nios2: Module support

/*

 * Kernel module support for Nios II.

 *

 * Copyright (C) 2004 Microtronix Datacom Ltd.

 *   Written by Wentao Xu <xuwentao@microtronix.com>

 * Copyright (C) 2001, 2003 Rusty Russell

 *

 * This file is subject to the terms and conditions of the GNU General

 * Public License.  See the file COPYING in the main directory of this

 * archive for more details.

 */

#include <linux/moduleloader.h>

#include <linux/elf.h>

#include <linux/mm.h>

#include <linux/vmalloc.h>

#include <linux/slab.h>

#include <linux/fs.h>

#include <linux/string.h>

#include <linux/kernel.h>

#include <asm/pgtable.h>

#include <asm/cacheflush.h>

/*

 * Modules should NOT be allocated with kmalloc for (obvious) reasons.

 * But we do it for now to avoid relocation issues. CALL26/PCREL26 cannot reach

 * from 0x80000000 (vmalloc area) to 0xc00000000 (kernel) (kmalloc returns

 * addresses in 0xc0000000)

 */

void *module_alloc(unsigned long size)

{

	if (size == 0)

		return NULL;

	return kmalloc(size, GFP_KERNEL);

}

/* Free memory returned from module_alloc */

void module_free(struct module *mod, void *module_region)

{

	kfree(module_region);

}

int apply_relocate_add(Elf32_Shdr *sechdrs, const char *strtab,

			unsigned int symindex, unsigned int relsec,

			struct module *mod)

{

	unsigned int i;

	Elf32_Rela *rela = (void *)sechdrs[relsec].sh_addr;

	pr_debug("Applying relocate section %u to %u\n", relsec,

		 sechdrs[relsec].sh_info);

	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) {

		/* This is where to make the change */

		uint32_t word;

		uint32_t *loc

			= ((void *)sechdrs[sechdrs[relsec].sh_info].sh_addr

			   + rela[i].r_offset);

		/* This is the symbol it is referring to.  Note that all

		   undefined symbols have been resolved.  */

		Elf32_Sym *sym

			= ((Elf32_Sym *)sechdrs[symindex].sh_addr

				+ ELF32_R_SYM(rela[i].r_info));

		uint32_t v = sym->st_value + rela[i].r_addend;

		pr_debug("reltype %d 0x%x name:<%s>\n",

			ELF32_R_TYPE(rela[i].r_info),

			rela[i].r_offset, strtab + sym->st_name);

		switch (ELF32_R_TYPE(rela[i].r_info)) {

		case R_NIOS2_NONE:

			break;

		case R_NIOS2_BFD_RELOC_32:

			*loc += v;

			break;

		case R_NIOS2_PCREL16:

			v -= (uint32_t)loc + 4;

			if ((int32_t)v > 0x7fff ||

				(int32_t)v < -(int32_t)0x8000) {

				pr_err("module %s: relocation overflow\n",

					mod->name);

				return -ENOEXEC;

			}

			word = *loc;

			*loc = ((((word >> 22) << 16) | (v & 0xffff)) << 6) |

				(word & 0x3f);

			break;

		case R_NIOS2_CALL26:

			if (v & 3) {

				pr_err("module %s: dangerous relocation\n",

					mod->name);

				return -ENOEXEC;

			}

			if ((v >> 28) != ((uint32_t)loc >> 28)) {

				pr_err("module %s: relocation overflow\n",

					mod->name);

				return -ENOEXEC;

			}

			*loc = (*loc & 0x3f) | ((v >> 2) << 6);

			break;

		case R_NIOS2_HI16:

			word = *loc;

			*loc = ((((word >> 22) << 16) |

				((v >> 16) & 0xffff)) << 6) | (word & 0x3f);

			break;

		case R_NIOS2_LO16:

			word = *loc;

			*loc = ((((word >> 22) << 16) | (v & 0xffff)) << 6) |

					(word & 0x3f);

			break;

		case R_NIOS2_HIADJ16:

			{

				Elf32_Addr word2;

				word = *loc;

				word2 = ((v >> 16) + ((v >> 15) & 1)) & 0xffff;

				*loc = ((((word >> 22) << 16) | word2) << 6) |

						(word & 0x3f);

			}

			break;

		default:

			pr_err("module %s: Unknown reloc: %u\n",

				mod->name, ELF32_R_TYPE(rela[i].r_info));

			return -ENOEXEC;

		}

	}

	return 0;

}

int module_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,

			struct module *me)

{

	flush_cache_all();

	return 0;

}