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linux/arch/arm/include/asm/memory.h
Nicolas Pitre d73cd42893 [ARM] kmap support 
The kmap virtual area borrows a 2MB range at the top of the 16MB area
below PAGE_OFFSET currently reserved for kernel modules and/or the
XIP kernel.  This 2MB corresponds to the range covered by 2 consecutive
second-level page tables, or a single pmd entry as seen by the Linux
page table abstraction.  Because XIP kernels are unlikely to be seen
on systems needing highmem support, there shouldn't be any shortage of
VM space for modules (14 MB for modules is still way more than twice the
typical usage).

Because the virtual mapping of highmem pages can go away at any moment
after kunmap() is called on them, we need to bypass the delayed cache
flushing provided by flush_dcache_page() in that case.

The atomic kmap versions are based on fixmaps, and
__cpuc_flush_dcache_page() is used directly in that case.

Signed-off-by: Nicolas Pitre <nico@marvell.com>
2009-03-15 21:01:20 -04:00

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/*
* arch/arm/include/asm/memory.h
*
* Copyright (C) 2000-2002 Russell King
* modification for nommu, Hyok S. Choi, 2004
*
* 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.
*
* Note: this file should not be included by non-asm/.h files
*/
#ifndef __ASM_ARM_MEMORY_H
#define __ASM_ARM_MEMORY_H
#include <linux/compiler.h>
#include <linux/const.h>
#include <mach/memory.h>
#include <asm/sizes.h>
/*
* Allow for constants defined here to be used from assembly code
* by prepending the UL suffix only with actual C code compilation.
*/
#define UL(x) _AC(x, UL)
#ifdef CONFIG_MMU
/*
* PAGE_OFFSET - the virtual address of the start of the kernel image
* TASK_SIZE - the maximum size of a user space task.
* TASK_UNMAPPED_BASE - the lower boundary of the mmap VM area
*/
#define PAGE_OFFSET UL(CONFIG_PAGE_OFFSET)
#define TASK_SIZE (UL(CONFIG_PAGE_OFFSET) - UL(0x01000000))
#define TASK_UNMAPPED_BASE (UL(CONFIG_PAGE_OFFSET) / 3)
/*
* The maximum size of a 26-bit user space task.
*/
#define TASK_SIZE_26 UL(0x04000000)
/*
* The module space lives between the addresses given by TASK_SIZE
* and PAGE_OFFSET - it must be within 32MB of the kernel text.
*/
#define MODULES_VADDR (PAGE_OFFSET - 16*1024*1024)
#if TASK_SIZE > MODULES_VADDR
#error Top of user space clashes with start of module space
#endif
/*
* The highmem pkmap virtual space shares the end of the module area.
*/
#ifdef CONFIG_HIGHMEM
#define MODULES_END (PAGE_OFFSET - PMD_SIZE)
#else
#define MODULES_END (PAGE_OFFSET)
#endif
/*
* The XIP kernel gets mapped at the bottom of the module vm area.
* Since we use sections to map it, this macro replaces the physical address
* with its virtual address while keeping offset from the base section.
*/
#define XIP_VIRT_ADDR(physaddr) (MODULES_VADDR + ((physaddr) & 0x000fffff))
/*
* Allow 16MB-aligned ioremap pages
*/
#define IOREMAP_MAX_ORDER 24
#else /* CONFIG_MMU */
/*
* The limitation of user task size can grow up to the end of free ram region.
* It is difficult to define and perhaps will never meet the original meaning
* of this define that was meant to.
* Fortunately, there is no reference for this in noMMU mode, for now.
*/
#ifndef TASK_SIZE
#define TASK_SIZE (CONFIG_DRAM_SIZE)
#endif
#ifndef TASK_UNMAPPED_BASE
#define TASK_UNMAPPED_BASE UL(0x00000000)
#endif
#ifndef PHYS_OFFSET
#define PHYS_OFFSET (CONFIG_DRAM_BASE)
#endif
#ifndef END_MEM
#define END_MEM (CONFIG_DRAM_BASE + CONFIG_DRAM_SIZE)
#endif
#ifndef PAGE_OFFSET
#define PAGE_OFFSET (PHYS_OFFSET)
#endif
/*
* The module can be at any place in ram in nommu mode.
*/
#define MODULES_END (END_MEM)
#define MODULES_VADDR (PHYS_OFFSET)
#endif /* !CONFIG_MMU */
/*
* Size of DMA-consistent memory region. Must be multiple of 2M,
* between 2MB and 14MB inclusive.
*/
#ifndef CONSISTENT_DMA_SIZE
#define CONSISTENT_DMA_SIZE SZ_2M
#endif
/*
* Physical vs virtual RAM address space conversion. These are
* private definitions which should NOT be used outside memory.h
* files. Use virt_to_phys/phys_to_virt/__pa/__va instead.
*/
#define __virt_to_phys(x) ((x) - PAGE_OFFSET + PHYS_OFFSET)
#define __phys_to_virt(x) ((x) - PHYS_OFFSET + PAGE_OFFSET)
/*
* Convert a physical address to a Page Frame Number and back
*/
#define __phys_to_pfn(paddr) ((paddr) >> PAGE_SHIFT)
#define __pfn_to_phys(pfn) ((pfn) << PAGE_SHIFT)
#ifndef __ASSEMBLY__
/*
* The DMA mask corresponding to the maximum bus address allocatable
* using GFP_DMA. The default here places no restriction on DMA
* allocations. This must be the smallest DMA mask in the system,
* so a successful GFP_DMA allocation will always satisfy this.
*/
#ifndef ISA_DMA_THRESHOLD
#define ISA_DMA_THRESHOLD (0xffffffffULL)
#endif
#ifndef arch_adjust_zones
#define arch_adjust_zones(node,size,holes) do { } while (0)
#elif !defined(CONFIG_ZONE_DMA)
#error "custom arch_adjust_zones() requires CONFIG_ZONE_DMA"
#endif
/*
* PFNs are used to describe any physical page; this means
* PFN 0 == physical address 0.
*
* This is the PFN of the first RAM page in the kernel
* direct-mapped view. We assume this is the first page
* of RAM in the mem_map as well.
*/
#define PHYS_PFN_OFFSET (PHYS_OFFSET >> PAGE_SHIFT)
/*
* These are *only* valid on the kernel direct mapped RAM memory.
* Note: Drivers should NOT use these. They are the wrong
* translation for translating DMA addresses. Use the driver
* DMA support - see dma-mapping.h.
*/
static inline unsigned long virt_to_phys(void *x)
{
return __virt_to_phys((unsigned long)(x));
}
static inline void *phys_to_virt(unsigned long x)
{
return (void *)(__phys_to_virt((unsigned long)(x)));
}
/*
* Drivers should NOT use these either.
*/
#define __pa(x) __virt_to_phys((unsigned long)(x))
#define __va(x) ((void *)__phys_to_virt((unsigned long)(x)))
#define pfn_to_kaddr(pfn) __va((pfn) << PAGE_SHIFT)
/*
* Virtual <-> DMA view memory address translations
* Again, these are *only* valid on the kernel direct mapped RAM
* memory. Use of these is *deprecated* (and that doesn't mean
* use the __ prefixed forms instead.) See dma-mapping.h.
*/
#ifndef __virt_to_bus
#define __virt_to_bus __virt_to_phys
#define __bus_to_virt __phys_to_virt
#endif
static inline __deprecated unsigned long virt_to_bus(void *x)
{
return __virt_to_bus((unsigned long)x);
}
static inline __deprecated void *bus_to_virt(unsigned long x)
{
return (void *)__bus_to_virt(x);
}
/*
* Conversion between a struct page and a physical address.
*
* Note: when converting an unknown physical address to a
* struct page, the resulting pointer must be validated
* using VALID_PAGE(). It must return an invalid struct page
* for any physical address not corresponding to a system
* RAM address.
*
* page_to_pfn(page) convert a struct page * to a PFN number
* pfn_to_page(pfn) convert a _valid_ PFN number to struct page *
* pfn_valid(pfn) indicates whether a PFN number is valid
*
* virt_to_page(k) convert a _valid_ virtual address to struct page *
* virt_addr_valid(k) indicates whether a virtual address is valid
*/
#ifndef CONFIG_DISCONTIGMEM
#define ARCH_PFN_OFFSET PHYS_PFN_OFFSET
#ifndef CONFIG_SPARSEMEM
#define pfn_valid(pfn) ((pfn) >= PHYS_PFN_OFFSET && (pfn) < (PHYS_PFN_OFFSET + max_mapnr))
#endif
#define virt_to_page(kaddr) pfn_to_page(__pa(kaddr) >> PAGE_SHIFT)
#define virt_addr_valid(kaddr) ((unsigned long)(kaddr) >= PAGE_OFFSET && (unsigned long)(kaddr) < (unsigned long)high_memory)
#define PHYS_TO_NID(addr) (0)
#else /* CONFIG_DISCONTIGMEM */
/*
* This is more complex. We have a set of mem_map arrays spread
* around in memory.
*/
#include <linux/numa.h>
#define arch_pfn_to_nid(pfn) PFN_TO_NID(pfn)
#define arch_local_page_offset(pfn, nid) LOCAL_MAP_NR((pfn) << PAGE_SHIFT)
#define pfn_valid(pfn) \
({ \
unsigned int nid = PFN_TO_NID(pfn); \
int valid = nid < MAX_NUMNODES; \
if (valid) { \
pg_data_t *node = NODE_DATA(nid); \
valid = (pfn - node->node_start_pfn) < \
node->node_spanned_pages; \
} \
valid; \
})
#define virt_to_page(kaddr) \
(ADDR_TO_MAPBASE(kaddr) + LOCAL_MAP_NR(kaddr))
#define virt_addr_valid(kaddr) (KVADDR_TO_NID(kaddr) < MAX_NUMNODES)
/*
* Common discontigmem stuff.
* PHYS_TO_NID is used by the ARM kernel/setup.c
*/
#define PHYS_TO_NID(addr) PFN_TO_NID((addr) >> PAGE_SHIFT)
/*
* Given a kaddr, ADDR_TO_MAPBASE finds the owning node of the memory
* and returns the mem_map of that node.
*/
#define ADDR_TO_MAPBASE(kaddr) NODE_MEM_MAP(KVADDR_TO_NID(kaddr))
/*
* Given a page frame number, find the owning node of the memory
* and returns the mem_map of that node.
*/
#define PFN_TO_MAPBASE(pfn) NODE_MEM_MAP(PFN_TO_NID(pfn))
#ifdef NODE_MEM_SIZE_BITS
#define NODE_MEM_SIZE_MASK ((1 << NODE_MEM_SIZE_BITS) - 1)
/*
* Given a kernel address, find the home node of the underlying memory.
*/
#define KVADDR_TO_NID(addr) \
(((unsigned long)(addr) - PAGE_OFFSET) >> NODE_MEM_SIZE_BITS)
/*
* Given a page frame number, convert it to a node id.
*/
#define PFN_TO_NID(pfn) \
(((pfn) - PHYS_PFN_OFFSET) >> (NODE_MEM_SIZE_BITS - PAGE_SHIFT))
/*
* Given a kaddr, LOCAL_MEM_MAP finds the owning node of the memory
* and returns the index corresponding to the appropriate page in the
* node's mem_map.
*/
#define LOCAL_MAP_NR(addr) \
(((unsigned long)(addr) & NODE_MEM_SIZE_MASK) >> PAGE_SHIFT)
#endif /* NODE_MEM_SIZE_BITS */
#endif /* !CONFIG_DISCONTIGMEM */
/*
* For BIO. "will die". Kill me when bio_to_phys() and bvec_to_phys() die.
*/
#define page_to_phys(page) (page_to_pfn(page) << PAGE_SHIFT)
/*
* Optional coherency support. Currently used only by selected
* Intel XSC3-based systems.
*/
#ifndef arch_is_coherent
#define arch_is_coherent() 0
#endif
#endif
#include <asm-generic/memory_model.h>
#endif
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