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/slab.h>
 17#include <linux/fs.h>
 18#include <linux/string.h>
 19#include <linux/kernel.h>
 20
 21#include <asm/cacheflush.h>
 22
 23int apply_relocate_add(Elf32_Shdr *sechdrs, const char *strtab,
 24			unsigned int symindex, unsigned int relsec,
 25			struct module *mod)
 26{
 27	unsigned int i;
 28	Elf32_Rela *rela = (void *)sechdrs[relsec].sh_addr;
 29
 30	pr_debug("Applying relocate section %u to %u\n", relsec,
 31		 sechdrs[relsec].sh_info);
 32
 33	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) {
 34		/* This is where to make the change */
 35		uint32_t word;
 36		uint32_t *loc
 37			= ((void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
 38			   + rela[i].r_offset);
 39		/* This is the symbol it is referring to.  Note that all
 40		   undefined symbols have been resolved.  */
 41		Elf32_Sym *sym
 42			= ((Elf32_Sym *)sechdrs[symindex].sh_addr
 43				+ ELF32_R_SYM(rela[i].r_info));
 44		uint32_t v = sym->st_value + rela[i].r_addend;
 45
 46		pr_debug("reltype %d 0x%x name:<%s>\n",
 47			ELF32_R_TYPE(rela[i].r_info),
 48			rela[i].r_offset, strtab + sym->st_name);
 49
 50		switch (ELF32_R_TYPE(rela[i].r_info)) {
 51		case R_NIOS2_NONE:
 52			break;
 53		case R_NIOS2_BFD_RELOC_32:
 54			*loc += v;
 55			break;
 56		case R_NIOS2_PCREL16:
 57			v -= (uint32_t)loc + 4;
 58			if ((int32_t)v > 0x7fff ||
 59				(int32_t)v < -(int32_t)0x8000) {
 60				pr_err("module %s: relocation overflow\n",
 61					mod->name);
 62				return -ENOEXEC;
 63			}
 64			word = *loc;
 65			*loc = ((((word >> 22) << 16) | (v & 0xffff)) << 6) |
 66				(word & 0x3f);
 67			break;
 68		case R_NIOS2_CALL26:
 69			if (v & 3) {
 70				pr_err("module %s: dangerous relocation\n",
 71					mod->name);
 72				return -ENOEXEC;
 73			}
 74			if ((v >> 28) != ((uint32_t)loc >> 28)) {
 75				pr_err("module %s: relocation overflow\n",
 76					mod->name);
 77				return -ENOEXEC;
 78			}
 79			*loc = (*loc & 0x3f) | ((v >> 2) << 6);
 80			break;
 81		case R_NIOS2_HI16:
 82			word = *loc;
 83			*loc = ((((word >> 22) << 16) |
 84				((v >> 16) & 0xffff)) << 6) | (word & 0x3f);
 85			break;
 86		case R_NIOS2_LO16:
 87			word = *loc;
 88			*loc = ((((word >> 22) << 16) | (v & 0xffff)) << 6) |
 89					(word & 0x3f);
 90			break;
 91		case R_NIOS2_HIADJ16:
 92			{
 93				Elf32_Addr word2;
 94
 95				word = *loc;
 96				word2 = ((v >> 16) + ((v >> 15) & 1)) & 0xffff;
 97				*loc = ((((word >> 22) << 16) | word2) << 6) |
 98						(word & 0x3f);
 99			}
100			break;
101
102		default:
103			pr_err("module %s: Unknown reloc: %u\n",
104				mod->name, ELF32_R_TYPE(rela[i].r_info));
105			return -ENOEXEC;
106		}
107	}
108
109	return 0;
110}
111
112int module_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,
113			struct module *me)
114{
115	flush_cache_all();
116	return 0;
117}