Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753622AbaBRW76 (ORCPT ); Tue, 18 Feb 2014 17:59:58 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:51156 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753380AbaBRWrM (ORCPT ); Tue, 18 Feb 2014 17:47:12 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Nathan Lynch , Will Deacon , Catalin Marinas Subject: [PATCH 3.13 15/40] arm64: vdso: fix coarse clock handling Date: Tue, 18 Feb 2014 14:47:16 -0800 Message-Id: <20140218224433.766930668@linuxfoundation.org> X-Mailer: git-send-email 1.8.5.1.163.gd7aced9 In-Reply-To: <20140218224433.337299968@linuxfoundation.org> References: <20140218224433.337299968@linuxfoundation.org> User-Agent: quilt/0.61-1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.13-stable review patch. If anyone has any objections, please let me know. ------------------ From: Nathan Lynch commit 069b918623e1510e58dacf178905a72c3baa3ae4 upstream. When __kernel_clock_gettime is called with a CLOCK_MONOTONIC_COARSE or CLOCK_REALTIME_COARSE clock id, it returns incorrectly to whatever the caller has placed in x2 ("ret x2" to return from the fast path). Fix this by saving x30/LR to x2 only in code that will call __do_get_tspec, restoring x30 afterward, and using a plain "ret" to return from the routine. Also: while the resulting tv_nsec value for CLOCK_REALTIME and CLOCK_MONOTONIC must be computed using intermediate values that are left-shifted by cs_shift (x12, set by __do_get_tspec), the results for coarse clocks should be calculated using unshifted values (xtime_coarse_nsec is in units of actual nanoseconds). The current code shifts intermediate values by x12 unconditionally, but x12 is uninitialized when servicing a coarse clock. Fix this by setting x12 to 0 once we know we are dealing with a coarse clock id. Signed-off-by: Nathan Lynch Acked-by: Will Deacon Signed-off-by: Catalin Marinas Signed-off-by: Greg Kroah-Hartman --- arch/arm64/kernel/vdso/gettimeofday.S | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) --- a/arch/arm64/kernel/vdso/gettimeofday.S +++ b/arch/arm64/kernel/vdso/gettimeofday.S @@ -103,6 +103,8 @@ ENTRY(__kernel_clock_gettime) bl __do_get_tspec seqcnt_check w9, 1b + mov x30, x2 + cmp w0, #CLOCK_MONOTONIC b.ne 6f @@ -118,6 +120,9 @@ ENTRY(__kernel_clock_gettime) ccmp w0, #CLOCK_MONOTONIC_COARSE, #0x4, ne b.ne 8f + /* xtime_coarse_nsec is already right-shifted */ + mov x12, #0 + /* Get coarse timespec. */ adr vdso_data, _vdso_data 3: seqcnt_acquire @@ -156,7 +161,7 @@ ENTRY(__kernel_clock_gettime) lsr x11, x11, x12 stp x10, x11, [x1, #TSPEC_TV_SEC] mov x0, xzr - ret x2 + ret 7: mov x30, x2 8: /* Syscall fallback. */ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/