From bbc17704d5d3a8e4325dae74c2a2e77218c26057 Mon Sep 17 00:00:00 2001 From: James Hogan Date: Tue, 9 Oct 2012 10:54:17 +0100 Subject: [PATCH] metag: Highmem support Signed-off-by: James Hogan --- arch/metag/include/asm/fixmap.h | 99 +++++++++++++++++++++++ arch/metag/include/asm/highmem.h | 62 ++++++++++++++ arch/metag/mm/highmem.c | 133 +++++++++++++++++++++++++++++++ 3 files changed, 294 insertions(+) create mode 100644 arch/metag/include/asm/fixmap.h create mode 100644 arch/metag/include/asm/highmem.h create mode 100644 arch/metag/mm/highmem.c diff --git a/arch/metag/include/asm/fixmap.h b/arch/metag/include/asm/fixmap.h new file mode 100644 index 00000000000..33312751c92 --- /dev/null +++ b/arch/metag/include/asm/fixmap.h @@ -0,0 +1,99 @@ +/* + * fixmap.h: compile-time virtual memory allocation + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + * + * Copyright (C) 1998 Ingo Molnar + * + * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999 + */ + +#ifndef _ASM_FIXMAP_H +#define _ASM_FIXMAP_H + +#include +#ifdef CONFIG_HIGHMEM +#include +#include +#endif + +/* + * Here we define all the compile-time 'special' virtual + * addresses. The point is to have a constant address at + * compile time, but to set the physical address only + * in the boot process. We allocate these special addresses + * from the end of the consistent memory region backwards. + * Also this lets us do fail-safe vmalloc(), we + * can guarantee that these special addresses and + * vmalloc()-ed addresses never overlap. + * + * these 'compile-time allocated' memory buffers are + * fixed-size 4k pages. (or larger if used with an increment + * higher than 1) use fixmap_set(idx,phys) to associate + * physical memory with fixmap indices. + * + * TLB entries of such buffers will not be flushed across + * task switches. + */ +enum fixed_addresses { +#define FIX_N_COLOURS 8 +#ifdef CONFIG_HIGHMEM + /* reserved pte's for temporary kernel mappings */ + FIX_KMAP_BEGIN, + FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1, +#endif + __end_of_fixed_addresses +}; + +#define FIXADDR_TOP (CONSISTENT_START - PAGE_SIZE) +#define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT) +#define FIXADDR_START ((FIXADDR_TOP - FIXADDR_SIZE) & PMD_MASK) + +#define __fix_to_virt(x) (FIXADDR_TOP - ((x) << PAGE_SHIFT)) +#define __virt_to_fix(x) ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT) + +extern void __this_fixmap_does_not_exist(void); +/* + * 'index to address' translation. If anyone tries to use the idx + * directly without tranlation, we catch the bug with a NULL-deference + * kernel oops. Illegal ranges of incoming indices are caught too. + */ +static inline unsigned long fix_to_virt(const unsigned int idx) +{ + /* + * this branch gets completely eliminated after inlining, + * except when someone tries to use fixaddr indices in an + * illegal way. (such as mixing up address types or using + * out-of-range indices). + * + * If it doesn't get removed, the linker will complain + * loudly with a reasonably clear error message.. + */ + if (idx >= __end_of_fixed_addresses) + __this_fixmap_does_not_exist(); + + return __fix_to_virt(idx); +} + +static inline unsigned long virt_to_fix(const unsigned long vaddr) +{ + BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START); + return __virt_to_fix(vaddr); +} + +#define kmap_get_fixmap_pte(vaddr) \ + pte_offset_kernel( \ + pmd_offset(pud_offset(pgd_offset_k(vaddr), (vaddr)), (vaddr)), \ + (vaddr) \ + ) + +/* + * Called from pgtable_init() + */ +extern void fixrange_init(unsigned long start, unsigned long end, + pgd_t *pgd_base); + + +#endif diff --git a/arch/metag/include/asm/highmem.h b/arch/metag/include/asm/highmem.h new file mode 100644 index 00000000000..6646a15c73d --- /dev/null +++ b/arch/metag/include/asm/highmem.h @@ -0,0 +1,62 @@ +#ifndef _ASM_HIGHMEM_H +#define _ASM_HIGHMEM_H + +#include +#include +#include + +/* + * Right now we initialize only a single pte table. It can be extended + * easily, subsequent pte tables have to be allocated in one physical + * chunk of RAM. + */ +/* + * Ordering is (from lower to higher memory addresses): + * + * high_memory + * Persistent kmap area + * PKMAP_BASE + * fixed_addresses + * FIXADDR_START + * FIXADDR_TOP + * Vmalloc area + * VMALLOC_START + * VMALLOC_END + */ +#define PKMAP_BASE (FIXADDR_START - PMD_SIZE) +#define LAST_PKMAP PTRS_PER_PTE +#define LAST_PKMAP_MASK (LAST_PKMAP - 1) +#define PKMAP_NR(virt) (((virt) - PKMAP_BASE) >> PAGE_SHIFT) +#define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT)) + +#define kmap_prot PAGE_KERNEL + +static inline void flush_cache_kmaps(void) +{ + flush_cache_all(); +} + +/* declarations for highmem.c */ +extern unsigned long highstart_pfn, highend_pfn; + +extern pte_t *pkmap_page_table; + +extern void *kmap_high(struct page *page); +extern void kunmap_high(struct page *page); + +extern void kmap_init(void); + +/* + * The following functions are already defined by + * when CONFIG_HIGHMEM is not set. + */ +#ifdef CONFIG_HIGHMEM +extern void *kmap(struct page *page); +extern void kunmap(struct page *page); +extern void *kmap_atomic(struct page *page); +extern void __kunmap_atomic(void *kvaddr); +extern void *kmap_atomic_pfn(unsigned long pfn); +extern struct page *kmap_atomic_to_page(void *ptr); +#endif + +#endif diff --git a/arch/metag/mm/highmem.c b/arch/metag/mm/highmem.c new file mode 100644 index 00000000000..d71f621a2c0 --- /dev/null +++ b/arch/metag/mm/highmem.c @@ -0,0 +1,133 @@ +#include +#include +#include +#include +#include +#include +#include + +static pte_t *kmap_pte; + +unsigned long highstart_pfn, highend_pfn; + +void *kmap(struct page *page) +{ + might_sleep(); + if (!PageHighMem(page)) + return page_address(page); + return kmap_high(page); +} +EXPORT_SYMBOL(kmap); + +void kunmap(struct page *page) +{ + BUG_ON(in_interrupt()); + if (!PageHighMem(page)) + return; + kunmap_high(page); +} +EXPORT_SYMBOL(kunmap); + +/* + * kmap_atomic/kunmap_atomic is significantly faster than kmap/kunmap because + * no global lock is needed and because the kmap code must perform a global TLB + * invalidation when the kmap pool wraps. + * + * However when holding an atomic kmap is is not legal to sleep, so atomic + * kmaps are appropriate for short, tight code paths only. + */ + +void *kmap_atomic(struct page *page) +{ + enum fixed_addresses idx; + unsigned long vaddr; + int type; + + /* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */ + pagefault_disable(); + if (!PageHighMem(page)) + return page_address(page); + + type = kmap_atomic_idx_push(); + idx = type + KM_TYPE_NR * smp_processor_id(); + vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); +#ifdef CONFIG_DEBUG_HIGHMEM + BUG_ON(!pte_none(*(kmap_pte - idx))); +#endif + set_pte(kmap_pte - idx, mk_pte(page, PAGE_KERNEL)); + + return (void *)vaddr; +} +EXPORT_SYMBOL(kmap_atomic); + +void __kunmap_atomic(void *kvaddr) +{ + unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK; + int idx, type; + + if (kvaddr >= (void *)FIXADDR_START) { + type = kmap_atomic_idx(); + idx = type + KM_TYPE_NR * smp_processor_id(); + + /* + * Force other mappings to Oops if they'll try to access this + * pte without first remap it. Keeping stale mappings around + * is a bad idea also, in case the page changes cacheability + * attributes or becomes a protected page in a hypervisor. + */ + pte_clear(&init_mm, vaddr, kmap_pte-idx); + flush_tlb_kernel_range(vaddr, vaddr + PAGE_SIZE); + + kmap_atomic_idx_pop(); + } + + pagefault_enable(); +} +EXPORT_SYMBOL(__kunmap_atomic); + +/* + * This is the same as kmap_atomic() but can map memory that doesn't + * have a struct page associated with it. + */ +void *kmap_atomic_pfn(unsigned long pfn) +{ + enum fixed_addresses idx; + unsigned long vaddr; + int type; + + pagefault_disable(); + + type = kmap_atomic_idx_push(); + idx = type + KM_TYPE_NR * smp_processor_id(); + vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); +#ifdef CONFIG_DEBUG_HIGHMEM + BUG_ON(!pte_none(*(kmap_pte - idx))); +#endif + set_pte(kmap_pte - idx, pfn_pte(pfn, PAGE_KERNEL)); + flush_tlb_kernel_range(vaddr, vaddr + PAGE_SIZE); + + return (void *)vaddr; +} + +struct page *kmap_atomic_to_page(void *ptr) +{ + unsigned long vaddr = (unsigned long)ptr; + int idx; + pte_t *pte; + + if (vaddr < FIXADDR_START) + return virt_to_page(ptr); + + idx = virt_to_fix(vaddr); + pte = kmap_pte - (idx - FIX_KMAP_BEGIN); + return pte_page(*pte); +} + +void __init kmap_init(void) +{ + unsigned long kmap_vstart; + + /* cache the first kmap pte */ + kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN); + kmap_pte = kmap_get_fixmap_pte(kmap_vstart); +} -- 2.43.2