1/*
  2 * Copyright 2010 Tilera Corporation. All Rights Reserved.
  3 *
  4 *   This program is free software; you can redistribute it and/or
  5 *   modify it under the terms of the GNU General Public License
  6 *   as published by the Free Software Foundation, version 2.
  7 *
  8 *   This program is distributed in the hope that it will be useful, but
  9 *   WITHOUT ANY WARRANTY; without even the implied warranty of
 10 *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
 11 *   NON INFRINGEMENT.  See the GNU General Public License for
 12 *   more details.
 13 */
 14
 15#include <linux/mm.h>
 16#include <linux/pagemap.h>
 17#include <linux/binfmts.h>
 18#include <linux/compat.h>
 19#include <linux/mman.h>
 20#include <linux/elf.h>
 21#include <asm/pgtable.h>
 22#include <asm/pgalloc.h>
 23#include <asm/sections.h>
 24#include <arch/sim_def.h>
 25
 26/* Notify a running simulator, if any, that an exec just occurred. */
 27static void sim_notify_exec(const char *binary_name)
 28{
 29	unsigned char c;
 30	do {
 31		c = *binary_name++;
 32		__insn_mtspr(SPR_SIM_CONTROL,
 33			     (SIM_CONTROL_OS_EXEC
 34			      | (c << _SIM_CONTROL_OPERATOR_BITS)));
 35
 36	} while (c);
 37}
 38
 39static int notify_exec(void)
 40{
 41	int retval = 0;  /* failure */
 42	struct vm_area_struct *vma = current->mm->mmap;
 43	while (vma) {
 44		if ((vma->vm_flags & VM_EXECUTABLE) && vma->vm_file)
 45			break;
 46		vma = vma->vm_next;
 47	}
 48	if (vma) {
 49		char *buf = (char *) __get_free_page(GFP_KERNEL);
 50		if (buf) {
 51			char *path = d_path(&vma->vm_file->f_path,
 52					    buf, PAGE_SIZE);
 53			if (!IS_ERR(path)) {
 54				sim_notify_exec(path);
 55				retval = 1;
 56			}
 57			free_page((unsigned long)buf);
 58		}
 59	}
 60	return retval;
 61}
 62
 63/* Notify a running simulator, if any, that we loaded an interpreter. */
 64static void sim_notify_interp(unsigned long load_addr)
 65{
 66	size_t i;
 67	for (i = 0; i < sizeof(load_addr); i++) {
 68		unsigned char c = load_addr >> (i * 8);
 69		__insn_mtspr(SPR_SIM_CONTROL,
 70			     (SIM_CONTROL_OS_INTERP
 71			      | (c << _SIM_CONTROL_OPERATOR_BITS)));
 72	}
 73}
 74
 75
 76/* Kernel address of page used to map read-only kernel data into userspace. */
 77static void *vdso_page;
 78
 79/* One-entry array used for install_special_mapping. */
 80static struct page *vdso_pages[1];
 81
 82static int __init vdso_setup(void)
 83{
 84	vdso_page = (void *)get_zeroed_page(GFP_ATOMIC);
 85	memcpy(vdso_page, __rt_sigreturn, __rt_sigreturn_end - __rt_sigreturn);
 86	vdso_pages[0] = virt_to_page(vdso_page);
 87	return 0;
 88}
 89device_initcall(vdso_setup);
 90
 91const char *arch_vma_name(struct vm_area_struct *vma)
 92{
 93	if (vma->vm_private_data == vdso_pages)
 94		return "[vdso]";
 95#ifndef __tilegx__
 96	if (vma->vm_start == MEM_USER_INTRPT)
 97		return "[intrpt]";
 98#endif
 99	return NULL;
100}
101
102int arch_setup_additional_pages(struct linux_binprm *bprm,
103				int executable_stack)
104{
105	struct mm_struct *mm = current->mm;
106	unsigned long vdso_base;
107	int retval = 0;
108
109	/*
110	 * Notify the simulator that an exec just occurred.
111	 * If we can't find the filename of the mapping, just use
112	 * whatever was passed as the linux_binprm filename.
113	 */
114	if (!notify_exec())
115		sim_notify_exec(bprm->filename);
116
117	down_write(&mm->mmap_sem);
118
119	/*
120	 * MAYWRITE to allow gdb to COW and set breakpoints
121	 */
122	vdso_base = VDSO_BASE;
123	retval = install_special_mapping(mm, vdso_base, PAGE_SIZE,
124					 VM_READ|VM_EXEC|
125					 VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
126					 vdso_pages);
127
128#ifndef __tilegx__
129	/*
130	 * Set up a user-interrupt mapping here; the user can't
131	 * create one themselves since it is above TASK_SIZE.
132	 * We make it unwritable by default, so the model for adding
133	 * interrupt vectors always involves an mprotect.
134	 */
135	if (!retval) {
136		unsigned long addr = MEM_USER_INTRPT;
137		addr = mmap_region(NULL, addr, INTRPT_SIZE,
138				   MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE,
139				   VM_READ|VM_EXEC|
140				   VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC, 0);
141		if (addr > (unsigned long) -PAGE_SIZE)
142			retval = (int) addr;
143	}
144#endif
145
146	up_write(&mm->mmap_sem);
147
148	return retval;
149}
150
151
152void elf_plat_init(struct pt_regs *regs, unsigned long load_addr)
153{
154	/* Zero all registers. */
155	memset(regs, 0, sizeof(*regs));
156
157	/* Report the interpreter's load address. */
158	sim_notify_interp(load_addr);
159}