From 98bf79cff1c60f85271a46dc000e611b7a593827 Mon Sep 17 00:00:00 2001
From: Cameron Cawley <[EMAIL REDACTED]>
Date: Tue, 16 Feb 2021 18:13:15 +0000
Subject: [PATCH] Minor improvements for CPU detection on ARM
---
src/cpuinfo/SDL_cpuinfo.c | 57 +++++++++++++++++----------------------
1 file changed, 24 insertions(+), 33 deletions(-)
diff --git a/src/cpuinfo/SDL_cpuinfo.c b/src/cpuinfo/SDL_cpuinfo.c
index 896b4dd81..f0d14e837 100644
--- a/src/cpuinfo/SDL_cpuinfo.c
+++ b/src/cpuinfo/SDL_cpuinfo.c
@@ -63,7 +63,13 @@
#include <sys/syspage.h>
#endif
-#if (defined(__LINUX__) || defined(__ANDROID__)) && defined(__ARM_ARCH)
+#if (defined(__LINUX__) || defined(__ANDROID__)) && defined(__arm__)
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <elf.h>
+
/*#include <asm/hwcap.h>*/
#ifndef AT_HWCAP
#define AT_HWCAP 16
@@ -71,27 +77,16 @@
#ifndef AT_PLATFORM
#define AT_PLATFORM 15
#endif
-/* Prevent compilation error when including elf.h would also try to define AT_* as an enum */
-#ifndef AT_NULL
-#define AT_NULL 0
-#endif
#ifndef HWCAP_NEON
#define HWCAP_NEON (1 << 12)
#endif
-#if defined HAVE_GETAUXVAL
-#include <sys/auxv.h>
-#else
-#include <fcntl.h>
-#endif
#endif
-#if defined(__ANDROID__) && defined(__ARM_ARCH) && !defined(HAVE_GETAUXVAL)
-#if __ARM_ARCH < 8
+#if defined(__ANDROID__) && defined(__arm__) && !defined(HAVE_GETAUXVAL)
#include <cpu-features.h>
#endif
-#endif
-#if defined(HAVE_ELF_AUX_INFO)
+#if defined(HAVE_GETAUXVAL) || defined(HAVE_ELF_AUX_INFO)
#include <sys/auxv.h>
#endif
@@ -345,7 +340,7 @@ CPU_haveAltiVec(void)
return altivec;
}
-#if defined(__ARM_ARCH) && (__ARM_ARCH >= 6)
+#if (defined(__ARM_ARCH) && (__ARM_ARCH >= 6)) || defined(__aarch64__)
static int
CPU_haveARMSIMD(void)
{
@@ -360,12 +355,6 @@ CPU_haveARMSIMD(void)
}
#elif defined(__LINUX__)
-#include <unistd.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <fcntl.h>
-#include <elf.h>
-
static int
CPU_haveARMSIMD(void)
{
@@ -393,7 +382,6 @@ CPU_haveARMSIMD(void)
}
#elif defined(__RISCOS__)
-
static int
CPU_haveARMSIMD(void)
{
@@ -422,17 +410,20 @@ CPU_haveARMSIMD(void)
}
#endif
-#if defined(__LINUX__) && defined(__ARM_ARCH) && !defined(HAVE_GETAUXVAL)
+#if defined(__LINUX__) && defined(__arm__) && !defined(HAVE_GETAUXVAL)
static int
readProcAuxvForNeon(void)
{
int neon = 0;
- int kv[2];
- const int fd = open("/proc/self/auxv", O_RDONLY);
- if (fd != -1) {
- while (read(fd, kv, sizeof (kv)) == sizeof (kv)) {
- if (kv[0] == AT_HWCAP) {
- neon = ((kv[1] & HWCAP_NEON) == HWCAP_NEON);
+ int fd;
+
+ fd = open("/proc/self/auxv", O_RDONLY);
+ if (fd >= 0)
+ {
+ Elf32_auxv_t aux;
+ while (read(fd, &aux, sizeof (aux)) == sizeof (aux)) {
+ if (aux.a_type == AT_HWCAP) {
+ neon = (aux.a_un.a_val & HWCAP_NEON) == HWCAP_NEON;
break;
}
}
@@ -457,22 +448,22 @@ CPU_haveNEON(void)
# endif
/* All WinRT ARM devices are required to support NEON, but just in case. */
return IsProcessorFeaturePresent(PF_ARM_NEON_INSTRUCTIONS_AVAILABLE) != 0;
-#elif defined(__ARM_ARCH) && (__ARM_ARCH >= 8)
+#elif (defined(__ARM_ARCH) && (__ARM_ARCH >= 8)) || defined(__aarch64__)
return 1; /* ARMv8 always has non-optional NEON support. */
#elif defined(__APPLE__) && defined(__ARM_ARCH) && (__ARM_ARCH >= 7)
/* (note that sysctlbyname("hw.optional.neon") doesn't work!) */
return 1; /* all Apple ARMv7 chips and later have NEON. */
#elif defined(__APPLE__)
return 0; /* assume anything else from Apple doesn't have NEON. */
+#elif !defined(__arm__)
+ return 0; /* not an ARM CPU at all. */
#elif defined(__OpenBSD__)
return 1; /* OpenBSD only supports ARMv7 CPUs that have NEON. */
-#elif defined(HAVE_ELF_AUX_INFO) && defined(HWCAP_NEON)
+#elif defined(HAVE_ELF_AUX_INFO)
unsigned long hasneon = 0;
if (elf_aux_info(AT_HWCAP, (void *)&hasneon, (int)sizeof(hasneon)) != 0)
return 0;
return ((hasneon & HWCAP_NEON) == HWCAP_NEON);
-#elif !defined(__arm__)
- return 0; /* not an ARM CPU at all. */
#elif defined(__QNXNTO__)
return SYSPAGE_ENTRY(cpuinfo)->flags & ARM_CPU_FLAG_NEON;
#elif (defined(__LINUX__) || defined(__ANDROID__)) && defined(HAVE_GETAUXVAL)