[v2,01/16] linux: Fix vDSO macros build with time64 interfaces

Message ID 20191217214728.2886-1-adhemerval.zanella@linaro.org
State Accepted
Commit d0def09ff6bbf1537beec305fdfe96a21174fb31
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Series
  • [v2,01/16] linux: Fix vDSO macros build with time64 interfaces
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Commit Message

Adhemerval Zanella Dec. 17, 2019, 9:47 p.m.
Changes from previous version:

  - Reinstate syscall fallback on INLINE_VSYSCALL, it simplifies
    when the macro is used multiple times (as for clock_gettime
    and clock_getres).

--

As indicated on libc-help [1] the ec138c67cb commit broke 32-bit
builds when configured with --enable-kernel=5.1 or higher.  The
scenario 10 from [2] might also occur in this configuration and
INLINE_VSYSCALL will try to use the vDSO symbol and
HAVE_CLOCK_GETTIME64_VSYSCALL does not set HAVE_VSYSCALL prior its
usage.

Also, there is no easy way to just enable the code to use one
vDSO sysmbo since the macro INLINE_VSYSCALL is redefined if
HAVE_VSYSCALL is set.

Instead of adding more pre-processor handling and making the code
even more convoluted, this patch removes the requirement of defining
HAVE_VSYSCALL before including sysdep-vdso.h to enable vDSO usage.

The INLINE_VSYSCALL is now expected to be issued inside a
HAVE_*_VSYSCALL check, since it will try to use the internal vDSO
pointers.

Both clock_getres and clock_gettime vDSO code for time64_t were
removed since there is no vDSO setup code for the symbol (an
architecture can not set HAVE_CLOCK_GETTIME64_VSYSCALL).

Checked on i686-linux-gnu (default and with --enable-kernel=5.1),
x86_64-linux-gnu, aarch64-linux-gnu, and powerpc64le-linux-gnu.
I also checked against a build to mips64-linux-gnu and
sparc64-linux-gnu.

[1] https://sourceware.org/ml/libc-help/2019-12/msg00014.html
---
 .../unix/sysv/linux/aarch64/gettimeofday.c    |  4 --
 sysdeps/unix/sysv/linux/clock_getres.c        | 36 +++++++++++-------
 sysdeps/unix/sysv/linux/clock_gettime.c       | 38 +++++++++++--------
 sysdeps/unix/sysv/linux/getcpu.c              |  9 +----
 .../unix/sysv/linux/powerpc/gettimeofday.c    |  4 --
 sysdeps/unix/sysv/linux/powerpc/time.c        |  4 --
 sysdeps/unix/sysv/linux/sched_getcpu.c        | 15 +++-----
 sysdeps/unix/sysv/linux/sysdep-vdso.h         | 34 +----------------
 sysdeps/unix/sysv/linux/x86/gettimeofday.c    |  4 --
 sysdeps/unix/sysv/linux/x86/time.c            |  8 ++--
 10 files changed, 58 insertions(+), 98 deletions(-)

-- 
2.17.1

Patch

diff --git a/sysdeps/unix/sysv/linux/aarch64/gettimeofday.c b/sysdeps/unix/sysv/linux/aarch64/gettimeofday.c
index 7e772e05ce..143c5c1507 100644
--- a/sysdeps/unix/sysv/linux/aarch64/gettimeofday.c
+++ b/sysdeps/unix/sysv/linux/aarch64/gettimeofday.c
@@ -22,10 +22,6 @@ 
 
 #include <time.h>
 #include <sysdep.h>
-
-#ifdef HAVE_GETTIMEOFDAY_VSYSCALL
-# define HAVE_VSYSCALL
-#endif
 #include <sysdep-vdso.h>
 
 /* Used as a fallback in the ifunc resolver if VDSO is not available
diff --git a/sysdeps/unix/sysv/linux/clock_getres.c b/sysdeps/unix/sysv/linux/clock_getres.c
index 9497f78787..52671fa641 100644
--- a/sysdeps/unix/sysv/linux/clock_getres.c
+++ b/sysdeps/unix/sysv/linux/clock_getres.c
@@ -20,9 +20,6 @@ 
 #include <errno.h>
 #include <time.h>
 
-#ifdef HAVE_CLOCK_GETRES_VSYSCALL
-# define HAVE_VSYSCALL
-#endif
 #include <sysdep-vdso.h>
 #include <shlib-compat.h>
 #include <kernel-features.h>
@@ -32,23 +29,34 @@  int
 __clock_getres64 (clockid_t clock_id, struct __timespec64 *res)
 {
 #ifdef __ASSUME_TIME64_SYSCALLS
-# ifndef __NR_clock_getres_time64
-  return INLINE_VSYSCALL (clock_getres, 2, clock_id, res);
+  /* 64 bit ABIs or Newer 32-bit ABIs that only support 64-bit time_t.  */
+# ifdef __NR_clock_getres_time64
+  return INLINE_SYSCALL_CALL (clock_getres_time64, clock_id, res);
 # else
-  return INLINE_SYSCALL (clock_getres_time64, 2, clock_id, res);
+#  ifdef HAVE_CLOCK_GETRES_VSYSCALL
+  return INLINE_VSYSCALL (clock_getres, 2, clock_id, res);
+#  else
+  return INLINE_SYSCALL_CALL (clock_getres, clock_id, res);
+#  endif
 # endif
 #else
+  int r;
+  /* Old 32-bit ABI with possible 64-bit time_t support.  */
 # ifdef __NR_clock_getres_time64
-  int ret = INLINE_SYSCALL (clock_getres_time64, 2, clock_id, res);
-  if (ret == 0 || errno != ENOSYS)
-    return ret;
+  r = INLINE_SYSCALL_CALL (clock_getres_time64, clock_id, res);
+  if (r == 0 || errno != ENOSYS)
+    return r;
 # endif
+  /* Fallback code that uses 32-bit support.  */
   struct timespec ts32;
-  int retval = INLINE_VSYSCALL (clock_getres, 2, clock_id, &ts32);
-  if (! retval && res)
+# ifdef HAVE_CLOCK_GETRES_VSYSCALL
+  r = INLINE_VSYSCALL (clock_getres, 2, clock_id, &ts32);
+# else
+  r = INLINE_SYSCALL_CALL (clock_getres, clock_id, &ts32);
+# endif
+  if (r == 0)
     *res = valid_timespec_to_timespec64 (ts32);
-
-  return retval;
+  return r;
 #endif
 }
 
@@ -60,7 +68,7 @@  __clock_getres (clockid_t clock_id, struct timespec *res)
   int retval;
 
   retval = __clock_getres64 (clock_id, &ts64);
-  if (! retval && res)
+  if (retval == 0 && res != NULL)
     *res = valid_timespec64_to_timespec (ts64);
 
   return retval;
diff --git a/sysdeps/unix/sysv/linux/clock_gettime.c b/sysdeps/unix/sysv/linux/clock_gettime.c
index 875c4fe905..e895812704 100644
--- a/sysdeps/unix/sysv/linux/clock_gettime.c
+++ b/sysdeps/unix/sysv/linux/clock_gettime.c
@@ -21,10 +21,6 @@ 
 #include <errno.h>
 #include <time.h>
 #include "kernel-posix-cpu-timers.h"
-
-#ifdef HAVE_CLOCK_GETTIME_VSYSCALL
-# define HAVE_VSYSCALL
-#endif
 #include <sysdep-vdso.h>
 
 #include <shlib-compat.h>
@@ -34,22 +30,34 @@  int
 __clock_gettime64 (clockid_t clock_id, struct __timespec64 *tp)
 {
 #ifdef __ASSUME_TIME64_SYSCALLS
-# ifndef __NR_clock_gettime64
-#  define __NR_clock_gettime64   __NR_clock_gettime
-#  define __vdso_clock_gettime64 __vdso_clock_gettime
+  /* 64 bit ABIs or Newer 32-bit ABIs that only support 64-bit time_t.  */
+# ifdef __NR_clock_gettime64
+  return INLINE_SYSCALL_CALL (clock_gettime64, clock_id, tp);
+# else
+#  ifdef HAVE_CLOCK_GETTIME_VSYSCALL
+  return INLINE_VSYSCALL (clock_gettime, 2, clock_id, tp);
+#  else
+  return INLINE_SYSCALL_CALL (clock_gettime, clock_id, tp);
+#  endif
 # endif
-   return INLINE_VSYSCALL (clock_gettime64, 2, clock_id, tp);
 #else
-# if defined HAVE_CLOCK_GETTIME64_VSYSCALL
-  int ret64 = INLINE_VSYSCALL (clock_gettime64, 2, clock_id, tp);
-  if (ret64 == 0 || errno != ENOSYS)
-    return ret64;
+  int r;
+  /* Old 32-bit ABI with possible 64-bit time_t support.  */
+# ifdef __NR_clock_gettime64
+  r = INLINE_SYSCALL_CALL (clock_gettime64, clock_id, tp);
+  if (r == 0 || errno != ENOSYS)
+    return r;
 # endif
+  /* Fallback code that uses 32-bit support.  */
   struct timespec tp32;
-  int ret = INLINE_VSYSCALL (clock_gettime, 2, clock_id, &tp32);
-  if (ret == 0)
+# ifdef HAVE_CLOCK_GETTIME_VSYSCALL
+  r = INLINE_VSYSCALL (clock_gettime, 2, clock_id, &tp32);
+# else
+  r = INLINE_SYSCALL_CALL (clock_gettime, clock_id, &tp32);
+# endif
+  if (r == 0)
     *tp = valid_timespec_to_timespec64 (tp32);
-  return ret;
+  return r;
 #endif
 }
 
diff --git a/sysdeps/unix/sysv/linux/getcpu.c b/sysdeps/unix/sysv/linux/getcpu.c
index fdd27203af..efb4bb7627 100644
--- a/sysdeps/unix/sysv/linux/getcpu.c
+++ b/sysdeps/unix/sysv/linux/getcpu.c
@@ -18,20 +18,15 @@ 
 #include <errno.h>
 #include <sched.h>
 #include <sysdep.h>
-
-#ifdef HAVE_GETCPU_VSYSCALL
-# define HAVE_VSYSCALL
-#endif
 #include <sysdep-vdso.h>
 
 int
 __getcpu (unsigned int *cpu, unsigned int *node)
 {
-#ifdef __NR_getcpu
+#ifdef HAVE_GETCPU_VSYSCALL
   return INLINE_VSYSCALL (getcpu, 3, cpu, node, NULL);
 #else
-  __set_errno (ENOSYS);
-  return -1;
+  return INLINE_SYSCALL_CALL (getcpu, cpu, node, NULL);
 #endif
 }
 weak_alias (__getcpu, getcpu)
diff --git a/sysdeps/unix/sysv/linux/powerpc/gettimeofday.c b/sysdeps/unix/sysv/linux/powerpc/gettimeofday.c
index 18d8f7cb7a..c40793fe64 100644
--- a/sysdeps/unix/sysv/linux/powerpc/gettimeofday.c
+++ b/sysdeps/unix/sysv/linux/powerpc/gettimeofday.c
@@ -17,10 +17,6 @@ 
 
 #include <time.h>
 #include <sysdep.h>
-
-#ifdef HAVE_GETTIMEOFDAY_VSYSCALL
-# define HAVE_VSYSCALL
-#endif
 #include <sysdep-vdso.h>
 
 static int
diff --git a/sysdeps/unix/sysv/linux/powerpc/time.c b/sysdeps/unix/sysv/linux/powerpc/time.c
index 80a4c73416..f2b4c76be8 100644
--- a/sysdeps/unix/sysv/linux/powerpc/time.c
+++ b/sysdeps/unix/sysv/linux/powerpc/time.c
@@ -18,10 +18,6 @@ 
 
 #include <time.h>
 #include <sysdep.h>
-
-#ifdef HAVE_TIME_VSYSCALL
-# define HAVE_VSYSCALL
-#endif
 #include <sysdep-vdso.h>
 
 static time_t
diff --git a/sysdeps/unix/sysv/linux/sched_getcpu.c b/sysdeps/unix/sysv/linux/sched_getcpu.c
index 65dd9fdda7..68ba7f3734 100644
--- a/sysdeps/unix/sysv/linux/sched_getcpu.c
+++ b/sysdeps/unix/sysv/linux/sched_getcpu.c
@@ -18,22 +18,17 @@ 
 #include <errno.h>
 #include <sched.h>
 #include <sysdep.h>
-
-#ifdef HAVE_GETCPU_VSYSCALL
-# define HAVE_VSYSCALL
-#endif
 #include <sysdep-vdso.h>
 
 int
 sched_getcpu (void)
 {
-#ifdef __NR_getcpu
   unsigned int cpu;
-  int r = INLINE_VSYSCALL (getcpu, 3, &cpu, NULL, NULL);
-
-  return r == -1 ? r : cpu;
+  int r = -1;
+#ifdef HAVE_GETCPU_VSYSCALL
+  r = INLINE_VSYSCALL (getcpu, 3, &cpu, NULL, NULL);
 #else
-  __set_errno (ENOSYS);
-  return -1;
+  r = INLINE_SYSCALL_CALL (getcpu, &cpu, NULL, NULL);
 #endif
+  return r == -1 ? r : cpu;
 }
diff --git a/sysdeps/unix/sysv/linux/sysdep-vdso.h b/sysdeps/unix/sysv/linux/sysdep-vdso.h
index cf614fbf8b..76a211e39b 100644
--- a/sysdeps/unix/sysv/linux/sysdep-vdso.h
+++ b/sysdeps/unix/sysv/linux/sysdep-vdso.h
@@ -20,17 +20,14 @@ 
 # define SYSDEP_VDSO_LINUX_H
 
 #include <dl-vdso.h>
+#include <libc-vdso.h>
 
 #ifndef INTERNAL_VSYSCALL_CALL
 # define INTERNAL_VSYSCALL_CALL(funcptr, err, nr, args...)		      \
      funcptr (args)
 #endif
 
-#ifdef HAVE_VSYSCALL
-
-# include <libc-vdso.h>
-
-# define INLINE_VSYSCALL(name, nr, args...)				      \
+#define INLINE_VSYSCALL(name, nr, args...)				      \
   ({									      \
     __label__ out;							      \
     __label__ iserr;							      \
@@ -59,31 +56,4 @@ 
     sc_ret;								      \
   })
 
-# define INTERNAL_VSYSCALL(name, err, nr, args...)			      \
-  ({									      \
-    __label__ out;							      \
-    long v_ret;								      \
-									      \
-    __typeof (__vdso_##name) vdsop = __vdso_##name;			      \
-    PTR_DEMANGLE (vdsop);						      \
-    if (vdsop != NULL)							      \
-      {									      \
-	v_ret = INTERNAL_VSYSCALL_CALL (vdsop, err, nr, ##args);	      \
-	if (!INTERNAL_SYSCALL_ERROR_P (v_ret, err)			      \
-	    || INTERNAL_SYSCALL_ERRNO (v_ret, err) != ENOSYS)		      \
-	  goto out;							      \
-      }									      \
-    v_ret = INTERNAL_SYSCALL (name, err, nr, ##args);			      \
-  out:									      \
-    v_ret;								      \
-  })
-#else
-
-# define INLINE_VSYSCALL(name, nr, args...) \
-   INLINE_SYSCALL (name, nr, ##args)
-# define INTERNAL_VSYSCALL(name, err, nr, args...) \
-   INTERNAL_SYSCALL (name, err, nr, ##args)
-
-#endif /* USE_VSYSCALL && defined HAVE_VSYSCALL */
-
 #endif /* SYSDEP_VDSO_LINUX_H  */
diff --git a/sysdeps/unix/sysv/linux/x86/gettimeofday.c b/sysdeps/unix/sysv/linux/x86/gettimeofday.c
index 190127d31e..8015c40210 100644
--- a/sysdeps/unix/sysv/linux/x86/gettimeofday.c
+++ b/sysdeps/unix/sysv/linux/x86/gettimeofday.c
@@ -18,10 +18,6 @@ 
 
 #include <time.h>
 #include <sysdep.h>
-
-#ifdef HAVE_GETTIMEOFDAY_VSYSCALL
-# define HAVE_VSYSCALL
-#endif
 #include <sysdep-vdso.h>
 
 static int
diff --git a/sysdeps/unix/sysv/linux/x86/time.c b/sysdeps/unix/sysv/linux/x86/time.c
index 4a03c46d21..85a9fc8a08 100644
--- a/sysdeps/unix/sysv/linux/x86/time.c
+++ b/sysdeps/unix/sysv/linux/x86/time.c
@@ -18,16 +18,16 @@ 
 
 #include <time.h>
 #include <sysdep.h>
-
-#ifdef HAVE_TIME_VSYSCALL
-# define HAVE_VSYSCALL
-#endif
 #include <sysdep-vdso.h>
 
 static time_t
 time_vsyscall (time_t *t)
 {
+#ifdef HAVE_TIME_VSYSCALL
   return INLINE_VSYSCALL (time, 1, t);
+#else
+  return INLINE_SYSCALL_CALL (time, t);
+#endif
 }
 
 #ifdef SHARED