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
25 /* Notify a running simulator, if any, that an exec just occurred. */
sim_notify_exec(const char * binary_name)26 static void sim_notify_exec(const char *binary_name)
27 {
28 unsigned char c;
29 do {
30 c = *binary_name++;
31 __insn_mtspr(SPR_SIM_CONTROL,
32 (SIM_CONTROL_OS_EXEC
33 | (c << _SIM_CONTROL_OPERATOR_BITS)));
34
35 } while (c);
36 }
37
notify_exec(void)38 static int notify_exec(void)
39 {
40 int retval = 0; /* failure */
41 struct vm_area_struct *vma = current->mm->mmap;
42 while (vma) {
43 if ((vma->vm_flags & VM_EXECUTABLE) && vma->vm_file)
44 break;
45 vma = vma->vm_next;
46 }
47 if (vma) {
48 char *buf = (char *) __get_free_page(GFP_KERNEL);
49 if (buf) {
50 char *path = d_path(&vma->vm_file->f_path,
51 buf, PAGE_SIZE);
52 if (!IS_ERR(path)) {
53 sim_notify_exec(path);
54 retval = 1;
55 }
56 free_page((unsigned long)buf);
57 }
58 }
59 return retval;
60 }
61
62 /* Notify a running simulator, if any, that we loaded an interpreter. */
sim_notify_interp(unsigned long load_addr)63 static void sim_notify_interp(unsigned long load_addr)
64 {
65 size_t i;
66 for (i = 0; i < sizeof(load_addr); i++) {
67 unsigned char c = load_addr >> (i * 8);
68 __insn_mtspr(SPR_SIM_CONTROL,
69 (SIM_CONTROL_OS_INTERP
70 | (c << _SIM_CONTROL_OPERATOR_BITS)));
71 }
72 }
73
74
75 /* Kernel address of page used to map read-only kernel data into userspace. */
76 static void *vdso_page;
77
78 /* One-entry array used for install_special_mapping. */
79 static struct page *vdso_pages[1];
80
vdso_setup(void)81 static int __init vdso_setup(void)
82 {
83 vdso_page = (void *)get_zeroed_page(GFP_ATOMIC);
84 memcpy(vdso_page, __rt_sigreturn, __rt_sigreturn_end - __rt_sigreturn);
85 vdso_pages[0] = virt_to_page(vdso_page);
86 return 0;
87 }
88 device_initcall(vdso_setup);
89
arch_vma_name(struct vm_area_struct * vma)90 const char *arch_vma_name(struct vm_area_struct *vma)
91 {
92 if (vma->vm_private_data == vdso_pages)
93 return "[vdso]";
94 #ifndef __tilegx__
95 if (vma->vm_start == MEM_USER_INTRPT)
96 return "[intrpt]";
97 #endif
98 return NULL;
99 }
100
arch_setup_additional_pages(struct linux_binprm * bprm,int executable_stack)101 int arch_setup_additional_pages(struct linux_binprm *bprm,
102 int executable_stack)
103 {
104 struct mm_struct *mm = current->mm;
105 unsigned long vdso_base;
106 int retval = 0;
107
108 /*
109 * Notify the simulator that an exec just occurred.
110 * If we can't find the filename of the mapping, just use
111 * whatever was passed as the linux_binprm filename.
112 */
113 if (!notify_exec())
114 sim_notify_exec(bprm->filename);
115
116 down_write(&mm->mmap_sem);
117
118 /*
119 * MAYWRITE to allow gdb to COW and set breakpoints
120 *
121 * Make sure the vDSO gets into every core dump. Dumping its
122 * contents makes post-mortem fully interpretable later
123 * without matching up the same kernel and hardware config to
124 * see what PC values meant.
125 */
126 vdso_base = VDSO_BASE;
127 retval = install_special_mapping(mm, vdso_base, PAGE_SIZE,
128 VM_READ|VM_EXEC|
129 VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC|
130 VM_ALWAYSDUMP,
131 vdso_pages);
132
133 #ifndef __tilegx__
134 /*
135 * Set up a user-interrupt mapping here; the user can't
136 * create one themselves since it is above TASK_SIZE.
137 * We make it unwritable by default, so the model for adding
138 * interrupt vectors always involves an mprotect.
139 */
140 if (!retval) {
141 unsigned long addr = MEM_USER_INTRPT;
142 addr = mmap_region(NULL, addr, INTRPT_SIZE,
143 MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE,
144 VM_READ|VM_EXEC|
145 VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC, 0);
146 if (addr > (unsigned long) -PAGE_SIZE)
147 retval = (int) addr;
148 }
149 #endif
150
151 up_write(&mm->mmap_sem);
152
153 return retval;
154 }
155
156
elf_plat_init(struct pt_regs * regs,unsigned long load_addr)157 void elf_plat_init(struct pt_regs *regs, unsigned long load_addr)
158 {
159 /* Zero all registers. */
160 memset(regs, 0, sizeof(*regs));
161
162 /* Report the interpreter's load address. */
163 sim_notify_interp(load_addr);
164 }
165