Remove some pre-2.6.16 Linux kernel conditionals

["Joseph S. Myers" <joseph at codesourcery dot com>]

This patch follows up on the increase of minimum kernel version to
2.6.16 by removing four __ASSUME_* macros that are now defined
unconditionally for Linux, and used only in Linux-specific files and
only in ways that are easy to remove.  (The remaining macros are
either more involved to remove although defined unconditionally -
those relating to POSIX timers - or only defined for particular
architectures and so requiring more detailed checks to determine if in
fact all architectures can be presumed to have the kernel feature in
question.)

(I checked that it was correct to remove PROT_GROWSDOWN || PROT_GROWSUP 
and __NR_waitid conditionals along with the __ASSUME_* ones - that the 
relevant definitions are present in all bits/mman.h headers / all unistd.h 
headers for supported kernel versions.)

Tested x86_64.

2012-08-07  Joseph Myers  <joseph@codesourcery.com>

	* sysdeps/unix/sysv/linux/kernel-features.h
	(__ASSUME_PROT_GROWSUPDOWN): Remove.
	(__ASSUME_NO_CLONE_DETACHED): Likewise.
	(__ASSUME_GETDENTS32_D_TYPE): Likewise.
	(__ASSUME_WAITID_SYSCALL): Likewise.
	* sysdeps/unix/sysv/linux/dl-execstack.c
	(_dl_make_stack_executable) [PROT_GROWSDOWN || PROT_GROWSUP]: Make
	code unconditional.
	(_dl_make_stack_executable) [!__ASSUME_PROT_GROWSUPDOWN]: Remove
	conditional code.
	* sysdeps/unix/sysv/linux/getdents.c (__GETDENTS)
	[__ASSUME_GETDENTS32_D_TYPE]: Make code unconditional.
	(__GETDENTS) [!__ASSUME_GETDENTS32_D_TYPE]: Remove conditional
	code.
	* sysdeps/unix/sysv/linux/waitid.c [__NR_waitid]: Make code
	unconditional.
	[__ASSUME_WAITID_SYSCALL]: Likewise.
	[!__ASSUME_WAITID_SYSCALL]: Remove conditional code.

nptl/ChangeLog:
2012-08-07  Joseph Myers  <joseph@codesourcery.com>

	* sysdeps/pthread/createthread.c (create_thread)
	[!__ASSUME_NO_CLONE_DETACHED]: Remove conditional code.

diff --git a/nptl/sysdeps/pthread/createthread.c b/nptl/sysdeps/pthread/createthread.c
index 3ead825..d58f8fa 100644
--- a/nptl/sysdeps/pthread/createthread.c
+++ b/nptl/sysdeps/pthread/createthread.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 2002-2007, 2008, 2010 Free Software Foundation, Inc.
+/* Copyright (C) 2002-2012 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
 
@@ -179,18 +179,11 @@ create_thread (struct pthread *pd, const struct pthread_attr *attr,
 	sys_exit() in the location pointed to by the seventh parameter
 	to CLONE.
 
-     CLONE_DETACHED
-	No signal is generated if the thread exists and it is
-	automatically reaped.
-
      The termination signal is chosen to be zero which means no signal
      is sent.  */
   int clone_flags = (CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGNAL
 		     | CLONE_SETTLS | CLONE_PARENT_SETTID
 		     | CLONE_CHILD_CLEARTID | CLONE_SYSVSEM
-#if __ASSUME_NO_CLONE_DETACHED == 0
-		     | CLONE_DETACHED
-#endif
 		     | 0);
 
   if (__builtin_expect (THREAD_GETMEM (THREAD_SELF, report_events), 0))
diff --git a/sysdeps/unix/sysv/linux/dl-execstack.c b/sysdeps/unix/sysv/linux/dl-execstack.c
index 6408adc..9aadb90 100644
--- a/sysdeps/unix/sysv/linux/dl-execstack.c
+++ b/sysdeps/unix/sysv/linux/dl-execstack.c
@@ -1,5 +1,5 @@
 /* Stack executability handling for GNU dynamic linker.  Linux version.
-   Copyright (C) 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
+   Copyright (C) 2003-2012 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -46,95 +46,11 @@ _dl_make_stack_executable (void **stack_endp)
       || __builtin_expect (*stack_endp != __libc_stack_end, 0))
     return EPERM;
 
-  /* Newer Linux kernels support a flag to make our job easy.  */
-#if defined  PROT_GROWSDOWN || defined PROT_GROWSUP
-# if __ASSUME_PROT_GROWSUPDOWN == 0
-  static bool no_growsupdown;
-  if (! no_growsupdown)
-# endif
-    {
-      if (__builtin_expect (__mprotect ((void *) page, GLRO(dl_pagesize),
-					__stack_prot) == 0, 1))
-	goto return_success;
-# if __ASSUME_PROT_GROWSUPDOWN == 0
-      if (errno == EINVAL)
-	no_growsupdown = true;
-      else
-# endif
-	{
-	  result = errno;
-	  goto out;
-	}
-    }
-#endif
-
-  /* There is always a hole in the address space below the bottom of the
-     stack.  So when we make an mprotect call that starts below the bottom
-     of the stack, it will include the hole and fail with ENOMEM.
-
-     We start with a random guess at how deep the stack might have gotten
-     so as to have extended the GROWSDOWN mapping to lower pages.  */
-
-#if __ASSUME_PROT_GROWSUPDOWN == 0
-  size_t size = GLRO(dl_pagesize) * 8;
-
-# if _STACK_GROWS_DOWN
-  page = page + GLRO(dl_pagesize) - size;
-  while (1)
-    {
-      if (__mprotect ((void *) page, size,
-		      __stack_prot & ~PROT_GROWSDOWN) == 0)
-	/* We got this chunk changed; loop to do another chunk below.  */
-	page -= size;
-      else
-	{
-	  if (errno != ENOMEM)	/* Unexpected failure mode.  */
-	    {
-	      result = errno;
-	      goto out;
-	    }
-
-	  if (size == GLRO(dl_pagesize))
-	    /* We just tried to mprotect the top hole page and failed.
-	       We are done.  */
-	    break;
-
-	  /* Our mprotect call failed because it started below the lowest
-	     stack page.  Try again on just the top half of that region.  */
-	  size /= 2;
-	  page += size;
-	}
-    }
-
-# elif _STACK_GROWS_UP
-  while (1)
-    {
-      if (__mprotect ((void *) page, size, __stack_prot & ~PROT_GROWSUP) == 0)
-	/* We got this chunk changed; loop to do another chunk below.  */
-	page += size;
-      else
-	{
-	  if (errno != ENOMEM)	/* Unexpected failure mode.  */
-	    {
-	      result = errno;
-	      goto out;
-	    }
-
-	  if (size == GLRO(dl_pagesize))
-	    /* We just tried to mprotect the lowest hole page and failed.
-	       We are done.  */
-	    break;
-
-	  /* Our mprotect call failed because it extended past the highest
-	     stack page.  Try again on just the bottom half of that region.  */
-	  size /= 2;
-	}
-    }
-
-# else
-#  error "Define either _STACK_GROWS_DOWN or _STACK_GROWS_UP"
-# endif
-#endif
+  if (__builtin_expect (__mprotect ((void *) page, GLRO(dl_pagesize),
+				    __stack_prot) == 0, 1))
+    goto return_success;
+  result = errno;
+  goto out;
 
  return_success:
   /* Clear the address.  */
diff --git a/sysdeps/unix/sysv/linux/getdents.c b/sysdeps/unix/sysv/linux/getdents.c
index ac4979e..babfbd0 100644
--- a/sysdeps/unix/sysv/linux/getdents.c
+++ b/sysdeps/unix/sysv/linux/getdents.c
@@ -97,7 +97,6 @@ __GETDENTS (int fd, char *buf, size_t nbytes)
 {
   ssize_t retval;
 
-#ifdef __ASSUME_GETDENTS32_D_TYPE
   /* The d_ino and d_off fields in kernel_dirent and dirent must have
      the same sizes and alignments.  */
   if (sizeof (DIRENT_TYPE) == sizeof (struct dirent)
@@ -135,7 +134,6 @@ __GETDENTS (int fd, char *buf, size_t nbytes)
 
       return retval;
     }
-#endif
 
   off64_t last_offset = -1;
 
@@ -293,11 +291,7 @@ __GETDENTS (int fd, char *buf, size_t nbytes)
 	DIRENT_SET_DP_INO(dp, kdp->d_ino);
 	dp->d_off = kdp->d_off;
 	dp->d_reclen = new_reclen;
-#ifdef __ASSUME_GETDENTS32_D_TYPE
 	dp->d_type = *((char *) kdp + kdp->d_reclen - 1);
-#else
-	dp->d_type = DT_UNKNOWN;
-#endif
 	memcpy (dp->d_name, kdp->d_name,
 		kdp->d_reclen - offsetof (struct kernel_dirent, d_name));
 
diff --git a/sysdeps/unix/sysv/linux/kernel-features.h b/sysdeps/unix/sysv/linux/kernel-features.h
index 7dfc4e3..9f0a8e6 100644
--- a/sysdeps/unix/sysv/linux/kernel-features.h
+++ b/sysdeps/unix/sysv/linux/kernel-features.h
@@ -139,10 +139,6 @@
 # define __ASSUME_FADVISE64_64_SYSCALL	1
 #endif
 
-/* The PROT_GROWSDOWN/PROT_GROWSUP flags were introduced in the 2.6.0-test
-   series.  */
-#define __ASSUME_PROT_GROWSUPDOWN	1
-
 /* Starting with 2.6.0 PowerPC adds signal/swapcontext support for Vector
    SIMD (AKA Altivec, VMX) instructions and register state.  This changes
    the overall size of the sigcontext and adds the swapcontext syscall.  */
@@ -150,19 +146,6 @@
 # define __ASSUME_SWAPCONTEXT_SYSCALL	1
 #endif
 
-/* The CLONE_DETACHED flag is not necessary in 2.6.2 kernels, it is
-   implied.  */
-#define __ASSUME_NO_CLONE_DETACHED	1
-
-/* Starting with version 2.6.4-rc1 the getdents syscall returns d_type
-   information as well and in between 2.6.5 and 2.6.8 most compat wrappers
-   were fixed too.  Except s390{,x} which was fixed in 2.6.11.  */
-#define __ASSUME_GETDENTS32_D_TYPE	1
-
-/* Starting with version 2.6.9, the waitid system call is available.
-   Except for powerpc{,64} and s390{,x}, where it is available in 2.6.12.  */
-#define __ASSUME_WAITID_SYSCALL	1
-
 /* On sparc64 stat64/lstat64/fstat64 syscalls were introduced in 2.6.12.  */
 #if defined __sparc__ && defined __arch64__
 # define __ASSUME_STAT64_SYSCALL	1
diff --git a/sysdeps/unix/sysv/linux/waitid.c b/sysdeps/unix/sysv/linux/waitid.c
index 7a8b6eb..0fe6330 100644
--- a/sysdeps/unix/sysv/linux/waitid.c
+++ b/sysdeps/unix/sysv/linux/waitid.c
@@ -1,5 +1,5 @@
 /* Linux implementation of waitid.
-   Copyright (C) 2004 Free Software Foundation, Inc.
+   Copyright (C) 2004-2012 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -19,14 +19,8 @@
 #include <stddef.h>
 #include <errno.h>
 #include <sys/wait.h>
-#include <kernel-features.h>
 #include <sysdep.h>
 
-
-#ifdef __NR_waitid
-
-# if __ASSUME_WAITID_SYSCALL > 0
-
 static inline int
 do_waitid (idtype_t idtype, id_t id, siginfo_t *infop, int options)
 {
@@ -34,37 +28,6 @@ do_waitid (idtype_t idtype, id_t id, siginfo_t *infop, int options)
      pass if we were using waitid to simulate wait3/wait4.  */
   return INLINE_SYSCALL (waitid, 5, idtype, id, infop, options, NULL);
 }
-# define NO_DO_WAITID
-
-# else
-
-static int do_compat_waitid (idtype_t idtype, id_t id,
-			     siginfo_t *infop, int options);
-# define DO_WAITID do_compat_waitid
-
-static int
-do_waitid (idtype_t idtype, id_t id, siginfo_t *infop, int options)
-{
-  static int waitid_works;
-  if (waitid_works > 0)
-    return INLINE_SYSCALL (waitid, 5, idtype, id, infop, options, NULL);
-  if (waitid_works == 0)
-    {
-      int result = INLINE_SYSCALL (waitid, 5,
-				   idtype, id, infop, options, NULL);
-      if (result < 0 && errno == ENOSYS)
-	waitid_works = -1;
-      else
-	{
-	  waitid_works = 1;
-	  return result;
-	}
-    }
-  return do_compat_waitid (idtype, id, infop, options);
-}
-
-# endif
-
-#endif
+#define NO_DO_WAITID
 
 #include "sysdeps/posix/waitid.c"

-- 
Joseph S. Myers
joseph@codesourcery.com