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Commit0a196848ca("perf: Fix arch_perf_out_copy_user default"), changes copy_from_user_nmi() to return the number of remaining bytes so that it behave like copy_from_user(). Unfortunately, when the range is outside of the process memory, the return value is still the number of byte copied, eg. 0, instead of the remaining bytes. As all users of copy_from_user_nmi() were modified as part of commit0a196848ca, the function should be fixed to return the total number of bytes if range is not correct. Signed-off-by: Yann Droneaud <ydroneaud@opteya.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1435001923-30986-1-git-send-email-ydroneaud@opteya.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
37 lines
837 B
C
37 lines
837 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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#include <asm/word-at-a-time.h>
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#include <linux/sched.h>
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/*
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* We rely on the nested NMI work to allow atomic faults from the NMI path; the
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* nested NMI paths are careful to preserve CR2.
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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 ret;
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if (__range_not_ok(from, n, TASK_SIZE))
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return n;
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/*
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* Even though this function is typically called from NMI/IRQ context
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* disable pagefaults so that its behaviour is consistent even when
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* called form other contexts.
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*/
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pagefault_disable();
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ret = __copy_from_user_inatomic(to, from, n);
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pagefault_enable();
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return ret;
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}
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EXPORT_SYMBOL_GPL(copy_from_user_nmi);
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