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linux/arch/mn10300/include/asm/pgtable.h
Mark Salter 5a226c6f5c MN10300: Map userspace atomic op regs as a vmalloc page 
The AM34 processor has an atomic operation that's the equivalent of LL/SC on
other architectures.  However, rather than being done through a pair of
instructions, it's driven by writing to a pair of memory-mapped CPU control
registers.

One set of these registers (AARU/ADRU/ASRU) is available for use by userspace,
but for userspace to access them a PTE must be set up to cover the region.
This is done by dedicating the first vmalloc region page to this purpose,
setting the permissions on its PTE such that userspace can access the page.

glibc is hardcoded to expect the registers to be there.

The way atomic ops are done through these registers is straightforward:

 (1) Write the address of the word you wish to access into AARU.  This causes
     the CPU to go and fetch that word and load it into ADRU.  The status bits
     are also cleared in ASRU.

 (2) The current data value is read from the ADRU register and modified.

 (3) To alter the data in RAM, the revised data is written back to the ADRU
     register, which causes the CPU to attempt to write it back.

 (4) The ASRU.RW flag (ASRU read watch), ASRU.LW flag (bus lock watch),
     ASRU.IW (interrupt watch) and the ASRU.BW (bus error watch) flags then
     must be checked to confirm that the operation wasn't aborted.  If any of
     the watches have been set to true, the operation was aborted.

Signed-off-by: Mark Salter <msalter@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
2010-10-27 17:28:56 +01:00

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/* MN10300 Page table manipulators and constants
*
* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
*
*
* The Linux memory management assumes a three-level page table setup. On
* the i386, we use that, but "fold" the mid level into the top-level page
* table, so that we physically have the same two-level page table as the
* i386 mmu expects.
*
* This file contains the functions and defines necessary to modify and use
* the i386 page table tree for the purposes of the MN10300 TLB handler
* functions.
*/
#ifndef _ASM_PGTABLE_H
#define _ASM_PGTABLE_H
#include <asm/cpu-regs.h>
#ifndef __ASSEMBLY__
#include <asm/processor.h>
#include <asm/cache.h>
#include <linux/threads.h>
#include <asm/bitops.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <linux/spinlock.h>
/*
* ZERO_PAGE is a global shared page that is always zero: used
* for zero-mapped memory areas etc..
*/
#define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
extern unsigned long empty_zero_page[1024];
extern spinlock_t pgd_lock;
extern struct page *pgd_list;
extern void pmd_ctor(void *, struct kmem_cache *, unsigned long);
extern void pgtable_cache_init(void);
extern void paging_init(void);
#endif /* !__ASSEMBLY__ */
/*
* The Linux mn10300 paging architecture only implements both the traditional
* 2-level page tables
*/
#define PGDIR_SHIFT 22
#define PTRS_PER_PGD 1024
#define PTRS_PER_PUD 1 /* we don't really have any PUD physically */
#define PTRS_PER_PMD 1 /* we don't really have any PMD physically */
#define PTRS_PER_PTE 1024
#define PGD_SIZE PAGE_SIZE
#define PMD_SIZE (1UL << PMD_SHIFT)
#define PGDIR_SIZE (1UL << PGDIR_SHIFT)
#define PGDIR_MASK (~(PGDIR_SIZE - 1))
#define USER_PTRS_PER_PGD (TASK_SIZE / PGDIR_SIZE)
#define FIRST_USER_ADDRESS 0
#define USER_PGD_PTRS (PAGE_OFFSET >> PGDIR_SHIFT)
#define KERNEL_PGD_PTRS (PTRS_PER_PGD - USER_PGD_PTRS)
#define TWOLEVEL_PGDIR_SHIFT 22
#define BOOT_USER_PGD_PTRS (__PAGE_OFFSET >> TWOLEVEL_PGDIR_SHIFT)
#define BOOT_KERNEL_PGD_PTRS (1024 - BOOT_USER_PGD_PTRS)
#ifndef __ASSEMBLY__
extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
#endif
/*
* Unfortunately, due to the way the MMU works on the MN10300, the vmalloc VM
* area has to be in the lower half of the virtual address range (the upper
* half is not translated through the TLB).
*
* So in this case, the vmalloc area goes at the bottom of the address map
* (leaving a hole at the very bottom to catch addressing errors), and
* userspace starts immediately above.
*
* The vmalloc() routines also leaves a hole of 4kB between each vmalloced
* area to catch addressing errors.
*/
#ifndef __ASSEMBLY__
#define VMALLOC_OFFSET (8UL * 1024 * 1024)
#define VMALLOC_START (0x70000000UL)
#define VMALLOC_END (0x7C000000UL)
#else
#define VMALLOC_OFFSET (8 * 1024 * 1024)
#define VMALLOC_START (0x70000000)
#define VMALLOC_END (0x7C000000)
#endif
#ifndef __ASSEMBLY__
extern pte_t kernel_vmalloc_ptes[(VMALLOC_END - VMALLOC_START) / PAGE_SIZE];
#endif
/* IPTEL2/DPTEL2 bit assignments */
#define _PAGE_BIT_VALID xPTEL2_V_BIT
#define _PAGE_BIT_CACHE xPTEL2_C_BIT
#define _PAGE_BIT_PRESENT xPTEL2_PV_BIT
#define _PAGE_BIT_DIRTY xPTEL2_D_BIT
#define _PAGE_BIT_GLOBAL xPTEL2_G_BIT
#define _PAGE_BIT_ACCESSED xPTEL2_UNUSED1_BIT /* mustn't be loaded into IPTEL2/DPTEL2 */
#define _PAGE_VALID xPTEL2_V
#define _PAGE_CACHE xPTEL2_C
#define _PAGE_PRESENT xPTEL2_PV
#define _PAGE_DIRTY xPTEL2_D
#define _PAGE_PROT xPTEL2_PR
#define _PAGE_PROT_RKNU xPTEL2_PR_ROK
#define _PAGE_PROT_WKNU xPTEL2_PR_RWK
#define _PAGE_PROT_RKRU xPTEL2_PR_ROK_ROU
#define _PAGE_PROT_WKRU xPTEL2_PR_RWK_ROU
#define _PAGE_PROT_WKWU xPTEL2_PR_RWK_RWU
#define _PAGE_GLOBAL xPTEL2_G
#define _PAGE_PS_MASK xPTEL2_PS
#define _PAGE_PS_4Kb xPTEL2_PS_4Kb
#define _PAGE_PS_128Kb xPTEL2_PS_128Kb
#define _PAGE_PS_1Kb xPTEL2_PS_1Kb
#define _PAGE_PS_4Mb xPTEL2_PS_4Mb
#define _PAGE_PSE xPTEL2_PS_4Mb /* 4MB page */
#define _PAGE_CACHE_WT xPTEL2_CWT
#define _PAGE_ACCESSED xPTEL2_UNUSED1
#define _PAGE_NX 0 /* no-execute bit */
/* If _PAGE_VALID is clear, we use these: */
#define _PAGE_FILE xPTEL2_C /* set:pagecache unset:swap */
#define _PAGE_PROTNONE 0x000 /* If not present */
#define __PAGE_PROT_UWAUX 0x010
#define __PAGE_PROT_USER 0x020
#define __PAGE_PROT_WRITE 0x040
#define _PAGE_PRESENTV (_PAGE_PRESENT|_PAGE_VALID)
#ifndef __ASSEMBLY__
#define VMALLOC_VMADDR(x) ((unsigned long)(x))
#define _PAGE_TABLE (_PAGE_PRESENTV | _PAGE_PROT_WKNU | _PAGE_ACCESSED | _PAGE_DIRTY)
#define _PAGE_CHG_MASK (PTE_MASK | _PAGE_ACCESSED | _PAGE_DIRTY)
#define __PAGE_NONE (_PAGE_PRESENTV | _PAGE_PROT_RKNU | _PAGE_ACCESSED | _PAGE_CACHE)
#define __PAGE_SHARED (_PAGE_PRESENTV | _PAGE_PROT_WKWU | _PAGE_ACCESSED | _PAGE_CACHE)
#define __PAGE_COPY (_PAGE_PRESENTV | _PAGE_PROT_RKRU | _PAGE_ACCESSED | _PAGE_CACHE)
#define __PAGE_READONLY (_PAGE_PRESENTV | _PAGE_PROT_RKRU | _PAGE_ACCESSED | _PAGE_CACHE)
#define PAGE_NONE __pgprot(__PAGE_NONE | _PAGE_NX)
#define PAGE_SHARED_NOEXEC __pgprot(__PAGE_SHARED | _PAGE_NX)
#define PAGE_COPY_NOEXEC __pgprot(__PAGE_COPY | _PAGE_NX)
#define PAGE_READONLY_NOEXEC __pgprot(__PAGE_READONLY | _PAGE_NX)
#define PAGE_SHARED_EXEC __pgprot(__PAGE_SHARED)
#define PAGE_COPY_EXEC __pgprot(__PAGE_COPY)
#define PAGE_READONLY_EXEC __pgprot(__PAGE_READONLY)
#define PAGE_COPY PAGE_COPY_NOEXEC
#define PAGE_READONLY PAGE_READONLY_NOEXEC
#define PAGE_SHARED PAGE_SHARED_EXEC
#define __PAGE_KERNEL_BASE (_PAGE_PRESENTV | _PAGE_DIRTY | _PAGE_ACCESSED | _PAGE_GLOBAL)
#define __PAGE_KERNEL (__PAGE_KERNEL_BASE | _PAGE_PROT_WKNU | _PAGE_CACHE | _PAGE_NX)
#define __PAGE_KERNEL_NOCACHE (__PAGE_KERNEL_BASE | _PAGE_PROT_WKNU | _PAGE_NX)
#define __PAGE_KERNEL_EXEC (__PAGE_KERNEL & ~_PAGE_NX)
#define __PAGE_KERNEL_RO (__PAGE_KERNEL_BASE | _PAGE_PROT_RKNU | _PAGE_CACHE | _PAGE_NX)
#define __PAGE_KERNEL_LARGE (__PAGE_KERNEL | _PAGE_PSE)
#define __PAGE_KERNEL_LARGE_EXEC (__PAGE_KERNEL_EXEC | _PAGE_PSE)
#define PAGE_KERNEL __pgprot(__PAGE_KERNEL)
#define PAGE_KERNEL_RO __pgprot(__PAGE_KERNEL_RO)
#define PAGE_KERNEL_EXEC __pgprot(__PAGE_KERNEL_EXEC)
#define PAGE_KERNEL_NOCACHE __pgprot(__PAGE_KERNEL_NOCACHE)
#define PAGE_KERNEL_LARGE __pgprot(__PAGE_KERNEL_LARGE)
#define PAGE_KERNEL_LARGE_EXEC __pgprot(__PAGE_KERNEL_LARGE_EXEC)
#define __PAGE_USERIO (__PAGE_KERNEL_BASE | _PAGE_PROT_WKWU | _PAGE_NX)
#define PAGE_USERIO __pgprot(__PAGE_USERIO)
/*
* Whilst the MN10300 can do page protection for execute (given separate data
* and insn TLBs), we are not supporting it at the moment. Write permission,
* however, always implies read permission (but not execute permission).
*/
#define __P000 PAGE_NONE
#define __P001 PAGE_READONLY_NOEXEC
#define __P010 PAGE_COPY_NOEXEC
#define __P011 PAGE_COPY_NOEXEC
#define __P100 PAGE_READONLY_EXEC
#define __P101 PAGE_READONLY_EXEC
#define __P110 PAGE_COPY_EXEC
#define __P111 PAGE_COPY_EXEC
#define __S000 PAGE_NONE
#define __S001 PAGE_READONLY_NOEXEC
#define __S010 PAGE_SHARED_NOEXEC
#define __S011 PAGE_SHARED_NOEXEC
#define __S100 PAGE_READONLY_EXEC
#define __S101 PAGE_READONLY_EXEC
#define __S110 PAGE_SHARED_EXEC
#define __S111 PAGE_SHARED_EXEC
/*
* Define this to warn about kernel memory accesses that are
* done without a 'verify_area(VERIFY_WRITE,..)'
*/
#undef TEST_VERIFY_AREA
#define pte_present(x) (pte_val(x) & _PAGE_VALID)
#define pte_clear(mm, addr, xp) \
do { \
set_pte_at((mm), (addr), (xp), __pte(0)); \
} while (0)
#define pmd_none(x) (!pmd_val(x))
#define pmd_present(x) (!pmd_none(x))
#define pmd_clear(xp) do { set_pmd(xp, __pmd(0)); } while (0)
#define pmd_bad(x) 0
#define pages_to_mb(x) ((x) >> (20 - PAGE_SHIFT))
#ifndef __ASSEMBLY__
/*
* The following only work if pte_present() is true.
* Undefined behaviour if not..
*/
static inline int pte_user(pte_t pte) { return pte_val(pte) & __PAGE_PROT_USER; }
static inline int pte_read(pte_t pte) { return pte_val(pte) & __PAGE_PROT_USER; }
static inline int pte_dirty(pte_t pte) { return pte_val(pte) & _PAGE_DIRTY; }
static inline int pte_young(pte_t pte) { return pte_val(pte) & _PAGE_ACCESSED; }
static inline int pte_write(pte_t pte) { return pte_val(pte) & __PAGE_PROT_WRITE; }
static inline int pte_special(pte_t pte){ return 0; }
/*
* The following only works if pte_present() is not true.
*/
static inline int pte_file(pte_t pte) { return pte_val(pte) & _PAGE_FILE; }
static inline pte_t pte_rdprotect(pte_t pte)
{
pte_val(pte) &= ~(__PAGE_PROT_USER|__PAGE_PROT_UWAUX); return pte;
}
static inline pte_t pte_exprotect(pte_t pte)
{
pte_val(pte) |= _PAGE_NX; return pte;
}
static inline pte_t pte_wrprotect(pte_t pte)
{
pte_val(pte) &= ~(__PAGE_PROT_WRITE|__PAGE_PROT_UWAUX); return pte;
}
static inline pte_t pte_mkclean(pte_t pte) { pte_val(pte) &= ~_PAGE_DIRTY; return pte; }
static inline pte_t pte_mkold(pte_t pte) { pte_val(pte) &= ~_PAGE_ACCESSED; return pte; }
static inline pte_t pte_mkdirty(pte_t pte) { pte_val(pte) |= _PAGE_DIRTY; return pte; }
static inline pte_t pte_mkyoung(pte_t pte) { pte_val(pte) |= _PAGE_ACCESSED; return pte; }
static inline pte_t pte_mkexec(pte_t pte) { pte_val(pte) &= ~_PAGE_NX; return pte; }
static inline pte_t pte_mkread(pte_t pte)
{
pte_val(pte) |= __PAGE_PROT_USER;
if (pte_write(pte))
pte_val(pte) |= __PAGE_PROT_UWAUX;
return pte;
}
static inline pte_t pte_mkwrite(pte_t pte)
{
pte_val(pte) |= __PAGE_PROT_WRITE;
if (pte_val(pte) & __PAGE_PROT_USER)
pte_val(pte) |= __PAGE_PROT_UWAUX;
return pte;
}
static inline pte_t pte_mkspecial(pte_t pte) { return pte; }
#define pte_ERROR(e) \
printk(KERN_ERR "%s:%d: bad pte %08lx.\n", \
__FILE__, __LINE__, pte_val(e))
#define pgd_ERROR(e) \
printk(KERN_ERR "%s:%d: bad pgd %08lx.\n", \
__FILE__, __LINE__, pgd_val(e))
/*
* The "pgd_xxx()" functions here are trivial for a folded two-level
* setup: the pgd is never bad, and a pmd always exists (as it's folded
* into the pgd entry)
*/
#define pgd_clear(xp) do { } while (0)
/*
* Certain architectures need to do special things when PTEs
* within a page table are directly modified. Thus, the following
* hook is made available.
*/
#define set_pte(pteptr, pteval) (*(pteptr) = pteval)
#define set_pte_at(mm, addr, ptep, pteval) set_pte((ptep), (pteval))
#define set_pte_atomic(pteptr, pteval) set_pte((pteptr), (pteval))
/*
* (pmds are folded into pgds so this doesn't get actually called,
* but the define is needed for a generic inline function.)
*/
#define set_pmd(pmdptr, pmdval) (*(pmdptr) = pmdval)
#define ptep_get_and_clear(mm, addr, ptep) \
__pte(xchg(&(ptep)->pte, 0))
#define pte_same(a, b) (pte_val(a) == pte_val(b))
#define pte_page(x) pfn_to_page(pte_pfn(x))
#define pte_none(x) (!pte_val(x))
#define pte_pfn(x) ((unsigned long) (pte_val(x) >> PAGE_SHIFT))
#define __pfn_addr(pfn) ((pfn) << PAGE_SHIFT)
#define pfn_pte(pfn, prot) __pte(__pfn_addr(pfn) | pgprot_val(prot))
#define pfn_pmd(pfn, prot) __pmd(__pfn_addr(pfn) | pgprot_val(prot))
/*
* All present user pages are user-executable:
*/
static inline int pte_exec(pte_t pte)
{
return pte_user(pte);
}
/*
* All present pages are kernel-executable:
*/
static inline int pte_exec_kernel(pte_t pte)
{
return 1;
}
#define PTE_FILE_MAX_BITS 30
#define pte_to_pgoff(pte) (pte_val(pte) >> 2)
#define pgoff_to_pte(off) __pte((off) << 2 | _PAGE_FILE)
/* Encode and de-code a swap entry */
#define __swp_type(x) (((x).val >> 2) & 0x3f)
#define __swp_offset(x) ((x).val >> 8)
#define __swp_entry(type, offset) \
((swp_entry_t) { ((type) << 2) | ((offset) << 8) })
#define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
#define __swp_entry_to_pte(x) __pte((x).val)
static inline
int ptep_test_and_clear_dirty(struct vm_area_struct *vma, unsigned long addr,
pte_t *ptep)
{
if (!pte_dirty(*ptep))
return 0;
return test_and_clear_bit(_PAGE_BIT_DIRTY, &ptep->pte);
}
static inline
int ptep_test_and_clear_young(struct vm_area_struct *vma, unsigned long addr,
pte_t *ptep)
{
if (!pte_young(*ptep))
return 0;
return test_and_clear_bit(_PAGE_BIT_ACCESSED, &ptep->pte);
}
static inline
void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
{
pte_val(*ptep) &= ~(__PAGE_PROT_WRITE|__PAGE_PROT_UWAUX);
}
static inline void ptep_mkdirty(pte_t *ptep)
{
set_bit(_PAGE_BIT_DIRTY, &ptep->pte);
}
/*
* Macro to mark a page protection value as "uncacheable". On processors which
* do not support it, this is a no-op.
*/
#define pgprot_noncached(prot) __pgprot(pgprot_val(prot) & ~_PAGE_CACHE)
/*
* Macro to mark a page protection value as "Write-Through".
* On processors which do not support it, this is a no-op.
*/
#define pgprot_through(prot) __pgprot(pgprot_val(prot) | _PAGE_CACHE_WT)
/*
* Conversion functions: convert a page and protection to a page entry,
* and a page entry and page directory to the page they refer to.
*/
#define mk_pte(page, pgprot) pfn_pte(page_to_pfn(page), (pgprot))
#define mk_pte_huge(entry) \
((entry).pte |= _PAGE_PRESENT | _PAGE_PSE | _PAGE_VALID)
static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
{
pte_val(pte) &= _PAGE_CHG_MASK;
pte_val(pte) |= pgprot_val(newprot);
return pte;
}
#define page_pte(page) page_pte_prot((page), __pgprot(0))
#define pmd_page_kernel(pmd) \
((unsigned long) __va(pmd_val(pmd) & PAGE_MASK))
#define pmd_page(pmd) pfn_to_page(pmd_val(pmd) >> PAGE_SHIFT)
#define pmd_large(pmd) \
((pmd_val(pmd) & (_PAGE_PSE | _PAGE_PRESENT)) == \
(_PAGE_PSE | _PAGE_PRESENT))
/*
* the pgd page can be thought of an array like this: pgd_t[PTRS_PER_PGD]
*
* this macro returns the index of the entry in the pgd page which would
* control the given virtual address
*/
#define pgd_index(address) (((address) >> PGDIR_SHIFT) & (PTRS_PER_PGD - 1))
/*
* pgd_offset() returns a (pgd_t *)
* pgd_index() is used get the offset into the pgd page's array of pgd_t's;
*/
#define pgd_offset(mm, address) ((mm)->pgd + pgd_index(address))
/*
* a shortcut which implies the use of the kernel's pgd, instead
* of a process's
*/
#define pgd_offset_k(address) pgd_offset(&init_mm, address)
/*
* the pmd page can be thought of an array like this: pmd_t[PTRS_PER_PMD]
*
* this macro returns the index of the entry in the pmd page which would
* control the given virtual address
*/
#define pmd_index(address) \
(((address) >> PMD_SHIFT) & (PTRS_PER_PMD - 1))
/*
* the pte page can be thought of an array like this: pte_t[PTRS_PER_PTE]
*
* this macro returns the index of the entry in the pte page which would
* control the given virtual address
*/
#define pte_index(address) \
(((address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
#define pte_offset_kernel(dir, address) \
((pte_t *) pmd_page_kernel(*(dir)) + pte_index(address))
/*
* Make a given kernel text page executable/non-executable.
* Returns the previous executability setting of that page (which
* is used to restore the previous state). Used by the SMP bootup code.
* NOTE: this is an __init function for security reasons.
*/
static inline int set_kernel_exec(unsigned long vaddr, int enable)
{
return 0;
}
#define pte_offset_map(dir, address) \
((pte_t *) page_address(pmd_page(*(dir))) + pte_index(address))
#define pte_unmap(pte) do {} while (0)
/*
* The MN10300 has external MMU info in the form of a TLB: this is adapted from
* the kernel page tables containing the necessary information by tlb-mn10300.S
*/
extern void update_mmu_cache(struct vm_area_struct *vma,
unsigned long address, pte_t *ptep);
#endif /* !__ASSEMBLY__ */
#define kern_addr_valid(addr) (1)
#define io_remap_pfn_range(vma, vaddr, pfn, size, prot) \
remap_pfn_range((vma), (vaddr), (pfn), (size), (prot))
#define MK_IOSPACE_PFN(space, pfn) (pfn)
#define GET_IOSPACE(pfn) 0
#define GET_PFN(pfn) (pfn)
#define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
#define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_DIRTY
#define __HAVE_ARCH_PTEP_GET_AND_CLEAR
#define __HAVE_ARCH_PTEP_SET_WRPROTECT
#define __HAVE_ARCH_PTEP_MKDIRTY
#define __HAVE_ARCH_PTE_SAME
#include <asm-generic/pgtable.h>
#endif /* !__ASSEMBLY__ */
#endif /* _ASM_PGTABLE_H */
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