From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sat, 16 Apr 2005 15:20:36 -0700 Subject: Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip! --- include/asm-ppc/highmem.h | 137 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 137 insertions(+) create mode 100644 include/asm-ppc/highmem.h (limited to 'include/asm-ppc/highmem.h') diff --git a/include/asm-ppc/highmem.h b/include/asm-ppc/highmem.h new file mode 100644 index 000000000000..1d2c4ef81c22 --- /dev/null +++ b/include/asm-ppc/highmem.h @@ -0,0 +1,137 @@ +/* + * highmem.h: virtual kernel memory mappings for high memory + * + * PowerPC version, stolen from the i386 version. + * + * Used in CONFIG_HIGHMEM systems for memory pages which + * are not addressable by direct kernel virtual addresses. + * + * Copyright (C) 1999 Gerhard Wichert, Siemens AG + * Gerhard.Wichert@pdb.siemens.de + * + * + * Redesigned the x86 32-bit VM architecture to deal with + * up to 16 Terrabyte physical memory. With current x86 CPUs + * we now support up to 64 Gigabytes physical RAM. + * + * Copyright (C) 1999 Ingo Molnar + */ + +#ifndef _ASM_HIGHMEM_H +#define _ASM_HIGHMEM_H + +#ifdef __KERNEL__ + +#include +#include +#include +#include +#include + +/* undef for production */ +#define HIGHMEM_DEBUG 1 + +extern pte_t *kmap_pte; +extern pgprot_t kmap_prot; +extern pte_t *pkmap_page_table; + +/* + * 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. + */ +#define PKMAP_BASE CONFIG_HIGHMEM_START +#define LAST_PKMAP (1 << PTE_SHIFT) +#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_FIX_BEGIN (PKMAP_BASE + 0x00400000UL) + +extern void *kmap_high(struct page *page); +extern void kunmap_high(struct page *page); + +static inline void *kmap(struct page *page) +{ + might_sleep(); + if (!PageHighMem(page)) + return page_address(page); + return kmap_high(page); +} + +static inline void kunmap(struct page *page) +{ + BUG_ON(in_interrupt()); + if (!PageHighMem(page)) + return; + kunmap_high(page); +} + +/* + * The use of kmap_atomic/kunmap_atomic is discouraged - kmap/kunmap + * gives a more generic (and caching) interface. But kmap_atomic can + * be used in IRQ contexts, so in some (very limited) cases we need + * it. + */ +static inline void *kmap_atomic(struct page *page, enum km_type type) +{ + unsigned int idx; + unsigned long vaddr; + + /* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */ + inc_preempt_count(); + if (!PageHighMem(page)) + return page_address(page); + + idx = type + KM_TYPE_NR*smp_processor_id(); + vaddr = KMAP_FIX_BEGIN + idx * PAGE_SIZE; +#ifdef HIGHMEM_DEBUG + BUG_ON(!pte_none(*(kmap_pte+idx))); +#endif + set_pte_at(&init_mm, vaddr, kmap_pte+idx, mk_pte(page, kmap_prot)); + flush_tlb_page(NULL, vaddr); + + return (void*) vaddr; +} + +static inline void kunmap_atomic(void *kvaddr, enum km_type type) +{ +#ifdef HIGHMEM_DEBUG + unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK; + unsigned int idx = type + KM_TYPE_NR*smp_processor_id(); + + if (vaddr < KMAP_FIX_BEGIN) { // FIXME + dec_preempt_count(); + preempt_check_resched(); + return; + } + + BUG_ON(vaddr != KMAP_FIX_BEGIN + idx * PAGE_SIZE); + + /* + * force other mappings to Oops if they'll try to access + * this pte without first remap it + */ + pte_clear(&init_mm, vaddr, kmap_pte+idx); + flush_tlb_page(NULL, vaddr); +#endif + dec_preempt_count(); + preempt_check_resched(); +} + +static inline struct page *kmap_atomic_to_page(void *ptr) +{ + unsigned long idx, vaddr = (unsigned long) ptr; + + if (vaddr < KMAP_FIX_BEGIN) + return virt_to_page(ptr); + + idx = (vaddr - KMAP_FIX_BEGIN) >> PAGE_SHIFT; + return pte_page(kmap_pte[idx]); +} + +#define flush_cache_kmaps() flush_cache_all() + +#endif /* __KERNEL__ */ + +#endif /* _ASM_HIGHMEM_H */ -- cgit v1.2.3