1ac2e6ca44
copy_from_user_nmi() is used in oprofile and perf. Moving it to other library functions like copy_from_user(). As this is x86 code for 32 and 64 bits, create a new file usercopy.c for unified code. Signed-off-by: Robert Richter <robert.richter@amd.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20110607172413.GJ20052@erda.amd.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
43 lines
815 B
C
43 lines
815 B
C
/*
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* User address space access functions.
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*
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* For licencing details see kernel-base/COPYING
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*/
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#include <linux/highmem.h>
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#include <linux/module.h>
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/*
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* best effort, GUP based copy_from_user() that is NMI-safe
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*/
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unsigned long
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copy_from_user_nmi(void *to, const void __user *from, unsigned long n)
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{
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unsigned long offset, addr = (unsigned long)from;
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unsigned long size, len = 0;
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struct page *page;
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void *map;
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int ret;
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do {
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ret = __get_user_pages_fast(addr, 1, 0, &page);
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if (!ret)
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break;
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offset = addr & (PAGE_SIZE - 1);
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size = min(PAGE_SIZE - offset, n - len);
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map = kmap_atomic(page);
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memcpy(to, map+offset, size);
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kunmap_atomic(map);
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put_page(page);
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len += size;
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to += size;
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addr += size;
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} while (len < n);
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return len;
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}
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EXPORT_SYMBOL_GPL(copy_from_user_nmi);
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