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/pgtable.h>
 24#include <asm/homecache.h>
 25#include <arch/opcode.h>
 26
 27#ifdef MODULE_DEBUG
 28#define DEBUGP printk
 29#else
 30#define DEBUGP(fmt...)
 31#endif
 32
 33/*
 34 * Allocate some address space in the range MEM_MODULE_START to
 35 * MEM_MODULE_END and populate it with memory.
 36 */
 37void *module_alloc(unsigned long size)
 38{
 39	struct page **pages;
 40	pgprot_t prot_rwx = __pgprot(_PAGE_KERNEL | _PAGE_KERNEL_EXEC);
 41	struct vm_struct *area;
 42	int i = 0;
 43	int npages;
 44
 45	npages = (size + PAGE_SIZE - 1) / PAGE_SIZE;
 46	pages = kmalloc_array(npages, sizeof(*pages), GFP_KERNEL);
 47	if (pages == NULL)
 48		return NULL;
 49	for (; i < npages; ++i) {
 50		pages[i] = alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
 51		if (!pages[i])
 52			goto free_pages;
 53	}
 54
 55	area = __get_vm_area(size, VM_ALLOC, MEM_MODULE_START, MEM_MODULE_END);
 56	if (!area)
 57		goto free_pages;
 58	area->nr_pages = npages;
 59	area->pages = pages;
 60
 61	if (map_vm_area(area, prot_rwx, pages)) {
 62		vunmap(area->addr);
 63		goto free_pages;
 64	}
 65
 66	return area->addr;
 67 free_pages:
 68	while (--i >= 0)
 69		__free_page(pages[i]);
 70	kfree(pages);
 71	return NULL;
 72}
 73
 74
 75/* Free memory returned from module_alloc */
 76void module_memfree(void *module_region)
 77{
 78	vfree(module_region);
 79
 80	/* Globally flush the L1 icache. */
 81	flush_remote(0, HV_FLUSH_EVICT_L1I, cpu_online_mask,
 82		     0, 0, 0, NULL, NULL, 0);
 83
 84	/*
 85	 * FIXME: Add module_arch_freeing_init to trim exception
 86	 * table entries.
 87	 */
 88}
 89
 90#ifdef __tilegx__
 91/*
 92 * Validate that the high 16 bits of "value" is just the sign-extension of
 93 * the low 48 bits.
 94 */
 95static int validate_hw2_last(long value, struct module *me)
 96{
 97	if (((value << 16) >> 16) != value) {
 98		pr_warn("module %s: Out of range HW2_LAST value %#lx\n",
 99			me->name, value);
100		return 0;
101	}
102	return 1;
103}
104
105/*
106 * Validate that "value" isn't too big to hold in a JumpOff relocation.
107 */
108static int validate_jumpoff(long value)
109{
110	/* Determine size of jump offset. */
111	int shift = __builtin_clzl(get_JumpOff_X1(create_JumpOff_X1(-1)));
112
113	/* Check to see if it fits into the relocation slot. */
114	long f = get_JumpOff_X1(create_JumpOff_X1(value));
115	f = (f << shift) >> shift;
116
117	return f == value;
118}
119#endif
120
121int apply_relocate_add(Elf_Shdr *sechdrs,
122		       const char *strtab,
123		       unsigned int symindex,
124		       unsigned int relsec,
125		       struct module *me)
126{
127	unsigned int i;
128	Elf_Rela *rel = (void *)sechdrs[relsec].sh_addr;
129	Elf_Sym *sym;
130	u64 *location;
131	unsigned long value;
132
133	DEBUGP("Applying relocate section %u to %u\n", relsec,
134	       sechdrs[relsec].sh_info);
135	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
136		/* This is where to make the change */
137		location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
138			+ rel[i].r_offset;
139		/*
140		 * This is the symbol it is referring to.
141		 * Note that all undefined symbols have been resolved.
142		 */
143		sym = (Elf_Sym *)sechdrs[symindex].sh_addr
144			+ ELF_R_SYM(rel[i].r_info);
145		value = sym->st_value + rel[i].r_addend;
146
147		switch (ELF_R_TYPE(rel[i].r_info)) {
148
149#ifdef __LITTLE_ENDIAN
150# define MUNGE(func) \
151	(*location = ((*location & ~func(-1)) | func(value)))
152#else
153/*
154 * Instructions are always little-endian, so when we read them as data,
155 * we have to swap them around before and after modifying them.
156 */
157# define MUNGE(func) \
158	(*location = swab64((swab64(*location) & ~func(-1)) | func(value)))
159#endif
160
161#ifndef __tilegx__
162		case R_TILE_32:
163			*(uint32_t *)location = value;
164			break;
165		case R_TILE_IMM16_X0_HA:
166			value = (value + 0x8000) >> 16;
167			/*FALLTHROUGH*/
168		case R_TILE_IMM16_X0_LO:
169			MUNGE(create_Imm16_X0);
170			break;
171		case R_TILE_IMM16_X1_HA:
172			value = (value + 0x8000) >> 16;
173			/*FALLTHROUGH*/
174		case R_TILE_IMM16_X1_LO:
175			MUNGE(create_Imm16_X1);
176			break;
177		case R_TILE_JOFFLONG_X1:
178			value -= (unsigned long) location;  /* pc-relative */
179			value = (long) value >> 3;     /* count by instrs */
180			MUNGE(create_JOffLong_X1);
181			break;
182#else
183		case R_TILEGX_64:
184			*location = value;
185			break;
186		case R_TILEGX_IMM16_X0_HW2_LAST:
187			if (!validate_hw2_last(value, me))
188				return -ENOEXEC;
189			value >>= 16;
190			/*FALLTHROUGH*/
191		case R_TILEGX_IMM16_X0_HW1:
192			value >>= 16;
193			/*FALLTHROUGH*/
194		case R_TILEGX_IMM16_X0_HW0:
195			MUNGE(create_Imm16_X0);
196			break;
197		case R_TILEGX_IMM16_X1_HW2_LAST:
198			if (!validate_hw2_last(value, me))
199				return -ENOEXEC;
200			value >>= 16;
201			/*FALLTHROUGH*/
202		case R_TILEGX_IMM16_X1_HW1:
203			value >>= 16;
204			/*FALLTHROUGH*/
205		case R_TILEGX_IMM16_X1_HW0:
206			MUNGE(create_Imm16_X1);
207			break;
208		case R_TILEGX_JUMPOFF_X1:
209			value -= (unsigned long) location;  /* pc-relative */
210			value = (long) value >> 3;     /* count by instrs */
211			if (!validate_jumpoff(value)) {
212				pr_warn("module %s: Out of range jump to %#llx at %#llx (%p)\n",
213					me->name,
214					sym->st_value + rel[i].r_addend,
215					rel[i].r_offset, location);
216				return -ENOEXEC;
217			}
218			MUNGE(create_JumpOff_X1);
219			break;
220#endif
221
222#undef MUNGE
223
224		default:
225			pr_err("module %s: Unknown relocation: %d\n",
226			       me->name, (int) ELF_R_TYPE(rel[i].r_info));
227			return -ENOEXEC;
228		}
229	}
230	return 0;
231}