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			14 KiB
		
	
	
	
		
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			399 lines
		
	
	
	
		
			14 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /*
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|  * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
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|  *
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|  * This program is free software; you can redistribute it and/or modify
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|  * it under the terms of the GNU General Public License version 2 as
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|  * published by the Free Software Foundation.
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|  *
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|  * vineetg: May 2011
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|  *  -Folded PAGE_PRESENT (used by VM) and PAGE_VALID (used by MMU) into 1.
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|  *     They are semantically the same although in different contexts
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|  *     VALID marks a TLB entry exists and it will only happen if PRESENT
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|  *  - Utilise some unused free bits to confine PTE flags to 12 bits
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|  *     This is a must for 4k pg-sz
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|  *
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|  * vineetg: Mar 2011 - changes to accomodate MMU TLB Page Descriptor mods
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|  *  -TLB Locking never really existed, except for initial specs
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|  *  -SILENT_xxx not needed for our port
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|  *  -Per my request, MMU V3 changes the layout of some of the bits
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|  *     to avoid a few shifts in TLB Miss handlers.
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|  *
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|  * vineetg: April 2010
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|  *  -PGD entry no longer contains any flags. If empty it is 0, otherwise has
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|  *   Pg-Tbl ptr. Thus pmd_present(), pmd_valid(), pmd_set( ) become simpler
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|  *
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|  * vineetg: April 2010
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|  *  -Switched form 8:11:13 split for page table lookup to 11:8:13
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|  *  -this speeds up page table allocation itself as we now have to memset 1K
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|  *    instead of 8k per page table.
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|  * -TODO: Right now page table alloc is 8K and rest 7K is unused
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|  *    need to optimise it
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|  *
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|  * Amit Bhor, Sameer Dhavale: Codito Technologies 2004
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|  */
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| 
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| #ifndef _ASM_ARC_PGTABLE_H
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| #define _ASM_ARC_PGTABLE_H
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| 
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| #include <asm/page.h>
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| #include <asm/mmu.h>
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| #include <asm-generic/pgtable-nopmd.h>
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| 
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| /**************************************************************************
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|  * Page Table Flags
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|  *
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|  * ARC700 MMU only deals with softare managed TLB entries.
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|  * Page Tables are purely for Linux VM's consumption and the bits below are
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|  * suited to that (uniqueness). Hence some are not implemented in the TLB and
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|  * some have different value in TLB.
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|  * e.g. MMU v2: K_READ bit is 8 and so is GLOBAL (possible becoz they live in
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|  *      seperate PD0 and PD1, which combined forms a translation entry)
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|  *      while for PTE perspective, they are 8 and 9 respectively
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|  * with MMU v3: Most bits (except SHARED) represent the exact hardware pos
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|  *      (saves some bit shift ops in TLB Miss hdlrs)
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|  */
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| 
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| #if (CONFIG_ARC_MMU_VER <= 2)
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| 
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| #define _PAGE_ACCESSED      (1<<1)	/* Page is accessed (S) */
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| #define _PAGE_CACHEABLE     (1<<2)	/* Page is cached (H) */
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| #define _PAGE_EXECUTE       (1<<3)	/* Page has user execute perm (H) */
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| #define _PAGE_WRITE         (1<<4)	/* Page has user write perm (H) */
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| #define _PAGE_READ          (1<<5)	/* Page has user read perm (H) */
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| #define _PAGE_MODIFIED      (1<<6)	/* Page modified (dirty) (S) */
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| #define _PAGE_FILE          (1<<7)	/* page cache/ swap (S) */
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| #define _PAGE_GLOBAL        (1<<8)	/* Page is global (H) */
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| #define _PAGE_PRESENT       (1<<10)	/* TLB entry is valid (H) */
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| 
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| #else	/* MMU v3 onwards */
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| 
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| #define _PAGE_CACHEABLE     (1<<0)	/* Page is cached (H) */
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| #define _PAGE_EXECUTE       (1<<1)	/* Page has user execute perm (H) */
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| #define _PAGE_WRITE         (1<<2)	/* Page has user write perm (H) */
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| #define _PAGE_READ          (1<<3)	/* Page has user read perm (H) */
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| #define _PAGE_ACCESSED      (1<<4)	/* Page is accessed (S) */
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| #define _PAGE_MODIFIED      (1<<5)	/* Page modified (dirty) (S) */
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| #define _PAGE_FILE          (1<<6)	/* page cache/ swap (S) */
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| #define _PAGE_GLOBAL        (1<<8)	/* Page is global (H) */
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| #define _PAGE_PRESENT       (1<<9)	/* TLB entry is valid (H) */
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| #define _PAGE_SHARED_CODE   (1<<11)	/* Shared Code page with cmn vaddr
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| 					   usable for shared TLB entries (H) */
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| #endif
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| 
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| /* vmalloc permissions */
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| #define _K_PAGE_PERMS  (_PAGE_EXECUTE | _PAGE_WRITE | _PAGE_READ | \
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| 			_PAGE_GLOBAL | _PAGE_PRESENT)
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| 
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| #ifdef CONFIG_ARC_CACHE_PAGES
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| #define _PAGE_DEF_CACHEABLE _PAGE_CACHEABLE
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| #else
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| #define _PAGE_DEF_CACHEABLE (0)
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| #endif
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| 
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| /* Helper for every "user" page
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|  * -kernel can R/W/X
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|  * -by default cached, unless config otherwise
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|  * -present in memory
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|  */
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| #define ___DEF (_PAGE_PRESENT | _PAGE_DEF_CACHEABLE)
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| 
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| /* Set of bits not changed in pte_modify */
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| #define _PAGE_CHG_MASK	(PAGE_MASK | _PAGE_ACCESSED | _PAGE_MODIFIED)
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| 
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| /* More Abbrevaited helpers */
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| #define PAGE_U_NONE     __pgprot(___DEF)
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| #define PAGE_U_R        __pgprot(___DEF | _PAGE_READ)
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| #define PAGE_U_W_R      __pgprot(___DEF | _PAGE_READ | _PAGE_WRITE)
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| #define PAGE_U_X_R      __pgprot(___DEF | _PAGE_READ | _PAGE_EXECUTE)
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| #define PAGE_U_X_W_R    __pgprot(___DEF | _PAGE_READ | _PAGE_WRITE | \
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| 						       _PAGE_EXECUTE)
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| 
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| #define PAGE_SHARED	PAGE_U_W_R
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| 
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| /* While kernel runs out of unstranslated space, vmalloc/modules use a chunk of
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|  * user vaddr space - visible in all addr spaces, but kernel mode only
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|  * Thus Global, all-kernel-access, no-user-access, cached
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|  */
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| #define PAGE_KERNEL          __pgprot(_K_PAGE_PERMS | _PAGE_DEF_CACHEABLE)
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| 
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| /* ioremap */
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| #define PAGE_KERNEL_NO_CACHE __pgprot(_K_PAGE_PERMS)
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| 
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| /* Masks for actual TLB "PD"s */
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| #define PTE_BITS_IN_PD0		(_PAGE_GLOBAL | _PAGE_PRESENT)
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| #define PTE_BITS_RWX		(_PAGE_EXECUTE | _PAGE_WRITE | _PAGE_READ)
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| #define PTE_BITS_NON_RWX_IN_PD1	(PAGE_MASK | _PAGE_CACHEABLE)
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| 
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| /**************************************************************************
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|  * Mapping of vm_flags (Generic VM) to PTE flags (arch specific)
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|  *
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|  * Certain cases have 1:1 mapping
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|  *  e.g. __P101 means VM_READ, VM_EXEC and !VM_SHARED
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|  *       which directly corresponds to  PAGE_U_X_R
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|  *
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|  * Other rules which cause the divergence from 1:1 mapping
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|  *
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|  *  1. Although ARC700 can do exclusive execute/write protection (meaning R
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|  *     can be tracked independet of X/W unlike some other CPUs), still to
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|  *     keep things consistent with other archs:
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|  *      -Write implies Read:   W => R
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|  *      -Execute implies Read: X => R
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|  *
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|  *  2. Pvt Writable doesn't have Write Enabled initially: Pvt-W => !W
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|  *     This is to enable COW mechanism
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|  */
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| 	/* xwr */
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| #define __P000  PAGE_U_NONE
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| #define __P001  PAGE_U_R
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| #define __P010  PAGE_U_R	/* Pvt-W => !W */
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| #define __P011  PAGE_U_R	/* Pvt-W => !W */
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| #define __P100  PAGE_U_X_R	/* X => R */
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| #define __P101  PAGE_U_X_R
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| #define __P110  PAGE_U_X_R	/* Pvt-W => !W and X => R */
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| #define __P111  PAGE_U_X_R	/* Pvt-W => !W */
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| 
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| #define __S000  PAGE_U_NONE
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| #define __S001  PAGE_U_R
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| #define __S010  PAGE_U_W_R	/* W => R */
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| #define __S011  PAGE_U_W_R
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| #define __S100  PAGE_U_X_R	/* X => R */
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| #define __S101  PAGE_U_X_R
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| #define __S110  PAGE_U_X_W_R	/* X => R */
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| #define __S111  PAGE_U_X_W_R
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| 
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| /****************************************************************
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|  * Page Table Lookup split
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|  *
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|  * We implement 2 tier paging and since this is all software, we are free
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|  * to customize the span of a PGD / PTE entry to suit us
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|  *
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|  *			32 bit virtual address
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|  * -------------------------------------------------------
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|  * | BITS_FOR_PGD    |  BITS_FOR_PTE    |  BITS_IN_PAGE  |
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|  * -------------------------------------------------------
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|  *       |                  |                |
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|  *       |                  |                --> off in page frame
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|  *       |		    |
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|  *       |                  ---> index into Page Table
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|  *       |
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|  *       ----> index into Page Directory
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|  */
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| 
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| #define BITS_IN_PAGE	PAGE_SHIFT
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| 
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| /* Optimal Sizing of Pg Tbl - based on MMU page size */
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| #if defined(CONFIG_ARC_PAGE_SIZE_8K)
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| #define BITS_FOR_PTE	8
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| #elif defined(CONFIG_ARC_PAGE_SIZE_16K)
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| #define BITS_FOR_PTE	8
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| #elif defined(CONFIG_ARC_PAGE_SIZE_4K)
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| #define BITS_FOR_PTE	9
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| #endif
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| 
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| #define BITS_FOR_PGD	(32 - BITS_FOR_PTE - BITS_IN_PAGE)
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| 
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| #define PGDIR_SHIFT	(BITS_FOR_PTE + BITS_IN_PAGE)
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| #define PGDIR_SIZE	(1UL << PGDIR_SHIFT)	/* vaddr span, not PDG sz */
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| #define PGDIR_MASK	(~(PGDIR_SIZE-1))
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| 
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| #ifdef __ASSEMBLY__
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| #define	PTRS_PER_PTE	(1 << BITS_FOR_PTE)
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| #define	PTRS_PER_PGD	(1 << BITS_FOR_PGD)
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| #else
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| #define	PTRS_PER_PTE	(1UL << BITS_FOR_PTE)
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| #define	PTRS_PER_PGD	(1UL << BITS_FOR_PGD)
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| #endif
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| /*
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|  * Number of entries a user land program use.
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|  * TASK_SIZE is the maximum vaddr that can be used by a userland program.
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|  */
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| #define	USER_PTRS_PER_PGD	(TASK_SIZE / PGDIR_SIZE)
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| 
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| /*
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|  * No special requirements for lowest virtual address we permit any user space
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|  * mapping to be mapped at.
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|  */
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| #define FIRST_USER_ADDRESS      0
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| 
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| 
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| /****************************************************************
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|  * Bucket load of VM Helpers
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|  */
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| 
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| #ifndef __ASSEMBLY__
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| 
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| #define pte_ERROR(e) \
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| 	pr_crit("%s:%d: bad pte %08lx.\n", __FILE__, __LINE__, pte_val(e))
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| #define pgd_ERROR(e) \
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| 	pr_crit("%s:%d: bad pgd %08lx.\n", __FILE__, __LINE__, pgd_val(e))
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| 
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| /* the zero page used for uninitialized and anonymous pages */
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| extern char empty_zero_page[PAGE_SIZE];
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| #define ZERO_PAGE(vaddr)	(virt_to_page(empty_zero_page))
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| 
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| #define pte_unmap(pte)		do { } while (0)
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| #define pte_unmap_nested(pte)		do { } while (0)
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| 
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| #define set_pte(pteptr, pteval)	((*(pteptr)) = (pteval))
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| #define set_pmd(pmdptr, pmdval)	(*(pmdptr) = pmdval)
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| 
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| /* find the page descriptor of the Page Tbl ref by PMD entry */
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| #define pmd_page(pmd)		virt_to_page(pmd_val(pmd) & PAGE_MASK)
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| 
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| /* find the logical addr (phy for ARC) of the Page Tbl ref by PMD entry */
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| #define pmd_page_vaddr(pmd)	(pmd_val(pmd) & PAGE_MASK)
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| 
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| /* In a 2 level sys, setup the PGD entry with PTE value */
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| static inline void pmd_set(pmd_t *pmdp, pte_t *ptep)
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| {
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| 	pmd_val(*pmdp) = (unsigned long)ptep;
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| }
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| 
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| #define pte_none(x)			(!pte_val(x))
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| #define pte_present(x)			(pte_val(x) & _PAGE_PRESENT)
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| #define pte_clear(mm, addr, ptep)	set_pte_at(mm, addr, ptep, __pte(0))
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| 
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| #define pmd_none(x)			(!pmd_val(x))
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| #define	pmd_bad(x)			((pmd_val(x) & ~PAGE_MASK))
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| #define pmd_present(x)			(pmd_val(x))
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| #define pmd_clear(xp)			do { pmd_val(*(xp)) = 0; } while (0)
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| 
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| #define pte_page(x) (mem_map + \
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| 		(unsigned long)(((pte_val(x) - CONFIG_LINUX_LINK_BASE) >> \
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| 				PAGE_SHIFT)))
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| 
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| #define mk_pte(page, pgprot)						\
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| ({									\
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| 	pte_t pte;							\
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| 	pte_val(pte) = __pa(page_address(page)) + pgprot_val(pgprot);	\
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| 	pte;								\
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| })
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| 
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| /* TBD: Non linear mapping stuff */
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| static inline int pte_file(pte_t pte)
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| {
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| 	return pte_val(pte) & _PAGE_FILE;
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| }
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| 
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| #define PTE_FILE_MAX_BITS	30
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| #define pgoff_to_pte(x)         __pte(x)
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| #define pte_to_pgoff(x)		(pte_val(x) >> 2)
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| #define pte_pfn(pte)		(pte_val(pte) >> PAGE_SHIFT)
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| #define pfn_pte(pfn, prot)	(__pte(((pfn) << PAGE_SHIFT) | pgprot_val(prot)))
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| #define __pte_index(addr)	(((addr) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
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| 
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| /*
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|  * pte_offset gets a @ptr to PMD entry (PGD in our 2-tier paging system)
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|  * and returns ptr to PTE entry corresponding to @addr
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|  */
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| #define pte_offset(dir, addr) ((pte_t *)(pmd_page_vaddr(*dir)) +\
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| 					 __pte_index(addr))
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| 
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| /* No mapping of Page Tables in high mem etc, so following same as above */
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| #define pte_offset_kernel(dir, addr)		pte_offset(dir, addr)
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| #define pte_offset_map(dir, addr)		pte_offset(dir, addr)
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| 
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| /* Zoo of pte_xxx function */
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| #define pte_read(pte)		(pte_val(pte) & _PAGE_READ)
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| #define pte_write(pte)		(pte_val(pte) & _PAGE_WRITE)
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| #define pte_dirty(pte)		(pte_val(pte) & _PAGE_MODIFIED)
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| #define pte_young(pte)		(pte_val(pte) & _PAGE_ACCESSED)
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| #define pte_special(pte)	(0)
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| 
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| #define PTE_BIT_FUNC(fn, op) \
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| 	static inline pte_t pte_##fn(pte_t pte) { pte_val(pte) op; return pte; }
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| 
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| PTE_BIT_FUNC(wrprotect,	&= ~(_PAGE_WRITE));
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| PTE_BIT_FUNC(mkwrite,	|= (_PAGE_WRITE));
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| PTE_BIT_FUNC(mkclean,	&= ~(_PAGE_MODIFIED));
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| PTE_BIT_FUNC(mkdirty,	|= (_PAGE_MODIFIED));
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| PTE_BIT_FUNC(mkold,	&= ~(_PAGE_ACCESSED));
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| PTE_BIT_FUNC(mkyoung,	|= (_PAGE_ACCESSED));
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| PTE_BIT_FUNC(exprotect,	&= ~(_PAGE_EXECUTE));
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| PTE_BIT_FUNC(mkexec,	|= (_PAGE_EXECUTE));
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| 
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| static inline pte_t pte_mkspecial(pte_t pte) { return pte; }
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| 
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| static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
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| {
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| 	return __pte((pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot));
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| }
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| 
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| /* Macro to mark a page protection as uncacheable */
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| #define pgprot_noncached(prot)	(__pgprot(pgprot_val(prot) & ~_PAGE_CACHEABLE))
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| 
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| static inline void set_pte_at(struct mm_struct *mm, unsigned long addr,
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| 			      pte_t *ptep, pte_t pteval)
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| {
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| 	set_pte(ptep, pteval);
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| }
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| 
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| /*
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|  * All kernel related VM pages are in init's mm.
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|  */
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| #define pgd_offset_k(address)	pgd_offset(&init_mm, address)
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| #define pgd_index(addr)		((addr) >> PGDIR_SHIFT)
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| #define pgd_offset(mm, addr)	(((mm)->pgd)+pgd_index(addr))
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| 
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| /*
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|  * Macro to quickly access the PGD entry, utlising the fact that some
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|  * arch may cache the pointer to Page Directory of "current" task
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|  * in a MMU register
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|  *
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|  * Thus task->mm->pgd (3 pointer dereferences, cache misses etc simply
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|  * becomes read a register
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|  *
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|  * ********CAUTION*******:
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|  * Kernel code might be dealing with some mm_struct of NON "current"
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|  * Thus use this macro only when you are certain that "current" is current
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|  * e.g. when dealing with signal frame setup code etc
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|  */
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| #ifndef CONFIG_SMP
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| #define pgd_offset_fast(mm, addr)	\
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| ({					\
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| 	pgd_t *pgd_base = (pgd_t *) read_aux_reg(ARC_REG_SCRATCH_DATA0);  \
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| 	pgd_base + pgd_index(addr);	\
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| })
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| #else
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| #define pgd_offset_fast(mm, addr)	pgd_offset(mm, addr)
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| #endif
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| 
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| extern void paging_init(void);
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| extern pgd_t swapper_pg_dir[] __aligned(PAGE_SIZE);
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| void update_mmu_cache(struct vm_area_struct *vma, unsigned long address,
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| 		      pte_t *ptep);
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| 
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| /* Encode swap {type,off} tuple into PTE
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|  * We reserve 13 bits for 5-bit @type, keeping bits 12-5 zero, ensuring that
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|  * both PAGE_FILE and PAGE_PRESENT are zero in a PTE holding swap "identifier"
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|  */
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| #define __swp_entry(type, off)	((swp_entry_t) { \
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| 					((type) & 0x1f) | ((off) << 13) })
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| 
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| /* Decode a PTE containing swap "identifier "into constituents */
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| #define __swp_type(pte_lookalike)	(((pte_lookalike).val) & 0x1f)
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| #define __swp_offset(pte_lookalike)	((pte_lookalike).val << 13)
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| 
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| /* NOPs, to keep generic kernel happy */
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| #define __pte_to_swp_entry(pte)	((swp_entry_t) { pte_val(pte) })
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| #define __swp_entry_to_pte(x)	((pte_t) { (x).val })
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| 
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| #define kern_addr_valid(addr)	(1)
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| 
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| /*
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|  * remap a physical page `pfn' of size `size' with page protection `prot'
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|  * into virtual address `from'
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|  */
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| #include <asm-generic/pgtable.h>
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| 
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| /* to cope with aliasing VIPT cache */
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| #define HAVE_ARCH_UNMAPPED_AREA
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| 
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| /*
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|  * No page table caches to initialise
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|  */
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| #define pgtable_cache_init()   do { } while (0)
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| 
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| #endif /* __ASSEMBLY__ */
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| 
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| #endif
 | 
