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linux/arch/arc/include/asm/pgtable.h
Vineet Gupta d091fcb97f ARC: MMUv4 preps/2 - Reshuffle PTE bits 
With previous commit freeing up PTE bits, reassign them so as to:

- Match the bit to H/w counterpart where possible
  (e.g. MMUv2 GLOBAL/PRESENT, this avoids a shift in create_tlb())
- Avoid holes in _PAGE_xxx definitions

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2013-08-30 10:19:12 +05:30

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