I got a message from someone working towards compiling plex86
on Linux kernel 2.4:
> Still getting an error -- MAP_NR (host-linux.c, line 954 or nearby) -- what's
> that do? I'm no kernel hacker ;)
It takes an address as returned by get_free_page(), and returns
the top 20bits of the physical address of the page.
Pages returned by get_free_page() are called 'physical', but
really they are offset by a kernel offset on newer kernels.
We want the real physical address, shifted right 12 bits;
the physical page index.
I'm including include/asm/page.h from my linux kernel.
If anyone else has ideas, please chime in.
It looks like MAP_NR() was supplanted by virt_to_page(),
probably because of reworking of kernel virtual memory
handling to take advantage of large system RAM.
You could try that macro instead. Not guaranteeing anything. :^)
-Kevin
#ifndef _I386_PAGE_H
#define _I386_PAGE_H
/* PAGE_SHIFT determines the page size */
#define PAGE_SHIFT 12
#define PAGE_SIZE (1UL << PAGE_SHIFT)
#define PAGE_MASK (~(PAGE_SIZE-1))
#ifdef __KERNEL__
#ifndef __ASSEMBLY__
#define STRICT_MM_TYPECHECKS
#define clear_page(page) memset((void *)(page), 0, PAGE_SIZE)
#define copy_page(to,from) memcpy((void *)(to), (void *)(from), PAGE_SIZE)
#ifdef STRICT_MM_TYPECHECKS
/*
* These are used to make use of C type-checking..
*/
typedef struct { unsigned long pte; } pte_t;
typedef struct { unsigned long pmd; } pmd_t;
typedef struct { unsigned long pgd; } pgd_t;
typedef struct { unsigned long pgprot; } pgprot_t;
#define pte_val(x) ((x).pte)
#define pmd_val(x) ((x).pmd)
#define pgd_val(x) ((x).pgd)
#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) } )
#else
/*
* .. while these make it easier on the compiler
*/
typedef unsigned long pte_t;
typedef unsigned long pmd_t;
typedef unsigned long 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)
#endif
#endif /* !__ASSEMBLY__ */
/* to align the pointer to the (next) page boundary */
#define PAGE_ALIGN(addr) (((addr)+PAGE_SIZE-1)&PAGE_MASK)
/*
* This handles the memory map.. We could make this a config
* option, but too many people screw it up, and too few need
* it.
*
* A __PAGE_OFFSET of 0xC0000000 means that the kernel has
* a virtual address space of one gigabyte, which limits the
* amount of physical memory you can use to about 950MB. If
* you want to use more physical memory, change this define.
*
* For example, if you have 2GB worth of physical memory, you
* could change this define to 0x80000000, which gives the
* kernel 2GB of virtual memory (enough to most of your physical memory
* as the kernel needs a bit extra for various io-memory mappings)
*
* IF YOU CHANGE THIS, PLEASE ALSO CHANGE
*
* arch/i386/vmlinux.lds
*
* which has the same constant encoded..
*/
#include <asm/page_offset.h>
#define __PAGE_OFFSET (PAGE_OFFSET_RAW)
#define PAGE_OFFSET ((unsigned long)__PAGE_OFFSET)
#define __pa(x) ((unsigned long)(x)-PAGE_OFFSET)
#define __va(x) ((void *)((unsigned long)(x)+PAGE_OFFSET))
#define MAP_NR(addr) (__pa(addr) >> PAGE_SHIFT)
#define PHYSMAP_NR(addr) ((unsigned long)(addr) >> PAGE_SHIFT)
#endif /* __KERNEL__ */
#endif /* _I386_PAGE_H */
