text: /*
   * Copyright 2010 Tilera Corporation. All Rights Reserved.
   *
   *   This program is free software; you can redistribute it and/or
   *   modify it under the terms of the GNU General Public License
   *   as published by the Free Software Foundation, version 2.
   *
   *   This program is distributed in the hope that it will be useful, but
   *   WITHOUT ANY WARRANTY; without even the implied warranty of
   *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
   *   NON INFRINGEMENT.  See the GNU General Public License for
   *   more details.
   *
   * Based on i386 version, copyright (C) 2001 Rusty Russell.
   */
  
  #include <linux/moduleloader.h>
  #include <linux/elf.h>
  #include <linux/vmalloc.h>
  #include <linux/fs.h>
  #include <linux/string.h>
  #include <linux/kernel.h>
  #include <asm/pgtable.h>
  #include <asm/homecache.h>
  #include <arch/opcode.h>
  
  #ifdef MODULE_DEBUG
  #define DEBUGP printk
  #else
  #define DEBUGP(fmt...)
  #endif
  
  /*
   * Allocate some address space in the range MEM_MODULE_START to
   * MEM_MODULE_END and populate it with memory.
   */
  void *module_alloc(unsigned long size)
  {
  	struct page **pages;
  	pgprot_t prot_rwx = __pgprot(_PAGE_KERNEL | _PAGE_KERNEL_EXEC);
  	struct vm_struct *area;
  	int i = 0;
  	int npages;
  
  	npages = (size + PAGE_SIZE - 1) / PAGE_SIZE;
  	pages = kmalloc(npages * sizeof(struct page *), GFP_KERNEL);
  	if (pages == NULL)
  		return NULL;
  	for (; i < npages; ++i) {
  		pages[i] = alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
  		if (!pages[i])
  			goto error;
  	}
  
  	area = __get_vm_area(size, VM_ALLOC, MEM_MODULE_START, MEM_MODULE_END);
  	if (!area)
  		goto error;
  	area->nr_pages = npages;
  	area->pages = pages;
  
  	if (map_vm_area(area, prot_rwx, pages)) {
  		vunmap(area->addr);
  		goto error;
  	}
  
  	return area->addr;
  
  error:
  	while (--i >= 0)
  		__free_page(pages[i]);
  	kfree(pages);
  	return NULL;
  }
  
  
  /* Free memory returned from module_alloc */
  void module_free(struct module *mod, void *module_region)
  {
  	vfree(module_region);
  
  	/* Globally flush the L1 icache. */
  	flush_remote(0, HV_FLUSH_EVICT_L1I, cpu_online_mask,
  		     0, 0, 0, NULL, NULL, 0);
  
  	/*
  	 * FIXME: If module_region == mod->module_init, trim exception
  	 * table entries.
  	 */
  }
  
  #ifdef __tilegx__
  /*
   * Validate that the high 16 bits of "value" is just the sign-extension of
   * the low 48 bits.
   */
  static int validate_hw2_last(long value, struct module *me)
  {
  	if (((value << 16) >> 16) != value) {
  		pr_warning("module %s: Out of range HW2_LAST value %#lx\n",
  			   me->name, value);
  		return 0;
  	}
  	return 1;
  }
  
  /*
   * Validate that "value" isn't too big to hold in a JumpOff relocation.
   */
  static int validate_jumpoff(long value)
  {
  	/* Determine size of jump offset. */
  	int shift = __builtin_clzl(get_JumpOff_X1(create_JumpOff_X1(-1)));
  
  	/* Check to see if it fits into the relocation slot. */
  	long f = get_JumpOff_X1(create_JumpOff_X1(value));
  	f = (f << shift) >> shift;
  
  	return f == value;
  }
  #endif
  
  int apply_relocate_add(Elf_Shdr *sechdrs,
  		       const char *strtab,
  		       unsigned int symindex,
  		       unsigned int relsec,
  		       struct module *me)
  {
  	unsigned int i;
  	Elf_Rela *rel = (void *)sechdrs[relsec].sh_addr;
  	Elf_Sym *sym;
  	u64 *location;
  	unsigned long value;
  
  	DEBUGP("Applying relocate section %u to %u\n", relsec,
  	       sechdrs[relsec].sh_info);
  	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
  		/* This is where to make the change */
  		location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
  			+ rel[i].r_offset;
  		/*
  		 * This is the symbol it is referring to.
  		 * Note that all undefined symbols have been resolved.
  		 */
  		sym = (Elf_Sym *)sechdrs[symindex].sh_addr
  			+ ELF_R_SYM(rel[i].r_info);
  		value = sym->st_value + rel[i].r_addend;
  
  		switch (ELF_R_TYPE(rel[i].r_info)) {
  
  #ifdef __LITTLE_ENDIAN
  # define MUNGE(func) \
  	(*location = ((*location & ~func(-1)) | func(value)))
  #else
  /*
   * Instructions are always little-endian, so when we read them as data,
   * we have to swap them around before and after modifying them.
   */
  # define MUNGE(func) \
  	(*location = swab64((swab64(*location) & ~func(-1)) | func(value)))
  #endif
  
  #ifndef __tilegx__
  		case R_TILE_32:
  			*(uint32_t *)location = value;
  			break;
  		case R_TILE_IMM16_X0_HA:
  			value = (value + 0x8000) >> 16;
  			/*FALLTHROUGH*/
  		case R_TILE_IMM16_X0_LO:
  			MUNGE(create_Imm16_X0);
  			break;
  		case R_TILE_IMM16_X1_HA:
  			value = (value + 0x8000) >> 16;
  			/*FALLTHROUGH*/
  		case R_TILE_IMM16_X1_LO:
  			MUNGE(create_Imm16_X1);
  			break;
  		case R_TILE_JOFFLONG_X1:
  			value -= (unsigned long) location;  /* pc-relative */
  			value = (long) value >> 3;     /* count by instrs */
  			MUNGE(create_JOffLong_X1);
  			break;
  #else
  		case R_TILEGX_64:
  			*location = value;
  			break;
  		case R_TILEGX_IMM16_X0_HW2_LAST:
  			if (!validate_hw2_last(value, me))
  				return -ENOEXEC;
  			value >>= 16;
  			/*FALLTHROUGH*/
  		case R_TILEGX_IMM16_X0_HW1:
  			value >>= 16;
  			/*FALLTHROUGH*/
  		case R_TILEGX_IMM16_X0_HW0:
  			MUNGE(create_Imm16_X0);
  			break;
  		case R_TILEGX_IMM16_X1_HW2_LAST:
  			if (!validate_hw2_last(value, me))
  				return -ENOEXEC;
  			value >>= 16;
  			/*FALLTHROUGH*/
  		case R_TILEGX_IMM16_X1_HW1:
  			value >>= 16;
  			/*FALLTHROUGH*/
  		case R_TILEGX_IMM16_X1_HW0:
  			MUNGE(create_Imm16_X1);
  			break;
  		case R_TILEGX_JUMPOFF_X1:
  			value -= (unsigned long) location;  /* pc-relative */
  			value = (long) value >> 3;     /* count by instrs */
  			if (!validate_jumpoff(value)) {
  				pr_warning("module %s: Out of range jump to"
  					   " %#llx at %#llx (%p)\n", me->name,
  					   sym->st_value + rel[i].r_addend,
  					   rel[i].r_offset, location);
  				return -ENOEXEC;
  			}
  			MUNGE(create_JumpOff_X1);
  			break;
  #endif
  
  #undef MUNGE
  
  		default:
  			pr_err("module %s: Unknown relocation: %d\n",
  			       me->name, (int) ELF_R_TYPE(rel[i].r_info));
  			return -ENOEXEC;
  		}
  	}
  	return 0;
  }
  