nios2: Add sys/user.h

This is a fixed version containing copyright information. The patch should now
apply using 'git am'.

linux/user.h is no longer exported during kernel make headers_install

Signed-off-by: Atle Nissestad <atle@nissestad.no>
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>

libc/sysdeps/linux/nios2/sys/user.h

@@ -0,0 +1,93 @@
+#ifndef _SYS_USER_H
+#define _SYS_USER_H     1
+
+/*
+   This file was taken from the nios2 port of the Linux Kernel.
+
+   Copyright (c) 2008 Atle Nissestad <atle@nissestad.no>
+   Copyright (c) 2010 Tobias Klauser <tklauser@distanz.ch>
+
+   This file is licensed under the terms of the GNU General Public License,
+   Version 2.
+ */
+
+#include <bits/uClibc_page.h>
+
+/* Core file format: The core file is written in such a way that gdb
+   can understand it and provide useful information to the user (under
+   linux we use the 'trad-core' bfd).  There are quite a number of
+   obstacles to being able to view the contents of the floating point
+   registers, and until these are solved you will not be able to view the
+   contents of them.  Actually, you can read in the core file and look at
+   the contents of the user struct to find out what the floating point
+   registers contain.
+   The actual file contents are as follows:
+   UPAGE: 1 page consisting of a user struct that tells gdb what is present
+   in the file.  Directly after this is a copy of the task_struct, which
+   is currently not used by gdb, but it may come in useful at some point.
+   All of the registers are stored as part of the upage.  The upage should
+   always be only one page.
+   DATA: The data area is stored.  We use current->end_text to
+   current->brk to pick up all of the user variables, plus any memory
+   that may have been malloced.  No attempt is made to determine if a page
+   is demand-zero or if a page is totally unused, we just cover the entire
+   range.  All of the addresses are rounded in such a way that an integral
+   number of pages is written.
+   STACK: We need the stack information in order to get a meaningful
+   backtrace.  We need to write the data from (esp) to
+   current->start_stack, so we round each of these off in order to be able
+   to write an integer number of pages.
+   The minimum core file size is 3 pages, or 12288 bytes.
+*/
+
+struct user_nios2fp_struct {
+};
+
+/* This is the old layout of "struct pt_regs" as of Linux 1.x, and
+   is still the layout used by user (the new pt_regs doesn't have
+   all registers). */
+struct user_regs_struct {
+	long r1,r2,r3,r4,r5,r6,r7,r8;
+	long r9,r10,r11,r12,r13,r14,r15;
+	long r16,r17,r18,r19,r20,r21,r22,r23;
+	long gp;
+	long sp;
+	long ra;
+	long fp;
+	long orig_r2;
+	long estatus;
+	long status_extension;
+	long ea;
+};
+
+/* When the kernel dumps core, it starts by dumping the user struct -
+   this will be used by gdb to figure out where the data and stack segments
+   are within the file, and what virtual addresses to use. */
+struct user {
+/* We start with the registers, to mimic the way that "memory" is returned
+   from the ptrace(3,...) function.  */
+	struct user_regs_struct regs;	/* Where the registers are actually stored */
+
+/* The rest of this junk is to help gdb figure out what goes where */
+	unsigned long int u_tsize;	/* Text segment size (pages). */
+	unsigned long int u_dsize;	/* Data segment size (pages). */
+	unsigned long int u_ssize;	/* Stack segment size (pages). */
+	unsigned long start_code;	/* Starting virtual address of text. */
+	unsigned long start_stack;	/* Starting virtual address of stack area.
+					   This is actually the bottom of the stack,
+					   the top of the stack is always found in the
+					   esp register.  */
+	long int signal;		/* Signal that caused the core dump. */
+	int reserved;			/* No longer used */
+	unsigned long u_ar0;		/* Used by gdb to help find the values for */
+					/* the registers. */
+	unsigned long magic;		/* To uniquely identify a core file */
+	char u_comm[32];		/* User command that was responsible */
+};
+
+#define NBPG PAGE_SIZE
+#define UPAGES 1
+#define HOST_TEXT_START_ADDR (u.start_code)
+#define HOST_STACK_END_ADDR (u.start_stack + u.u_ssize * NBPG)
+
+#endif