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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. */
sim_notify_exec(const char * binary_name)28 static 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 
notify_exec(struct mm_struct * mm)40 static 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. */
sim_notify_interp(unsigned long load_addr)94 static 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 
arch_setup_additional_pages(struct linux_binprm * bprm,int executable_stack)106 int 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 
elf_plat_init(struct pt_regs * regs,unsigned long load_addr)147 void 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 }
155