPN %08x in %s PTE\n",
	dtlb ? 'D' : 'I', w, e, vpn,
	kernel ? "kernel" : "user");
	rc \|= TLB_INSANE;
	}

	if (tlb_asid == mm_asid) {
	unsigned r1 = dtlb ? read_dtlb_translation(tlbidx) :
	read_itlb_translation(tlbidx);
	if ((pte ^ r1) & PAGE_MASK) {
	pr_err("%cTLB: way: %u, entry: %u, mapping: %08x->%08x, PTE: %08x\n",
	dtlb ? 'D' : 'I', w, e, r0, r1, pte);
	if (pte == 0 \|\| !pte_present(__pte(pte))) {
	struct page *p = pfn_to_page(r1 >> PAGE_SHIFT);
	pr_err("page refcount: %d, mapcount: %d\n",
	page_count(p),
	page_mapcount(p));
	if (!page_count(p))
	rc \|= TLB_INSANE;
	else if (page_mapcount(p))
	rc \|= TLB_SUSPICIOUS;
	} else {
	rc \|= TLB_INSANE;
	}
	}
	}
	return rc;
	}

	void check_tlb_sanity(void)
	{
	unsigned long flags;
	unsigned w, e;
	int bug = 0;

	local_irq_save(flags);
	for (w = 0; w < DTLB_ARF_WAYS; ++w)
	for (e = 0; e < (1 << XCHAL_DTLB_ARF_ENTRIES_LOG2); ++e)
	bug \|= check_tlb_entry(w, e, true);
	for (w = 0; w < ITLB_ARF_WAYS; ++w)
	for (e = 0; e < (1 << XCHAL_ITLB_ARF_ENTRIES_LOG2); ++e)
	bug \|= check_tlb_entry(w, e, false);
	if (bug & TLB_INSANE)
	tlb_insane();
	if (bug & TLB_SUSPICIOUS)
	tlb_suspicious();
	local_irq_restore(flags);
	}

	#endif /* CONFIG_DEBUG_TLB_SANITY */