diff mbox

[v2,12/16] Use shmat syscall for Linux implementation

Message ID 1478114813-3526-13-git-send-email-adhemerval.zanella@linaro.org
State Dropped
Headers

Commit Message

Adhemerval Zanella Nov. 2, 2016, 7:26 p.m. UTC 
  Changes from previous version:

  - Use __ASSUME_SYSVIPC_SYSCALL instead of __NR_syscall to issue the
    wired syscall or the ipc one.

--

This patch add a direct call to shmat syscall if it is supported by
kernel features.

Checked on x86_64, i686, powerpc64le, aarch64, and armhf.

	* sysdeps/unix/sysv/linux/shmat.c (shmat): Use shmat syscall if it is
	defined.
---
 ChangeLog                       |  3 +++
 sysdeps/unix/sysv/linux/shmat.c | 17 ++++++++---------
 2 files changed, 11 insertions(+), 9 deletions(-)

Comments

Arnd Bergmann Nov. 7, 2016, 11:02 a.m. UTC | #1 
On Wednesday, November 2, 2016 5:26:49 PM CET Adhemerval Zanella wrote:
> @@ -31,17 +28,19 @@
>  void *
>  shmat (int shmid, const void *shmaddr, int shmflg)
>  {
> +#ifdef __ASSUME_SYSVIPC_SYSCALL
> +  return INLINE_SYSCALL_CALL (shmat, shmid, shmaddr, shmflg);
> +#else
>    INTERNAL_SYSCALL_DECL(err);
>    unsigned long resultvar;
>    void *raddr;
> 

I looked at the cross-reference for system call tables and found
that alpha does not define __NR_shmat but instead has __NR_osf_shmat

Will that get handled correctly by your code?

	Arnd
Adhemerval Zanella Nov. 7, 2016, 1:10 p.m. UTC | #2 
On 07/11/2016 09:02, Arnd Bergmann wrote:
> On Wednesday, November 2, 2016 5:26:49 PM CET Adhemerval Zanella wrote:
>> @@ -31,17 +28,19 @@
>>  void *
>>  shmat (int shmid, const void *shmaddr, int shmflg)
>>  {
>> +#ifdef __ASSUME_SYSVIPC_SYSCALL
>> +  return INLINE_SYSCALL_CALL (shmat, shmid, shmaddr, shmflg);
>> +#else
>>    INTERNAL_SYSCALL_DECL(err);
>>    unsigned long resultvar;
>>    void *raddr;
>>
> 
> I looked at the cross-reference for system call tables and found
> that alpha does not define __NR_shmat but instead has __NR_osf_shmat
> 
> Will that get handled correctly by your code?
> 
> 	Arnd

No, but at least it does not prevent alpha build since it uses
the syscalls.list instead.  However adjusting it should be simple,
it would be something like __NR_fadvise64_64 for arm (where it
should be __NR_arm_fadvise64_64 and it is handled on
kernel-features.h).

I tried to avoid remove the syscalls.list usage for architecture
that is already using it, but thinking twice for consolidation idea
it would be better to have all architecture to use only a simple
syscall generation mechanism for a syscall. I will add it on the
patch and send a v3.
diff mbox

Patch

diff --git a/sysdeps/unix/sysv/linux/shmat.c b/sysdeps/unix/sysv/linux/shmat.c
index 5afc93c..97a15c2 100644
--- a/sysdeps/unix/sysv/linux/shmat.c
+++ b/sysdeps/unix/sysv/linux/shmat.c
@@ -16,13 +16,10 @@ 
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <errno.h>
-#include <sys/shm.h>
+#include <sys/msg.h>
 #include <ipc_priv.h>
-
 #include <sysdep.h>
-#include <unistd.h>
-#include <sys/syscall.h>
+#include <errno.h>
 
 /* Attach the shared memory segment associated with SHMID to the data
    segment of the calling process.  SHMADDR and SHMFLG determine how
@@ -31,17 +28,19 @@ 
 void *
 shmat (int shmid, const void *shmaddr, int shmflg)
 {
+#ifdef __ASSUME_SYSVIPC_SYSCALL
+  return INLINE_SYSCALL_CALL (shmat, shmid, shmaddr, shmflg);
+#else
   INTERNAL_SYSCALL_DECL(err);
   unsigned long resultvar;
   void *raddr;
 
-  resultvar = INTERNAL_SYSCALL (ipc, err, 5, IPCOP_shmat,
-				shmid, shmflg,
-				(long int) &raddr,
-				(void *) shmaddr);
+  resultvar = INTERNAL_SYSCALL_CALL (ipc, err, IPCOP_shmat, shmid, shmflg,
+				     &raddr, shmaddr);
   if (INTERNAL_SYSCALL_ERROR_P (resultvar, err))
     return (void *) INLINE_SYSCALL_ERROR_RETURN_VALUE (INTERNAL_SYSCALL_ERRNO (resultvar,
 									       err));
 
   return raddr;
+#endif
 }