linux: Consolidate brk implementation

It removes all the arch-specific assembly implementation.  The
outliers are alpha, where its kernel ABI explict return -ENOMEM
in case of failure; and i686, where it can't use
"call *%gs:SYSINFO_OFFSET" during statup in static PIE.

Also some ABIs exports an additional ___brk_addr symbol and to
handle it an internal HAVE_INTERNAL_BRK_ADDR_SYMBOL is added.

Checked on x86_64-linux-gnu, i686-linux-gnu, adn with builsd for
the affected ABIs.

Reviewed-by: Tulio Magno Quites Machado Filho <tuliom@linux.ibm.com>

1 files changed, 38 insertions, 0 deletions

diff --git a/sysdeps/unix/sysv/linux/alpha/brk.c b/sysdeps/unix/sysv/linux/alpha/brk.c
new file mode 100644
index 0000000..d105a50
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/alpha/brk.c
@@ -0,0 +1,38 @@
+/* Change data segment size.  Linux/Alpha.
+   Copyright (C) 2020 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
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library.  If not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <errno.h>
+#include <unistd.h>
+#include <sysdep.h>
+
+void *__curbrk = 0;
+
+int
+__brk (void *addr)
+{
+  /* Alpha brk returns -ENOMEM in case of failure.  */
+  __curbrk = (void *) INTERNAL_SYSCALL_CALL (brk, addr);
+  if ((unsigned long) __curbrk == -ENOMEM)
+    {
+      __set_errno (ENOMEM);
+      return -1;
+    }
+
+  return 0;
+}
+weak_alias (__brk, brk)