mips: add vdso support

vdso support is available on mips starting with kernel 4.4, see kernel
commit a7f4df4e21 "MIPS: VDSO: Add implementations of gettimeofday()
and clock_gettime()" for details.

In Linux kernel 4.4.0 the mips code returns -ENOSYS in case it can not
handle the vdso call and assumes the libc will call the original
syscall in this case. Handle this case in musl. Currently Linux kernel
4.4.0 handles the following types: CLOCK_REALTIME_COARSE,
CLOCK_MONOTONIC_COARSE, CLOCK_REALTIME and CLOCK_MONOTONIC.

diff --git a/arch/mips/syscall_arch.h b/arch/mips/syscall_arch.h
index e74e0ad0e8bdbc657e5a940b698e4059c616d343..39c0ea32f15152ac87d9c1b2341e8132f11a4387 100644 (file)
--- a/arch/mips/syscall_arch.h
+++ b/arch/mips/syscall_arch.h
@@ -161,3 +161,7 @@ static inline long __syscall6(long n, long a, long b, long c, long d, long e, lo
        if (n == SYS_fstatat) __stat_fix(c);
        return r2;
 }
+
+#define VDSO_USEFUL
+#define VDSO_CGT_SYM "__vdso_clock_gettime"
+#define VDSO_CGT_VER "LINUX_2.6"