From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:49080 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933317AbeD0OCT (ORCPT ); Fri, 27 Apr 2018 10:02:19 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Martin Schwidefsky Subject: [PATCH 4.4 14/50] s390: add optimized array_index_mask_nospec Date: Fri, 27 Apr 2018 15:58:16 +0200 Message-Id: <20180427135656.542157500@linuxfoundation.org> In-Reply-To: <20180427135655.623669681@linuxfoundation.org> References: <20180427135655.623669681@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Martin Schwidefsky [ Upstream commit e2dd833389cc4069a96b57bdd24227b5f52288f5 ] Add an optimized version of the array_index_mask_nospec function for s390 based on a compare and a subtract with borrow. Signed-off-by: Martin Schwidefsky Signed-off-by: Greg Kroah-Hartman --- arch/s390/include/asm/barrier.h | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) --- a/arch/s390/include/asm/barrier.h +++ b/arch/s390/include/asm/barrier.h @@ -53,4 +53,28 @@ do { \ ___p1; \ }) +/** + * array_index_mask_nospec - generate a mask for array_idx() that is + * ~0UL when the bounds check succeeds and 0 otherwise + * @index: array element index + * @size: number of elements in array + */ +#define array_index_mask_nospec array_index_mask_nospec +static inline unsigned long array_index_mask_nospec(unsigned long index, + unsigned long size) +{ + unsigned long mask; + + if (__builtin_constant_p(size) && size > 0) { + asm(" clgr %2,%1\n" + " slbgr %0,%0\n" + :"=d" (mask) : "d" (size-1), "d" (index) :"cc"); + return mask; + } + asm(" clgr %1,%2\n" + " slbgr %0,%0\n" + :"=d" (mask) : "d" (size), "d" (index) :"cc"); + return ~mask; +} + #endif /* __ASM_BARRIER_H */