src/arm/windows/init.c

#include <errno.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>

#include <cpuinfo.h>
#include <cpuinfo/internal-api.h>
#include <cpuinfo/log.h>

#include "windows-arm-init.h"

struct cpuinfo_arm_isa cpuinfo_isa;

static void set_cpuinfo_isa_fields(void);
static struct woa_chip_info* get_system_info_from_registry(void);

static struct woa_chip_info woa_chip_unknown = {
	L"Unknown",
	woa_chip_name_unknown,
	{{cpuinfo_vendor_unknown, cpuinfo_uarch_unknown, 0}}};

/* Please add new SoC/chip info here! */
static struct woa_chip_info woa_chips[woa_chip_name_last] = {
	/* Microsoft SQ1 Kryo 495 4 + 4 cores (3 GHz + 1.80 GHz) */
	[woa_chip_name_microsoft_sq_1] =
		{L"Microsoft SQ1",
		 woa_chip_name_microsoft_sq_1,
		 {{
			  cpuinfo_vendor_arm,
			  cpuinfo_uarch_cortex_a55,
			  1800000000,
		  },
		  {
			  cpuinfo_vendor_arm,
			  cpuinfo_uarch_cortex_a76,
			  3000000000,
		  }}},
	/* Microsoft SQ2 Kryo 495 4 + 4 cores (3.15 GHz + 2.42 GHz) */
	[woa_chip_name_microsoft_sq_2] =
		{L"Microsoft SQ2",
		 woa_chip_name_microsoft_sq_2,
		 {{
			  cpuinfo_vendor_arm,
			  cpuinfo_uarch_cortex_a55,
			  2420000000,
		  },
		  {cpuinfo_vendor_arm, cpuinfo_uarch_cortex_a76, 3150000000}}},
	/* Snapdragon (TM) 8cx Gen 3 @ 3.0 GHz */
	[woa_chip_name_microsoft_sq_3] =
		{L"Snapdragon (TM) 8cx Gen 3",
		 woa_chip_name_microsoft_sq_3,
		 {{
			  cpuinfo_vendor_arm,
			  cpuinfo_uarch_cortex_a78,
			  2420000000,
		  },
		  {cpuinfo_vendor_arm, cpuinfo_uarch_cortex_x1, 3000000000}}},
	/* Microsoft Windows Dev Kit 2023 */
	[woa_chip_name_microsoft_sq_3_devkit] =
		{L"Snapdragon Compute Platform",
		 woa_chip_name_microsoft_sq_3_devkit,
		 {{
			  cpuinfo_vendor_arm,
			  cpuinfo_uarch_cortex_a78,
			  2420000000,
		  },
		  {cpuinfo_vendor_arm, cpuinfo_uarch_cortex_x1, 3000000000}}},
	/* Ampere Altra */
	[woa_chip_name_ampere_altra] = {
		L"Ampere(R) Altra(R) Processor",
		woa_chip_name_ampere_altra,
		{{cpuinfo_vendor_arm, cpuinfo_uarch_neoverse_n1, 3000000000}}}};

BOOL CALLBACK cpuinfo_arm_windows_init(PINIT_ONCE init_once, PVOID parameter, PVOID* context) {
	struct woa_chip_info* chip_info = NULL;
	enum cpuinfo_vendor vendor = cpuinfo_vendor_unknown;

	set_cpuinfo_isa_fields();

	chip_info = get_system_info_from_registry();
	if (chip_info == NULL) {
		chip_info = &woa_chip_unknown;
	}

	cpuinfo_is_initialized = cpu_info_init_by_logical_sys_info(chip_info, chip_info->uarchs[0].vendor);

	return true;
}

bool get_core_uarch_for_efficiency(
	enum woa_chip_name chip,
	BYTE EfficiencyClass,
	enum cpuinfo_uarch* uarch,
	uint64_t* frequency) {
	/* For currently supported WoA chips, the Efficiency class selects
	 * the pre-defined little and big core.
	 * Any further supported SoC's logic should be implemented here.
	 */
	if (uarch && frequency && chip < woa_chip_name_last && EfficiencyClass < MAX_WOA_VALID_EFFICIENCY_CLASSES) {
		*uarch = woa_chips[chip].uarchs[EfficiencyClass].uarch;
		*frequency = woa_chips[chip].uarchs[EfficiencyClass].frequency;
		return true;
	}
	return false;
}

/* Static helper functions */

static wchar_t* read_registry(LPCWSTR subkey, LPCWSTR value) {
	DWORD key_type = 0;
	DWORD data_size = 0;
	const DWORD flags = RRF_RT_REG_SZ; /* Only read strings (REG_SZ) */
	wchar_t* text_buffer = NULL;
	LSTATUS result = 0;
	HANDLE heap = GetProcessHeap();

	result = RegGetValueW(
		HKEY_LOCAL_MACHINE,
		subkey,
		value,
		flags,
		&key_type,
		NULL, /* Request buffer size */
		&data_size);
	if (result != 0 || data_size == 0) {
		cpuinfo_log_error("Registry entry size read error");
		return NULL;
	}

	text_buffer = HeapAlloc(heap, HEAP_ZERO_MEMORY, data_size);
	if (text_buffer == NULL) {
		cpuinfo_log_error("Registry textbuffer allocation error");
		return NULL;
	}

	result = RegGetValueW(
		HKEY_LOCAL_MACHINE,
		subkey,
		value,
		flags,
		NULL,
		text_buffer, /* Write string in this destination buffer */
		&data_size);
	if (result != 0) {
		cpuinfo_log_error("Registry read error");
		HeapFree(heap, 0, text_buffer);
		return NULL;
	}
	return text_buffer;
}

static struct woa_chip_info* get_system_info_from_registry(void) {
	wchar_t* text_buffer = NULL;
	LPCWSTR cpu0_subkey = L"HARDWARE\\DESCRIPTION\\System\\CentralProcessor\\0";
	LPCWSTR chip_name_value = L"ProcessorNameString";
	struct woa_chip_info* chip_info = NULL;

	HANDLE heap = GetProcessHeap();

	/* Read processor model name from registry and find in the hard-coded
	 * list. */
	text_buffer = read_registry(cpu0_subkey, chip_name_value);
	if (text_buffer == NULL) {
		cpuinfo_log_error("Registry read error");
		return NULL;
	}
	for (uint32_t i = 0; i < (uint32_t)woa_chip_name_last; i++) {
		size_t compare_length = wcsnlen(woa_chips[i].chip_name_string, CPUINFO_PACKAGE_NAME_MAX);
		int compare_result = wcsncmp(text_buffer, woa_chips[i].chip_name_string, compare_length);
		if (compare_result == 0) {
			chip_info = woa_chips + i;
			break;
		}
	}
	if (chip_info == NULL) {
		/* No match was found, so print a warning and assign the unknown
		 * case. */
		cpuinfo_log_error(
			"Unknown chip model name '%ls'.\nPlease add new Windows on Arm SoC/chip support to arm/windows/init.c!",
			text_buffer);
	} else {
		cpuinfo_log_debug("detected chip model name: %s", chip_info->chip_name_string);
	}

	HeapFree(heap, 0, text_buffer);
	return chip_info;
}

static void set_cpuinfo_isa_fields(void) {
	cpuinfo_isa.atomics = IsProcessorFeaturePresent(PF_ARM_V81_ATOMIC_INSTRUCTIONS_AVAILABLE) != 0;

	const bool dotprod = IsProcessorFeaturePresent(PF_ARM_V82_DP_INSTRUCTIONS_AVAILABLE) != 0;
	cpuinfo_isa.dot = dotprod;

	SYSTEM_INFO system_info;
	GetSystemInfo(&system_info);
	switch (system_info.wProcessorLevel) {
		case 0x803: // Kryo 385 Silver (Snapdragon 850)
			cpuinfo_isa.fp16arith = dotprod;
			cpuinfo_isa.rdm = dotprod;
			break;
		default:
			// Assume that Dot Product support implies FP16
			// arithmetics and RDM support. ARM manuals don't
			// guarantee that, but it holds in practice.
			cpuinfo_isa.fp16arith = dotprod;
			cpuinfo_isa.rdm = dotprod;
			break;
	}

	/* Windows API reports all or nothing for cryptographic instructions. */
	const bool crypto = IsProcessorFeaturePresent(PF_ARM_V8_CRYPTO_INSTRUCTIONS_AVAILABLE) != 0;
	cpuinfo_isa.aes = crypto;
	cpuinfo_isa.sha1 = crypto;
	cpuinfo_isa.sha2 = crypto;
	cpuinfo_isa.pmull = crypto;

	cpuinfo_isa.crc32 = IsProcessorFeaturePresent(PF_ARM_V8_CRC32_INSTRUCTIONS_AVAILABLE) != 0;
}