S390: Add support for vdso getcpu symbol.

This patch adds support for symbol __kernel_getcpu in vDSO,
which is available with kernel 4.5.
Now sched_getcpu is using this symbol if available in mapped vDSO
by defining macro HAVE_GETCPU_VSYSCALL. If not available at runtime,
the former syscall is used.

diff --git a/ChangeLog b/ChangeLog
index 4677e87..1f5261a 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,14 @@
+2016-05-09  Stefan Liebler  <stli@linux.vnet.ibm.com>
+
+       * sysdeps/unix/sysv/linux/s390/init-first.c:
+       Add VDSO_SYMBOL(getcpu).
+       (_libc_vdso_platform_setup): Initialize VDSO_SYMBOL(getcpu).
+       * sysdeps/unix/sysv/linux/s390/libc-vdso.h:
+       Add VDSO_SYMBOL(getcpu).
+       * sysdeps/unix/sysv/linux/s390/s390-32/sysdep.h:
+       New define HAVE_GETCPU_VSYSCALL.
+       * sysdeps/unix/sysv/linux/s390/s390-64/sysdep.h: Likewise.
+
 2016-05-08  H.J. Lu  <hongjiu.lu@intel.com>
 
        * sysdeps/i386/cacheinfo.c: Include <sysdeps/x86/cacheinfo.c>

diff --git a/sysdeps/unix/sysv/linux/s390/init-first.c b/sysdeps/unix/sysv/linux/s390/init-first.c
index d3a20fd..7498cbe 100644 (file)
--- a/sysdeps/unix/sysv/linux/s390/init-first.c
+++ b/sysdeps/unix/sysv/linux/s390/init-first.c
@@ -29,6 +29,8 @@ long int (*VDSO_SYMBOL(clock_gettime)) (clockid_t, struct timespec *)
 long int (*VDSO_SYMBOL(clock_getres)) (clockid_t, struct timespec *)
   __attribute__ ((nocommon));
 
+long int (*VDSO_SYMBOL(getcpu)) (unsigned *, unsigned *, void *)
+   attribute_hidden;
 
 static inline void
 _libc_vdso_platform_setup (void)
@@ -46,6 +48,10 @@ _libc_vdso_platform_setup (void)
   p = _dl_vdso_vsym ("__kernel_clock_getres", &linux2629);
   PTR_MANGLE (p);
   VDSO_SYMBOL (clock_getres) = p;
+
+  p = _dl_vdso_vsym ("__kernel_getcpu", &linux2629);
+  PTR_MANGLE (p);
+  VDSO_SYMBOL (getcpu) = p;
 }
 
 # define VDSO_SETUP _libc_vdso_platform_setup

diff --git a/sysdeps/unix/sysv/linux/s390/libc-vdso.h b/sysdeps/unix/sysv/linux/s390/libc-vdso.h
index d2a8316..512b3ba 100644 (file)
--- a/sysdeps/unix/sysv/linux/s390/libc-vdso.h
+++ b/sysdeps/unix/sysv/linux/s390/libc-vdso.h
@@ -31,6 +31,8 @@ extern long int (*VDSO_SYMBOL(clock_gettime)) (clockid_t, struct timespec *);
 
 extern long int (*VDSO_SYMBOL(clock_getres)) (clockid_t, struct timespec *);
 
+extern long int (*VDSO_SYMBOL(getcpu)) (unsigned *, unsigned *, void *)
+   attribute_hidden;
 #endif
 
 #endif /* _LIBC_VDSO_H */

diff --git a/sysdeps/unix/sysv/linux/s390/s390-32/sysdep.h b/sysdeps/unix/sysv/linux/s390/s390-32/sysdep.h
index 3540416..651e1ee 100644 (file)
--- a/sysdeps/unix/sysv/linux/s390/s390-32/sysdep.h
+++ b/sysdeps/unix/sysv/linux/s390/s390-32/sysdep.h
@@ -283,6 +283,7 @@
 #define HAVE_CLOCK_GETRES_VSYSCALL     1
 #define HAVE_CLOCK_GETTIME_VSYSCALL    1
 #define HAVE_GETTIMEOFDAY_VSYSCALL     1
+#define HAVE_GETCPU_VSYSCALL           1
 
 /* This version is for internal uses when there is no desire
    to set errno */

diff --git a/sysdeps/unix/sysv/linux/s390/s390-64/sysdep.h b/sysdeps/unix/sysv/linux/s390/s390-64/sysdep.h
index 6f390ff..702b0b6 100644 (file)
--- a/sysdeps/unix/sysv/linux/s390/s390-64/sysdep.h
+++ b/sysdeps/unix/sysv/linux/s390/s390-64/sysdep.h
@@ -289,6 +289,7 @@
 #define HAVE_CLOCK_GETRES_VSYSCALL     1
 #define HAVE_CLOCK_GETTIME_VSYSCALL    1
 #define HAVE_GETTIMEOFDAY_VSYSCALL     1
+#define HAVE_GETCPU_VSYSCALL           1
 
 /* This version is for internal uses when there is no desire
    to set errno */