1 /*
2  * Kernel module support for Nios II.
3  *
4  * Copyright (C) 2004 Microtronix Datacom Ltd.
5  *   Written by Wentao Xu <xuwentao@microtronix.com>
6  * Copyright (C) 2001, 2003 Rusty Russell
7  *
8  * This file is subject to the terms and conditions of the GNU General
9  * Public License.  See the file COPYING in the main directory of this
10  * archive for more details.
11  */
12 
13 #include <linux/moduleloader.h>
14 #include <linux/elf.h>
15 #include <linux/mm.h>
16 #include <linux/vmalloc.h>
17 #include <linux/slab.h>
18 #include <linux/fs.h>
19 #include <linux/string.h>
20 #include <linux/kernel.h>
21 
22 #include <asm/cacheflush.h>
23 
24 /*
25  * Modules should NOT be allocated with kmalloc for (obvious) reasons.
26  * But we do it for now to avoid relocation issues. CALL26/PCREL26 cannot reach
27  * from 0x80000000 (vmalloc area) to 0xc00000000 (kernel) (kmalloc returns
28  * addresses in 0xc0000000)
29  */
module_alloc(unsigned long size)30 void *module_alloc(unsigned long size)
31 {
32 	if (size == 0)
33 		return NULL;
34 	return kmalloc(size, GFP_KERNEL);
35 }
36 
37 /* Free memory returned from module_alloc */
module_memfree(void * module_region)38 void module_memfree(void *module_region)
39 {
40 	kfree(module_region);
41 }
42 
apply_relocate_add(Elf32_Shdr * sechdrs,const char * strtab,unsigned int symindex,unsigned int relsec,struct module * mod)43 int apply_relocate_add(Elf32_Shdr *sechdrs, const char *strtab,
44 			unsigned int symindex, unsigned int relsec,
45 			struct module *mod)
46 {
47 	unsigned int i;
48 	Elf32_Rela *rela = (void *)sechdrs[relsec].sh_addr;
49 
50 	pr_debug("Applying relocate section %u to %u\n", relsec,
51 		 sechdrs[relsec].sh_info);
52 
53 	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) {
54 		/* This is where to make the change */
55 		uint32_t word;
56 		uint32_t *loc
57 			= ((void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
58 			   + rela[i].r_offset);
59 		/* This is the symbol it is referring to.  Note that all
60 		   undefined symbols have been resolved.  */
61 		Elf32_Sym *sym
62 			= ((Elf32_Sym *)sechdrs[symindex].sh_addr
63 				+ ELF32_R_SYM(rela[i].r_info));
64 		uint32_t v = sym->st_value + rela[i].r_addend;
65 
66 		pr_debug("reltype %d 0x%x name:<%s>\n",
67 			ELF32_R_TYPE(rela[i].r_info),
68 			rela[i].r_offset, strtab + sym->st_name);
69 
70 		switch (ELF32_R_TYPE(rela[i].r_info)) {
71 		case R_NIOS2_NONE:
72 			break;
73 		case R_NIOS2_BFD_RELOC_32:
74 			*loc += v;
75 			break;
76 		case R_NIOS2_PCREL16:
77 			v -= (uint32_t)loc + 4;
78 			if ((int32_t)v > 0x7fff ||
79 				(int32_t)v < -(int32_t)0x8000) {
80 				pr_err("module %s: relocation overflow\n",
81 					mod->name);
82 				return -ENOEXEC;
83 			}
84 			word = *loc;
85 			*loc = ((((word >> 22) << 16) | (v & 0xffff)) << 6) |
86 				(word & 0x3f);
87 			break;
88 		case R_NIOS2_CALL26:
89 			if (v & 3) {
90 				pr_err("module %s: dangerous relocation\n",
91 					mod->name);
92 				return -ENOEXEC;
93 			}
94 			if ((v >> 28) != ((uint32_t)loc >> 28)) {
95 				pr_err("module %s: relocation overflow\n",
96 					mod->name);
97 				return -ENOEXEC;
98 			}
99 			*loc = (*loc & 0x3f) | ((v >> 2) << 6);
100 			break;
101 		case R_NIOS2_HI16:
102 			word = *loc;
103 			*loc = ((((word >> 22) << 16) |
104 				((v >> 16) & 0xffff)) << 6) | (word & 0x3f);
105 			break;
106 		case R_NIOS2_LO16:
107 			word = *loc;
108 			*loc = ((((word >> 22) << 16) | (v & 0xffff)) << 6) |
109 					(word & 0x3f);
110 			break;
111 		case R_NIOS2_HIADJ16:
112 			{
113 				Elf32_Addr word2;
114 
115 				word = *loc;
116 				word2 = ((v >> 16) + ((v >> 15) & 1)) & 0xffff;
117 				*loc = ((((word >> 22) << 16) | word2) << 6) |
118 						(word & 0x3f);
119 			}
120 			break;
121 
122 		default:
123 			pr_err("module %s: Unknown reloc: %u\n",
124 				mod->name, ELF32_R_TYPE(rela[i].r_info));
125 			return -ENOEXEC;
126 		}
127 	}
128 
129 	return 0;
130 }
131 
module_finalize(const Elf_Ehdr * hdr,const Elf_Shdr * sechdrs,struct module * me)132 int module_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,
133 			struct module *me)
134 {
135 	flush_cache_all();
136 	return 0;
137 }
138