Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965989Ab3GSFmq (ORCPT ); Fri, 19 Jul 2013 01:42:46 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:39693 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965609Ab3GSF0d (ORCPT ); Fri, 19 Jul 2013 01:26:33 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Helge Deller Subject: [ 21/72] parisc: document the shadow registers Date: Thu, 18 Jul 2013 22:25:38 -0700 Message-Id: <20130719052601.314654160@linuxfoundation.org> X-Mailer: git-send-email 1.8.3.2 In-Reply-To: <20130719052559.852627424@linuxfoundation.org> References: <20130719052559.852627424@linuxfoundation.org> User-Agent: quilt/0.60-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1382 Lines: 39 3.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Helge Deller commit a83f58bcb24003b9de2364de7c829a263423ead7 upstream. Signed-off-by: Helge Deller Signed-off-by: Greg Kroah-Hartman --- Documentation/parisc/registers | 8 ++++++++ 1 file changed, 8 insertions(+) --- a/Documentation/parisc/registers +++ b/Documentation/parisc/registers @@ -78,6 +78,14 @@ Shadow Registers used by interruption h TOC enable bit 1 ========================================================================= + +The PA-RISC architecture defines 7 registers as "shadow registers". +Those are used in RETURN FROM INTERRUPTION AND RESTORE instruction to reduce +the state save and restore time by eliminating the need for general register +(GR) saves and restores in interruption handlers. +Shadow registers are the GRs 1, 8, 9, 16, 17, 24, and 25. + +========================================================================= Register usage notes, originally from John Marvin, with some additional notes from Randolph Chung. -- 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/