1/*
  2 * Copyright 2010 Tilera Corporation. All Rights Reserved.
  3 *
  4 *   This program is free software; you can redistribute it and/or
  5 *   modify it under the terms of the GNU General Public License
  6 *   as published by the Free Software Foundation, version 2.
  7 *
  8 *   This program is distributed in the hope that it will be useful, but
  9 *   WITHOUT ANY WARRANTY; without even the implied warranty of
 10 *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
 11 *   NON INFRINGEMENT.  See the GNU General Public License for
 12 *   more details.
 13 *
 14 * Based on i386 version, copyright (C) 2001 Rusty Russell.
 15 */
 16
 17#include <linux/moduleloader.h>
 18#include <linux/elf.h>
 19#include <linux/vmalloc.h>
 20#include <linux/fs.h>
 21#include <linux/string.h>
 22#include <linux/kernel.h>
 23#include <asm/opcode-tile.h>
 24#include <asm/pgtable.h>
 25#include <asm/homecache.h>
 26
 27#ifdef __tilegx__
 28# define Elf_Rela Elf64_Rela
 29# define ELF_R_SYM ELF64_R_SYM
 30# define ELF_R_TYPE ELF64_R_TYPE
 31#else
 32# define Elf_Rela Elf32_Rela
 33# define ELF_R_SYM ELF32_R_SYM
 34# define ELF_R_TYPE ELF32_R_TYPE
 35#endif
 36
 37#ifdef MODULE_DEBUG
 38#define DEBUGP printk
 39#else
 40#define DEBUGP(fmt...)
 41#endif
 42
 43/*
 44 * Allocate some address space in the range MEM_MODULE_START to
 45 * MEM_MODULE_END and populate it with memory.
 46 */
 47void *module_alloc(unsigned long size)
 48{
 49	struct page **pages;
 50	pgprot_t prot_rwx = __pgprot(_PAGE_KERNEL | _PAGE_KERNEL_EXEC);
 51	struct vm_struct *area;
 52	int i = 0;
 53	int npages;
 54
 55	if (size == 0)
 56		return NULL;
 57	npages = (size + PAGE_SIZE - 1) / PAGE_SIZE;
 58	pages = kmalloc(npages * sizeof(struct page *), GFP_KERNEL);
 59	if (pages == NULL)
 60		return NULL;
 61	for (; i < npages; ++i) {
 62		pages[i] = alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
 63		if (!pages[i])
 64			goto error;
 65	}
 66
 67	area = __get_vm_area(size, VM_ALLOC, MEM_MODULE_START, MEM_MODULE_END);
 68	if (!area)
 69		goto error;
 70
 71	if (map_vm_area(area, prot_rwx, &pages)) {
 72		vunmap(area->addr);
 73		goto error;
 74	}
 75
 76	return area->addr;
 77
 78error:
 79	while (--i >= 0)
 80		__free_page(pages[i]);
 81	kfree(pages);
 82	return NULL;
 83}
 84
 85
 86/* Free memory returned from module_alloc */
 87void module_free(struct module *mod, void *module_region)
 88{
 89	vfree(module_region);
 90
 91	/* Globally flush the L1 icache. */
 92	flush_remote(0, HV_FLUSH_EVICT_L1I, cpu_online_mask,
 93		     0, 0, 0, NULL, NULL, 0);
 94
 95	/*
 96	 * FIXME: If module_region == mod->module_init, trim exception
 97	 * table entries.
 98	 */
 99}
100
101#ifdef __tilegx__
102/*
103 * Validate that the high 16 bits of "value" is just the sign-extension of
104 * the low 48 bits.
105 */
106static int validate_hw2_last(long value, struct module *me)
107{
108	if (((value << 16) >> 16) != value) {
109		pr_warning("module %s: Out of range HW2_LAST value %#lx\n",
110			   me->name, value);
111		return 0;
112	}
113	return 1;
114}
115
116/*
117 * Validate that "value" isn't too big to hold in a JumpOff relocation.
118 */
119static int validate_jumpoff(long value)
120{
121	/* Determine size of jump offset. */
122	int shift = __builtin_clzl(get_JumpOff_X1(create_JumpOff_X1(-1)));
123
124	/* Check to see if it fits into the relocation slot. */
125	long f = get_JumpOff_X1(create_JumpOff_X1(value));
126	f = (f << shift) >> shift;
127
128	return f == value;
129}
130#endif
131
132int apply_relocate_add(Elf_Shdr *sechdrs,
133		       const char *strtab,
134		       unsigned int symindex,
135		       unsigned int relsec,
136		       struct module *me)
137{
138	unsigned int i;
139	Elf_Rela *rel = (void *)sechdrs[relsec].sh_addr;
140	Elf_Sym *sym;
141	u64 *location;
142	unsigned long value;
143
144	DEBUGP("Applying relocate section %u to %u\n", relsec,
145	       sechdrs[relsec].sh_info);
146	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
147		/* This is where to make the change */
148		location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
149			+ rel[i].r_offset;
150		/*
151		 * This is the symbol it is referring to.
152		 * Note that all undefined symbols have been resolved.
153		 */
154		sym = (Elf_Sym *)sechdrs[symindex].sh_addr
155			+ ELF_R_SYM(rel[i].r_info);
156		value = sym->st_value + rel[i].r_addend;
157
158		switch (ELF_R_TYPE(rel[i].r_info)) {
159
160#define MUNGE(func) (*location = ((*location & ~func(-1)) | func(value)))
161
162#ifndef __tilegx__
163		case R_TILE_32:
164			*(uint32_t *)location = value;
165			break;
166		case R_TILE_IMM16_X0_HA:
167			value = (value + 0x8000) >> 16;
168			/*FALLTHROUGH*/
169		case R_TILE_IMM16_X0_LO:
170			MUNGE(create_Imm16_X0);
171			break;
172		case R_TILE_IMM16_X1_HA:
173			value = (value + 0x8000) >> 16;
174			/*FALLTHROUGH*/
175		case R_TILE_IMM16_X1_LO:
176			MUNGE(create_Imm16_X1);
177			break;
178		case R_TILE_JOFFLONG_X1:
179			value -= (unsigned long) location;  /* pc-relative */
180			value = (long) value >> 3;     /* count by instrs */
181			MUNGE(create_JOffLong_X1);
182			break;
183#else
184		case R_TILEGX_64:
185			*location = value;
186			break;
187		case R_TILEGX_IMM16_X0_HW2_LAST:
188			if (!validate_hw2_last(value, me))
189				return -ENOEXEC;
190			value >>= 16;
191			/*FALLTHROUGH*/
192		case R_TILEGX_IMM16_X0_HW1:
193			value >>= 16;
194			/*FALLTHROUGH*/
195		case R_TILEGX_IMM16_X0_HW0:
196			MUNGE(create_Imm16_X0);
197			break;
198		case R_TILEGX_IMM16_X1_HW2_LAST:
199			if (!validate_hw2_last(value, me))
200				return -ENOEXEC;
201			value >>= 16;
202			/*FALLTHROUGH*/
203		case R_TILEGX_IMM16_X1_HW1:
204			value >>= 16;
205			/*FALLTHROUGH*/
206		case R_TILEGX_IMM16_X1_HW0:
207			MUNGE(create_Imm16_X1);
208			break;
209		case R_TILEGX_JUMPOFF_X1:
210			value -= (unsigned long) location;  /* pc-relative */
211			value = (long) value >> 3;     /* count by instrs */
212			if (!validate_jumpoff(value)) {
213				pr_warning("module %s: Out of range jump to"
214					   " %#llx at %#llx (%p)\n", me->name,
215					   sym->st_value + rel[i].r_addend,
216					   rel[i].r_offset, location);
217				return -ENOEXEC;
218			}
219			MUNGE(create_JumpOff_X1);
220			break;
221#endif
222
223#undef MUNGE
224
225		default:
226			pr_err("module %s: Unknown relocation: %d\n",
227			       me->name, (int) ELF_R_TYPE(rel[i].r_info));
228			return -ENOEXEC;
229		}
230	}
231	return 0;
232}