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![Linus Torvalds](/assets/img/avatar_default.png)
"[RFC - PATCH 0/7] consolidation of BUG support code." https://lkml.org/lkml/2012/1/26/525 -- The changes shown here are to unify linux's BUG support under the one <linux/bug.h> file. Due to historical reasons, we have some BUG code in bug.h and some in kernel.h -- i.e. the support for BUILD_BUG in linux/kernel.h predates the addition of linux/bug.h, but old code in kernel.h wasn't moved to bug.h at that time. As a band-aid, kernel.h was including <asm/bug.h> to pseudo link them. This has caused confusion[1] and general yuck/WTF[2] reactions. Here is an example that violates the principle of least surprise: CC lib/string.o lib/string.c: In function 'strlcat': lib/string.c:225:2: error: implicit declaration of function 'BUILD_BUG_ON' make[2]: *** [lib/string.o] Error 1 $ $ grep linux/bug.h lib/string.c #include <linux/bug.h> $ We've included <linux/bug.h> for the BUG infrastructure and yet we still get a compile fail! [We've not kernel.h for BUILD_BUG_ON.] Ugh - very confusing for someone who is new to kernel development. With the above in mind, the goals of this changeset are: 1) find and fix any include/*.h files that were relying on the implicit presence of BUG code. 2) find and fix any C files that were consuming kernel.h and hence relying on implicitly getting some/all BUG code. 3) Move the BUG related code living in kernel.h to <linux/bug.h> 4) remove the asm/bug.h from kernel.h to finally break the chain. During development, the order was more like 3-4, build-test, 1-2. But to ensure that git history for bisect doesn't get needless build failures introduced, the commits have been reorderd to fix the problem areas in advance. [1] https://lkml.org/lkml/2012/1/3/90 [2] https://lkml.org/lkml/2012/1/17/414 -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) iQIcBAABAgAGBQJPbNwpAAoJEOvOhAQsB9HWrqYP/A0t9VB0nK6e42F0OR2P14MZ GJFtf1B++wwioIrx+KSWSRfSur1C5FKhDbxLR3I/pvkAYl4+T4JvRdMG6xJwxyip CC1kVQQNDjWVVqzjz2x6rYkOffx6dUlw/ERyIyk+OzP+1HzRIsIrugMqbzGLlX0X y0v2Tbd0G6xg1DV8lcRdp95eIzcGuUvdb2iY2LGadWZczEOeSXx64Jz3QCFxg3aL LFU4oovsg8Nb7MRJmqDvHK/oQf5vaTm9WSrS0pvVte0msSQRn8LStYdWC0G9BPCS GwL86h/eLXlUXQlC5GpgWg1QQt5i2QpjBFcVBIG0IT5SgEPMx+gXyiqZva2KwbHu LKicjKtfnzPitQnyEV/N6JyV1fb1U6/MsB7ebU5nCCzt9Gr7MYbjZ44peNeprAtu HMvJ/BNnRr4Ha6nPQNu952AdASPKkxmeXFUwBL1zUbLkOX/bK/vy1ujlcdkFxCD7 fP3t7hghYa737IHk0ehUOhrE4H67hvxTSCKioLUAy/YeN1IcfH/iOQiCBQVLWmoS AqYV6ou9cqgdYoyila2UeAqegb+8xyubPIHt+lebcaKxs5aGsTg+r3vq5juMDAPs iwSVYUDcIw9dHer1lJfo7QCy3QUTRDTxh+LB9VlHXQICgeCK02sLBOi9hbEr4/H8 Ko9g8J3BMxcMkXLHT9ud =PYQT -----END PGP SIGNATURE----- Merge tag 'bug-for-3.4' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux Pull <linux/bug.h> cleanup from Paul Gortmaker: "The changes shown here are to unify linux's BUG support under the one <linux/bug.h> file. Due to historical reasons, we have some BUG code in bug.h and some in kernel.h -- i.e. the support for BUILD_BUG in linux/kernel.h predates the addition of linux/bug.h, but old code in kernel.h wasn't moved to bug.h at that time. As a band-aid, kernel.h was including <asm/bug.h> to pseudo link them. This has caused confusion[1] and general yuck/WTF[2] reactions. Here is an example that violates the principle of least surprise: CC lib/string.o lib/string.c: In function 'strlcat': lib/string.c:225:2: error: implicit declaration of function 'BUILD_BUG_ON' make[2]: *** [lib/string.o] Error 1 $ $ grep linux/bug.h lib/string.c #include <linux/bug.h> $ We've included <linux/bug.h> for the BUG infrastructure and yet we still get a compile fail! [We've not kernel.h for BUILD_BUG_ON.] Ugh - very confusing for someone who is new to kernel development. With the above in mind, the goals of this changeset are: 1) find and fix any include/*.h files that were relying on the implicit presence of BUG code. 2) find and fix any C files that were consuming kernel.h and hence relying on implicitly getting some/all BUG code. 3) Move the BUG related code living in kernel.h to <linux/bug.h> 4) remove the asm/bug.h from kernel.h to finally break the chain. During development, the order was more like 3-4, build-test, 1-2. But to ensure that git history for bisect doesn't get needless build failures introduced, the commits have been reorderd to fix the problem areas in advance. [1] https://lkml.org/lkml/2012/1/3/90 [2] https://lkml.org/lkml/2012/1/17/414" Fix up conflicts (new radeon file, reiserfs header cleanups) as per Paul and linux-next. * tag 'bug-for-3.4' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux: kernel.h: doesn't explicitly use bug.h, so don't include it. bug: consolidate BUILD_BUG_ON with other bug code BUG: headers with BUG/BUG_ON etc. need linux/bug.h bug.h: add include of it to various implicit C users lib: fix implicit users of kernel.h for TAINT_WARN spinlock: macroize assert_spin_locked to avoid bug.h dependency x86: relocate get/set debugreg fcns to include/asm/debugreg.
287 lines
7.1 KiB
C
287 lines
7.1 KiB
C
#ifndef _LINUX_HIGHMEM_H
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#define _LINUX_HIGHMEM_H
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#include <linux/fs.h>
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#include <linux/kernel.h>
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#include <linux/bug.h>
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#include <linux/mm.h>
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#include <linux/uaccess.h>
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#include <linux/hardirq.h>
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#include <asm/cacheflush.h>
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#ifndef ARCH_HAS_FLUSH_ANON_PAGE
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static inline void flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned long vmaddr)
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{
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}
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#endif
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#ifndef ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE
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static inline void flush_kernel_dcache_page(struct page *page)
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{
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}
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static inline void flush_kernel_vmap_range(void *vaddr, int size)
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{
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}
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static inline void invalidate_kernel_vmap_range(void *vaddr, int size)
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{
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}
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#endif
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#include <asm/kmap_types.h>
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#ifdef CONFIG_HIGHMEM
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#include <asm/highmem.h>
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/* declarations for linux/mm/highmem.c */
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unsigned int nr_free_highpages(void);
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extern unsigned long totalhigh_pages;
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void kmap_flush_unused(void);
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#else /* CONFIG_HIGHMEM */
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static inline unsigned int nr_free_highpages(void) { return 0; }
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#define totalhigh_pages 0UL
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#ifndef ARCH_HAS_KMAP
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static inline void *kmap(struct page *page)
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{
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might_sleep();
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return page_address(page);
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}
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static inline void kunmap(struct page *page)
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{
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}
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static inline void *kmap_atomic(struct page *page)
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{
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pagefault_disable();
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return page_address(page);
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}
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#define kmap_atomic_prot(page, prot) kmap_atomic(page)
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static inline void __kunmap_atomic(void *addr)
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{
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pagefault_enable();
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}
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#define kmap_atomic_pfn(pfn) kmap_atomic(pfn_to_page(pfn))
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#define kmap_atomic_to_page(ptr) virt_to_page(ptr)
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#define kmap_flush_unused() do {} while(0)
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#endif
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#endif /* CONFIG_HIGHMEM */
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#if defined(CONFIG_HIGHMEM) || defined(CONFIG_X86_32)
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DECLARE_PER_CPU(int, __kmap_atomic_idx);
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static inline int kmap_atomic_idx_push(void)
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{
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int idx = __this_cpu_inc_return(__kmap_atomic_idx) - 1;
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#ifdef CONFIG_DEBUG_HIGHMEM
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WARN_ON_ONCE(in_irq() && !irqs_disabled());
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BUG_ON(idx > KM_TYPE_NR);
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#endif
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return idx;
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}
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static inline int kmap_atomic_idx(void)
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{
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return __this_cpu_read(__kmap_atomic_idx) - 1;
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}
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static inline void kmap_atomic_idx_pop(void)
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{
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#ifdef CONFIG_DEBUG_HIGHMEM
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int idx = __this_cpu_dec_return(__kmap_atomic_idx);
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BUG_ON(idx < 0);
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#else
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__this_cpu_dec(__kmap_atomic_idx);
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#endif
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}
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#endif
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/*
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* NOTE:
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* kmap_atomic() and kunmap_atomic() with two arguments are deprecated.
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* We only keep them for backward compatibility, any usage of them
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* are now warned.
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*/
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#define PASTE(a, b) a ## b
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#define PASTE2(a, b) PASTE(a, b)
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#define NARG_(_2, _1, n, ...) n
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#define NARG(...) NARG_(__VA_ARGS__, 2, 1, :)
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static inline void __deprecated *kmap_atomic_deprecated(struct page *page,
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enum km_type km)
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{
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return kmap_atomic(page);
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}
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#define kmap_atomic1(...) kmap_atomic(__VA_ARGS__)
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#define kmap_atomic2(...) kmap_atomic_deprecated(__VA_ARGS__)
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#define kmap_atomic(...) PASTE2(kmap_atomic, NARG(__VA_ARGS__)(__VA_ARGS__))
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static inline void __deprecated __kunmap_atomic_deprecated(void *addr,
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enum km_type km)
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{
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__kunmap_atomic(addr);
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}
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/*
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* Prevent people trying to call kunmap_atomic() as if it were kunmap()
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* kunmap_atomic() should get the return value of kmap_atomic, not the page.
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*/
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#define kunmap_atomic_deprecated(addr, km) \
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do { \
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BUILD_BUG_ON(__same_type((addr), struct page *)); \
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__kunmap_atomic_deprecated(addr, km); \
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} while (0)
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#define kunmap_atomic_withcheck(addr) \
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do { \
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BUILD_BUG_ON(__same_type((addr), struct page *)); \
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__kunmap_atomic(addr); \
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} while (0)
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#define kunmap_atomic1(...) kunmap_atomic_withcheck(__VA_ARGS__)
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#define kunmap_atomic2(...) kunmap_atomic_deprecated(__VA_ARGS__)
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#define kunmap_atomic(...) PASTE2(kunmap_atomic, NARG(__VA_ARGS__)(__VA_ARGS__))
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/**** End of C pre-processor tricks for deprecated macros ****/
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/* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */
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#ifndef clear_user_highpage
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static inline void clear_user_highpage(struct page *page, unsigned long vaddr)
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{
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void *addr = kmap_atomic(page);
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clear_user_page(addr, vaddr, page);
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kunmap_atomic(addr);
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}
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#endif
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#ifndef __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE
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/**
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* __alloc_zeroed_user_highpage - Allocate a zeroed HIGHMEM page for a VMA with caller-specified movable GFP flags
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* @movableflags: The GFP flags related to the pages future ability to move like __GFP_MOVABLE
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* @vma: The VMA the page is to be allocated for
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* @vaddr: The virtual address the page will be inserted into
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*
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* This function will allocate a page for a VMA but the caller is expected
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* to specify via movableflags whether the page will be movable in the
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* future or not
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*
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* An architecture may override this function by defining
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* __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE and providing their own
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* implementation.
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*/
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static inline struct page *
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__alloc_zeroed_user_highpage(gfp_t movableflags,
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struct vm_area_struct *vma,
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unsigned long vaddr)
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{
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struct page *page = alloc_page_vma(GFP_HIGHUSER | movableflags,
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vma, vaddr);
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if (page)
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clear_user_highpage(page, vaddr);
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return page;
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}
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#endif
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/**
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* alloc_zeroed_user_highpage_movable - Allocate a zeroed HIGHMEM page for a VMA that the caller knows can move
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* @vma: The VMA the page is to be allocated for
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* @vaddr: The virtual address the page will be inserted into
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*
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* This function will allocate a page for a VMA that the caller knows will
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* be able to migrate in the future using move_pages() or reclaimed
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*/
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static inline struct page *
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alloc_zeroed_user_highpage_movable(struct vm_area_struct *vma,
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unsigned long vaddr)
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{
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return __alloc_zeroed_user_highpage(__GFP_MOVABLE, vma, vaddr);
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}
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static inline void clear_highpage(struct page *page)
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{
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void *kaddr = kmap_atomic(page);
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clear_page(kaddr);
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kunmap_atomic(kaddr);
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}
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static inline void zero_user_segments(struct page *page,
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unsigned start1, unsigned end1,
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unsigned start2, unsigned end2)
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{
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void *kaddr = kmap_atomic(page);
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BUG_ON(end1 > PAGE_SIZE || end2 > PAGE_SIZE);
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if (end1 > start1)
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memset(kaddr + start1, 0, end1 - start1);
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if (end2 > start2)
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memset(kaddr + start2, 0, end2 - start2);
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kunmap_atomic(kaddr);
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flush_dcache_page(page);
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}
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static inline void zero_user_segment(struct page *page,
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unsigned start, unsigned end)
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{
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zero_user_segments(page, start, end, 0, 0);
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}
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static inline void zero_user(struct page *page,
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unsigned start, unsigned size)
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{
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zero_user_segments(page, start, start + size, 0, 0);
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}
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static inline void __deprecated memclear_highpage_flush(struct page *page,
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unsigned int offset, unsigned int size)
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{
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zero_user(page, offset, size);
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}
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#ifndef __HAVE_ARCH_COPY_USER_HIGHPAGE
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static inline void copy_user_highpage(struct page *to, struct page *from,
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unsigned long vaddr, struct vm_area_struct *vma)
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{
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char *vfrom, *vto;
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vfrom = kmap_atomic(from);
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vto = kmap_atomic(to);
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copy_user_page(vto, vfrom, vaddr, to);
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kunmap_atomic(vto);
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kunmap_atomic(vfrom);
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}
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#endif
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static inline void copy_highpage(struct page *to, struct page *from)
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{
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char *vfrom, *vto;
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vfrom = kmap_atomic(from);
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vto = kmap_atomic(to);
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copy_page(vto, vfrom);
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kunmap_atomic(vto);
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kunmap_atomic(vfrom);
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}
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#endif /* _LINUX_HIGHMEM_H */
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