blob: 09ba5f585634a8e223e9da74d51c85894f3bac1c [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0-or-later
/*
*
* Copyright (C) 2001 Rusty Russell.
* Copyright (C) 2003, 2004 Ralf Baechle (ralf@linux-mips.org)
* Copyright (C) 2005 Thiemo Seufer
*/
#undef DEBUG
#include <linux/extable.h>
#include <linux/moduleloader.h>
#include <linux/elf.h>
#include <linux/mm.h>
#include <linux/numa.h>
#include <linux/vmalloc.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/spinlock.h>
#include <linux/jump_label.h>
#include <asm/pgtable.h> /* MODULE_START */
struct mips_hi16 {
struct mips_hi16 *next;
Elf_Addr *addr;
Elf_Addr value;
};
static LIST_HEAD(dbe_list);
static DEFINE_SPINLOCK(dbe_lock);
/*
* Get the potential max trampolines size required of the init and
* non-init sections. Only used if we cannot find enough contiguous
* physically mapped memory to put the module into.
*/
static unsigned int
get_plt_size(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,
const char *secstrings, unsigned int symindex, bool is_init)
{
unsigned long ret = 0;
unsigned int i, j;
Elf_Sym *syms;
/* Everything marked ALLOC (this includes the exported symbols) */
for (i = 1; i < hdr->e_shnum; ++i) {
unsigned int info = sechdrs[i].sh_info;
if (sechdrs[i].sh_type != SHT_REL
&& sechdrs[i].sh_type != SHT_RELA)
continue;
/* Not a valid relocation section? */
if (info >= hdr->e_shnum)
continue;
/* Don't bother with non-allocated sections */
if (!(sechdrs[info].sh_flags & SHF_ALLOC))
continue;
/* If it's called *.init*, and we're not init, we're
not interested */
if ((strstr(secstrings + sechdrs[i].sh_name, ".init") != 0)
!= is_init)
continue;
syms = (Elf_Sym *) sechdrs[symindex].sh_addr;
if (sechdrs[i].sh_type == SHT_REL) {
Elf_Mips_Rel *rel = (void *) sechdrs[i].sh_addr;
unsigned int size = sechdrs[i].sh_size / sizeof(*rel);
for (j = 0; j < size; ++j) {
Elf_Sym *sym;
if (ELF_MIPS_R_TYPE(rel[j]) != R_MIPS_26)
continue;
sym = syms + ELF_MIPS_R_SYM(rel[j]);
if (!is_init && sym->st_shndx != SHN_UNDEF)
continue;
ret += 4 * sizeof(int);
}
} else {
Elf_Mips_Rela *rela = (void *) sechdrs[i].sh_addr;
unsigned int size = sechdrs[i].sh_size / sizeof(*rela);
for (j = 0; j < size; ++j) {
Elf_Sym *sym;
if (ELF_MIPS_R_TYPE(rela[j]) != R_MIPS_26)
continue;
sym = syms + ELF_MIPS_R_SYM(rela[j]);
if (!is_init && sym->st_shndx != SHN_UNDEF)
continue;
ret += 4 * sizeof(int);
}
}
}
return ret;
}
#ifndef MODULE_START
static void *alloc_phys(unsigned long size)
{
unsigned order;
struct page *page;
struct page *p;
size = PAGE_ALIGN(size);
order = get_order(size);
page = alloc_pages(GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN |
__GFP_THISNODE, order);
if (!page)
return NULL;
split_page(page, order);
/* mark all pages except for the last one */
for (p = page; p + 1 < page + (size >> PAGE_SHIFT); ++p)
set_bit(PG_owner_priv_1, &p->flags);
for (p = page + (size >> PAGE_SHIFT); p < page + (1 << order); ++p)
__free_page(p);
return page_address(page);
}
#endif
static void free_phys(void *ptr)
{
struct page *page;
bool free;
page = virt_to_page(ptr);
do {
free = test_and_clear_bit(PG_owner_priv_1, &page->flags);
__free_page(page);
page++;
} while (free);
}
void *module_alloc(unsigned long size)
{
#ifdef MODULE_START
return __vmalloc_node_range(size, 1, MODULE_START, MODULE_END,
GFP_KERNEL, PAGE_KERNEL, 0, NUMA_NO_NODE,
__builtin_return_address(0));
#else
void *ptr;
if (size == 0)
return NULL;
ptr = alloc_phys(size);
/* If we failed to allocate physically contiguous memory,
* fall back to regular vmalloc. The module loader code will
* create jump tables to handle long jumps */
if (!ptr)
return vmalloc(size);
return ptr;
#endif
}
static inline bool is_phys_addr(void *ptr)
{
#ifdef CONFIG_64BIT
return (KSEGX((unsigned long)ptr) == CKSEG0);
#else
return (KSEGX(ptr) == KSEG0);
#endif
}
/* Free memory returned from module_alloc */
void module_memfree(void *module_region)
{
if (is_phys_addr(module_region))
free_phys(module_region);
else
vfree(module_region);
}
static void *__module_alloc(int size, bool phys)
{
void *ptr;
if (phys)
ptr = kmalloc(size, GFP_KERNEL);
else
ptr = vmalloc(size);
return ptr;
}
static void __module_free(void *ptr)
{
if (is_phys_addr(ptr))
kfree(ptr);
else
vfree(ptr);
}
int module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
char *secstrings, struct module *mod)
{
unsigned int symindex = 0;
unsigned int core_size, init_size;
int i;
mod->arch.phys_plt_offset = 0;
mod->arch.virt_plt_offset = 0;
mod->arch.phys_plt_tbl = NULL;
mod->arch.virt_plt_tbl = NULL;
if (IS_ENABLED(CONFIG_64BIT))
return 0;
for (i = 1; i < hdr->e_shnum; i++)
if (sechdrs[i].sh_type == SHT_SYMTAB)
symindex = i;
core_size = get_plt_size(hdr, sechdrs, secstrings, symindex, false);
init_size = get_plt_size(hdr, sechdrs, secstrings, symindex, true);
if ((core_size + init_size) == 0)
return 0;
mod->arch.phys_plt_tbl = __module_alloc(core_size + init_size, 1);
if (!mod->arch.phys_plt_tbl)
return -ENOMEM;
mod->arch.virt_plt_tbl = __module_alloc(core_size + init_size, 0);
if (!mod->arch.virt_plt_tbl) {
__module_free(mod->arch.phys_plt_tbl);
mod->arch.phys_plt_tbl = NULL;
return -ENOMEM;
}
return 0;
}
static int apply_r_mips_none(struct module *me, u32 *location,
u32 base, Elf_Addr v, bool rela)
{
return 0;
}
static int apply_r_mips_32(struct module *me, u32 *location,
u32 base, Elf_Addr v, bool rela)
{
*location = base + v;
return 0;
}
static Elf_Addr add_plt_entry_to(unsigned *plt_offset,
void *start, Elf_Addr v)
{
unsigned *tramp = start + *plt_offset;
*plt_offset += 4 * sizeof(int);
/* adjust carry for addiu */
if (v & 0x00008000)
v += 0x10000;
tramp[0] = 0x3c190000 | (v >> 16); /* lui t9, hi16 */
tramp[1] = 0x27390000 | (v & 0xffff); /* addiu t9, t9, lo16 */
tramp[2] = 0x03200008; /* jr t9 */
tramp[3] = 0x00000000; /* nop */
return (Elf_Addr) tramp;
}
static Elf_Addr add_plt_entry(struct module *me, void *location, Elf_Addr v)
{
if (is_phys_addr(location))
return add_plt_entry_to(&me->arch.phys_plt_offset,
me->arch.phys_plt_tbl, v);
else
return add_plt_entry_to(&me->arch.virt_plt_offset,
me->arch.virt_plt_tbl, v);
}
static int apply_r_mips_26(struct module *me, u32 *location,
u32 base, Elf_Addr v, bool rela)
{
u32 ofs = base & 0x03ffffff;
if (v % 4) {
pr_err("module %s: dangerous R_MIPS_26 relocation\n",
me->name);
return -ENOEXEC;
}
if ((v & 0xf0000000) != (((unsigned long)location + 4) & 0xf0000000)) {
v = add_plt_entry(me, location, v + (ofs << 2));
if (!v) {
pr_err("module %s: relocation overflow\n",
me->name);
return -ENOEXEC;
}
ofs = 0;
}
*location = (*location & ~0x03ffffff) |
((ofs + (v >> 2)) & 0x03ffffff);
return 0;
}
static int apply_r_mips_hi16(struct module *me, u32 *location,
u32 base, Elf_Addr v, bool rela)
{
struct mips_hi16 *n;
if (rela) {
*location = (*location & 0xffff0000) |
((((long long) v + 0x8000LL) >> 16) & 0xffff);
return 0;
}
/*
* We cannot relocate this one now because we don't know the value of
* the carry we need to add. Save the information, and let LO16 do the
* actual relocation.
*/
n = kmalloc(sizeof *n, GFP_KERNEL);
if (!n)
return -ENOMEM;
n->addr = (Elf_Addr *)location;
n->value = v;
n->next = me->arch.r_mips_hi16_list;
me->arch.r_mips_hi16_list = n;
return 0;
}
static void free_relocation_chain(struct mips_hi16 *l)
{
struct mips_hi16 *next;
while (l) {
next = l->next;
kfree(l);
l = next;
}
}
static int apply_r_mips_lo16(struct module *me, u32 *location,
u32 base, Elf_Addr v, bool rela)
{
unsigned long insnlo = base;
struct mips_hi16 *l;
Elf_Addr val, vallo;
if (rela) {
*location = (*location & 0xffff0000) | (v & 0xffff);
return 0;
}
/* Sign extend the addend we extract from the lo insn. */
vallo = ((insnlo & 0xffff) ^ 0x8000) - 0x8000;
if (me->arch.r_mips_hi16_list != NULL) {
l = me->arch.r_mips_hi16_list;
while (l != NULL) {
struct mips_hi16 *next;
unsigned long insn;
/*
* The value for the HI16 had best be the same.
*/
if (v != l->value)
goto out_danger;
/*
* Do the HI16 relocation. Note that we actually don't
* need to know anything about the LO16 itself, except
* where to find the low 16 bits of the addend needed
* by the LO16.
*/
insn = *l->addr;
val = ((insn & 0xffff) << 16) + vallo;
val += v;
/*
* Account for the sign extension that will happen in
* the low bits.
*/
val = ((val >> 16) + ((val & 0x8000) != 0)) & 0xffff;
insn = (insn & ~0xffff) | val;
*l->addr = insn;
next = l->next;
kfree(l);
l = next;
}
me->arch.r_mips_hi16_list = NULL;
}
/*
* Ok, we're done with the HI16 relocs. Now deal with the LO16.
*/
val = v + vallo;
insnlo = (insnlo & ~0xffff) | (val & 0xffff);
*location = insnlo;
return 0;
out_danger:
free_relocation_chain(l);
me->arch.r_mips_hi16_list = NULL;
pr_err("module %s: dangerous R_MIPS_LO16 relocation\n", me->name);
return -ENOEXEC;
}
static int apply_r_mips_pc(struct module *me, u32 *location, u32 base,
Elf_Addr v, unsigned int bits)
{
unsigned long mask = GENMASK(bits - 1, 0);
unsigned long se_bits;
long offset;
if (v % 4) {
pr_err("module %s: dangerous R_MIPS_PC%u relocation\n",
me->name, bits);
return -ENOEXEC;
}
/* retrieve & sign extend implicit addend if any */
offset = base & mask;
offset |= (offset & BIT(bits - 1)) ? ~mask : 0;
offset += ((long)v - (long)location) >> 2;
/* check the sign bit onwards are identical - ie. we didn't overflow */
se_bits = (offset & BIT(bits - 1)) ? ~0ul : 0;
if ((offset & ~mask) != (se_bits & ~mask)) {
pr_err("module %s: relocation overflow\n", me->name);
return -ENOEXEC;
}
*location = (*location & ~mask) | (offset & mask);
return 0;
}
static int apply_r_mips_pc16(struct module *me, u32 *location,
u32 base, Elf_Addr v, bool rela)
{
return apply_r_mips_pc(me, location, base, v, 16);
}
static int apply_r_mips_pc21(struct module *me, u32 *location,
u32 base, Elf_Addr v, bool rela)
{
return apply_r_mips_pc(me, location, base, v, 21);
}
static int apply_r_mips_pc26(struct module *me, u32 *location,
u32 base, Elf_Addr v, bool rela)
{
return apply_r_mips_pc(me, location, base, v, 26);
}
static int apply_r_mips_64(struct module *me, u32 *location,
u32 base, Elf_Addr v, bool rela)
{
if (WARN_ON(!rela))
return -EINVAL;
*(Elf_Addr *)location = v;
return 0;
}
static int apply_r_mips_higher(struct module *me, u32 *location,
u32 base, Elf_Addr v, bool rela)
{
if (WARN_ON(!rela))
return -EINVAL;
*location = (*location & 0xffff0000) |
((((long long)v + 0x80008000LL) >> 32) & 0xffff);
return 0;
}
static int apply_r_mips_highest(struct module *me, u32 *location,
u32 base, Elf_Addr v, bool rela)
{
if (WARN_ON(!rela))
return -EINVAL;
*location = (*location & 0xffff0000) |
((((long long)v + 0x800080008000LL) >> 48) & 0xffff);
return 0;
}
/**
* reloc_handler() - Apply a particular relocation to a module
* @me: the module to apply the reloc to
* @location: the address at which the reloc is to be applied
* @base: the existing value at location for REL-style; 0 for RELA-style
* @v: the value of the reloc, with addend for RELA-style
*
* Each implemented reloc_handler function applies a particular type of
* relocation to the module @me. Relocs that may be found in either REL or RELA
* variants can be handled by making use of the @base & @v parameters which are
* set to values which abstract the difference away from the particular reloc
* implementations.
*
* Return: 0 upon success, else -ERRNO
*/
typedef int (*reloc_handler)(struct module *me, u32 *location,
u32 base, Elf_Addr v, bool rela);
/* The handlers for known reloc types */
static reloc_handler reloc_handlers[] = {
[R_MIPS_NONE] = apply_r_mips_none,
[R_MIPS_32] = apply_r_mips_32,
[R_MIPS_26] = apply_r_mips_26,
[R_MIPS_HI16] = apply_r_mips_hi16,
[R_MIPS_LO16] = apply_r_mips_lo16,
[R_MIPS_PC16] = apply_r_mips_pc16,
[R_MIPS_64] = apply_r_mips_64,
[R_MIPS_HIGHER] = apply_r_mips_higher,
[R_MIPS_HIGHEST] = apply_r_mips_highest,
[R_MIPS_PC21_S2] = apply_r_mips_pc21,
[R_MIPS_PC26_S2] = apply_r_mips_pc26,
};
static int __apply_relocate(Elf_Shdr *sechdrs, const char *strtab,
unsigned int symindex, unsigned int relsec,
struct module *me, bool rela)
{
union {
Elf_Mips_Rel *rel;
Elf_Mips_Rela *rela;
} r;
reloc_handler handler;
Elf_Sym *sym;
u32 *location, base;
unsigned int i, type;
Elf_Addr v;
int err = 0;
size_t reloc_sz;
pr_debug("Applying relocate section %u to %u\n", relsec,
sechdrs[relsec].sh_info);
r.rel = (void *)sechdrs[relsec].sh_addr;
reloc_sz = rela ? sizeof(*r.rela) : sizeof(*r.rel);
me->arch.r_mips_hi16_list = NULL;
for (i = 0; i < sechdrs[relsec].sh_size / reloc_sz; i++) {
/* This is where to make the change */
location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
+ r.rel->r_offset;
/* This is the symbol it is referring to */
sym = (Elf_Sym *)sechdrs[symindex].sh_addr
+ ELF_MIPS_R_SYM(*r.rel);
if (sym->st_value >= -MAX_ERRNO) {
/* Ignore unresolved weak symbol */
if (ELF_ST_BIND(sym->st_info) == STB_WEAK)
continue;
pr_warn("%s: Unknown symbol %s\n",
me->name, strtab + sym->st_name);
err = -ENOENT;
goto out;
}
type = ELF_MIPS_R_TYPE(*r.rel);
if (type < ARRAY_SIZE(reloc_handlers))
handler = reloc_handlers[type];
else
handler = NULL;
if (!handler) {
pr_err("%s: Unknown relocation type %u\n",
me->name, type);
err = -EINVAL;
goto out;
}
if (rela) {
v = sym->st_value + r.rela->r_addend;
base = 0;
r.rela = &r.rela[1];
} else {
v = sym->st_value;
base = *location;
r.rel = &r.rel[1];
}
err = handler(me, location, base, v, rela);
if (err)
goto out;
}
out:
/*
* Normally the hi16 list should be deallocated at this point. A
* malformed binary however could contain a series of R_MIPS_HI16
* relocations not followed by a R_MIPS_LO16 relocation, or if we hit
* an error processing a reloc we might have gotten here before
* reaching the R_MIPS_LO16. In either case, free up the list and
* return an error.
*/
if (me->arch.r_mips_hi16_list) {
free_relocation_chain(me->arch.r_mips_hi16_list);
me->arch.r_mips_hi16_list = NULL;
err = err ?: -ENOEXEC;
}
return err;
}
int apply_relocate(Elf_Shdr *sechdrs, const char *strtab,
unsigned int symindex, unsigned int relsec,
struct module *me)
{
return __apply_relocate(sechdrs, strtab, symindex, relsec, me, false);
}
#ifdef CONFIG_MODULES_USE_ELF_RELA
int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
unsigned int symindex, unsigned int relsec,
struct module *me)
{
return __apply_relocate(sechdrs, strtab, symindex, relsec, me, true);
}
#endif /* CONFIG_MODULES_USE_ELF_RELA */
/* Given an address, look for it in the module exception tables. */
const struct exception_table_entry *search_module_dbetables(unsigned long addr)
{
unsigned long flags;
const struct exception_table_entry *e = NULL;
struct mod_arch_specific *dbe;
spin_lock_irqsave(&dbe_lock, flags);
list_for_each_entry(dbe, &dbe_list, dbe_list) {
e = search_extable(dbe->dbe_start,
dbe->dbe_end - dbe->dbe_start, addr);
if (e)
break;
}
spin_unlock_irqrestore(&dbe_lock, flags);
/* Now, if we found one, we are running inside it now, hence
we cannot unload the module, hence no refcnt needed. */
return e;
}
/* Put in dbe list if necessary. */
int module_finalize(const Elf_Ehdr *hdr,
const Elf_Shdr *sechdrs,
struct module *me)
{
const Elf_Shdr *s;
char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
/* Make jump label nops. */
jump_label_apply_nops(me);
INIT_LIST_HEAD(&me->arch.dbe_list);
for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
if (strcmp("__dbe_table", secstrings + s->sh_name) != 0)
continue;
me->arch.dbe_start = (void *)s->sh_addr;
me->arch.dbe_end = (void *)s->sh_addr + s->sh_size;
spin_lock_irq(&dbe_lock);
list_add(&me->arch.dbe_list, &dbe_list);
spin_unlock_irq(&dbe_lock);
}
/* Get rid of the fixup trampoline if we're running the module
* from physically mapped address space */
if (me->arch.phys_plt_offset == 0) {
__module_free(me->arch.phys_plt_tbl);
me->arch.phys_plt_tbl = NULL;
}
if (me->arch.virt_plt_offset == 0) {
__module_free(me->arch.virt_plt_tbl);
me->arch.virt_plt_tbl = NULL;
}
return 0;
}
void module_arch_freeing_init(struct module *mod)
{
if (mod->state == MODULE_STATE_LIVE)
return;
if (mod->arch.phys_plt_tbl) {
__module_free(mod->arch.phys_plt_tbl);
mod->arch.phys_plt_tbl = NULL;
}
if (mod->arch.virt_plt_tbl) {
__module_free(mod->arch.virt_plt_tbl);
mod->arch.virt_plt_tbl = NULL;
}
}
void module_arch_cleanup(struct module *mod)
{
spin_lock_irq(&dbe_lock);
list_del(&mod->arch.dbe_list);
spin_unlock_irq(&dbe_lock);
}