linux/arch/parisc/include/asm/page.h
Helge Deller 48d27cb229 parisc: fix usage of 32bit PTE page table entries on 32bit kernels
This patch fixes a long outstanding bug on 32bit parisc linux kernels
which prevented us from using 32bit PTE table entries (instead of 64bit
entries of which 32bit were unused).

The problem was caused by this assembler statement in the L2_ptep
macro in arch/parisc/kernel/entry.S:447:
	EXTR \va,31-ASM_PGDIR_SHIFT,ASM_BITS_PER_PGD,\index
which expanded to
	extrw,u r8,9,11,r1
and which has undefined behavior since the length value (11) extends
beyond the leftmost bit (11-1 > 9).
Interestingly PA2.0 processors seem to don't care and just zero-extend
the value, while PA1.1 processors don't.

Fix this problem by detecting an address space overflow with ASM_BITS_PER_PGD
and adjusting it accordingly. To prevent such problems in the future,
some compile time sanity checks in arch/parisc/mm/init.c were added.

Since the page table now only consumes half of it's old size, we can
use the freed memory to harmonize 32- and 64bit kernels and let both
map 16MB for the initial page table.

Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Kyle McMartin <kyle@mcmartin.ca>
2009-03-31 02:51:33 +00:00

165 lines
4.6 KiB
C

#ifndef _PARISC_PAGE_H
#define _PARISC_PAGE_H
#include <linux/const.h>
#if defined(CONFIG_PARISC_PAGE_SIZE_4KB)
# define PAGE_SHIFT 12
#elif defined(CONFIG_PARISC_PAGE_SIZE_16KB)
# define PAGE_SHIFT 14
#elif defined(CONFIG_PARISC_PAGE_SIZE_64KB)
# define PAGE_SHIFT 16
#else
# error "unknown default kernel page size"
#endif
#define PAGE_SIZE (_AC(1,UL) << PAGE_SHIFT)
#define PAGE_MASK (~(PAGE_SIZE-1))
#ifndef __ASSEMBLY__
#include <asm/types.h>
#include <asm/cache.h>
#define clear_page(page) memset((void *)(page), 0, PAGE_SIZE)
#define copy_page(to,from) copy_user_page_asm((void *)(to), (void *)(from))
struct page;
void copy_user_page_asm(void *to, void *from);
void copy_user_page(void *vto, void *vfrom, unsigned long vaddr,
struct page *pg);
void clear_user_page(void *page, unsigned long vaddr, struct page *pg);
/*
* These are used to make use of C type-checking..
*/
#define STRICT_MM_TYPECHECKS
#ifdef STRICT_MM_TYPECHECKS
typedef struct { unsigned long pte; } pte_t; /* either 32 or 64bit */
/* NOTE: even on 64 bits, these entries are __u32 because we allocate
* the pmd and pgd in ZONE_DMA (i.e. under 4GB) */
typedef struct { __u32 pmd; } pmd_t;
typedef struct { __u32 pgd; } pgd_t;
typedef struct { unsigned long pgprot; } pgprot_t;
#define pte_val(x) ((x).pte)
/* These do not work lvalues, so make sure we don't use them as such. */
#define pmd_val(x) ((x).pmd + 0)
#define pgd_val(x) ((x).pgd + 0)
#define pgprot_val(x) ((x).pgprot)
#define __pte(x) ((pte_t) { (x) } )
#define __pmd(x) ((pmd_t) { (x) } )
#define __pgd(x) ((pgd_t) { (x) } )
#define __pgprot(x) ((pgprot_t) { (x) } )
#define __pmd_val_set(x,n) (x).pmd = (n)
#define __pgd_val_set(x,n) (x).pgd = (n)
#else
/*
* .. while these make it easier on the compiler
*/
typedef unsigned long pte_t;
typedef __u32 pmd_t;
typedef __u32 pgd_t;
typedef unsigned long pgprot_t;
#define pte_val(x) (x)
#define pmd_val(x) (x)
#define pgd_val(x) (x)
#define pgprot_val(x) (x)
#define __pte(x) (x)
#define __pmd(x) (x)
#define __pgd(x) (x)
#define __pgprot(x) (x)
#define __pmd_val_set(x,n) (x) = (n)
#define __pgd_val_set(x,n) (x) = (n)
#endif /* STRICT_MM_TYPECHECKS */
typedef struct page *pgtable_t;
typedef struct __physmem_range {
unsigned long start_pfn;
unsigned long pages; /* PAGE_SIZE pages */
} physmem_range_t;
extern physmem_range_t pmem_ranges[];
extern int npmem_ranges;
#endif /* !__ASSEMBLY__ */
/* WARNING: The definitions below must match exactly to sizeof(pte_t)
* etc
*/
#ifdef CONFIG_64BIT
#define BITS_PER_PTE_ENTRY 3
#define BITS_PER_PMD_ENTRY 2
#define BITS_PER_PGD_ENTRY 2
#else
#define BITS_PER_PTE_ENTRY 2
#define BITS_PER_PMD_ENTRY 2
#define BITS_PER_PGD_ENTRY BITS_PER_PMD_ENTRY
#endif
#define PGD_ENTRY_SIZE (1UL << BITS_PER_PGD_ENTRY)
#define PMD_ENTRY_SIZE (1UL << BITS_PER_PMD_ENTRY)
#define PTE_ENTRY_SIZE (1UL << BITS_PER_PTE_ENTRY)
#define LINUX_GATEWAY_SPACE 0
/* This governs the relationship between virtual and physical addresses.
* If you alter it, make sure to take care of our various fixed mapping
* segments in fixmap.h */
#ifdef CONFIG_64BIT
#define __PAGE_OFFSET (0x40000000) /* 1GB */
#else
#define __PAGE_OFFSET (0x10000000) /* 256MB */
#endif
#define PAGE_OFFSET ((unsigned long)__PAGE_OFFSET)
/* The size of the gateway page (we leave lots of room for expansion) */
#define GATEWAY_PAGE_SIZE 0x4000
/* The start of the actual kernel binary---used in vmlinux.lds.S
* Leave some space after __PAGE_OFFSET for detecting kernel null
* ptr derefs */
#define KERNEL_BINARY_TEXT_START (__PAGE_OFFSET + 0x100000)
/* These macros don't work for 64-bit C code -- don't allow in C at all */
#ifdef __ASSEMBLY__
# define PA(x) ((x)-__PAGE_OFFSET)
# define VA(x) ((x)+__PAGE_OFFSET)
#endif
#define __pa(x) ((unsigned long)(x)-PAGE_OFFSET)
#define __va(x) ((void *)((unsigned long)(x)+PAGE_OFFSET))
#ifndef CONFIG_DISCONTIGMEM
#define pfn_valid(pfn) ((pfn) < max_mapnr)
#endif /* CONFIG_DISCONTIGMEM */
#ifdef CONFIG_HUGETLB_PAGE
#define HPAGE_SHIFT 22 /* 4MB (is this fixed?) */
#define HPAGE_SIZE ((1UL) << HPAGE_SHIFT)
#define HPAGE_MASK (~(HPAGE_SIZE - 1))
#define HUGETLB_PAGE_ORDER (HPAGE_SHIFT - PAGE_SHIFT)
#endif
#define virt_addr_valid(kaddr) pfn_valid(__pa(kaddr) >> PAGE_SHIFT)
#define page_to_phys(page) (page_to_pfn(page) << PAGE_SHIFT)
#define virt_to_page(kaddr) pfn_to_page(__pa(kaddr) >> PAGE_SHIFT)
#define VM_DATA_DEFAULT_FLAGS (VM_READ | VM_WRITE | VM_EXEC | \
VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)
#include <asm-generic/memory_model.h>
#include <asm-generic/page.h>
#endif /* _PARISC_PAGE_H */