[glibc] linux: Add sparck brk implementation

[glibc] linux: Add sparck brk implementation

[Adhemerval Zanella]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=5b86241a032c50462988bdd1439e078384690d34

commit 5b86241a032c50462988bdd1439e078384690d34
Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date:   Wed Aug 4 21:34:12 2021 +0300

    linux: Add sparck brk implementation
    
    It turned that the generic implementation of brk() does not work
    for sparc, since on failure kernel will just return the previous
    input value without setting the conditional register.
    
    This patches adds back a sparc32 and sparc64 implementation removed
    by 720480934ab9107.
    
    Checked on sparc64-linux-gnu and sparcv9-linux-gnu.

Diff:
---
 sysdeps/unix/sysv/linux/sparc/brk.c | 58 +++++++++++++++++++++++++++++++++++++
 1 file changed, 58 insertions(+)

diff --git a/sysdeps/unix/sysv/linux/sparc/brk.c b/sysdeps/unix/sysv/linux/sparc/brk.c
new file mode 100644
index 0000000000..aafe9673e3
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/sparc/brk.c
@@ -0,0 +1,58 @@
+/* Change data segment.  Linux SPARC version.
+   Copyright (C) 2021 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>
+
+/* This must be initialized data because commons can't have aliases.  */
+void *__curbrk = 0;
+
+#if HAVE_INTERNAL_BRK_ADDR_SYMBOL
+/* Old braindamage in GCC's crtstuff.c requires this symbol in an attempt
+   to work around different old braindamage in the old Linux ELF dynamic
+   linker.  */
+weak_alias (__curbrk, ___brk_addr)
+#endif
+
+#ifdef __arch64__
+# define SYSCALL_NUM "0x6d"
+#else
+# define SYSCALL_NUM "0x10"
+#endif
+
+int
+__brk (void *addr)
+{
+  register long int g1 asm ("g1") = __NR_brk;
+  register long int o0 asm ("o0") = (long int) addr;
+  asm volatile ("ta " SYSCALL_NUM
+		: "=r"(o0)
+		: "r"(g1), "0"(o0)
+		: "cc");
+  __curbrk = (void *) o0;
+
+  if (__curbrk < addr)
+    {
+      __set_errno (ENOMEM);
+      return -1;
+    }
+
+  return 0;
+}
+weak_alias (__brk, brk)