Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753913Ab3DVBNq (ORCPT ); Sun, 21 Apr 2013 21:13:46 -0400 Received: from ozlabs.org ([203.10.76.45]:51966 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752573Ab3DVBNp (ORCPT ); Sun, 21 Apr 2013 21:13:45 -0400 From: Michael Neuling To: Michael Ellerman cc: Anshuman Khandual , linuxppc-dev@ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH V3 1/5] powerpc, perf: Add new BHRB related instructions for POWER8 In-reply-to: <20130421234109.GC22246@concordia> References: <1366287976-3900-1-git-send-email-khandual@linux.vnet.ibm.com> <1366287976-3900-2-git-send-email-khandual@linux.vnet.ibm.com> <20130421234109.GC22246@concordia> Comments: In-reply-to Michael Ellerman message dated "Mon, 22 Apr 2013 09:41:10 +1000." X-Mailer: MH-E 8.2; nmh 1.5; GNU Emacs 23.4.1 Date: Mon, 22 Apr 2013 11:13:43 +1000 Message-ID: <14010.1366593223@ale.ozlabs.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1804 Lines: 50 Michael Ellerman wrote: > On Thu, Apr 18, 2013 at 05:56:12PM +0530, Anshuman Khandual wrote: > > This patch adds new POWER8 instruction encoding for reading > > the BHRB buffer entries and also clearing it. Encoding for > > "clrbhrb" instruction is straight forward. > > Which is "clear branch history rolling buffer" ? > > > But "mfbhrbe" > > encoding involves reading a certain index of BHRB buffer > > into a particular GPR register. > > And "Move from branch history rolling buffer entry" ? > > > diff --git a/arch/powerpc/include/asm/ppc-opcode.h b/arch/powerpc/include/asm/ppc-opcode.h > > index 8752bc8..93ae5a1 100644 > > --- a/arch/powerpc/include/asm/ppc-opcode.h > > +++ b/arch/powerpc/include/asm/ppc-opcode.h > > @@ -82,6 +82,7 @@ > > #define __REGA0_R31 31 > > > > /* sorted alphabetically */ > > +#define PPC_INST_BHRBE 0x7c00025c > > I don't think you really need this, just use the literal value below. The rest of the defines in this file do this, so Anshuman's right. > > @@ -297,6 +298,12 @@ > > #define PPC_NAP stringify_in_c(.long PPC_INST_NAP) > > #define PPC_SLEEP stringify_in_c(.long PPC_INST_SLEEP) > > > > +/* BHRB instructions */ > > +#define PPC_CLRBHRB stringify_in_c(.long 0x7c00035c) > > +#define PPC_MFBHRBE(r, n) stringify_in_c(.long PPC_INST_BHRBE | \ > > + __PPC_RS(r) | \ > > + (((n) & 0x1f) << 11)) > > Why are you not using ___PPC_RB(n) here ? Actually, this is wrong. The number field should be 10 bits (0x3ff), not 5 (0x1f) Anshuman please fix. Mikey -- 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/