summaryrefslogtreecommitdiffstats
path: root/arch/tile/mm/elf.c
blob: 1a00fb64fc88316df271121ae6ced4bc96817e2e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
/*
 * Copyright 2010 Tilera Corporation. All Rights Reserved.
 *
 *   This program is free software; you can redistribute it and/or
 *   modify it under the terms of the GNU General Public License
 *   as published by the Free Software Foundation, version 2.
 *
 *   This program 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, GOOD TITLE or
 *   NON INFRINGEMENT.  See the GNU General Public License for
 *   more details.
 */

#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/binfmts.h>
#include <linux/compat.h>
#include <linux/mman.h>
#include <linux/elf.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/sections.h>

/* Notify a running simulator, if any, that an exec just occurred. */
static void sim_notify_exec(const char *binary_name)
{
	unsigned char c;
	do {
		c = *binary_name++;
		__insn_mtspr(SPR_SIM_CONTROL,
			     (SIM_CONTROL_OS_EXEC
			      | (c << _SIM_CONTROL_OPERATOR_BITS)));

	} while (c);
}

static int notify_exec(void)
{
	int retval = 0;  /* failure */
	struct vm_area_struct *vma = current->mm->mmap;
	while (vma) {
		if ((vma->vm_flags & VM_EXECUTABLE) && vma->vm_file)
			break;
		vma = vma->vm_next;
	}
	if (vma) {
		char *buf = (char *) __get_free_page(GFP_KERNEL);
		if (buf) {
			char *path = d_path(&vma->vm_file->f_path,
					    buf, PAGE_SIZE);
			if (!IS_ERR(path)) {
				sim_notify_exec(path);
				retval = 1;
			}
			free_page((unsigned long)buf);
		}
	}
	return retval;
}

/* Notify a running simulator, if any, that we loaded an interpreter. */
static void sim_notify_interp(unsigned long load_addr)
{
	size_t i;
	for (i = 0; i < sizeof(load_addr); i++) {
		unsigned char c = load_addr >> (i * 8);
		__insn_mtspr(SPR_SIM_CONTROL,
			     (SIM_CONTROL_OS_INTERP
			      | (c << _SIM_CONTROL_OPERATOR_BITS)));
	}
}


/* Kernel address of page used to map read-only kernel data into userspace. */
static void *vdso_page;

/* One-entry array used for install_special_mapping. */
static struct page *vdso_pages[1];

static int __init vdso_setup(void)
{
	vdso_page = (void *)get_zeroed_page(GFP_ATOMIC);
	memcpy(vdso_page, __rt_sigreturn, __rt_sigreturn_end - __rt_sigreturn);
	vdso_pages[0] = virt_to_page(vdso_page);
	return 0;
}
device_initcall(vdso_setup);

const char *arch_vma_name(struct vm_area_struct *vma)
{
	if (vma->vm_private_data == vdso_pages)
		return "[vdso]";
#ifndef __tilegx__
	if (vma->vm_start == MEM_USER_INTRPT)
		return "[intrpt]";
#endif
	return NULL;
}

int arch_setup_additional_pages(struct linux_binprm *bprm,
				int executable_stack)
{
	struct mm_struct *mm = current->mm;
	unsigned long vdso_base;
	int retval = 0;

	/*
	 * Notify the simulator that an exec just occurred.
	 * If we can't find the filename of the mapping, just use
	 * whatever was passed as the linux_binprm filename.
	 */
	if (!notify_exec())
		sim_notify_exec(bprm->filename);

	down_write(&mm->mmap_sem);

	/*
	 * MAYWRITE to allow gdb to COW and set breakpoints
	 */
	vdso_base = VDSO_BASE;
	retval = install_special_mapping(mm, vdso_base, PAGE_SIZE,
					 VM_READ|VM_EXEC|
					 VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
					 vdso_pages);

#ifndef __tilegx__
	/*
	 * Set up a user-interrupt mapping here; the user can't
	 * create one themselves since it is above TASK_SIZE.
	 * We make it unwritable by default, so the model for adding
	 * interrupt vectors always involves an mprotect.
	 */
	if (!retval) {
		unsigned long addr = MEM_USER_INTRPT;
		addr = mmap_region(NULL, addr, INTRPT_SIZE,
				   MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE,
				   VM_READ|VM_EXEC|
				   VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC, 0);
		if (addr > (unsigned long) -PAGE_SIZE)
			retval = (int) addr;
	}
#endif

	up_write(&mm->mmap_sem);

	return retval;
}


void elf_plat_init(struct pt_regs *regs, unsigned long load_addr)
{
	/* Zero all registers. */
	memset(regs, 0, sizeof(*regs));

	/* Report the interpreter's load address. */
	sim_notify_interp(load_addr);
}