Message ID | 1470133216-6758-2-git-send-email-vijay.kilari@gmail.com |
---|---|
State | New |
Headers | show |
----- Original Message ----- > From: "vijay kilari" <vijay.kilari@gmail.com> > To: qemu-arm@nongnu.org, "peter maydell" <peter.maydell@linaro.org>, pbonzini@redhat.com > Cc: qemu-devel@nongnu.org, "Prasun Kapoor" <Prasun.Kapoor@cavium.com>, "vijay kilari" <vijay.kilari@gmail.com>, > "Vijaya Kumar K" <Vijaya.Kumar@cavium.com> > 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 <Vijaya.Kumar@cavium.com> > > 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 <Vijaya.Kumar@cavium.com> > --- > 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 <Vijaya.Kumar@cavium.com> > + * > + * 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 > >
On 2 August 2016 at 11:20, <vijay.kilari@gmail.com> wrote: > +long int qemu_read_cpuid_info(void) Don't use "long" here, it might be 32 or 64 bits. The kernel ABI for the /sys/ file we're reading says it is a 64-bit value, so uint64_t is what you want. > +{ > + 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; > + } g_file_get_contents() is probably easier than manually opening the file and reading it into an allocated buffer. > + > + if (qemu_strtol(buf, NULL, 0, &midr) < 0) { qemu_strtoull(). > + goto out; > + } > + > +out: > + g_free(buf); > + fclose(fp); > + > + return midr; > +} > +#endif > -- > 1.7.9.5 > thanks -- PMM
Hi Paolo, On Tue, Aug 2, 2016 at 4:18 PM, Paolo Bonzini <pbonzini@redhat.com> wrote: > ----- Original Message ----- >> From: "vijay kilari" <vijay.kilari@gmail.com> >> To: qemu-arm@nongnu.org, "peter maydell" <peter.maydell@linaro.org>, pbonzini@redhat.com >> Cc: qemu-devel@nongnu.org, "Prasun Kapoor" <Prasun.Kapoor@cavium.com>, "vijay kilari" <vijay.kilari@gmail.com>, >> "Vijaya Kumar K" <Vijaya.Kumar@cavium.com> >> 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 <Vijaya.Kumar@cavium.com> >> >> 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 <Vijaya.Kumar@cavium.com> >> --- >> 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. OK > > 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. > You mean to say, move contents of this patch to util/cutils.c and make it static and define under __aarch64__ and 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 <Vijaya.Kumar@cavium.com> >> + * >> + * 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 >> >>
> > 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. > > > > You mean to say, move contents of this patch to util/cutils.c and make it > static and define under __aarch64__ and CONFIG_LINUX?. I don't think util/cutils.c is the right file. It should be a new file, something like util/aarch64-cpuid.c. If CONFIG_LINUX is not defined, the ThunderX detection function should return zero. If __aarch64__ is not defined, the function should not be defined at all. Paolo
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); #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 <Vijaya.Kumar@cavium.com> + * + * 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