[PATCH 1/2] eal: introduce x86 processor identification

[David Marchand <david.marchand@redhat.com>]

In some really specific cases, it may be needed to get a detailed
information on the processor running a DPDK application for drivers to
achieve better performance, or for matters that concern only them.

Those information are highly arch-specific and require a specific API.

Introduce a set of functions to get brand, family and model of a x86
processor.
Those functions do not make sense on other arches and a
driver must first check rte_cpu_is_x86() before anything else.

Signed-off-by: David Marchand <david.marchand@redhat.com>
---
 MAINTAINERS                     |   1 +
 app/test/meson.build            |   1 +
 app/test/test_cpu.c             |  37 +++++++++
 lib/eal/common/eal_common_cpu.c | 141 ++++++++++++++++++++++++++++++++
 lib/eal/common/eal_cpu.h        |  77 +++++++++++++++++
 lib/eal/common/meson.build      |   1 +
 lib/eal/version.map             |   6 ++
 7 files changed, 264 insertions(+)
 create mode 100644 app/test/test_cpu.c
 create mode 100644 lib/eal/common/eal_common_cpu.c
 create mode 100644 lib/eal/common/eal_cpu.h

diff --git a/MAINTAINERS b/MAINTAINERS
index 698608cdb2..b87d47a1e4 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -158,6 +158,7 @@ F: app/test/test_barrier.c
 F: app/test/test_bitcount.c
 F: app/test/test_byteorder.c
 F: app/test/test_common.c
+F: app/test/test_cpu.c
 F: app/test/test_cpuflags.c
 F: app/test/test_cycles.c
 F: app/test/test_debug.c
diff --git a/app/test/meson.build b/app/test/meson.build
index 05bae9216d..4b37ad02fa 100644
--- a/app/test/meson.build
+++ b/app/test/meson.build
@@ -44,6 +44,7 @@ source_file_deps = {
     'test_cmdline_string.c': [],
     'test_common.c': [],
     'test_compressdev.c': ['compressdev'],
+    'test_cpu.c': [],
     'test_cpuflags.c': [],
     'test_crc.c': ['net'],
     'test_cryptodev.c': test_cryptodev_deps,
diff --git a/app/test/test_cpu.c b/app/test/test_cpu.c
new file mode 100644
index 0000000000..40d8bd94eb
--- /dev/null
+++ b/app/test/test_cpu.c
@@ -0,0 +1,37 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2023 Red Hat, Inc.
+ */
+
+#include <stdio.h>
+#include <inttypes.h>
+
+#include "eal_cpu.h"
+
+#include "test.h"
+
+static int
+test_cpu(void)
+{
+#ifndef RTE_ARCH_X86
+	RTE_TEST_ASSERT(!rte_cpu_is_x86(), "rte_cpu_is_x86() returned true on " RTE_STR(RTE_ARCH));
+#else
+	const char *vendor;
+
+	RTE_TEST_ASSERT(rte_cpu_is_x86(), "rte_cpu_is_x86() returned false");
+
+	if (rte_cpu_x86_is_amd())
+		vendor = "AMD";
+	else if (rte_cpu_x86_is_intel())
+		vendor = "Intel";
+	else
+		vendor = "unknown";
+
+	printf("The processor running this program is a x86 %s processor, brand=0x%"
+		PRIx8", family=0x%"PRIx8", model=0x%"PRIx8"\n", vendor, rte_cpu_x86_brand(),
+		rte_cpu_x86_family(), rte_cpu_x86_model());
+#endif
+
+	return TEST_SUCCESS;
+}
+
+REGISTER_FAST_TEST(cpu_autotest, true, true, test_cpu);
diff --git a/lib/eal/common/eal_common_cpu.c b/lib/eal/common/eal_common_cpu.c
new file mode 100644
index 0000000000..18cdb27f75
--- /dev/null
+++ b/lib/eal/common/eal_common_cpu.c
@@ -0,0 +1,141 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2023 Red Hat, Inc.
+ */
+
+#include <rte_debug.h>
+
+#include "eal_cpu.h"
+
+#ifdef RTE_ARCH_X86
+#ifndef RTE_TOOLCHAIN_MSVC
+#include <cpuid.h>
+#endif
+
+static void
+x86_cpuid(uint32_t leaf, uint32_t subleaf, uint32_t *eax, uint32_t *ebx,
+	uint32_t *ecx, uint32_t *edx)
+{
+	uint32_t regs[4] = { 0 };
+
+#ifdef RTE_TOOLCHAIN_MSVC
+	__cpuidex(regs, leaf, subleaf);
+#else
+	__cpuid_count(leaf, subleaf, regs[0], regs[1], regs[2], regs[3]);
+#endif
+
+	*eax = regs[0];
+	*ebx = regs[1];
+	*ecx = regs[2];
+	*edx = regs[3];
+}
+#endif /* RTE_ARCH_X86 */
+
+bool
+rte_cpu_is_x86(void)
+{
+#ifndef RTE_ARCH_X86
+	return false;
+#else
+	return true;
+#endif
+}
+
+bool
+rte_cpu_x86_is_amd(void)
+{
+#ifndef RTE_ARCH_X86
+	rte_panic("Calling %s does not make sense on %s architecture.\n",
+		__func__, RTE_STR(RTE_ARCH));
+#else
+	uint32_t eax, ebx, ecx, edx;
+
+	x86_cpuid(0x0, 0x0, &eax, &ebx, &ecx, &edx);
+	/* ascii_to_little_endian("Auth enti cAMD") */
+	return ebx == 0x68747541 && ecx == 0x444d4163 && edx == 0x69746e65;
+#endif
+}
+
+bool
+rte_cpu_x86_is_intel(void)
+{
+#ifndef RTE_ARCH_X86
+	rte_panic("Calling %s does not make sense on %s architecture.\n",
+		__func__, RTE_STR(RTE_ARCH));
+#else
+	uint32_t eax, ebx, ecx, edx;
+
+	x86_cpuid(0x0, 0x0, &eax, &ebx, &ecx, &edx);
+	/* ascii_to_little_endian("Genu ineI ntel") */
+	return ebx == 0x756e6547 && ecx == 0x6c65746e && edx == 0x49656e69;
+#endif
+}
+
+uint8_t
+rte_cpu_x86_brand(void)
+{
+#ifndef RTE_ARCH_X86
+	rte_panic("Calling %s does not make sense on %s architecture.\n",
+		__func__, RTE_STR(RTE_ARCH));
+#else
+	uint32_t eax, ebx, ecx, edx;
+	uint8_t brand = 0;
+
+	x86_cpuid(0x0, 0x0, &eax, &ebx, &ecx, &edx);
+	if (eax >= 1) {
+		x86_cpuid(0x1, 0x0, &eax, &ebx, &ecx, &edx);
+		brand = ebx & 0xff;
+	}
+
+	return brand;
+#endif
+}
+
+uint8_t
+rte_cpu_x86_family(void)
+{
+#ifndef RTE_ARCH_X86
+	rte_panic("Calling %s does not make sense on %s architecture.\n",
+		__func__, RTE_STR(RTE_ARCH));
+#else
+	uint32_t eax, ebx, ecx, edx;
+	uint8_t family = 0;
+
+	x86_cpuid(0x0, 0x0, &eax, &ebx, &ecx, &edx);
+	if (eax >= 1) {
+		uint8_t family_id;
+
+		x86_cpuid(0x1, 0x0, &eax, &ebx, &ecx, &edx);
+		family_id = (eax >> 8) & 0x0f;
+		family = family_id;
+		if (family_id == 0xf)
+			family += (eax >> 20) & 0xff;
+	}
+
+	return family;
+#endif
+}
+
+uint8_t
+rte_cpu_x86_model(void)
+{
+#ifndef RTE_ARCH_X86
+	rte_panic("Calling %s does not make sense on %s architecture.\n",
+		__func__, RTE_STR(RTE_ARCH));
+#else
+	uint32_t eax, ebx, ecx, edx;
+	uint8_t model = 0;
+
+	x86_cpuid(0x0, 0x0, &eax, &ebx, &ecx, &edx);
+	if (eax >= 1) {
+		uint8_t family_id;
+
+		x86_cpuid(0x1, 0x0, &eax, &ebx, &ecx, &edx);
+		family_id = (eax >> 8) & 0x0f;
+		model = (eax >> 4) & 0x0f;
+		if (family_id == 0x6 || family_id == 0xf)
+			model += (eax >> 12) & 0xf0;
+	}
+
+	return model;
+#endif
+}
diff --git a/lib/eal/common/eal_cpu.h b/lib/eal/common/eal_cpu.h
new file mode 100644
index 0000000000..26d8e06bf0
--- /dev/null
+++ b/lib/eal/common/eal_cpu.h
@@ -0,0 +1,77 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2023 Red Hat, Inc.
+ */
+
+#ifndef EAL_CPU_H
+#define EAL_CPU_H
+
+#include <stdbool.h>
+#include <stdint.h>
+
+#include <rte_compat.h>
+
+/**
+ * Returns whether the processor running this program is a x86 one.
+ *
+ * @return
+ *      true or false
+ */
+__rte_internal
+bool rte_cpu_is_x86(void);
+
+/**
+ * Returns whether the processor running this program is a AMD x86 one.
+ *
+ * Note: calling this function only makes sense if rte_cpu_is_x86() == true.
+ *
+ * @return
+ *      true or false
+ */
+__rte_internal
+bool rte_cpu_x86_is_amd(void);
+
+/**
+ * Returns whether the processor running this program is a Intel x86 one.
+ *
+ * Note: calling this function only makes sense if rte_cpu_is_x86() == true.
+ *
+ * @return
+ *      true or false
+ */
+__rte_internal
+bool rte_cpu_x86_is_intel(void);
+
+/**
+ * Returns the processor brand (as returned by CPUID).
+ *
+ * Note: calling this function only makes sense if rte_cpu_is_x86() == true.
+ *
+ * @return
+ *      x86 processor brand
+ */
+__rte_internal
+uint8_t rte_cpu_x86_brand(void);
+
+/**
+ * Returns the processor family (as returned by CPUID).
+ *
+ * Note: calling this function only makes sense if rte_cpu_is_x86() == true.
+ *
+ * @return
+ *      x86 processor family
+ */
+__rte_internal
+uint8_t rte_cpu_x86_family(void);
+
+/**
+ * Returns the processor model (as returned by CPUID).
+ *
+ * Note: calling this function only makes sense if rte_cpu_is_x86() == true.
+ *
+ * @return
+ *      x86 processor model
+ */
+__rte_internal
+uint8_t rte_cpu_x86_model(void);
+
+#endif /* EAL_CPU_H */
diff --git a/lib/eal/common/meson.build b/lib/eal/common/meson.build
index 22a626ba6f..bef5b2575b 100644
--- a/lib/eal/common/meson.build
+++ b/lib/eal/common/meson.build
@@ -9,6 +9,7 @@ sources += files(
         'eal_common_bus.c',
         'eal_common_class.c',
         'eal_common_config.c',
+        'eal_common_cpu.c',
         'eal_common_debug.c',
         'eal_common_dev.c',
         'eal_common_devargs.c',
diff --git a/lib/eal/version.map b/lib/eal/version.map
index 7940431e5a..62632202c5 100644
--- a/lib/eal/version.map
+++ b/lib/eal/version.map
@@ -424,6 +424,12 @@ INTERNAL {
 
 	rte_bus_register;
 	rte_bus_unregister;
+	rte_cpu_is_x86;
+	rte_cpu_x86_brand;
+	rte_cpu_x86_family;
+	rte_cpu_x86_is_amd;
+	rte_cpu_x86_is_intel;
+	rte_cpu_x86_model;
 	rte_eal_get_baseaddr;
 	rte_eal_parse_coremask;
 	rte_firmware_read;
-- 
2.41.0