[11/18] linux: Only use 64-bit syscall if required for semtimedop

Message ID 20210617115104.1359598-12-adhemerval.zanella@linaro.org
State New
Headers show
Series
  • More y2038 fixes
Related show

Commit Message

H.J. Lu via Libc-alpha June 17, 2021, 11:50 a.m.
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.

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.
---
 sysdeps/unix/sysv/linux/semtimedop.c | 54 ++++++++++++++++------------
 sysvipc/Makefile                     |  9 +++++
 sysvipc/test-sysvsem.c               | 22 +++++++++---
 3 files changed, 57 insertions(+), 28 deletions(-)

-- 
2.30.2

Comments

Lukasz Majewski June 21, 2021, 7:43 a.m. | #1
On Thu, 17 Jun 2021 08:50:57 -0300
Adhemerval Zanella <adhemerval.zanella@linaro.org> wrote:

> 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.

> 

> 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.

> ---

>  sysdeps/unix/sysv/linux/semtimedop.c | 54

> ++++++++++++++++------------ sysvipc/Makefile                     |

> 9 +++++ sysvipc/test-sysvsem.c               | 22 +++++++++---

>  3 files changed, 57 insertions(+), 28 deletions(-)

> 

> diff --git a/sysdeps/unix/sysv/linux/semtimedop.c

> b/sysdeps/unix/sysv/linux/semtimedop.c index b732b6db48..65a8c080f7

> 100644 --- a/sysdeps/unix/sysv/linux/semtimedop.c

> +++ b/sysdeps/unix/sysv/linux/semtimedop.c

> @@ -21,44 +21,52 @@

>  #include <sysdep.h>

>  #include <errno.h>

>  

> +static int

> +semtimedop_syscall (int semid, struct sembuf *sops, size_t nsops,

> +		    const struct __timespec64 *timeout)

> +{

> +#ifdef __NR_semtimedop_time64

> +  return INLINE_SYSCALL_CALL (semtimedop_time64, semid, sops, nsops,

> timeout); +#elif defined __ASSUME_DIRECT_SYSVIPC_SYSCALLS && defined

> __NR_semtimedop

> +  return INLINE_SYSCALL_CALL (semtimedop, semid, sops, nsops,

> timeout); +#else

> +  return INLINE_SYSCALL_CALL (ipc, IPCOP_semtimedop, semid,

> +			      SEMTIMEDOP_IPC_ARGS (nsops, sops,

> timeout)); +#endif

> +}

> +

>  /* Perform user-defined atomical operation of array of semaphores.

> */ int

>  __semtimedop64 (int semid, struct sembuf *sops, size_t nsops,

>  		const struct __timespec64 *timeout)

>  {

> -  int r;

> -#if defined __NR_semtimedop_time64

> -  r = INLINE_SYSCALL_CALL (semtimedop_time64, semid, sops, nsops,

> timeout); -#elif defined __ASSUME_DIRECT_SYSVIPC_SYSCALLS && defined

> __NR_semtimedop

> -  r = INLINE_SYSCALL_CALL (semtimedop, semid, sops, nsops, timeout);

> +#ifdef __ASSUME_TIME64_SYSCALLS

> +  return semtimedop_syscall (semid, sops, nsops, timeout);

>  #else

> -  r = INLINE_SYSCALL_CALL (ipc, IPCOP_semtimedop, semid,

> -			   SEMTIMEDOP_IPC_ARGS (nsops, sops,

> timeout)); -#endif

> -

> -#ifndef __ASSUME_TIME64_SYSCALLS

> -  if (r == 0 || errno != ENOSYS)

> -    return r;

> +  bool is32bit = timeout != NULL

> +		 ? in_time_t_range (timeout->tv_sec) : true;

> +  if (!is32bit)

> +    {

> +      int r = semtimedop_syscall (semid, sops, nsops, timeout);

> +      if (r == 0 || errno != ENOSYS)

> +	return r;

> +      __set_errno (EOVERFLOW);

> +      return -1;

> +    }

>  

>    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;

>      }

> -# if defined __ASSUME_DIRECT_SYSVIPC_SYSCALLS

> -  r = INLINE_SYSCALL_CALL (semtimedop, semid, sops, nsops, pts32);

> +# ifdef __ASSUME_DIRECT_SYSVIPC_SYSCALLS

> +  return INLINE_SYSCALL_CALL (semtimedop, semid, sops, nsops, pts32);

>  # else

> -  r = INLINE_SYSCALL_CALL (ipc, IPCOP_semtimedop, semid,

> -			   SEMTIMEDOP_IPC_ARGS (nsops, sops, pts32));

> +  return INLINE_SYSCALL_CALL (ipc, IPCOP_semtimedop, semid,

> +			      SEMTIMEDOP_IPC_ARGS (nsops, sops,

> pts32)); # endif

> -#endif /* __ASSUME_TIME64_SYSCALLS  */

> -  return r;

> +#endif

>  }

>  #if __TIMESIZE != 64

>  libc_hidden_def (__semtimedop64)

> diff --git a/sysvipc/Makefile b/sysvipc/Makefile

> index 86911803b5..d2acb6a70b 100644

> --- a/sysvipc/Makefile

> +++ b/sysvipc/Makefile

> @@ -38,3 +38,12 @@ include ../Rules

>  

>  CFLAGS-msgrcv.c += -fexceptions -fasynchronous-unwind-tables

>  CFLAGS-msgsnd.c += -fexceptions -fasynchronous-unwind-tables

> +

> +ifeq (yes,$(build-shared))

> +librt = $(common-objpfx)rt/librt.so

> +else

> +librt = $(common-objpfx)rt/librt.a

> +endif

> +

> +$(objpfx)test-sysvsem: $(librt)

> +$(objpfx)test-sysvsem-time64: $(librt)

> diff --git a/sysvipc/test-sysvsem.c b/sysvipc/test-sysvsem.c

> index 092418205d..d9034c3dae 100644

> --- a/sysvipc/test-sysvsem.c

> +++ b/sysvipc/test-sysvsem.c

> @@ -16,6 +16,7 @@

>     License along with the GNU C Library; if not, see

>     <https://www.gnu.org/licenses/>.  */

>  

> +#include <intprops.h>

>  #include <stdio.h>

>  #include <stdlib.h>

>  #include <errno.h>

> @@ -30,6 +31,8 @@

>  #include <support/support.h>

>  #include <support/check.h>

>  #include <support/temp_file.h>

> +#include <support/xtime.h>

> +#include <support/xsignal.h>

>  

>  /* These are for the temporary file we generate.  */

>  static char *name;

> @@ -112,11 +115,20 @@ do_test (void)

>  #ifdef _GNU_SOURCE

>    /* Set a time for half a second.  The semaphore operation should

> timeout with EAGAIN.  */

> -  struct timespec ts = { 0 /* sec */, 500000000 /* nsec */ };

> -  if (semtimedop (semid, &sb2, 1, &ts) != -1

> -      || (errno != EAGAIN && errno != ENOSYS))

> -    FAIL_EXIT1 ("semtimedop succeed or returned errno !=

> {EAGAIN,ENOSYS} "

> -		"(errno=%i)", errno);

> +  {

> +    struct timespec ts = { 0 /* sec */, 500000000 /* nsec */ };

> +    if (semtimedop (semid, &sb2, 1, &ts) != -1

> +        || (errno != EAGAIN && errno != ENOSYS))

> +      FAIL_EXIT1 ("semtimedop succeed or returned errno !=

> {EAGAIN,ENOSYS} "

> +		  "(errno=%i)", errno);

> +  }

> +

> +  {

> +    support_create_timer (0, 100000000, false, NULL);

> +    struct timespec ts = { TYPE_MAXIMUM (time_t), 0 };

> +    TEST_COMPARE (semtimedop (semid, &sb2, 1, &ts), -1);

> +    TEST_VERIFY (errno == EINTR || errno == EOVERFLOW);

> +  }

>  #endif

>  

>    /* Finally free up the semnaphore resource.  */


Reviewed-by: Lukasz Majewski <lukma@denx.de>



Best regards,

Lukasz Majewski

--

DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma@denx.de

Patch

diff --git a/sysdeps/unix/sysv/linux/semtimedop.c b/sysdeps/unix/sysv/linux/semtimedop.c
index b732b6db48..65a8c080f7 100644
--- a/sysdeps/unix/sysv/linux/semtimedop.c
+++ b/sysdeps/unix/sysv/linux/semtimedop.c
@@ -21,44 +21,52 @@ 
 #include <sysdep.h>
 #include <errno.h>
 
+static int
+semtimedop_syscall (int semid, struct sembuf *sops, size_t nsops,
+		    const struct __timespec64 *timeout)
+{
+#ifdef __NR_semtimedop_time64
+  return INLINE_SYSCALL_CALL (semtimedop_time64, semid, sops, nsops, timeout);
+#elif defined __ASSUME_DIRECT_SYSVIPC_SYSCALLS && defined __NR_semtimedop
+  return INLINE_SYSCALL_CALL (semtimedop, semid, sops, nsops, timeout);
+#else
+  return INLINE_SYSCALL_CALL (ipc, IPCOP_semtimedop, semid,
+			      SEMTIMEDOP_IPC_ARGS (nsops, sops, timeout));
+#endif
+}
+
 /* Perform user-defined atomical operation of array of semaphores.  */
 int
 __semtimedop64 (int semid, struct sembuf *sops, size_t nsops,
 		const struct __timespec64 *timeout)
 {
-  int r;
-#if defined __NR_semtimedop_time64
-  r = INLINE_SYSCALL_CALL (semtimedop_time64, semid, sops, nsops, timeout);
-#elif defined __ASSUME_DIRECT_SYSVIPC_SYSCALLS && defined __NR_semtimedop
-  r = INLINE_SYSCALL_CALL (semtimedop, semid, sops, nsops, timeout);
+#ifdef __ASSUME_TIME64_SYSCALLS
+  return semtimedop_syscall (semid, sops, nsops, timeout);
 #else
-  r = INLINE_SYSCALL_CALL (ipc, IPCOP_semtimedop, semid,
-			   SEMTIMEDOP_IPC_ARGS (nsops, sops, timeout));
-#endif
-
-#ifndef __ASSUME_TIME64_SYSCALLS
-  if (r == 0 || errno != ENOSYS)
-    return r;
+  bool is32bit = timeout != NULL
+		 ? in_time_t_range (timeout->tv_sec) : true;
+  if (!is32bit)
+    {
+      int r = semtimedop_syscall (semid, sops, nsops, timeout);
+      if (r == 0 || errno != ENOSYS)
+	return r;
+      __set_errno (EOVERFLOW);
+      return -1;
+    }
 
   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;
     }
-# if defined __ASSUME_DIRECT_SYSVIPC_SYSCALLS
-  r = INLINE_SYSCALL_CALL (semtimedop, semid, sops, nsops, pts32);
+# ifdef __ASSUME_DIRECT_SYSVIPC_SYSCALLS
+  return INLINE_SYSCALL_CALL (semtimedop, semid, sops, nsops, pts32);
 # else
-  r = INLINE_SYSCALL_CALL (ipc, IPCOP_semtimedop, semid,
-			   SEMTIMEDOP_IPC_ARGS (nsops, sops, pts32));
+  return INLINE_SYSCALL_CALL (ipc, IPCOP_semtimedop, semid,
+			      SEMTIMEDOP_IPC_ARGS (nsops, sops, pts32));
 # endif
-#endif /* __ASSUME_TIME64_SYSCALLS  */
-  return r;
+#endif
 }
 #if __TIMESIZE != 64
 libc_hidden_def (__semtimedop64)
diff --git a/sysvipc/Makefile b/sysvipc/Makefile
index 86911803b5..d2acb6a70b 100644
--- a/sysvipc/Makefile
+++ b/sysvipc/Makefile
@@ -38,3 +38,12 @@  include ../Rules
 
 CFLAGS-msgrcv.c += -fexceptions -fasynchronous-unwind-tables
 CFLAGS-msgsnd.c += -fexceptions -fasynchronous-unwind-tables
+
+ifeq (yes,$(build-shared))
+librt = $(common-objpfx)rt/librt.so
+else
+librt = $(common-objpfx)rt/librt.a
+endif
+
+$(objpfx)test-sysvsem: $(librt)
+$(objpfx)test-sysvsem-time64: $(librt)
diff --git a/sysvipc/test-sysvsem.c b/sysvipc/test-sysvsem.c
index 092418205d..d9034c3dae 100644
--- a/sysvipc/test-sysvsem.c
+++ b/sysvipc/test-sysvsem.c
@@ -16,6 +16,7 @@ 
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
+#include <intprops.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <errno.h>
@@ -30,6 +31,8 @@ 
 #include <support/support.h>
 #include <support/check.h>
 #include <support/temp_file.h>
+#include <support/xtime.h>
+#include <support/xsignal.h>
 
 /* These are for the temporary file we generate.  */
 static char *name;
@@ -112,11 +115,20 @@  do_test (void)
 #ifdef _GNU_SOURCE
   /* Set a time for half a second.  The semaphore operation should timeout
      with EAGAIN.  */
-  struct timespec ts = { 0 /* sec */, 500000000 /* nsec */ };
-  if (semtimedop (semid, &sb2, 1, &ts) != -1
-      || (errno != EAGAIN && errno != ENOSYS))
-    FAIL_EXIT1 ("semtimedop succeed or returned errno != {EAGAIN,ENOSYS} "
-		"(errno=%i)", errno);
+  {
+    struct timespec ts = { 0 /* sec */, 500000000 /* nsec */ };
+    if (semtimedop (semid, &sb2, 1, &ts) != -1
+        || (errno != EAGAIN && errno != ENOSYS))
+      FAIL_EXIT1 ("semtimedop succeed or returned errno != {EAGAIN,ENOSYS} "
+		  "(errno=%i)", errno);
+  }
+
+  {
+    support_create_timer (0, 100000000, false, NULL);
+    struct timespec ts = { TYPE_MAXIMUM (time_t), 0 };
+    TEST_COMPARE (semtimedop (semid, &sb2, 1, &ts), -1);
+    TEST_VERIFY (errno == EINTR || errno == EOVERFLOW);
+  }
 #endif
 
   /* Finally free up the semnaphore resource.  */