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(npages * sizeof(struct page *), 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 error;
53	}
54
55	area = __get_vm_area(size, VM_ALLOC, MEM_MODULE_START, MEM_MODULE_END);
56	if (!area)
57		goto error;
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 error;
64	}
65
66	return area->addr;
67
68error:
69	while (--i >= 0)
70		__free_page(pages[i]);
71	kfree(pages);
72	return NULL;
73}
74
75
76/* Free memory returned from module_alloc */
77void module_memfree(void *module_region)
78{
79	vfree(module_region);
80
81	/* Globally flush the L1 icache. */
82	flush_remote(0, HV_FLUSH_EVICT_L1I, cpu_online_mask,
83		     0, 0, 0, NULL, NULL, 0);
84
85	/*
86	 * FIXME: Add module_arch_freeing_init to trim exception
87	 * table entries.
88	 */
89}
90
91#ifdef __tilegx__
92/*
93 * Validate that the high 16 bits of "value" is just the sign-extension of
94 * the low 48 bits.
95 */
96static int validate_hw2_last(long value, struct module *me)
97{
98	if (((value << 16) >> 16) != value) {
99		pr_warn("module %s: Out of range HW2_LAST value %#lx\n",
100			me->name, value);
101		return 0;
102	}
103	return 1;
104}
105
106/*
107 * Validate that "value" isn't too big to hold in a JumpOff relocation.
108 */
109static int validate_jumpoff(long value)
110{
111	/* Determine size of jump offset. */
112	int shift = __builtin_clzl(get_JumpOff_X1(create_JumpOff_X1(-1)));
113
114	/* Check to see if it fits into the relocation slot. */
115	long f = get_JumpOff_X1(create_JumpOff_X1(value));
116	f = (f << shift) >> shift;
117
118	return f == value;
119}
120#endif
121
122int apply_relocate_add(Elf_Shdr *sechdrs,
123		       const char *strtab,
124		       unsigned int symindex,
125		       unsigned int relsec,
126		       struct module *me)
127{
128	unsigned int i;
129	Elf_Rela *rel = (void *)sechdrs[relsec].sh_addr;
130	Elf_Sym *sym;
131	u64 *location;
132	unsigned long value;
133
134	DEBUGP("Applying relocate section %u to %u\n", relsec,
135	       sechdrs[relsec].sh_info);
136	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
137		/* This is where to make the change */
138		location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
139			+ rel[i].r_offset;
140		/*
141		 * This is the symbol it is referring to.
142		 * Note that all undefined symbols have been resolved.
143		 */
144		sym = (Elf_Sym *)sechdrs[symindex].sh_addr
145			+ ELF_R_SYM(rel[i].r_info);
146		value = sym->st_value + rel[i].r_addend;
147
148		switch (ELF_R_TYPE(rel[i].r_info)) {
149
150#ifdef __LITTLE_ENDIAN
151# define MUNGE(func) \
152	(*location = ((*location & ~func(-1)) | func(value)))
153#else
154/*
155 * Instructions are always little-endian, so when we read them as data,
156 * we have to swap them around before and after modifying them.
157 */
158# define MUNGE(func) \
159	(*location = swab64((swab64(*location) & ~func(-1)) | func(value)))
160#endif
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_warn("module %s: Out of range jump to %#llx at %#llx (%p)\n",
214					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}
233