[net-next-2.6.git] / arch / microblaze / mm / pgtable.c

/*
 *  This file contains the routines setting up the linux page tables.
 *
 * Copyright (C) 2008 Michal Simek
 * Copyright (C) 2008 PetaLogix
 *
 *    Copyright (C) 2007 Xilinx, Inc.  All rights reserved.
 *
 *  Derived from arch/ppc/mm/pgtable.c:
 *    -- paulus
 *
 *  Derived from arch/ppc/mm/init.c:
 *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
 *
 *  Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
 *  and Cort Dougan (PReP) (cort@cs.nmt.edu)
 *    Copyright (C) 1996 Paul Mackerras
 *  Amiga/APUS changes by Jesper Skov (jskov@cygnus.co.uk).
 *
 *  Derived from "arch/i386/mm/init.c"
 *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
 *
 *  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.
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/vmalloc.h>
#include <linux/init.h>

#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <linux/io.h>
#include <asm/mmu.h>
#include <asm/sections.h>

#define flush_HPTE(X, va, pg)	_tlbie(va)

unsigned long ioremap_base;
unsigned long ioremap_bot;

/* The maximum lowmem defaults to 768Mb, but this can be configured to
 * another value.
 */
#define MAX_LOW_MEM	CONFIG_LOWMEM_SIZE

#ifndef CONFIG_SMP
struct pgtable_cache_struct quicklists;
#endif

static void __iomem *__ioremap(phys_addr_t addr, unsigned long size,
		unsigned long flags)
{
	unsigned long v, i;
	phys_addr_t p;
	int err;

	/*
	 * Choose an address to map it to.
	 * Once the vmalloc system is running, we use it.
	 * Before then, we use space going down from ioremap_base
	 * (ioremap_bot records where we're up to).
	 */
	p = addr & PAGE_MASK;
	size = PAGE_ALIGN(addr + size) - p;

	/*
	 * Don't allow anybody to remap normal RAM that we're using.
	 * mem_init() sets high_memory so only do the check after that.
	 *
	 * However, allow remap of rootfs: TBD
	 */
	if (mem_init_done &&
		p >= memory_start && p < virt_to_phys(high_memory) &&
		!(p >= virt_to_phys((unsigned long)&__bss_stop) &&
		p < virt_to_phys((unsigned long)__bss_stop))) {
		printk(KERN_WARNING "__ioremap(): phys addr "PTE_FMT
			" is RAM lr %p\n", (unsigned long)p,
			__builtin_return_address(0));
		return NULL;
	}

	if (size == 0)
		return NULL;

	/*
	 * Is it already mapped? If the whole area is mapped then we're
	 * done, otherwise remap it since we want to keep the virt addrs for
	 * each request contiguous.
	 *
	 * We make the assumption here that if the bottom and top
	 * of the range we want are mapped then it's mapped to the
	 * same virt address (and this is contiguous).
	 *  -- Cort
	 */

	if (mem_init_done) {
		struct vm_struct *area;
		area = get_vm_area(size, VM_IOREMAP);
		if (area == NULL)
			return NULL;
		v = (unsigned long) area->addr;
	} else {
		v = (ioremap_bot -= size);
	}

	if ((flags & _PAGE_PRESENT) == 0)
		flags |= _PAGE_KERNEL;
	if (flags & _PAGE_NO_CACHE)
		flags |= _PAGE_GUARDED;

	err = 0;
	for (i = 0; i < size && err == 0; i += PAGE_SIZE)
		err = map_page(v + i, p + i, flags);
	if (err) {
		if (mem_init_done)
			vfree((void *)v);
		return NULL;
	}

	return (void __iomem *) (v + ((unsigned long)addr & ~PAGE_MASK));
}

void __iomem *ioremap(phys_addr_t addr, unsigned long size)
{
	return __ioremap(addr, size, _PAGE_NO_CACHE);
}
EXPORT_SYMBOL(ioremap);

void iounmap(void *addr)
{
	if (addr > high_memory && (unsigned long) addr < ioremap_bot)
		vfree((void *) (PAGE_MASK & (unsigned long) addr));
}
EXPORT_SYMBOL(iounmap);


int map_page(unsigned long va, phys_addr_t pa, int flags)
{
	pmd_t *pd;
	pte_t *pg;
	int err = -ENOMEM;
	/* Use upper 10 bits of VA to index the first level map */
	pd = pmd_offset(pgd_offset_k(va), va);
	/* Use middle 10 bits of VA to index the second-level map */
	pg = pte_alloc_kernel(pd, va); /* from powerpc - pgtable.c */
	/* pg = pte_alloc_kernel(&init_mm, pd, va); */

	if (pg != NULL) {
		err = 0;
		set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT,
				__pgprot(flags)));
		if (unlikely(mem_init_done))
			flush_HPTE(0, va, pmd_val(*pd));
			/* flush_HPTE(0, va, pg); */
	}
	return err;
}

/*
 * Map in all of physical memory starting at CONFIG_KERNEL_START.
 */
void __init mapin_ram(void)
{
	unsigned long v, p, s, f;

	v = CONFIG_KERNEL_START;
	p = memory_start;
	for (s = 0; s < memory_size; s += PAGE_SIZE) {
		f = _PAGE_PRESENT | _PAGE_ACCESSED |
				_PAGE_SHARED | _PAGE_HWEXEC;
		if ((char *) v < _stext || (char *) v >= _etext)
			f |= _PAGE_WRENABLE;
		else
			/* On the MicroBlaze, no user access
			   forces R/W kernel access */
			f |= _PAGE_USER;
		map_page(v, p, f);
		v += PAGE_SIZE;
		p += PAGE_SIZE;
	}
}

/* is x a power of 2? */
#define is_power_of_2(x)	((x) != 0 && (((x) & ((x) - 1)) == 0))

/* Scan the real Linux page tables and return a PTE pointer for
 * a virtual address in a context.
 * Returns true (1) if PTE was found, zero otherwise.  The pointer to
 * the PTE pointer is unmodified if PTE is not found.
 */
static int get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep)
{
	pgd_t	*pgd;
	pmd_t	*pmd;
	pte_t	*pte;
	int     retval = 0;

	pgd = pgd_offset(mm, addr & PAGE_MASK);
	if (pgd) {
		pmd = pmd_offset(pgd, addr & PAGE_MASK);
		if (pmd_present(*pmd)) {
			pte = pte_offset_kernel(pmd, addr & PAGE_MASK);
			if (pte) {
				retval = 1;
				*ptep = pte;
			}
		}
	}
	return retval;
}

/* Find physical address for this virtual address.  Normally used by
 * I/O functions, but anyone can call it.
 */
unsigned long iopa(unsigned long addr)
{
	unsigned long pa;

	pte_t *pte;
	struct mm_struct *mm;

	/* Allow mapping of user addresses (within the thread)
	 * for DMA if necessary.
	 */
	if (addr < TASK_SIZE)
		mm = current->mm;
	else
		mm = &init_mm;

	pa = 0;
	if (get_pteptr(mm, addr, &pte))
		pa = (pte_val(*pte) & PAGE_MASK) | (addr & ~PAGE_MASK);

	return pa;
}

__init_refok pte_t *pte_alloc_one_kernel(struct mm_struct *mm,
		unsigned long address)
{
	pte_t *pte;
	if (mem_init_done) {
		pte = (pte_t *)__get_free_page(GFP_KERNEL |
					__GFP_REPEAT | __GFP_ZERO);
	} else {
		pte = (pte_t *)early_get_page();
		if (pte)
			clear_page(pte);
	}
	return pte;
}
Commit	Line	Data
15902bf6 MS	1	/*
	2	* This file contains the routines setting up the linux page tables.
	3	*
	4	* Copyright (C) 2008 Michal Simek
	5	* Copyright (C) 2008 PetaLogix
	6	*
	7	* Copyright (C) 2007 Xilinx, Inc. All rights reserved.
	8	*
	9	* Derived from arch/ppc/mm/pgtable.c:
	10	* -- paulus
	11	*
	12	* Derived from arch/ppc/mm/init.c:
	13	* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
	14	*
	15	* Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
	16	* and Cort Dougan (PReP) (cort@cs.nmt.edu)
	17	* Copyright (C) 1996 Paul Mackerras
	18	* Amiga/APUS changes by Jesper Skov (jskov@cygnus.co.uk).
	19	*
	20	* Derived from "arch/i386/mm/init.c"
	21	* Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
	22	*
	23	* This file is subject to the terms and conditions of the GNU General
	24	* Public License. See the file COPYING in the main directory of this
	25	* archive for more details.
	26	*
	27	*/
	28
	29	#include <linux/kernel.h>
	30	#include <linux/module.h>
	31	#include <linux/types.h>
	32	#include <linux/vmalloc.h>
	33	#include <linux/init.h>
	34
	35	#include <asm/pgtable.h>
	36	#include <asm/pgalloc.h>
	37	#include <linux/io.h>
	38	#include <asm/mmu.h>
	39	#include <asm/sections.h>
	40
	41	#define flush_HPTE(X, va, pg) _tlbie(va)
	42
	43	unsigned long ioremap_base;
	44	unsigned long ioremap_bot;
	45
	46	/* The maximum lowmem defaults to 768Mb, but this can be configured to
	47	* another value.
	48	*/
	49	#define MAX_LOW_MEM CONFIG_LOWMEM_SIZE
	50
	51	#ifndef CONFIG_SMP
	52	struct pgtable_cache_struct quicklists;
	53	#endif
	54
	55	static void __iomem *__ioremap(phys_addr_t addr, unsigned long size,
	56	unsigned long flags)
	57	{
	58	unsigned long v, i;
	59	phys_addr_t p;
	60	int err;
	61
	62	/*
	63	* Choose an address to map it to.
	64	* Once the vmalloc system is running, we use it.
65	* Before then, we use space going down from ioremap_base
66	* (ioremap_bot records where we're up to).
67	*/
68	p = addr & PAGE_MASK;
69	size = PAGE_ALIGN(addr + size) - p;
70
71	/*
72	* Don't allow anybody to remap normal RAM that we're using.
73	* mem_init() sets high_memory so only do the check after that.
74	*
75	* However, allow remap of rootfs: TBD
76	*/
77	if (mem_init_done &&
78	p >= memory_start && p < virt_to_phys(high_memory) &&
79	!(p >= virt_to_phys((unsigned long)&__bss_stop) &&
80	p < virt_to_phys((unsigned long)__bss_stop))) {
81	printk(KERN_WARNING "__ioremap(): phys addr "PTE_FMT
82	" is RAM lr %p\n", (unsigned long)p,
83	__builtin_return_address(0));
84	return NULL;
85	}
86
87	if (size == 0)
88	return NULL;
89
90	/*
91	* Is it already mapped? If the whole area is mapped then we're
92	* done, otherwise remap it since we want to keep the virt addrs for
93	* each request contiguous.
94	*
95	* We make the assumption here that if the bottom and top
96	* of the range we want are mapped then it's mapped to the
97	* same virt address (and this is contiguous).
98	* -- Cort
99	*/
100
101	if (mem_init_done) {
102	struct vm_struct *area;
103	area = get_vm_area(size, VM_IOREMAP);
104	if (area == NULL)
105	return NULL;
cca5613f	106	v = (unsigned long) area->addr;
15902bf6 MS	107	} else {
	108	v = (ioremap_bot -= size);
	109	}
	110
	111	if ((flags & _PAGE_PRESENT) == 0)
	112	flags \|= _PAGE_KERNEL;
	113	if (flags & _PAGE_NO_CACHE)
	114	flags \|= _PAGE_GUARDED;
	115
	116	err = 0;
	117	for (i = 0; i < size && err == 0; i += PAGE_SIZE)
	118	err = map_page(v + i, p + i, flags);
	119	if (err) {
	120	if (mem_init_done)
	121	vfree((void *)v);
	122	return NULL;
	123	}
	124
	125	return (void __iomem *) (v + ((unsigned long)addr & ~PAGE_MASK));
	126	}
	127
	128	void __iomem *ioremap(phys_addr_t addr, unsigned long size)
	129	{
	130	return __ioremap(addr, size, _PAGE_NO_CACHE);
	131	}
	132	EXPORT_SYMBOL(ioremap);
	133
	134	void iounmap(void *addr)
	135	{
	136	if (addr > high_memory && (unsigned long) addr < ioremap_bot)
	137	vfree((void *) (PAGE_MASK & (unsigned long) addr));
	138	}
	139	EXPORT_SYMBOL(iounmap);
	140
	141
	142	int map_page(unsigned long va, phys_addr_t pa, int flags)
	143	{
	144	pmd_t *pd;
	145	pte_t *pg;
	146	int err = -ENOMEM;
15902bf6 MS	147	/* Use upper 10 bits of VA to index the first level map */
	148	pd = pmd_offset(pgd_offset_k(va), va);
	149	/* Use middle 10 bits of VA to index the second-level map */
	150	pg = pte_alloc_kernel(pd, va); /* from powerpc - pgtable.c */
	151	/* pg = pte_alloc_kernel(&init_mm, pd, va); */
	152
	153	if (pg != NULL) {
	154	err = 0;
	155	set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT,
	156	__pgprot(flags)));
78ebfa88	157	if (unlikely(mem_init_done))
15902bf6 MS	158	flush_HPTE(0, va, pmd_val(*pd));
15902bf6 MS	159	/* flush_HPTE(0, va, pg); */
15902bf6	160	}
15902bf6 MS	161	return err;
	162	}
	163
15902bf6 MS	164	/*
	165	* Map in all of physical memory starting at CONFIG_KERNEL_START.
	166	*/
	167	void __init mapin_ram(void)
	168	{
	169	unsigned long v, p, s, f;
	170
	171	v = CONFIG_KERNEL_START;
	172	p = memory_start;
15902bf6 MS	173	for (s = 0; s < memory_size; s += PAGE_SIZE) {
	174	f = _PAGE_PRESENT \| _PAGE_ACCESSED \|
	175	_PAGE_SHARED \| _PAGE_HWEXEC;
	176	if ((char ) v < _stext \|\| (char ) v >= _etext)
	177	f \|= _PAGE_WRENABLE;
	178	else
	179	/* On the MicroBlaze, no user access
	180	forces R/W kernel access */
	181	f \|= _PAGE_USER;
	182	map_page(v, p, f);
	183	v += PAGE_SIZE;
	184	p += PAGE_SIZE;
	185	}
	186	}
	187
	188	/* is x a power of 2? */
	189	#define is_power_of_2(x) ((x) != 0 && (((x) & ((x) - 1)) == 0))
	190
15902bf6 MS	191	/* Scan the real Linux page tables and return a PTE pointer for
	192	* a virtual address in a context.
	193	* Returns true (1) if PTE was found, zero otherwise. The pointer to
	194	* the PTE pointer is unmodified if PTE is not found.
	195	*/
	196	static int get_pteptr(struct mm_struct mm, unsigned long addr, pte_t *ptep)
	197	{
	198	pgd_t *pgd;
	199	pmd_t *pmd;
	200	pte_t *pte;
	201	int retval = 0;
	202
	203	pgd = pgd_offset(mm, addr & PAGE_MASK);
	204	if (pgd) {
	205	pmd = pmd_offset(pgd, addr & PAGE_MASK);
	206	if (pmd_present(*pmd)) {
	207	pte = pte_offset_kernel(pmd, addr & PAGE_MASK);
	208	if (pte) {
	209	retval = 1;
	210	*ptep = pte;
	211	}
	212	}
	213	}
	214	return retval;
	215	}
	216
	217	/* Find physical address for this virtual address. Normally used by
	218	* I/O functions, but anyone can call it.
	219	*/
	220	unsigned long iopa(unsigned long addr)
	221	{
	222	unsigned long pa;
	223
	224	pte_t *pte;
	225	struct mm_struct *mm;
	226
	227	/* Allow mapping of user addresses (within the thread)
	228	* for DMA if necessary.
	229	*/
	230	if (addr < TASK_SIZE)
	231	mm = current->mm;
	232	else
	233	mm = &init_mm;
	234
	235	pa = 0;
	236	if (get_pteptr(mm, addr, &pte))
	237	pa = (pte_val(*pte) & PAGE_MASK) \| (addr & ~PAGE_MASK);
	238
	239	return pa;
	240	}
63f1032b MS	241
	242	__init_refok pte_t pte_alloc_one_kernel(struct mm_struct mm,
	243	unsigned long address)
	244	{
	245	pte_t *pte;
	246	if (mem_init_done) {
	247	pte = (pte_t *)__get_free_page(GFP_KERNEL \|
	248	__GFP_REPEAT \| __GFP_ZERO);
	249	} else {
	250	pte = (pte_t *)early_get_page();
	251	if (pte)
	252	clear_page(pte);
	253	}
	254	return pte;
	255	}