[FFmpeg-devel] aarch64: Implement support for elf_aux_info(3) on FreeBSD and OpenBSD

[Brad Smith]

aarch64: Implement support for elf_aux_info(3) on FreeBSD and OpenBSD

FreeBSD 12.0+, OpenBSD -current and what will be OpenBSD 7.6 support
elf_aux_info(3).

Signed-off-by: Brad Smith <brad at comstyle.com>
---
 configure               |  2 ++
 libavutil/aarch64/cpu.c | 23 ++++++++++++++++++++++-
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/configure b/configure
index f6f5c29fea..e80b549582 100755
--- a/configure
+++ b/configure
@@ -2366,6 +2366,7 @@ SYSTEM_FUNCS="
     clock_gettime
     closesocket
     CommandLineToArgvW
+    elf_aux_info
     fcntl
     getaddrinfo
     getauxval
@@ -6565,6 +6566,7 @@ check_func_headers mach/mach_time.h mach_absolute_time
 check_func_headers stdlib.h getenv
 check_func_headers sys/stat.h lstat
 check_func_headers sys/auxv.h getauxval
+check_func_headers sys/auxv.h elf_aux_info
 check_func_headers sys/sysctl.h sysctlbyname
 
 check_func_headers windows.h GetModuleHandle
diff --git a/libavutil/aarch64/cpu.c b/libavutil/aarch64/cpu.c
index cfa9306663..05272b4db4 100644
--- a/libavutil/aarch64/cpu.c
+++ b/libavutil/aarch64/cpu.c
@@ -42,6 +42,27 @@ static int detect_flags(void)
     return flags;
 }
 
+#elif (defined(__FreeBSD__) || defined(__OpenBSD__)) && HAVE_ELF_AUX_INFO
+#include <stdint.h>
+#include <sys/auxv.h>
+
+static int detect_flags(void)
+{
+    int flags = 0;
+
+    unsigned long hwcap = 0;
+    elf_aux_info(AT_HWCAP, &hwcap, sizeof hwcap);
+    unsigned long hwcap2 = 0;
+    elf_aux_info(AT_HWCAP2, &hwcap2, sizeof hwcap2);
+
+    if (hwcap & HWCAP_ASIMDDP)
+        flags |= AV_CPU_FLAG_DOTPROD;
+    if (hwcap2 & HWCAP2_I8MM)
+        flags |= AV_CPU_FLAG_I8MM;
+
+    return flags;
+}
+
 #elif defined(__APPLE__) && HAVE_SYSCTLBYNAME
 #include <sys/sysctl.h>
 
@@ -65,7 +86,7 @@ static int detect_flags(void)
     return flags;
 }
 
-#elif defined(__OpenBSD__)
+#elif defined(__OpenBSD__) && !HAVE_ELF_AUX_INFO
 #include <machine/armreg.h>
 #include <machine/cpu.h>
 #include <sys/types.h>
-- 
2.45.2