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. */
sim_notify_exec(const char * binary_name)27 static 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
notify_exec(void)39 static 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. */
sim_notify_interp(unsigned long load_addr)64 static 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. */
77 static void *vdso_page;
78
79 /* One-entry array used for install_special_mapping. */
80 static struct page *vdso_pages[1];
81
vdso_setup(void)82 static 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 }
89 device_initcall(vdso_setup);
90
arch_vma_name(struct vm_area_struct * vma)91 const 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
arch_setup_additional_pages(struct linux_binprm * bprm,int executable_stack)102 int 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
elf_plat_init(struct pt_regs * regs,unsigned long load_addr)152 void 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 }
160