Commit-ID: 10013ebb5d7856c243541870f4e62fed68253e88 Gitweb: http://git.kernel.org/tip/10013ebb5d7856c243541870f4e62fed68253e88 Author: Andi Kleen <ak@xxxxxxxxxxxxxxx> AuthorDate: Thu, 22 Oct 2015 15:07:20 -0700 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitDate: Mon, 23 Nov 2015 09:58:24 +0100 x86: Add an inlined __copy_from_user_nmi() variant Add a inlined __ variant of copy_from_user_nmi. The inlined variant allows the user to: - batch the access_ok() check for multiple accesses - avoid having a pagefault_disable/enable() on every access if the caller already ensures disabled page faults due to its context. - get all the optimizations in copy_*_user() for small constant sized transfers It is just a define to __copy_from_user_inatomic(). Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> Cc: Jiri Olsa <jolsa@xxxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Link: http://lkml.kernel.org/r/1445551641-13379-1-git-send-email-andi@xxxxxxxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> --- arch/x86/include/asm/uaccess.h | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h index 09b1b0a..660458a 100644 --- a/arch/x86/include/asm/uaccess.h +++ b/arch/x86/include/asm/uaccess.h @@ -745,5 +745,14 @@ copy_to_user(void __user *to, const void *from, unsigned long n) #undef __copy_from_user_overflow #undef __copy_to_user_overflow +/* + * We rely on the nested NMI work to allow atomic faults from the NMI path; the + * nested NMI paths are careful to preserve CR2. + * + * Caller must use pagefault_enable/disable, or run in interrupt context, + * and also do a uaccess_ok() check + */ +#define __copy_from_user_nmi __copy_from_user_inatomic + #endif /* _ASM_X86_UACCESS_H */ -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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