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ppc: linux: Check altivec using the auxv

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Should prevent trying to use altivec when it is disabled by the kernel.
This commit is contained in:
Luca Barbato 2015-04-03 15:31:32 +02:00
parent 7014b65995
commit baa94563fe
1 changed files with 31 additions and 0 deletions
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31
libavutil/ppc/cpu.c
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@ -18,6 +18,11 @@
#ifdef __APPLE__
#include <sys/sysctl.h>
#elif defined(__linux__)
#include <asm/cputable.h>
#include <linux/auxvec.h>
#include <fcntl.h>
#include <unistd.h>
#elif defined(__OpenBSD__)
#include <sys/param.h>
#include <sys/sysctl.h>
@ -62,6 +67,32 @@ int ff_get_cpu_flags_ppc(void)
if (err == 0)
return has_vu ? AV_CPU_FLAG_ALTIVEC : 0;
return 0;
#elif defined(__linux__)
// The linux kernel could have the altivec support disabled
// even if the cpu has it.
int i, ret = 0;
int fd = open("/proc/self/auxv", O_RDONLY);
unsigned long buf[64] = { 0 };
ssize_t count;
if (fd < 0)
return 0;
while ((count = read(fd, buf, sizeof(buf))) > 0) {
for (i = 0; i < count / sizeof(*buf); i += 2) {
if (buf[i] == AT_NULL)
goto out;
if (buf[i] == AT_HWCAP) {
if (buf[i + 1] & PPC_FEATURE_HAS_ALTIVEC)
ret = AV_CPU_FLAG_ALTIVEC;
goto out;
}
}
}
out:
close(fd);
return ret;
#elif CONFIG_RUNTIME_CPUDETECT
int proc_ver;
// Support of mfspr PVR emulation added in Linux 2.6.17.