On 24/10/2016 11:39, Dr. David Alan Gilbert wrote: > * [email protected] ([email protected]) wrote: >> From: Vijaya Kumar K <[email protected]> >> >> 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 <[email protected]> >> --- >> include/qemu/aarch64-cpuid.h | 9 +++++ >> util/Makefile.objs | 1 + >> util/aarch64-cpuid.c | 87 >> ++++++++++++++++++++++++++++++++++++++++++++ > > It feels like there should be somewhere else to put this very ARM specific > thing > that in util/ - not sure where though.
It's okay I guess, the name is pretty clear. What's important is a clear split of arch-specific and generic code in bufferiszero.c. Paolo >> 3 files changed, 97 insertions(+) >> >> diff --git a/include/qemu/aarch64-cpuid.h b/include/qemu/aarch64-cpuid.h > >> new file mode 100644 >> index 0000000..dbcb5ff >> --- /dev/null >> +++ b/include/qemu/aarch64-cpuid.h >> @@ -0,0 +1,9 @@ >> +#ifndef QEMU_AARCH64_CPUID_H >> +#define QEMU_AARCH64_CPUID_H >> + >> +#if defined(__aarch64__) >> +uint64_t get_aarch64_cpu_id(void); >> +bool is_thunderx_pass2_cpu(void); >> +#endif >> + >> +#endif >> diff --git a/util/Makefile.objs b/util/Makefile.objs >> index 36c7dcc..d14a455 100644 >> --- a/util/Makefile.objs >> +++ b/util/Makefile.objs >> @@ -37,3 +37,4 @@ util-obj-y += log.o >> util-obj-y += qdist.o >> util-obj-y += qht.o >> util-obj-y += range.o >> +util-obj-y += aarch64-cpuid.o >> diff --git a/util/aarch64-cpuid.c b/util/aarch64-cpuid.c >> new file mode 100644 >> index 0000000..a6352ad >> --- /dev/null >> +++ b/util/aarch64-cpuid.c >> @@ -0,0 +1,87 @@ >> +/* >> + * Dealing with arm cpu identification information. >> + * >> + * Copyright (C) 2016 Cavium, Inc. >> + * >> + * Authors: >> + * Vijaya Kumar K <[email protected]> >> + * >> + * 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 <math.h> >> +#include "qemu/osdep.h" >> +#include "qemu-common.h" >> +#include "qemu/cutils.h" >> +#include "qemu/aarch64-cpuid.h" >> + >> +#if defined(__aarch64__) >> +#define MIDR_IMPLEMENTER_SHIFT 24 >> +#define MIDR_IMPLEMENTER_MASK (0xffULL << MIDR_IMPLEMENTER_SHIFT) >> +#define MIDR_ARCHITECTURE_SHIFT 16 >> +#define MIDR_ARCHITECTURE_MASK (0xf << MIDR_ARCHITECTURE_SHIFT) >> +#define MIDR_PARTNUM_SHIFT 4 >> +#define MIDR_PARTNUM_MASK (0xfff << MIDR_PARTNUM_SHIFT) >> + >> +#define MIDR_CPU_PART(imp, partnum) \ >> + (((imp) << MIDR_IMPLEMENTER_SHIFT) | \ >> + (0xf << MIDR_ARCHITECTURE_SHIFT) | \ >> + ((partnum) << MIDR_PARTNUM_SHIFT)) >> + >> +#define ARM_CPU_IMP_CAVIUM 0x43 >> +#define CAVIUM_CPU_PART_THUNDERX 0x0A1 >> + >> +#define MIDR_THUNDERX_PASS2 \ >> + MIDR_CPU_PART(ARM_CPU_IMP_CAVIUM, CAVIUM_CPU_PART_THUNDERX) >> +#define CPU_MODEL_MASK (MIDR_IMPLEMENTER_MASK | MIDR_ARCHITECTURE_MASK | \ >> + MIDR_PARTNUM_MASK) >> + >> +static uint64_t qemu_read_aarch64_midr_el1(void) >> +{ >> +#ifdef CONFIG_LINUX >> + const char *file = >> "/sys/devices/system/cpu/cpu0/regs/identification/midr_el1"; >> + char *buf; >> + uint64_t midr = 0; >> + >> +#define BUF_SIZE 32 >> + buf = g_malloc0(BUF_SIZE); >> + if (!buf) { >> + return 0; >> + } > > Do you need to do that? Isn't g_file_get_contents doing the allocation? > > Dave > >> + if (!g_file_get_contents(file, &buf, 0, NULL)) { >> + goto out; >> + } >> + >> + if (qemu_strtoull(buf, NULL, 0, &midr) < 0) { >> + goto out; >> + } >> + >> +out: >> + g_free(buf); >> + >> + return midr; >> +#else >> + return 0; >> +#endif >> +} >> + >> +static uint64_t aarch64_midr_val; >> +uint64_t get_aarch64_cpu_id(void) >> +{ >> +#ifdef CONFIG_LINUX >> + aarch64_midr_val = qemu_read_aarch64_midr_el1(); >> + aarch64_midr_val &= CPU_MODEL_MASK; >> + >> + return aarch64_midr_val; >> +#else >> + return 0; >> +#endif >> +} >> + >> +bool is_thunderx_pass2_cpu(void) >> +{ >> + return aarch64_midr_val == MIDR_THUNDERX_PASS2; >> +} >> +#endif >> -- >> 1.9.1 >> >> > -- > Dr. David Alan Gilbert / [email protected] / Manchester, UK >
