syscall: use SYS_GETDENTS64 on linux/mips64{,le}

The getdents64 syscall is only available for mips64/mips64le starting
with Linux kernel 3.10. Since mips64le requires at least 4.8 according
to [1] (regarding #16848) using it should be fine.

[1] https://golang.org/wiki/MinimumRequirements

This CL changes the binary layout of type Dirent for mips64/mips64le,
but not the public API. But since the currently used layout doesn't
match the struct linux_dirent returned by the getdents syscall this
should be fine as well.

Fixes #23624

Change-Id: Iaa7306fa6e4442ad2fed41c60b37627a7314f117
Reviewed-on: https://go-review.googlesource.com/91055
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

1 files changed, 1 insertions, 8 deletions

diff --git a/src/syscall/syscall_linux_mips64x.go b/src/syscall/syscall_linux_mips64x.go
index e4bc77530c..d9eba62b06 100644
--- a/src/syscall/syscall_linux_mips64x.go
+++ b/src/syscall/syscall_linux_mips64x.go
@@ -8,14 +8,7 @@
 package syscall
 
 const (
-	_SYS_dup = SYS_DUP2
-
-	// Linux introduced getdents64 syscall for N64 ABI only in 3.10
-	// (May 21 2013, rev dec33abaafc89bcbd78f85fad0513170415a26d5),
-	// to support older kernels, we have to use getdents for mips64.
-	// Also note that struct dirent is different for these two.
-	// Lookup linux_dirent{,64} in kernel source code for details.
-	_SYS_getdents  = SYS_GETDENTS
+	_SYS_dup       = SYS_DUP2
 	_SYS_setgroups = SYS_SETGROUPS
 )