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authorAdhemerval Zanella <adhemerval.zanella@linaro.org>2021-06-15 16:59:50 -0300
committerAdhemerval Zanella <adhemerval.zanella@linaro.org>2021-06-22 12:09:52 -0300
commit91cf411ad3ef10bd18ec053854fcb919be4f6789 (patch)
tree9d3f802bd16bda2cee81aa61509384890b9f596f /sysdeps
parentecf2661281c71a9752c7238ab93bc12b16cfff23 (diff)
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linux: Only use 64-bit syscall if required for pselect
For !__ASSUME_TIME64_SYSCALLS there is no need to issue a 64-bit syscall
if the provided timeout fits in a 32-bit one.  The 64-bit usage should
be rare since the timeout is a relative one.  This also avoids the need
to use supports_time64() (which breaks the usage case of live migration
like CRIU or similar).

Checked on i686-linux-gnu on a 4.15 kernel and on a 5.11 kernel
(with and without --enable-kernel=5.1) and on x86_64-linux-gnu.

Reviewed-by: Lukasz Majewski <lukma@denx.de>
Diffstat (limited to 'sysdeps')
-rw-r--r--sysdeps/unix/sysv/linux/microblaze/pselect32.c3
-rw-r--r--sysdeps/unix/sysv/linux/pselect.c47
-rw-r--r--sysdeps/unix/sysv/linux/pselect32.c6
3 files changed, 29 insertions, 27 deletions
diff --git a/sysdeps/unix/sysv/linux/microblaze/pselect32.c b/sysdeps/unix/sysv/linux/microblaze/pselect32.c
index a4f436462b..70b7b52a48 100644
--- a/sysdeps/unix/sysv/linux/microblaze/pselect32.c
+++ b/sysdeps/unix/sysv/linux/microblaze/pselect32.c
@@ -35,8 +35,7 @@ __pselect32 (int nfds, fd_set *readfds, fd_set *writefds,
   struct timeval tv32, *ptv32 = NULL;
   if (timeout != NULL)
     {
-      if (! in_time_t_range (timeout->tv_sec)
-	  || ! valid_nanoseconds (timeout->tv_nsec))
+      if (! valid_nanoseconds (timeout->tv_nsec))
 	{
 	  __set_errno (EINVAL);
 	  return -1;
diff --git a/sysdeps/unix/sysv/linux/pselect.c b/sysdeps/unix/sysv/linux/pselect.c
index 5e8a0cc2dc..e7df6e7465 100644
--- a/sysdeps/unix/sysv/linux/pselect.c
+++ b/sysdeps/unix/sysv/linux/pselect.c
@@ -18,7 +18,23 @@
 
 #include <sys/select.h>
 #include <sysdep-cancel.h>
-#include <time64-support.h>
+
+static int
+pselect64_syscall (int nfds, fd_set *readfds, fd_set *writefds,
+		   fd_set *exceptfds, const struct __timespec64 *timeout,
+		   const sigset_t *sigmask)
+{
+#ifndef __NR_pselect6_time64
+# define __NR_pselect6_time64 __NR_pselect6
+#endif
+  /* NB: This is required by ARGIFY used in x32 internal_syscallN.  */
+  __syscall_ulong_t data[2] =
+    {
+      (uintptr_t) sigmask, __NSIG_BYTES
+    };
+  return SYSCALL_CANCEL (pselect6_time64, nfds, readfds, writefds, exceptfds,
+			 timeout, data);
+}
 
 int
 __pselect64 (int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
@@ -37,30 +53,23 @@ __pselect64 (int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
      we can only pass in 6 directly.  If there is an architecture with
      support for more parameters a new version of this file needs to
      be created.  */
-
-#ifndef __NR_pselect6_time64
-# define __NR_pselect6_time64 __NR_pselect6
-#endif
-  int r;
-  if (supports_time64 ())
+#ifdef __ASSUME_TIME64_SYSCALLS
+  return pselect64_syscall (nfds, readfds, writefds, exceptfds, timeout,
+			    sigmask);
+#else
+  bool need_time64 = timeout != NULL && !in_time_t_range (timeout->tv_sec);
+  if (need_time64)
     {
-      /* NB: This is required by ARGIFY used in x32 internal_syscallN.  */
-      __syscall_ulong_t data[2] =
-	{
-	  (uintptr_t) sigmask, __NSIG_BYTES
-	};
-      r = SYSCALL_CANCEL (pselect6_time64, nfds, readfds, writefds, exceptfds,
-			  timeout, data);
+      int r = pselect64_syscall (nfds, readfds, writefds, exceptfds, timeout,
+				 sigmask);
       if (r == 0 || errno != ENOSYS)
 	return r;
-
-      mark_time64_unsupported ();
+      __set_errno (EOVERFLOW);
+      return -1;
     }
 
-#ifndef __ASSUME_TIME64_SYSCALLS
-  r = __pselect32 (nfds, readfds, writefds, exceptfds, timeout, sigmask);
+  return __pselect32 (nfds, readfds, writefds, exceptfds, timeout, sigmask);
 #endif
-  return r;
 }
 
 #if __TIMESIZE != 64
diff --git a/sysdeps/unix/sysv/linux/pselect32.c b/sysdeps/unix/sysv/linux/pselect32.c
index eb59b51cdf..48724d8727 100644
--- a/sysdeps/unix/sysv/linux/pselect32.c
+++ b/sysdeps/unix/sysv/linux/pselect32.c
@@ -29,12 +29,6 @@ __pselect32 (int nfds, fd_set *readfds, fd_set *writefds,
   struct timespec ts32, *pts32 = NULL;
   if (timeout != NULL)
     {
-      if (! in_time_t_range (timeout->tv_sec))
-	{
-	  __set_errno (EINVAL);
-	  return -1;
-	}
-
       ts32 = valid_timespec64_to_timespec (*timeout);
       pts32 = &ts32;
     }