dhcpcd: fix delay after dhcp down.

[ipfire-2.x.git] / src / patches / glibc / glibc-rh1028285.patch

From a5675717e35a02a3eba7e13701c6f9c0d7222e13 Mon Sep 17 00:00:00 2001
From: Adhemerval Zanella <azanella@linux.vnet.ibm.com>
Date: Fri, 7 Jun 2013 14:50:23 -0500
Subject: [PATCH 2/2] PowerPC: gettimeofday optimization by using IFUNC

Backport of ef26eece6331a1f6d959818e37c438cc7ce68e53 from master.
---
 sysdeps/unix/sysv/linux/powerpc/bits/libc-vdso.h |   10 ++++
 sysdeps/unix/sysv/linux/powerpc/gettimeofday.c   |   49 +++++++++++++++-------
 2 files changed, 44 insertions(+), 15 deletions(-)

commit 76a9b9986141b1a7d9fd290c349d27fcee780c7a
Author: Adhemerval Zanella <azanella@linux.vnet.ibm.com>
Date:   Thu Nov 7 05:34:22 2013 -0600

    PowerPC: Fix vDSO missing ODP entries
    
    This patch fixes the vDSO symbol used directed in IFUNC resolver where
    they do not have an associated ODP entry leading to undefined behavior
    in some cases. It adds an artificial OPD static entry to such cases
    and set its TOC to non 0 to avoid triggering lazy resolutions.

commit d98720e07f67fbeec00f9e1347840404240d3c48
Author: Adhemerval Zanella <azanella@linux.vnet.ibm.com>
Date:   Mon Jan 20 12:29:51 2014 -0600

    PowerPC: Fix gettimeofday ifunc selection
    
    The IFUNC selector for gettimeofday runs before _libc_vdso_platform_setup where
    __vdso_gettimeofday is set. The selector then sets __gettimeofday (the internal
    version used within GLIBC) to use the system call version instead of the vDSO one.
    This patch changes the check if vDSO is available to get its value directly
    instead of rely on __vdso_gettimeofday.
    
    This patch changes it by getting the vDSO value directly.
    
    It fixes BZ#16431.

diff -pruN a/sysdeps/unix/sysv/linux/powerpc/bits/libc-vdso.h b/sysdeps/unix/sysv/linux/powerpc/bits/libc-vdso.h
--- a/sysdeps/unix/sysv/linux/powerpc/bits/libc-vdso.h	2014-05-20 14:46:51.026871920 +0530
+++ b/sysdeps/unix/sysv/linux/powerpc/bits/libc-vdso.h	2014-05-20 14:44:39.294877321 +0530
@@ -33,6 +33,36 @@ extern void *__vdso_get_tbfreq;
 
 extern void *__vdso_getcpu;
 
+#if defined(__PPC64__) || defined(__powerpc64__)
+/* The correct solution is for _dl_vdso_vsym to return the address of the OPD
+   for the kernel VDSO function.  That address would then be stored in the
+   __vdso_* variables and returned as the result of the IFUNC resolver function.
+   Yet, the kernel does not contain any OPD entries for the VDSO functions
+   (incomplete implementation).  However, PLT relocations for IFUNCs still expect
+   the address of an OPD to be returned from the IFUNC resolver function (since
+   PLT entries on PPC64 are just copies of OPDs).  The solution for now is to
+   create an artificial static OPD for each VDSO function returned by a resolver
+   function.  The TOC value is set to a non-zero value to avoid triggering lazy
+   symbol resolution via .glink0/.plt0 for a zero TOC (requires thread-safe PLT
+   sequences) when the dynamic linker isn't prepared for it e.g. RTLD_NOW.  None
+   of the kernel VDSO routines use the TOC or AUX values so any non-zero value
+   will work.  Note that function pointer comparisons will not use this artificial
+   static OPD since those are resolved via ADDR64 relocations and will point at
+   the non-IFUNC default OPD for the symbol.  Lastly, because the IFUNC relocations
+   are processed immediately at startup the resolver functions and this code need
+   not be thread-safe, but if the caller writes to a PLT slot it must do so in a
+   thread-safe manner with all the required barriers.  */
+#define VDSO_IFUNC_RET(value)                            \
+  ({                                                     \
+    static Elf64_FuncDesc vdso_opd = { .fd_toc = ~0x0 }; \
+    vdso_opd.fd_func = (Elf64_Addr)value;                \
+    &vdso_opd;                                           \
+  })
+
+#else
+#define VDSO_IFUNC_RET(value)  ((void *) (value))
+#endif
+
 #endif
 
 #endif /* _LIBC_VDSO_H */
diff -pruN a/sysdeps/unix/sysv/linux/powerpc/gettimeofday.c b/sysdeps/unix/sysv/linux/powerpc/gettimeofday.c
--- a/sysdeps/unix/sysv/linux/powerpc/gettimeofday.c	2010-05-04 16:57:23.000000000 +0530
+++ b/sysdeps/unix/sysv/linux/powerpc/gettimeofday.c	2014-05-20 14:44:39.298877321 +0530
@@ -16,27 +16,51 @@
    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
    02111-1307 USA.  */
 
-#include <sysdep.h>
-#include <bp-checks.h>
-#include <stddef.h>
 #include <sys/time.h>
-#include <time.h>
-#include <hp-timing.h>
 
-#undef __gettimeofday
-#include <bits/libc-vdso.h>
+#ifdef SHARED
 
-/* Get the current time of day and timezone information,
-   putting it into *TV and *TZ.  If TZ is NULL, *TZ is not filled.
-   Returns 0 on success, -1 on errors.  */
-
-int
-__gettimeofday (tv, tz)
-     struct timeval *tv;
-     struct timezone *tz;
+# include <dl-vdso.h>
+# include <bits/libc-vdso.h>
+# include <dl-machine.h>
+
+void *gettimeofday_ifunc (void) __asm__ ("__gettimeofday");
+
+static int
+__gettimeofday_syscall (struct timeval *tv, struct timezone *tz)
+{
+  return INLINE_SYSCALL (gettimeofday, 2, tv, tz);
+}
+
+void *
+gettimeofday_ifunc (void)
+{
+  PREPARE_VERSION (linux2615, "LINUX_2.6.15", 123718565);
+
+  /* If the vDSO is not available we fall back syscall.  */
+  void *vdso_gettimeofday = _dl_vdso_vsym ("__kernel_gettimeofday", &linux2615);
+  return (vdso_gettimeofday ? VDSO_IFUNC_RET (vdso_gettimeofday)
+	  : (void*)__gettimeofday_syscall);
+}
+asm (".type __gettimeofday, %gnu_indirect_function");
+
+/* This is doing "libc_hidden_def (__gettimeofday)" but the compiler won't
+   let us do it in C because it doesn't know we're defining __gettimeofday
+   here in this file.  */
+asm (".globl __GI___gettimeofday\n"
+     "__GI___gettimeofday = __gettimeofday");
+
+#else
+
+# include <sysdep.h>
+# include <errno.h>
+
+int
+__gettimeofday (struct timeval *tv, struct timezone *tz)
 {
-  return INLINE_VSYSCALL (gettimeofday, 2, CHECK_1 (tv), CHECK_1 (tz));
+  return INLINE_SYSCALL (gettimeofday, 2, tv, tz);
 }
 
+#endif
 INTDEF (__gettimeofday)
 weak_alias (__gettimeofday, gettimeofday)