From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60937) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bUXFK-00075o-Ca for qemu-devel@nongnu.org; Tue, 02 Aug 2016 06:48:31 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bUXFD-00019w-7T for qemu-devel@nongnu.org; Tue, 02 Aug 2016 06:48:24 -0400 Date: Tue, 2 Aug 2016 06:48:12 -0400 (EDT) From: Paolo Bonzini Message-ID: <107219873.13018814.1470134892902.JavaMail.zimbra@redhat.com> In-Reply-To: <1470133216-6758-2-git-send-email-vijay.kilari@gmail.com> References: <1470133216-6758-1-git-send-email-vijay.kilari@gmail.com> <1470133216-6758-2-git-send-email-vijay.kilari@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [RFC PATCH v1 1/2] utils: Add helper to read arm MIDR_EL1 register List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: vijay kilari Cc: qemu-arm@nongnu.org, peter maydell , qemu-devel@nongnu.org, Prasun Kapoor , Vijaya Kumar K ----- Original Message ----- > From: "vijay kilari" > To: qemu-arm@nongnu.org, "peter maydell" , pbonzini@redhat.com > Cc: qemu-devel@nongnu.org, "Prasun Kapoor" , "vijay kilari" , > "Vijaya Kumar K" > Sent: Tuesday, August 2, 2016 12:20:15 PM > Subject: [RFC PATCH v1 1/2] utils: Add helper to read arm MIDR_EL1 register > > From: Vijaya Kumar K > > Add helper API to read MIDR_EL1 registers to fetch > cpu identification information. This helps in > adding errata's and architecture specific features. > > This is implemented only for arm architecture. > > Signed-off-by: Vijaya Kumar K > --- > include/qemu-common.h | 1 + > util/Makefile.objs | 1 + > util/cpuinfo.c | 52 > +++++++++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 54 insertions(+) > > diff --git a/include/qemu-common.h b/include/qemu-common.h > index 1f2cb94..62ad674 100644 > --- a/include/qemu-common.h > +++ b/include/qemu-common.h > @@ -134,4 +134,5 @@ void page_size_init(void); > * returned. */ > bool dump_in_progress(void); > > +long int qemu_read_cpuid_info(void); First, please avoid adding to include/qemu-common.h (it really should go away). Second, this is too generic a name. Please call it something like qemu_read_aarch64_midr_el1. Third, it's probably a bad idea to call this function from generic code, so make it static and add the detection function from patch 2/2 already here. By making it static, it's also possible to define it only if CONFIG_LINUX is defined; the ThunderX detection will then return false if !CONFIG_LINUX. Thanks, Paolo > #endif > diff --git a/util/Makefile.objs b/util/Makefile.objs > index 96cb1e0..9d25a72 100644 > --- a/util/Makefile.objs > +++ b/util/Makefile.objs > @@ -35,3 +35,4 @@ util-obj-y += log.o > util-obj-y += qdist.o > util-obj-y += qht.o > util-obj-y += range.o > +util-obj-y += cpuinfo.o > diff --git a/util/cpuinfo.c b/util/cpuinfo.c > new file mode 100644 > index 0000000..3ba7194 > --- /dev/null > +++ b/util/cpuinfo.c > @@ -0,0 +1,52 @@ > +/* > + * Dealing with arm cpu identification information. > + * > + * Copyright (C) 2016 Cavium, Inc. > + * > + * Authors: > + * Vijaya Kumar K > + * > + * This work is licensed under the terms of the GNU LGPL, version 2.1 > + * or later. See the COPYING.LIB file in the top-level directory. > + */ > + > +#include "qemu/osdep.h" > +#include "qemu-common.h" > +#include "qemu/cutils.h" > + > +#if defined(__aarch64__) > + > +long int qemu_read_cpuid_info(void) > +{ > + FILE *fp; > + char *buf; > + long int midr = 0; > +#define BUF_SIZE 32 > + > + fp = fopen("/sys/devices/system/cpu/cpu0/regs/identification/midr_el1", > + "r"); > + if (!fp) { > + return 0; > + } > + > + buf = g_malloc0(BUF_SIZE); > + if (!buf) { > + fclose(fp); > + return 0; > + } > + > + if (buf != fgets(buf, BUF_SIZE - 1, fp)) { > + goto out; > + } > + > + if (qemu_strtol(buf, NULL, 0, &midr) < 0) { > + goto out; > + } > + > +out: > + g_free(buf); > + fclose(fp); > + > + return midr; > +} > +#endif > -- > 1.7.9.5 > >