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