arch/m68k/mm/mcfmmu.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * Based upon linux/arch/m68k/mm/sun3mmu.c
  * Based upon linux/arch/ppc/mm/mmu_context.c
  *
  * Implementations of mm routines specific to the Coldfire MMU.
  *
  * Copyright (c) 2008 Freescale Semiconductor, Inc.
  */

 #include <linux/kernel.h>
 #include <linux/types.h>
 #include <linux/mm.h>
 #include <linux/init.h>
 #include <linux/string.h>
 #include <linux/memblock.h>

 #include <asm/setup.h>
 #include <asm/page.h>
 #include <asm/mmu_context.h>
 #include <asm/mcf_pgalloc.h>
 #include <asm/tlbflush.h>
 #include <asm/pgalloc.h>

 #define KMAPAREA(x)	((x >= VMALLOC_START) && (x < KMAP_END))

 mm_context_t next_mmu_context;
 unsigned long context_map[LAST_CONTEXT / BITS_PER_LONG + 1];
 atomic_t nr_free_contexts;
 struct mm_struct *context_mm[LAST_CONTEXT+1];
 unsigned long num_pages;

 /*
  * ColdFire paging_init derived from sun3.
  */
 void __init paging_init(void)
 {
 	pgd_t *pg_dir;
 	pte_t *pg_table;
 	unsigned long address, size;
 	unsigned long next_pgtable, bootmem_end;
 	unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 };
 	int i;

 	empty_zero_page = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
 	if (!empty_zero_page)
 		panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
 		      __func__, PAGE_SIZE, PAGE_SIZE);

 	pg_dir = swapper_pg_dir;
 	memset(swapper_pg_dir, 0, sizeof(swapper_pg_dir));

 	size = num_pages * sizeof(pte_t);
 	size = (size + PAGE_SIZE) & ~(PAGE_SIZE-1);
 	next_pgtable = (unsigned long) memblock_alloc(size, PAGE_SIZE);
 	if (!next_pgtable)
 		panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
 		      __func__, size, PAGE_SIZE);

 	bootmem_end = (next_pgtable + size + PAGE_SIZE) & PAGE_MASK;
 	pg_dir += PAGE_OFFSET >> PGDIR_SHIFT;

 	address = PAGE_OFFSET;
 	while (address < (unsigned long)high_memory) {
 		pg_table = (pte_t *) next_pgtable;
 		next_pgtable += PTRS_PER_PTE * sizeof(pte_t);
 		pgd_val(*pg_dir) = (unsigned long) pg_table;
 		pg_dir++;

 		/* now change pg_table to kernel virtual addresses */
 		for (i = 0; i < PTRS_PER_PTE; ++i, ++pg_table) {
 			pte_t pte = pfn_pte(virt_to_pfn(address), PAGE_INIT);
 			if (address >= (unsigned long) high_memory)
 				pte_val(pte) = 0;

 			set_pte(pg_table, pte);
 			address += PAGE_SIZE;
 		}
 	}

 	current->mm = NULL;
 	max_zone_pfn[ZONE_DMA] = PFN_DOWN(_ramend);
 	free_area_init(max_zone_pfn);
 }

 int cf_tlb_miss(struct pt_regs *regs, int write, int dtlb, int extension_word)
 {
 	unsigned long flags, mmuar, mmutr;
 	struct mm_struct *mm;
 	pgd_t *pgd;
 	p4d_t *p4d;
 	pud_t *pud;
 	pmd_t *pmd;
 	pte_t *pte;
 	int asid;

 	local_irq_save(flags);

 	mmuar = (dtlb) ? mmu_read(MMUAR) :
 		regs->pc + (extension_word * sizeof(long));

 	mm = (!user_mode(regs) && KMAPAREA(mmuar)) ? &init_mm : current->mm;
 	if (!mm) {
 		local_irq_restore(flags);
 		return -1;
 	}

 	pgd = pgd_offset(mm, mmuar);
 	if (pgd_none(*pgd))  {
 		local_irq_restore(flags);
 		return -1;
 	}

 	p4d = p4d_offset(pgd, mmuar);
 	if (p4d_none(*p4d)) {
 		local_irq_restore(flags);
 		return -1;
 	}

 	pud = pud_offset(p4d, mmuar);
 	if (pud_none(*pud)) {
 		local_irq_restore(flags);
 		return -1;
 	}

 	pmd = pmd_offset(pud, mmuar);
 	if (pmd_none(*pmd)) {
 		local_irq_restore(flags);
 		return -1;
 	}

 	pte = (KMAPAREA(mmuar)) ? pte_offset_kernel(pmd, mmuar)
 				: pte_offset_map(pmd, mmuar);
 	if (pte_none(*pte) || !pte_present(*pte)) {
 		local_irq_restore(flags);
 		return -1;
 	}

 	if (write) {
 		if (!pte_write(*pte)) {
 			local_irq_restore(flags);
 			return -1;
 		}
 		set_pte(pte, pte_mkdirty(*pte));
 	}

 	set_pte(pte, pte_mkyoung(*pte));
 	asid = mm->context & 0xff;
 	if (!pte_dirty(*pte) && !KMAPAREA(mmuar))
 		set_pte(pte, pte_wrprotect(*pte));

 	mmutr = (mmuar & PAGE_MASK) | (asid << MMUTR_IDN) | MMUTR_V;
 	if ((mmuar < TASK_UNMAPPED_BASE) || (mmuar >= TASK_SIZE))
 		mmutr |= (pte->pte & CF_PAGE_MMUTR_MASK) >> CF_PAGE_MMUTR_SHIFT;
 	mmu_write(MMUTR, mmutr);

 	mmu_write(MMUDR, (pte_val(*pte) & PAGE_MASK) |
 		((pte->pte) & CF_PAGE_MMUDR_MASK) | MMUDR_SZ_8KB | MMUDR_X);

 	if (dtlb)
 		mmu_write(MMUOR, MMUOR_ACC | MMUOR_UAA);
 	else
 		mmu_write(MMUOR, MMUOR_ITLB | MMUOR_ACC | MMUOR_UAA);

 	local_irq_restore(flags);
 	return 0;
 }

 void __init cf_bootmem_alloc(void)
 {
 	unsigned long memstart;

 	/* _rambase and _ramend will be naturally page aligned */
 	m68k_memory[0].addr = _rambase;
 	m68k_memory[0].size = _ramend - _rambase;

 	memblock_add_node(m68k_memory[0].addr, m68k_memory[0].size, 0,
 			  MEMBLOCK_NONE);

 	/* compute total pages in system */
 	num_pages = PFN_DOWN(_ramend - _rambase);

 	/* page numbers */
 	memstart = PAGE_ALIGN(_ramstart);
 	min_low_pfn = PFN_DOWN(_rambase);
 	max_pfn = max_low_pfn = PFN_DOWN(_ramend);
 	high_memory = (void *)_ramend;

 	/* Reserve kernel text/data/bss */
 	memblock_reserve(_rambase, memstart - _rambase);

 	m68k_virt_to_node_shift = fls(_ramend - 1) - 6;
 	module_fixup(NULL, __start_fixup, __stop_fixup);

 	/* setup node data */
 	m68k_setup_node(0);
 }

 /*
  * Initialize the context management stuff.
  * The following was taken from arch/ppc/mmu_context.c
  */
 void __init cf_mmu_context_init(void)
 {
 	/*
 	 * Some processors have too few contexts to reserve one for
 	 * init_mm, and require using context 0 for a normal task.
 	 * Other processors reserve the use of context zero for the kernel.
 	 * This code assumes FIRST_CONTEXT < 32.
 	 */
 	context_map[0] = (1 << FIRST_CONTEXT) - 1;
 	next_mmu_context = FIRST_CONTEXT;
 	atomic_set(&nr_free_contexts, LAST_CONTEXT - FIRST_CONTEXT + 1);
 }

 /*
  * Steal a context from a task that has one at the moment.
  * This isn't an LRU system, it just frees up each context in
  * turn (sort-of pseudo-random replacement :).  This would be the
  * place to implement an LRU scheme if anyone was motivated to do it.
  *  -- paulus
  */
 void steal_context(void)
 {
 	struct mm_struct *mm;
 	/*
 	 * free up context `next_mmu_context'
 	 * if we shouldn't free context 0, don't...
 	 */
 	if (next_mmu_context < FIRST_CONTEXT)
 		next_mmu_context = FIRST_CONTEXT;
 	mm = context_mm[next_mmu_context];
 	flush_tlb_mm(mm);
 	destroy_context(mm);
 }

 static const pgprot_t protection_map[16] = {
 	[VM_NONE]					= PAGE_NONE,
 	[VM_READ]					= __pgprot(CF_PAGE_VALID |
 								   CF_PAGE_ACCESSED |
 								   CF_PAGE_READABLE),
 	[VM_WRITE]					= __pgprot(CF_PAGE_VALID |
 								   CF_PAGE_ACCESSED |
 								   CF_PAGE_WRITABLE),
 	[VM_WRITE | VM_READ]				= __pgprot(CF_PAGE_VALID |
 								   CF_PAGE_ACCESSED |
 								   CF_PAGE_READABLE |
 								   CF_PAGE_WRITABLE),
 	[VM_EXEC]					= __pgprot(CF_PAGE_VALID |
 								   CF_PAGE_ACCESSED |
 								   CF_PAGE_EXEC),
 	[VM_EXEC | VM_READ]				= __pgprot(CF_PAGE_VALID |
 								   CF_PAGE_ACCESSED |
 								   CF_PAGE_READABLE |
 								   CF_PAGE_EXEC),
 	[VM_EXEC | VM_WRITE]				= __pgprot(CF_PAGE_VALID |
 								   CF_PAGE_ACCESSED |
 								   CF_PAGE_WRITABLE |
 								   CF_PAGE_EXEC),
 	[VM_EXEC | VM_WRITE | VM_READ]			=  __pgprot(CF_PAGE_VALID |
 								    CF_PAGE_ACCESSED |
 								    CF_PAGE_READABLE |
 								    CF_PAGE_WRITABLE |
 								    CF_PAGE_EXEC),
 	[VM_SHARED]					= PAGE_NONE,
 	[VM_SHARED | VM_READ]				= __pgprot(CF_PAGE_VALID |
 								   CF_PAGE_ACCESSED |
 								   CF_PAGE_READABLE),
 	[VM_SHARED | VM_WRITE]				= PAGE_SHARED,
 	[VM_SHARED | VM_WRITE | VM_READ]		= __pgprot(CF_PAGE_VALID |
 								   CF_PAGE_ACCESSED |
 								   CF_PAGE_READABLE |
 								   CF_PAGE_SHARED),
 	[VM_SHARED | VM_EXEC]				= __pgprot(CF_PAGE_VALID |
 								   CF_PAGE_ACCESSED |
 								   CF_PAGE_EXEC),
 	[VM_SHARED | VM_EXEC | VM_READ]			= __pgprot(CF_PAGE_VALID |
 								   CF_PAGE_ACCESSED |
 								   CF_PAGE_READABLE |
 								   CF_PAGE_EXEC),
 	[VM_SHARED | VM_EXEC | VM_WRITE]		= __pgprot(CF_PAGE_VALID |
 								   CF_PAGE_ACCESSED |
 								   CF_PAGE_SHARED |
 								   CF_PAGE_EXEC),
 	[VM_SHARED | VM_EXEC | VM_WRITE | VM_READ]	= __pgprot(CF_PAGE_VALID |
 								   CF_PAGE_ACCESSED |
 								   CF_PAGE_READABLE |
 								   CF_PAGE_SHARED |
 								   CF_PAGE_EXEC)
 };
 DECLARE_VM_GET_PAGE_PROT
	// SPDX-License-Identifier: GPL-2.0
	/*
	* Based upon linux/arch/m68k/mm/sun3mmu.c
	* Based upon linux/arch/ppc/mm/mmu_context.c
	*
	* Implementations of mm routines specific to the Coldfire MMU.
	*
	* Copyright (c) 2008 Freescale Semiconductor, Inc.
	*/

	#include <linux/kernel.h>
	#include <linux/types.h>
	#include <linux/mm.h>
	#include <linux/init.h>
	#include <linux/string.h>
	#include <linux/memblock.h>

	#include <asm/setup.h>
	#include <asm/page.h>
	#include <asm/mmu_context.h>
	#include <asm/mcf_pgalloc.h>
	#include <asm/tlbflush.h>
	#include <asm/pgalloc.h>

	#define KMAPAREA(x) ((x >= VMALLOC_START) && (x < KMAP_END))

	mm_context_t next_mmu_context;
	unsigned long context_map[LAST_CONTEXT / BITS_PER_LONG + 1];
	atomic_t nr_free_contexts;
	struct mm_struct *context_mm[LAST_CONTEXT+1];
	unsigned long num_pages;

	/*
	* ColdFire paging_init derived from sun3.
	*/
	void __init paging_init(void)
	{
	pgd_t *pg_dir;
	pte_t *pg_table;
	unsigned long address, size;
	unsigned long next_pgtable, bootmem_end;
	unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 };
	int i;

	empty_zero_page = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
	if (!empty_zero_page)
	panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
	__func__, PAGE_SIZE, PAGE_SIZE);

	pg_dir = swapper_pg_dir;
	memset(swapper_pg_dir, 0, sizeof(swapper_pg_dir));

	size = num_pages * sizeof(pte_t);
	size = (size + PAGE_SIZE) & ~(PAGE_SIZE-1);
	next_pgtable = (unsigned long) memblock_alloc(size, PAGE_SIZE);
	if (!next_pgtable)
	panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
	__func__, size, PAGE_SIZE);

	bootmem_end = (next_pgtable + size + PAGE_SIZE) & PAGE_MASK;
	pg_dir += PAGE_OFFSET >> PGDIR_SHIFT;

	address = PAGE_OFFSET;
	while (address < (unsigned long)high_memory) {
	pg_table = (pte_t *) next_pgtable;
	next_pgtable += PTRS_PER_PTE * sizeof(pte_t);
	pgd_val(*pg_dir) = (unsigned long) pg_table;
	pg_dir++;

	/* now change pg_table to kernel virtual addresses */
	for (i = 0; i < PTRS_PER_PTE; ++i, ++pg_table) {
	pte_t pte = pfn_pte(virt_to_pfn(address), PAGE_INIT);
	if (address >= (unsigned long) high_memory)
	pte_val(pte) = 0;

	set_pte(pg_table, pte);
	address += PAGE_SIZE;
	}
	}

	current->mm = NULL;
	max_zone_pfn[ZONE_DMA] = PFN_DOWN(_ramend);
	free_area_init(max_zone_pfn);
	}

	int cf_tlb_miss(struct pt_regs *regs, int write, int dtlb, int extension_word)
	{
	unsigned long flags, mmuar, mmutr;
	struct mm_struct *mm;
	pgd_t *pgd;
	p4d_t *p4d;
	pud_t *pud;
	pmd_t *pmd;
	pte_t *pte;
	int asid;

	local_irq_save(flags);

	mmuar = (dtlb) ? mmu_read(MMUAR) :
	regs->pc + (extension_word * sizeof(long));

	mm = (!user_mode(regs) && KMAPAREA(mmuar)) ? &init_mm : current->mm;
	if (!mm) {
	local_irq_restore(flags);
	return -1;
	}

	pgd = pgd_offset(mm, mmuar);
	if (pgd_none(*pgd)) {
	local_irq_restore(flags);
	return -1;
	}

	p4d = p4d_offset(pgd, mmuar);
	if (p4d_none(*p4d)) {
	local_irq_restore(flags);
	return -1;
	}

	pud = pud_offset(p4d, mmuar);
	if (pud_none(*pud)) {
	local_irq_restore(flags);
	return -1;
	}

	pmd = pmd_offset(pud, mmuar);
	if (pmd_none(*pmd)) {
	local_irq_restore(flags);
	return -1;
	}

	pte = (KMAPAREA(mmuar)) ? pte_offset_kernel(pmd, mmuar)
	: pte_offset_map(pmd, mmuar);
	if (pte_none(pte) \|\| !pte_present(pte)) {
	local_irq_restore(flags);
	return -1;
	}

	if (write) {
	if (!pte_write(*pte)) {
	local_irq_restore(flags);
	return -1;
	}
	set_pte(pte, pte_mkdirty(*pte));
	}

	set_pte(pte, pte_mkyoung(*pte));
	asid = mm->context & 0xff;
	if (!pte_dirty(*pte) && !KMAPAREA(mmuar))
	set_pte(pte, pte_wrprotect(*pte));

	mmutr = (mmuar & PAGE_MASK) \| (asid << MMUTR_IDN) \| MMUTR_V;
	if ((mmuar < TASK_UNMAPPED_BASE) \|\| (mmuar >= TASK_SIZE))
	mmutr \|= (pte->pte & CF_PAGE_MMUTR_MASK) >> CF_PAGE_MMUTR_SHIFT;
	mmu_write(MMUTR, mmutr);

	mmu_write(MMUDR, (pte_val(*pte) & PAGE_MASK) \|
	((pte->pte) & CF_PAGE_MMUDR_MASK) \| MMUDR_SZ_8KB \| MMUDR_X);

	if (dtlb)
	mmu_write(MMUOR, MMUOR_ACC \| MMUOR_UAA);
	else
	mmu_write(MMUOR, MMUOR_ITLB \| MMUOR_ACC \| MMUOR_UAA);

	local_irq_restore(flags);
	return 0;
	}

	void __init cf_bootmem_alloc(void)
	{
	unsigned long memstart;

	/* _rambase and _ramend will be naturally page aligned */
	m68k_memory[0].addr = _rambase;
	m68k_memory[0].size = _ramend - _rambase;

	memblock_add_node(m68k_memory[0].addr, m68k_memory[0].size, 0,
	MEMBLOCK_NONE);

	/* compute total pages in system */
	num_pages = PFN_DOWN(_ramend - _rambase);

	/* page numbers */
	memstart = PAGE_ALIGN(_ramstart);
	min_low_pfn = PFN_DOWN(_rambase);
	max_pfn = max_low_pfn = PFN_DOWN(_ramend);
	high_memory = (void *)_ramend;

	/* Reserve kernel text/data/bss */
	memblock_reserve(_rambase, memstart - _rambase);

	m68k_virt_to_node_shift = fls(_ramend - 1) - 6;
	module_fixup(NULL, __start_fixup, __stop_fixup);

	/* setup node data */
	m68k_setup_node(0);
	}

	/*
	* Initialize the context management stuff.
	* The following was taken from arch/ppc/mmu_context.c
	*/
	void __init cf_mmu_context_init(void)
	{
	/*
	* Some processors have too few contexts to reserve one for
	* init_mm, and require using context 0 for a normal task.
	* Other processors reserve the use of context zero for the kernel.
	* This code assumes FIRST_CONTEXT < 32.
	*/
	context_map[0] = (1 << FIRST_CONTEXT) - 1;
	next_mmu_context = FIRST_CONTEXT;
	atomic_set(&nr_free_contexts, LAST_CONTEXT - FIRST_CONTEXT + 1);
	}

	/*
	* Steal a context from a task that has one at the moment.
	* This isn't an LRU system, it just frees up each context in
	* turn (sort-of pseudo-random replacement :). This would be the
	* place to implement an LRU scheme if anyone was motivated to do it.
	* -- paulus
	*/
	void steal_context(void)
	{
	struct mm_struct *mm;
	/*
	* free up context `next_mmu_context'
	* if we shouldn't free context 0, don't...
	*/
	if (next_mmu_context < FIRST_CONTEXT)
	next_mmu_context = FIRST_CONTEXT;
	mm = context_mm[next_mmu_context];
	flush_tlb_mm(mm);
	destroy_context(mm);
	}

	static const pgprot_t protection_map[16] = {
	[VM_NONE] = PAGE_NONE,
	[VM_READ] = __pgprot(CF_PAGE_VALID \|
	CF_PAGE_ACCESSED \|
	CF_PAGE_READABLE),
	[VM_WRITE] = __pgprot(CF_PAGE_VALID \|
	CF_PAGE_ACCESSED \|
	CF_PAGE_WRITABLE),
	[VM_WRITE \| VM_READ] = __pgprot(CF_PAGE_VALID \|
	CF_PAGE_ACCESSED \|
	CF_PAGE_READABLE \|
	CF_PAGE_WRITABLE),
	[VM_EXEC] = __pgprot(CF_PAGE_VALID \|
	CF_PAGE_ACCESSED \|
	CF_PAGE_EXEC),
	[VM_EXEC \| VM_READ] = __pgprot(CF_PAGE_VALID \|
	CF_PAGE_ACCESSED \|
	CF_PAGE_READABLE \|
	CF_PAGE_EXEC),
	[VM_EXEC \| VM_WRITE] = __pgprot(CF_PAGE_VALID \|
	CF_PAGE_ACCESSED \|
	CF_PAGE_WRITABLE \|
	CF_PAGE_EXEC),
	[VM_EXEC \| VM_WRITE \| VM_READ] = __pgprot(CF_PAGE_VALID \|
	CF_PAGE_ACCESSED \|
	CF_PAGE_READABLE \|
	CF_PAGE_WRITABLE \|
	CF_PAGE_EXEC),
	[VM_SHARED] = PAGE_NONE,
	[VM_SHARED \| VM_READ] = __pgprot(CF_PAGE_VALID \|
	CF_PAGE_ACCESSED \|
	CF_PAGE_READABLE),
	[VM_SHARED \| VM_WRITE] = PAGE_SHARED,
	[VM_SHARED \| VM_WRITE \| VM_READ] = __pgprot(CF_PAGE_VALID \|
	CF_PAGE_ACCESSED \|
	CF_PAGE_READABLE \|
	CF_PAGE_SHARED),
	[VM_SHARED \| VM_EXEC] = __pgprot(CF_PAGE_VALID \|
	CF_PAGE_ACCESSED \|
	CF_PAGE_EXEC),
	[VM_SHARED \| VM_EXEC \| VM_READ] = __pgprot(CF_PAGE_VALID \|
	CF_PAGE_ACCESSED \|
	CF_PAGE_READABLE \|
	CF_PAGE_EXEC),
	[VM_SHARED \| VM_EXEC \| VM_WRITE] = __pgprot(CF_PAGE_VALID \|
	CF_PAGE_ACCESSED \|
	CF_PAGE_SHARED \|
	CF_PAGE_EXEC),
	[VM_SHARED \| VM_EXEC \| VM_WRITE \| VM_READ] = __pgprot(CF_PAGE_VALID \|
	CF_PAGE_ACCESSED \|
	CF_PAGE_READABLE \|
	CF_PAGE_SHARED \|
	CF_PAGE_EXEC)
	};
	DECLARE_VM_GET_PAGE_PROT