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/file.h>
 21#include <linux/elf.h>
 22#include <asm/pgtable.h>
 23#include <asm/pgalloc.h>
 24#include <asm/sections.h>
 25#include <asm/vdso.h>
 26#include <arch/sim.h>
 27
 28/* Notify a running simulator, if any, that an exec just occurred. */
 29static void sim_notify_exec(const char *binary_name)
 30{
 31	unsigned char c;
 32	do {
 33		c = *binary_name++;
 34		__insn_mtspr(SPR_SIM_CONTROL,
 35			     (SIM_CONTROL_OS_EXEC
 36			      | (c << _SIM_CONTROL_OPERATOR_BITS)));
 37
 38	} while (c);
 39}
 40
 41static int notify_exec(struct mm_struct *mm)
 42{
 43	int ret = 0;
 44	char *buf, *path;
 45	struct vm_area_struct *vma;
 46	struct file *exe_file;
 47
 48	if (!sim_is_simulator())
 49		return 1;
 50
 51	buf = (char *) __get_free_page(GFP_KERNEL);
 52	if (buf == NULL)
 53		return 0;
 54
 55	exe_file = get_mm_exe_file(mm);
 56	if (exe_file == NULL)
 57		goto done_free;
 58
 59	path = file_path(exe_file, buf, PAGE_SIZE);
 60	if (IS_ERR(path))
 61		goto done_put;
 62
 63	down_read(&mm->mmap_sem);
 64	for (vma = current->mm->mmap; ; vma = vma->vm_next) {
 65		if (vma == NULL) {
 66			up_read(&mm->mmap_sem);
 67			goto done_put;
 68		}
 69		if (vma->vm_file == exe_file)
 70			break;
 71	}
 72
 73	/*
 74	 * Notify simulator of an ET_DYN object so we know the load address.
 75	 * The somewhat cryptic overuse of SIM_CONTROL_DLOPEN allows us
 76	 * to be backward-compatible with older simulator releases.
 77	 */
 78	if (vma->vm_start == (ELF_ET_DYN_BASE & PAGE_MASK)) {
 79		char buf[64];
 80		int i;
 81
 82		snprintf(buf, sizeof(buf), "0x%lx:@", vma->vm_start);
 83		for (i = 0; ; ++i) {
 84			char c = buf[i];
 85			__insn_mtspr(SPR_SIM_CONTROL,
 86				     (SIM_CONTROL_DLOPEN
 87				      | (c << _SIM_CONTROL_OPERATOR_BITS)));
 88			if (c == '\0') {
 89				ret = 1; /* success */
 90				break;
 91			}
 92		}
 93	}
 94	up_read(&mm->mmap_sem);
 95
 96	sim_notify_exec(path);
 97done_put:
 98	fput(exe_file);
 99done_free:
100	free_page((unsigned long)buf);
101	return ret;
102}
103
104/* Notify a running simulator, if any, that we loaded an interpreter. */
105static void sim_notify_interp(unsigned long load_addr)
106{
107	size_t i;
108	for (i = 0; i < sizeof(load_addr); i++) {
109		unsigned char c = load_addr >> (i * 8);
110		__insn_mtspr(SPR_SIM_CONTROL,
111			     (SIM_CONTROL_OS_INTERP
112			      | (c << _SIM_CONTROL_OPERATOR_BITS)));
113	}
114}
115
116
117int arch_setup_additional_pages(struct linux_binprm *bprm,
118				int executable_stack)
119{
120	struct mm_struct *mm = current->mm;
121	int retval = 0;
122
123	/*
124	 * Notify the simulator that an exec just occurred.
125	 * If we can't find the filename of the mapping, just use
126	 * whatever was passed as the linux_binprm filename.
127	 */
128	if (!notify_exec(mm))
129		sim_notify_exec(bprm->filename);
130
131	down_write(&mm->mmap_sem);
132
133	retval = setup_vdso_pages();
134
135#ifndef __tilegx__
136	/*
137	 * Set up a user-interrupt mapping here; the user can't
138	 * create one themselves since it is above TASK_SIZE.
139	 * We make it unwritable by default, so the model for adding
140	 * interrupt vectors always involves an mprotect.
141	 */
142	if (!retval) {
143		unsigned long addr = MEM_USER_INTRPT;
144		addr = mmap_region(NULL, addr, INTRPT_SIZE,
145				   VM_READ|VM_EXEC|
146				   VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC, 0);
147		if (addr > (unsigned long) -PAGE_SIZE)
148			retval = (int) addr;
149	}
150#endif
151
152	up_write(&mm->mmap_sem);
153
154	return retval;
155}
156
157
158void elf_plat_init(struct pt_regs *regs, unsigned long load_addr)
159{
160	/* Zero all registers. */
161	memset(regs, 0, sizeof(*regs));
162
163	/* Report the interpreter's load address. */
164	sim_notify_interp(load_addr);
165}