metag: Highmem support
Signed-off-by: James Hogan <james.hogan@imgtec.com>
This commit is contained in:
James Hogan
99
arch/metag/include/asm/fixmap.h
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99
arch/metag/include/asm/fixmap.h
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/*
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* fixmap.h: compile-time virtual memory allocation
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*
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* Copyright (C) 1998 Ingo Molnar
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*
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* Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
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*/
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#ifndef _ASM_FIXMAP_H
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#define _ASM_FIXMAP_H
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#include <asm/pgtable.h>
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#ifdef CONFIG_HIGHMEM
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#include <linux/threads.h>
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#include <asm/kmap_types.h>
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#endif
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/*
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* Here we define all the compile-time 'special' virtual
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* addresses. The point is to have a constant address at
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* compile time, but to set the physical address only
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* in the boot process. We allocate these special addresses
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* from the end of the consistent memory region backwards.
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* Also this lets us do fail-safe vmalloc(), we
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* can guarantee that these special addresses and
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* vmalloc()-ed addresses never overlap.
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*
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* these 'compile-time allocated' memory buffers are
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* fixed-size 4k pages. (or larger if used with an increment
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* higher than 1) use fixmap_set(idx,phys) to associate
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* physical memory with fixmap indices.
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*
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* TLB entries of such buffers will not be flushed across
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* task switches.
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*/
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enum fixed_addresses {
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#define FIX_N_COLOURS 8
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#ifdef CONFIG_HIGHMEM
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/* reserved pte's for temporary kernel mappings */
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FIX_KMAP_BEGIN,
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FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1,
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#endif
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__end_of_fixed_addresses
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};
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#define FIXADDR_TOP (CONSISTENT_START - PAGE_SIZE)
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#define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT)
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#define FIXADDR_START ((FIXADDR_TOP - FIXADDR_SIZE) & PMD_MASK)
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#define __fix_to_virt(x) (FIXADDR_TOP - ((x) << PAGE_SHIFT))
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#define __virt_to_fix(x) ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)
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extern void __this_fixmap_does_not_exist(void);
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/*
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* 'index to address' translation. If anyone tries to use the idx
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* directly without tranlation, we catch the bug with a NULL-deference
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* kernel oops. Illegal ranges of incoming indices are caught too.
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*/
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static inline unsigned long fix_to_virt(const unsigned int idx)
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{
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/*
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* this branch gets completely eliminated after inlining,
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* except when someone tries to use fixaddr indices in an
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* illegal way. (such as mixing up address types or using
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* out-of-range indices).
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*
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* If it doesn't get removed, the linker will complain
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* loudly with a reasonably clear error message..
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*/
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if (idx >= __end_of_fixed_addresses)
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__this_fixmap_does_not_exist();
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return __fix_to_virt(idx);
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}
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static inline unsigned long virt_to_fix(const unsigned long vaddr)
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{
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BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);
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return __virt_to_fix(vaddr);
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}
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#define kmap_get_fixmap_pte(vaddr) \
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pte_offset_kernel( \
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pmd_offset(pud_offset(pgd_offset_k(vaddr), (vaddr)), (vaddr)), \
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(vaddr) \
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)
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/*
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* Called from pgtable_init()
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*/
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extern void fixrange_init(unsigned long start, unsigned long end,
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pgd_t *pgd_base);
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#endif
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62
arch/metag/include/asm/highmem.h
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62
arch/metag/include/asm/highmem.h
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#ifndef _ASM_HIGHMEM_H
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#define _ASM_HIGHMEM_H
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#include <asm/cacheflush.h>
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#include <asm/kmap_types.h>
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#include <asm/fixmap.h>
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/*
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* Right now we initialize only a single pte table. It can be extended
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* easily, subsequent pte tables have to be allocated in one physical
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* chunk of RAM.
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*/
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/*
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* Ordering is (from lower to higher memory addresses):
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*
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* high_memory
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* Persistent kmap area
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* PKMAP_BASE
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* fixed_addresses
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* FIXADDR_START
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* FIXADDR_TOP
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* Vmalloc area
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* VMALLOC_START
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* VMALLOC_END
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*/
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#define PKMAP_BASE (FIXADDR_START - PMD_SIZE)
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#define LAST_PKMAP PTRS_PER_PTE
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#define LAST_PKMAP_MASK (LAST_PKMAP - 1)
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#define PKMAP_NR(virt) (((virt) - PKMAP_BASE) >> PAGE_SHIFT)
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#define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT))
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#define kmap_prot PAGE_KERNEL
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static inline void flush_cache_kmaps(void)
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{
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flush_cache_all();
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}
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/* declarations for highmem.c */
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extern unsigned long highstart_pfn, highend_pfn;
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extern pte_t *pkmap_page_table;
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extern void *kmap_high(struct page *page);
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extern void kunmap_high(struct page *page);
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extern void kmap_init(void);
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/*
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* The following functions are already defined by <linux/highmem.h>
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* when CONFIG_HIGHMEM is not set.
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*/
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#ifdef CONFIG_HIGHMEM
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extern void *kmap(struct page *page);
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extern void kunmap(struct page *page);
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extern void *kmap_atomic(struct page *page);
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extern void __kunmap_atomic(void *kvaddr);
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extern void *kmap_atomic_pfn(unsigned long pfn);
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extern struct page *kmap_atomic_to_page(void *ptr);
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#endif
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#endif
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133
arch/metag/mm/highmem.c
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133
arch/metag/mm/highmem.c
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#include <linux/export.h>
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#include <linux/highmem.h>
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#include <linux/sched.h>
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#include <linux/smp.h>
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#include <linux/interrupt.h>
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#include <asm/fixmap.h>
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#include <asm/tlbflush.h>
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static pte_t *kmap_pte;
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unsigned long highstart_pfn, highend_pfn;
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void *kmap(struct page *page)
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{
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might_sleep();
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if (!PageHighMem(page))
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return page_address(page);
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return kmap_high(page);
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}
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EXPORT_SYMBOL(kmap);
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void kunmap(struct page *page)
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{
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BUG_ON(in_interrupt());
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if (!PageHighMem(page))
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return;
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kunmap_high(page);
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}
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EXPORT_SYMBOL(kunmap);
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/*
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* kmap_atomic/kunmap_atomic is significantly faster than kmap/kunmap because
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* no global lock is needed and because the kmap code must perform a global TLB
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* invalidation when the kmap pool wraps.
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*
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* However when holding an atomic kmap is is not legal to sleep, so atomic
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* kmaps are appropriate for short, tight code paths only.
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*/
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void *kmap_atomic(struct page *page)
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{
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enum fixed_addresses idx;
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unsigned long vaddr;
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int type;
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/* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */
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pagefault_disable();
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if (!PageHighMem(page))
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return page_address(page);
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type = kmap_atomic_idx_push();
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idx = type + KM_TYPE_NR * smp_processor_id();
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vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
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#ifdef CONFIG_DEBUG_HIGHMEM
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BUG_ON(!pte_none(*(kmap_pte - idx)));
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#endif
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set_pte(kmap_pte - idx, mk_pte(page, PAGE_KERNEL));
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return (void *)vaddr;
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}
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EXPORT_SYMBOL(kmap_atomic);
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void __kunmap_atomic(void *kvaddr)
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{
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unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
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int idx, type;
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if (kvaddr >= (void *)FIXADDR_START) {
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type = kmap_atomic_idx();
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idx = type + KM_TYPE_NR * smp_processor_id();
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/*
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* Force other mappings to Oops if they'll try to access this
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* pte without first remap it. Keeping stale mappings around
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* is a bad idea also, in case the page changes cacheability
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* attributes or becomes a protected page in a hypervisor.
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*/
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pte_clear(&init_mm, vaddr, kmap_pte-idx);
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flush_tlb_kernel_range(vaddr, vaddr + PAGE_SIZE);
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kmap_atomic_idx_pop();
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}
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pagefault_enable();
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}
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EXPORT_SYMBOL(__kunmap_atomic);
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/*
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* This is the same as kmap_atomic() but can map memory that doesn't
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* have a struct page associated with it.
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*/
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void *kmap_atomic_pfn(unsigned long pfn)
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{
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enum fixed_addresses idx;
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unsigned long vaddr;
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int type;
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pagefault_disable();
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type = kmap_atomic_idx_push();
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idx = type + KM_TYPE_NR * smp_processor_id();
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vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
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#ifdef CONFIG_DEBUG_HIGHMEM
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BUG_ON(!pte_none(*(kmap_pte - idx)));
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#endif
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set_pte(kmap_pte - idx, pfn_pte(pfn, PAGE_KERNEL));
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flush_tlb_kernel_range(vaddr, vaddr + PAGE_SIZE);
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return (void *)vaddr;
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}
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struct page *kmap_atomic_to_page(void *ptr)
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{
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unsigned long vaddr = (unsigned long)ptr;
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int idx;
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pte_t *pte;
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if (vaddr < FIXADDR_START)
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return virt_to_page(ptr);
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idx = virt_to_fix(vaddr);
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pte = kmap_pte - (idx - FIX_KMAP_BEGIN);
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return pte_page(*pte);
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}
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void __init kmap_init(void)
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{
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unsigned long kmap_vstart;
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/* cache the first kmap pte */
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kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
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kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
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}
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