avutil/cpu_internal: Provide ff_getauxval() wrapper for getauxvaul()

Initially used for getauxval() but will be used to add support for
other API, such as elf_aux_info().

Signed-off-by: Brad Smith <brad@comstyle.com>

libavutil/aarch64/cpu.c

@@ -31,8 +31,8 @@ static int detect_flags(void)
 {
     int flags = 0;
 
-    unsigned long hwcap = getauxval(AT_HWCAP);
-    unsigned long hwcap2 = getauxval(AT_HWCAP2);
+    unsigned long hwcap = ff_getauxval(AT_HWCAP);
+    unsigned long hwcap2 = ff_getauxval(AT_HWCAP2);
 
     if (hwcap & HWCAP_AARCH64_ASIMDDP)
         flags |= AV_CPU_FLAG_DOTPROD;

libavutil/arm/cpu.c

@@ -55,7 +55,7 @@
 static int get_auxval(uint32_t *hwcap)
 {
 #if HAVE_GETAUXVAL
-    unsigned long ret = getauxval(AT_HWCAP);
+    unsigned long ret = ff_getauxval(AT_HWCAP);
     if (ret == 0)
         return -1;
     *hwcap = ret;

libavutil/cpu.c

@@ -49,6 +49,10 @@
 #include <unistd.h>
 #endif
 
+#if HAVE_GETAUXVAL
+#include <sys/auxv.h>
+#endif
+
 static atomic_int cpu_flags = -1;
 static atomic_int cpu_count = -1;
 
@@ -283,3 +287,13 @@ size_t av_cpu_max_align(void)
 
     return 8;
 }
+
+unsigned long ff_getauxval(unsigned long type)
+{
+#if HAVE_GETAUXVAL
+    return getauxval(type);
+#else
+    errno = ENOSYS;
+    return 0;
+#endif
+}

libavutil/cpu_internal.h

@@ -59,4 +59,6 @@ size_t ff_get_cpu_max_align_ppc(void);
 size_t ff_get_cpu_max_align_x86(void);
 size_t ff_get_cpu_max_align_loongarch(void);
 
+unsigned long ff_getauxval(unsigned long type);
+
 #endif /* AVUTIL_CPU_INTERNAL_H */

libavutil/loongarch/cpu.c

@@ -28,7 +28,7 @@
 static int cpu_flags_getauxval(void)
 {
     int flags = 0;
-    int flag  = (int)getauxval(AT_HWCAP);
+    int flag  = (int)ff_getauxval(AT_HWCAP);
 
     if (flag & LA_HWCAP_LSX)
         flags |= AV_CPU_FLAG_LSX;

libavutil/mips/cpu.c

@@ -34,7 +34,7 @@
 
 static int cpucfg_available(void)
 {
-    return getauxval(AT_HWCAP) & HWCAP_LOONGSON_CPUCFG;
+    return ff_getauxval(AT_HWCAP) & HWCAP_LOONGSON_CPUCFG;
 }
 
 /* Most toolchains have no CPUCFG support yet */

libavutil/riscv/cpu.c

@@ -86,7 +86,7 @@ int ff_get_cpu_flags_riscv(void)
     }
 #elif HAVE_GETAUXVAL
     {
-        const unsigned long hwcap = getauxval(AT_HWCAP);
+        const unsigned long hwcap = ff_getauxval(AT_HWCAP);
 
         if (hwcap & HWCAP_RV('I'))
             ret |= AV_CPU_FLAG_RVI;