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}