Provide dav1d_getauxval() wrapper for getauxvaul() and elf_aux_info()

src/arm/cpu.c

@@ -43,15 +43,8 @@
 #define HWCAP2_AARCH64_I8MM   (1 << 13)
 
 COLD unsigned dav1d_get_cpu_flags_arm(void) {
-#if HAVE_GETAUXVAL
-    unsigned long hw_cap = getauxval(AT_HWCAP);
-    unsigned long hw_cap2 = getauxval(AT_HWCAP2);
-#else
-    unsigned long hw_cap = 0;
-    unsigned long hw_cap2 = 0;
-    elf_aux_info(AT_HWCAP, &hw_cap, sizeof(hw_cap));
-    elf_aux_info(AT_HWCAP2, &hw_cap2, sizeof(hw_cap2));
-#endif
+    unsigned long hw_cap = dav1d_getauxval(AT_HWCAP);
+    unsigned long hw_cap2 = dav1d_getauxval(AT_HWCAP2);
 
     unsigned flags = dav1d_get_default_cpu_flags();
     flags |= (hw_cap & HWCAP_AARCH64_ASIMDDP) ? DAV1D_ARM_CPU_FLAG_DOTPROD : 0;
@@ -69,12 +62,7 @@ COLD unsigned dav1d_get_cpu_flags_arm(void) {
 #define HWCAP_ARM_I8MM    (1 << 27)
 
 COLD unsigned dav1d_get_cpu_flags_arm(void) {
-#if HAVE_GETAUXVAL
-    unsigned long hw_cap = getauxval(AT_HWCAP);
-#else
-    unsigned long hw_cap = 0;
-    elf_aux_info(AT_HWCAP, &hw_cap, sizeof(hw_cap));
-#endif
+    unsigned long hw_cap = dav1d_getauxval(AT_HWCAP);
 
     unsigned flags = dav1d_get_default_cpu_flags();
     flags |= (hw_cap & HWCAP_ARM_NEON) ? DAV1D_ARM_CPU_FLAG_NEON : 0;

src/cpu.c

@@ -52,6 +52,10 @@
 #endif
 #endif
 
+#if HAVE_GETAUXVAL || HAVE_ELF_AUX_INFO
+#include <sys/auxv.h>
+#endif
+
 unsigned dav1d_cpu_flags = 0U;
 unsigned dav1d_cpu_flags_mask = ~0U;
 
@@ -107,3 +111,18 @@ COLD int dav1d_num_logical_processors(Dav1dContext *const c) {
         dav1d_log(c, "Unable to detect thread count, defaulting to single-threaded mode\n");
     return 1;
 }
+
+COLD unsigned long dav1d_getauxval(unsigned long type) {
+#if HAVE_GETAUXVAL
+    return getauxval(type);
+#elif HAVE_ELF_AUX_INFO
+    unsigned long aux = 0;
+    int ret = elf_aux_info(type, &aux, sizeof(aux));
+    if (ret != 0)
+        errno = ret;
+    return aux;
+#else
+    errno = ENOSYS;
+    return 0;
+#endif
+}

src/cpu.h

@@ -53,6 +53,7 @@ EXTERN unsigned dav1d_cpu_flags_mask;
 void dav1d_init_cpu(void);
 DAV1D_API void dav1d_set_cpu_flags_mask(unsigned mask);
 int dav1d_num_logical_processors(Dav1dContext *c);
+unsigned long dav1d_getauxval(unsigned long);
 
 static ALWAYS_INLINE unsigned dav1d_get_default_cpu_flags(void) {
     unsigned flags = 0;

src/loongarch/cpu.c

@@ -40,7 +40,7 @@
 COLD unsigned dav1d_get_cpu_flags_loongarch(void) {
     unsigned flags = dav1d_get_default_cpu_flags();
 #if HAVE_GETAUXVAL
-    unsigned long hw_cap = getauxval(AT_HWCAP);
+    unsigned long hw_cap = dav1d_getauxval(AT_HWCAP);
     flags |= (hw_cap & LA_HWCAP_LSX) ? DAV1D_LOONGARCH_CPU_FLAG_LSX : 0;
     flags |= (hw_cap & LA_HWCAP_LASX) ? DAV1D_LOONGARCH_CPU_FLAG_LASX : 0;
 #endif

src/ppc/cpu.c

@@ -39,16 +39,9 @@
 
 COLD unsigned dav1d_get_cpu_flags_ppc(void) {
     unsigned flags = dav1d_get_default_cpu_flags();
-#if HAVE_GETAUXVAL && ARCH_PPC64LE
-    unsigned long hw_cap = getauxval(AT_HWCAP);
-    unsigned long hw_cap2 = getauxval(AT_HWCAP2);
-#elif HAVE_ELF_AUX_INFO && ARCH_PPC64LE
-    unsigned long hw_cap = 0;
-    unsigned long hw_cap2 = 0;
-    elf_aux_info(AT_HWCAP, &hw_cap, sizeof(hw_cap));
-    elf_aux_info(AT_HWCAP2, &hw_cap2, sizeof(hw_cap2));
-#endif
 #if HAVE_AUX
+    unsigned long hw_cap = dav1d_getauxval(AT_HWCAP);
+    unsigned long hw_cap2 = dav1d_getauxval(AT_HWCAP2);
     flags |= (hw_cap & PPC_FEATURE_HAS_VSX) ? DAV1D_PPC_CPU_FLAG_VSX : 0;
     flags |= (hw_cap2 & PPC_FEATURE2_ARCH_3_00) ? DAV1D_PPC_CPU_FLAG_PWR9 : 0;
 #endif

src/riscv/cpu.c

@@ -44,7 +44,7 @@ int dav1d_has_compliant_rvv(void);
 COLD unsigned dav1d_get_cpu_flags_riscv(void) {
     unsigned flags = dav1d_get_default_cpu_flags();
 #if HAVE_GETAUXVAL
-    unsigned long hw_cap = getauxval(AT_HWCAP);
+    unsigned long hw_cap = dav1d_getauxval(AT_HWCAP);
     flags |= (hw_cap & HWCAP_RVV) && dav1d_has_compliant_rvv() ? DAV1D_RISCV_CPU_FLAG_V : 0;
 #endif