1/*
2 *  Port on Texas Instruments TMS320C6x architecture
3 *
4 *  Copyright (C) 2005, 2009, 2010, 2011 Texas Instruments Incorporated
5 *  Author: Thomas Charleux (thomas.charleux@jaluna.com)
6 *
7 *  This program is free software; you can redistribute it and/or modify
8 *  it under the terms of the GNU General Public License version 2 as
9 *  published by the Free Software Foundation.
10 *
11 */
12#include <linux/moduleloader.h>
13#include <linux/elf.h>
14#include <linux/vmalloc.h>
15#include <linux/kernel.h>
16
17static inline int fixup_pcr(u32 *ip, Elf32_Addr dest, u32 maskbits, int shift)
18{
19	u32 opcode;
20	long ep = (long)ip & ~31;
21	long delta = ((long)dest - ep) >> 2;
22	long mask = (1 << maskbits) - 1;
23
24	if ((delta >> (maskbits - 1)) == 0 ||
25	    (delta >> (maskbits - 1)) == -1) {
26		opcode = *ip;
27		opcode &= ~(mask << shift);
28		opcode |= ((delta & mask) << shift);
29		*ip = opcode;
30
31		pr_debug("REL PCR_S%d[%p] dest[%p] opcode[%08x]\n",
32			 maskbits, ip, (void *)dest, opcode);
33
34		return 0;
35	}
36	pr_err("PCR_S%d reloc %p -> %p out of range!\n",
37	       maskbits, ip, (void *)dest);
38
39	return -1;
40}
41
42/*
43 * apply a RELA relocation
44 */
45int apply_relocate_add(Elf32_Shdr *sechdrs,
46		       const char *strtab,
47		       unsigned int symindex,
48		       unsigned int relsec,
49		       struct module *me)
50{
51	Elf32_Rela *rel = (void *) sechdrs[relsec].sh_addr;
52	Elf_Sym *sym;
53	u32 *location, opcode;
54	unsigned int i;
55	Elf32_Addr v;
56	Elf_Addr offset = 0;
57
58	pr_debug("Applying relocate section %u to %u with offset 0x%x\n",
59		 relsec, sechdrs[relsec].sh_info, offset);
60
61	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
62		/* This is where to make the change */
63		location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
64			+ rel[i].r_offset - offset;
65
66		/* This is the symbol it is referring to.  Note that all
67		   undefined symbols have been resolved.  */
68		sym = (Elf_Sym *)sechdrs[symindex].sh_addr
69			+ ELF32_R_SYM(rel[i].r_info);
70
71		/* this is the adjustment to be made */
72		v = sym->st_value + rel[i].r_addend;
73
74		switch (ELF32_R_TYPE(rel[i].r_info)) {
75		case R_C6000_ABS32:
76			pr_debug("RELA ABS32: [%p] = 0x%x\n", location, v);
77			*location = v;
78			break;
79		case R_C6000_ABS16:
80			pr_debug("RELA ABS16: [%p] = 0x%x\n", location, v);
81			*(u16 *)location = v;
82			break;
83		case R_C6000_ABS8:
84			pr_debug("RELA ABS8: [%p] = 0x%x\n", location, v);
85			*(u8 *)location = v;
86			break;
87		case R_C6000_ABS_L16:
88			opcode = *location;
89			opcode &= ~0x7fff80;
90			opcode |= ((v & 0xffff) << 7);
91			pr_debug("RELA ABS_L16[%p] v[0x%x] opcode[0x%x]\n",
92				 location, v, opcode);
93			*location = opcode;
94			break;
95		case R_C6000_ABS_H16:
96			opcode = *location;
97			opcode &= ~0x7fff80;
98			opcode |= ((v >> 9) & 0x7fff80);
99			pr_debug("RELA ABS_H16[%p] v[0x%x] opcode[0x%x]\n",
100				 location, v, opcode);
101			*location = opcode;
102			break;
103		case R_C6000_PCR_S21:
104			if (fixup_pcr(location, v, 21, 7))
105				return -ENOEXEC;
106			break;
107		case R_C6000_PCR_S12:
108			if (fixup_pcr(location, v, 12, 16))
109				return -ENOEXEC;
110			break;
111		case R_C6000_PCR_S10:
112			if (fixup_pcr(location, v, 10, 13))
113				return -ENOEXEC;
114			break;
115		default:
116			pr_err("module %s: Unknown RELA relocation: %u\n",
117			       me->name, ELF32_R_TYPE(rel[i].r_info));
118			return -ENOEXEC;
119		}
120	}
121
122	return 0;
123}
124