From 3e4d3af501cccdc8a8cca41bdbe57d54ad7e7e73 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 26 Oct 2010 14:21:51 -0700 Subject: mm: stack based kmap_atomic() Keep the current interface but ignore the KM_type and use a stack based approach. The advantage is that we get rid of crappy code like: #define __KM_PTE \ (in_nmi() ? KM_NMI_PTE : \ in_irq() ? KM_IRQ_PTE : \ KM_PTE0) and in general can stop worrying about what context we're in and what kmap slots might be appropriate for that. The downside is that FRV kmap_atomic() gets more expensive. For now we use a CPP trick suggested by Andrew: #define kmap_atomic(page, args...) __kmap_atomic(page) to avoid having to touch all kmap_atomic() users in a single patch. [ not compiled on: - mn10300: the arch doesn't actually build with highmem to begin with ] [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: fix up drivers/gpu/drm/i915/intel_overlay.c] Acked-by: Rik van Riel Signed-off-by: Peter Zijlstra Acked-by: Chris Metcalf Cc: David Howells Cc: Hugh Dickins Cc: Ingo Molnar Cc: Thomas Gleixner Cc: "H. Peter Anvin" Cc: Steven Rostedt Cc: Russell King Cc: Ralf Baechle Cc: David Miller Cc: Paul Mackerras Cc: Benjamin Herrenschmidt Cc: Dave Airlie Cc: Li Zefan Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/x86/include/asm/highmem.h | 11 +++--- arch/x86/include/asm/iomap.h | 4 +-- arch/x86/kernel/crash_dump_32.c | 2 +- arch/x86/mm/highmem_32.c | 75 ++++++++++++++++++++++------------------- arch/x86/mm/iomap_32.c | 42 +++++++++++++---------- 5 files changed, 75 insertions(+), 59 deletions(-) (limited to 'arch/x86') diff --git a/arch/x86/include/asm/highmem.h b/arch/x86/include/asm/highmem.h index 8caac76..3bd0402 100644 --- a/arch/x86/include/asm/highmem.h +++ b/arch/x86/include/asm/highmem.h @@ -59,11 +59,12 @@ extern void kunmap_high(struct page *page); void *kmap(struct page *page); void kunmap(struct page *page); -void *kmap_atomic_prot(struct page *page, enum km_type type, pgprot_t prot); -void *kmap_atomic(struct page *page, enum km_type type); -void kunmap_atomic_notypecheck(void *kvaddr, enum km_type type); -void *kmap_atomic_pfn(unsigned long pfn, enum km_type type); -void *kmap_atomic_prot_pfn(unsigned long pfn, enum km_type type, pgprot_t prot); + +void *kmap_atomic_prot(struct page *page, pgprot_t prot); +void *__kmap_atomic(struct page *page); +void __kunmap_atomic(void *kvaddr); +void *kmap_atomic_pfn(unsigned long pfn); +void *kmap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot); struct page *kmap_atomic_to_page(void *ptr); #define flush_cache_kmaps() do { } while (0) diff --git a/arch/x86/include/asm/iomap.h b/arch/x86/include/asm/iomap.h index c4191b3..363e33e 100644 --- a/arch/x86/include/asm/iomap.h +++ b/arch/x86/include/asm/iomap.h @@ -27,10 +27,10 @@ #include void __iomem * -iomap_atomic_prot_pfn(unsigned long pfn, enum km_type type, pgprot_t prot); +iomap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot); void -iounmap_atomic(void __iomem *kvaddr, enum km_type type); +iounmap_atomic(void __iomem *kvaddr); int iomap_create_wc(resource_size_t base, unsigned long size, pgprot_t *prot); diff --git a/arch/x86/kernel/crash_dump_32.c b/arch/x86/kernel/crash_dump_32.c index 6741455..d5cd139 100644 --- a/arch/x86/kernel/crash_dump_32.c +++ b/arch/x86/kernel/crash_dump_32.c @@ -61,7 +61,7 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf, if (!is_crashed_pfn_valid(pfn)) return -EFAULT; - vaddr = kmap_atomic_pfn(pfn, KM_PTE0); + vaddr = kmap_atomic_pfn(pfn); if (!userbuf) { memcpy(buf, (vaddr + offset), csize); diff --git a/arch/x86/mm/highmem_32.c b/arch/x86/mm/highmem_32.c index 5e8fa12..d723e36 100644 --- a/arch/x86/mm/highmem_32.c +++ b/arch/x86/mm/highmem_32.c @@ -9,6 +9,7 @@ void *kmap(struct page *page) return page_address(page); return kmap_high(page); } +EXPORT_SYMBOL(kmap); void kunmap(struct page *page) { @@ -18,6 +19,7 @@ void kunmap(struct page *page) return; kunmap_high(page); } +EXPORT_SYMBOL(kunmap); /* * kmap_atomic/kunmap_atomic is significantly faster than kmap/kunmap because @@ -27,10 +29,10 @@ void kunmap(struct page *page) * However when holding an atomic kmap it is not legal to sleep, so atomic * kmaps are appropriate for short, tight code paths only. */ -void *kmap_atomic_prot(struct page *page, enum km_type type, pgprot_t prot) +void *kmap_atomic_prot(struct page *page, pgprot_t prot) { - enum fixed_addresses idx; unsigned long vaddr; + int idx, type; /* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */ pagefault_disable(); @@ -38,8 +40,7 @@ void *kmap_atomic_prot(struct page *page, enum km_type type, pgprot_t prot) if (!PageHighMem(page)) return page_address(page); - debug_kmap_atomic(type); - + type = kmap_atomic_idx_push(); idx = type + KM_TYPE_NR*smp_processor_id(); vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); BUG_ON(!pte_none(*(kmap_pte-idx))); @@ -47,44 +48,56 @@ void *kmap_atomic_prot(struct page *page, enum km_type type, pgprot_t prot) return (void *)vaddr; } +EXPORT_SYMBOL(kmap_atomic_prot); + +void *__kmap_atomic(struct page *page) +{ + return kmap_atomic_prot(page, kmap_prot); +} +EXPORT_SYMBOL(__kmap_atomic); -void *kmap_atomic(struct page *page, enum km_type type) +/* + * 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) { - return kmap_atomic_prot(page, type, kmap_prot); + return kmap_atomic_prot_pfn(pfn, kmap_prot); } +EXPORT_SYMBOL_GPL(kmap_atomic_pfn); -void kunmap_atomic_notypecheck(void *kvaddr, enum km_type type) +void __kunmap_atomic(void *kvaddr) { unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK; - enum fixed_addresses 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. - */ - if (vaddr == __fix_to_virt(FIX_KMAP_BEGIN+idx)) + + if (vaddr >= __fix_to_virt(FIX_KMAP_END) && + vaddr <= __fix_to_virt(FIX_KMAP_BEGIN)) { + int idx, type; + + type = kmap_atomic_idx_pop(); + idx = type + KM_TYPE_NR * smp_processor_id(); + +#ifdef CONFIG_DEBUG_HIGHMEM + WARN_ON_ONCE(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx)); +#endif + /* + * 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. + */ kpte_clear_flush(kmap_pte-idx, vaddr); - else { + } #ifdef CONFIG_DEBUG_HIGHMEM + else { BUG_ON(vaddr < PAGE_OFFSET); BUG_ON(vaddr >= (unsigned long)high_memory); -#endif } +#endif pagefault_enable(); } - -/* - * 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 km_type type) -{ - return kmap_atomic_prot_pfn(pfn, type, kmap_prot); -} -EXPORT_SYMBOL_GPL(kmap_atomic_pfn); /* temporarily in use by i915 GEM until vmap */ +EXPORT_SYMBOL(__kunmap_atomic); struct page *kmap_atomic_to_page(void *ptr) { @@ -98,12 +111,6 @@ struct page *kmap_atomic_to_page(void *ptr) pte = kmap_pte - (idx - FIX_KMAP_BEGIN); return pte_page(*pte); } - -EXPORT_SYMBOL(kmap); -EXPORT_SYMBOL(kunmap); -EXPORT_SYMBOL(kmap_atomic); -EXPORT_SYMBOL(kunmap_atomic_notypecheck); -EXPORT_SYMBOL(kmap_atomic_prot); EXPORT_SYMBOL(kmap_atomic_to_page); void __init set_highmem_pages_init(void) diff --git a/arch/x86/mm/iomap_32.c b/arch/x86/mm/iomap_32.c index 72fc70c..75a3d7f 100644 --- a/arch/x86/mm/iomap_32.c +++ b/arch/x86/mm/iomap_32.c @@ -48,21 +48,20 @@ int iomap_create_wc(resource_size_t base, unsigned long size, pgprot_t *prot) } EXPORT_SYMBOL_GPL(iomap_create_wc); -void -iomap_free(resource_size_t base, unsigned long size) +void iomap_free(resource_size_t base, unsigned long size) { io_free_memtype(base, base + size); } EXPORT_SYMBOL_GPL(iomap_free); -void *kmap_atomic_prot_pfn(unsigned long pfn, enum km_type type, pgprot_t prot) +void *kmap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot) { - enum fixed_addresses idx; unsigned long vaddr; + int idx, type; pagefault_disable(); - debug_kmap_atomic(type); + type = kmap_atomic_idx_push(); idx = type + KM_TYPE_NR * smp_processor_id(); vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); set_pte(kmap_pte - idx, pfn_pte(pfn, prot)); @@ -72,10 +71,10 @@ void *kmap_atomic_prot_pfn(unsigned long pfn, enum km_type type, pgprot_t prot) } /* - * Map 'pfn' using fixed map 'type' and protections 'prot' + * Map 'pfn' using protections 'prot' */ void __iomem * -iomap_atomic_prot_pfn(unsigned long pfn, enum km_type type, pgprot_t prot) +iomap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot) { /* * For non-PAT systems, promote PAGE_KERNEL_WC to PAGE_KERNEL_UC_MINUS. @@ -86,24 +85,33 @@ iomap_atomic_prot_pfn(unsigned long pfn, enum km_type type, pgprot_t prot) if (!pat_enabled && pgprot_val(prot) == pgprot_val(PAGE_KERNEL_WC)) prot = PAGE_KERNEL_UC_MINUS; - return (void __force __iomem *) kmap_atomic_prot_pfn(pfn, type, prot); + return (void __force __iomem *) kmap_atomic_prot_pfn(pfn, prot); } EXPORT_SYMBOL_GPL(iomap_atomic_prot_pfn); void -iounmap_atomic(void __iomem *kvaddr, enum km_type type) +iounmap_atomic(void __iomem *kvaddr) { unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK; - enum fixed_addresses 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. - */ - if (vaddr == __fix_to_virt(FIX_KMAP_BEGIN+idx)) + if (vaddr >= __fix_to_virt(FIX_KMAP_END) && + vaddr <= __fix_to_virt(FIX_KMAP_BEGIN)) { + int idx, type; + + type = kmap_atomic_idx_pop(); + idx = type + KM_TYPE_NR * smp_processor_id(); + +#ifdef CONFIG_DEBUG_HIGHMEM + WARN_ON_ONCE(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx)); +#endif + /* + * 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. + */ kpte_clear_flush(kmap_pte-idx, vaddr); + } pagefault_enable(); } -- cgit v1.1