zupt/src/zupt_cpuid.c
Cristian Cezar Moisés e5f5d32aab v2.2.2
2026-05-01 09:58:47 -03:00

111 lines
3.9 KiB
C

/*
* SPDX-License-Identifier: AGPL-3.0-or-later
* Copyright (c) 2025-2026 Cristian Cezar Moisés
* Zupt — CPU Feature Detection
* Copyright (c) 2026 Cristian Cezar Moisés — AGPL-3.0-or-later
*
* Detects AES-NI, PCLMUL, AVX2, SSE4.1 at runtime.
* Used to dispatch AES-256-CTR to hardware path when available.
*/
#include "zupt_cpuid.h"
#include <string.h>
/* Global instance */
zupt_cpu_features_t zupt_cpu = {0, 0, 0, 0, 0};
/* ═══════════════════════════════════════════════════════════════════
* CPUID intrinsics — platform-specific
* ═══════════════════════════════════════════════════════════════════ */
#if defined(__x86_64__) || defined(_M_X64) || defined(__i386__) || defined(_M_IX86)
#define ZUPT_HAS_CPUID 1
#else
#define ZUPT_HAS_CPUID 0
#endif
#if ZUPT_HAS_CPUID
#if defined(_MSC_VER)
#include <intrin.h>
static void zupt_cpuid(int leaf, int subleaf, int *eax, int *ebx, int *ecx, int *edx) {
int regs[4];
__cpuidex(regs, leaf, subleaf);
*eax = regs[0]; *ebx = regs[1]; *ecx = regs[2]; *edx = regs[3];
}
static uint64_t zupt_xgetbv(uint32_t idx) {
return _xgetbv(idx);
}
#elif defined(__GNUC__) || defined(__clang__)
#include <cpuid.h>
static void zupt_cpuid(int leaf, int subleaf, int *eax, int *ebx, int *ecx, int *edx) {
unsigned int a = 0, b = 0, c = 0, d = 0;
__cpuid_count((unsigned int)leaf, (unsigned int)subleaf, a, b, c, d);
*eax = (int)a; *ebx = (int)b; *ecx = (int)c; *edx = (int)d;
}
static uint64_t zupt_xgetbv(uint32_t idx) {
uint32_t lo, hi;
__asm__ __volatile__ ("xgetbv" : "=a"(lo), "=d"(hi) : "c"(idx));
return ((uint64_t)hi << 32) | lo;
}
#else
/* Inline assembly fallback */
static void zupt_cpuid(int leaf, int subleaf, int *eax, int *ebx, int *ecx, int *edx) {
__asm__ __volatile__ (
"cpuid"
: "=a"(*eax), "=b"(*ebx), "=c"(*ecx), "=d"(*edx)
: "a"(leaf), "c"(subleaf)
);
}
static uint64_t zupt_xgetbv(uint32_t idx) {
uint32_t lo, hi;
__asm__ __volatile__ ("xgetbv" : "=a"(lo), "=d"(hi) : "c"(idx));
return ((uint64_t)hi << 32) | lo;
}
#endif
void zupt_detect_cpu(zupt_cpu_features_t *f) {
memset(f, 0, sizeof(*f));
int eax, ebx, ecx, edx;
/* Check max supported leaf */
zupt_cpuid(0, 0, &eax, &ebx, &ecx, &edx);
int max_leaf = eax;
if (max_leaf >= 1) {
zupt_cpuid(1, 0, &eax, &ebx, &ecx, &edx);
f->has_aesni = (ecx >> 25) & 1; /* ECX bit 25 */
f->has_pclmul = (ecx >> 1) & 1; /* ECX bit 1 */
f->has_sse41 = (ecx >> 19) & 1; /* ECX bit 19 */
/* AVX detection: CPU must support AVX (ECX[28]) AND the OS must
* have enabled XSAVE/XRSTOR for YMM state (OSXSAVE, ECX[27]).
* If OSXSAVE is set, check XCR0 bits 1+2 (SSE+AVX state).
* Without this check, VEX-encoded instructions (vaesenc, vmovdqu,
* vpxor, etc.) will SIGILL even if the CPU supports them. */
int has_avx_cpu = (ecx >> 28) & 1;
int has_osxsave = (ecx >> 27) & 1;
if (has_avx_cpu && has_osxsave) {
uint64_t xcr0 = zupt_xgetbv(0);
/* Bits 1 (SSE/XMM) and 2 (AVX/YMM) must both be set */
if ((xcr0 & 0x6) == 0x6)
f->has_avx = 1;
}
}
if (max_leaf >= 7) {
zupt_cpuid(7, 0, &eax, &ebx, &ecx, &edx);
/* AVX2 also requires AVX (OS XSAVE) to be usable */
if (f->has_avx && ((ebx >> 5) & 1))
f->has_avx2 = 1;
}
}
#else /* Non-x86 architecture */
void zupt_detect_cpu(zupt_cpu_features_t *f) {
memset(f, 0, sizeof(*f));
/* No AES-NI/AVX on ARM/RISC-V/etc — use table fallback */
}
#endif /* ZUPT_HAS_CPUID */