Commit 9baa4bb9 authored by Rusty Russell's avatar Rusty Russell Committed by Paul Mackerras

PPC32: In-kernel module linker for PPC.

parent fdea9fc9
......@@ -25,7 +25,7 @@ obj-y := entry.o traps.o irq.o idle.o time.o misc.o \
cputable.o ppc_htab.o
obj-$(CONFIG_6xx) += l2cr.o ppc6xx_idle.o
obj-$(CONFIG_ALL_PPC) += ppc6xx_idle.o
obj-$(CONFIG_MODULES) += ppc_ksyms.o
obj-$(CONFIG_MODULES) += module.o ppc_ksyms.o
obj-$(CONFIG_PCI) += pci.o
ifneq ($(CONFIG_PPC_ISERIES),y)
obj-$(CONFIG_PCI) += pci-dma.o
......
......@@ -1182,10 +1182,10 @@ _GLOBAL(sys_call_table)
.long sys_adjtimex
.long sys_mprotect /* 125 */
.long sys_sigprocmask
.long sys_create_module
.long sys_ni_syscall /* old sys_create_module */
.long sys_init_module
.long sys_delete_module
.long sys_get_kernel_syms /* 130 */
.long sys_ni_syscall /* old sys_get_kernel_syms */ /* 130 */
.long sys_quotactl
.long sys_getpgid
.long sys_fchdir
......@@ -1221,7 +1221,7 @@ _GLOBAL(sys_call_table)
.long sys_mremap
.long sys_setresuid
.long sys_getresuid /* 165 */
.long sys_query_module
.long sys_ni_syscall /* old sys_query_module */
.long sys_poll
.long sys_nfsservctl
.long sys_setresgid
......
/* Kernel module help for PPC.
Copyright (C) 2001 Rusty Russell.
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; either version 2 of the License, or
(at your option) any later version.
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. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/module.h>
#include <linux/elf.h>
#include <linux/vmalloc.h>
#include <linux/fs.h>
#include <linux/string.h>
#include <linux/kernel.h>
#if 0
#define DEBUGP printk
#else
#define DEBUGP(fmt , ...)
#endif
void *module_alloc(unsigned long size)
{
if (size == 0)
return NULL;
return vmalloc(size);
}
/* Free memory returned from module_alloc */
void module_free(struct module *mod, void *module_region)
{
vfree(module_region);
/* FIXME: If module_region == mod->init_region, trim exception
table entries. */
}
/* Count how many different relocations (different symbol, different
addend) */
static unsigned int count_relocs(const Elf32_Rela *rela, unsigned int num)
{
unsigned int i, j, ret = 0;
/* Sure, this is order(n^2), but it's usually short, and not
time critical */
for (i = 0; i < num; i++) {
for (j = 0; j < i; j++) {
/* If this addend appeared before, it's
already been counted */
if (ELF32_R_SYM(rela[i].r_info)
== ELF32_R_SYM(rela[j].r_info)
&& rela[i].r_addend == rela[j].r_addend)
break;
}
if (j == i) ret++;
}
return ret;
}
/* Get the potential trampolines size required of the init and
non-init sections */
static unsigned long get_plt_size(const Elf32_Ehdr *hdr,
const Elf32_Shdr *sechdrs,
const char *secstrings,
int is_init)
{
unsigned long ret = 0;
unsigned i;
/* Everything marked ALLOC (this includes the exported
symbols) */
for (i = 1; i < hdr->e_shnum; i++) {
/* 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;
if (sechdrs[i].sh_type == SHT_RELA) {
DEBUGP("Found relocations in section %u\n", i);
DEBUGP("Ptr: %p. Number: %u\n",
(void *)hdr + sechdrs[i].sh_offset,
sechdrs[i].sh_size / sizeof(Elf32_Rela));
ret += count_relocs((void *)hdr
+ sechdrs[i].sh_offset,
sechdrs[i].sh_size
/ sizeof(Elf32_Rela))
* sizeof(struct ppc_plt_entry);
}
}
return ret;
}
long module_core_size(const Elf32_Ehdr *hdr,
const Elf32_Shdr *sechdrs,
const char *secstrings,
struct module *module)
{
module->arch.core_plt_offset = module->core_size;
return module->core_size + get_plt_size(hdr, sechdrs, secstrings, 0);
}
long module_init_size(const Elf32_Ehdr *hdr,
const Elf32_Shdr *sechdrs,
const char *secstrings,
struct module *module)
{
module->arch.init_plt_offset = module->init_size;
return module->init_size + get_plt_size(hdr, sechdrs, secstrings, 1);
}
int apply_relocate(Elf32_Shdr *sechdrs,
const char *strtab,
unsigned int symindex,
unsigned int relsec,
struct module *module)
{
printk(KERN_ERR "%s: Non-ADD RELOCATION unsupported\n",
module->name);
return -ENOEXEC;
}
static inline int entry_matches(struct ppc_plt_entry *entry, Elf32_Addr val)
{
if (entry->jump[0] == 0x3d600000 + ((val + 0x8000) >> 16)
&& entry->jump[1] == 0x396b0000 + (val & 0xffff))
return 1;
return 0;
}
/* Set up a trampoline in the PLT to bounce us to the distant function */
static uint32_t do_plt_call(void *location, Elf32_Addr val, struct module *mod)
{
struct ppc_plt_entry *entry;
DEBUGP("Doing plt for %u\n", (unsigned int)location);
/* Init, or core PLT? */
if (location >= mod->module_core
&& location < mod->module_core + mod->arch.core_plt_offset)
entry = mod->module_core + mod->arch.core_plt_offset;
else
entry = mod->module_init + mod->arch.init_plt_offset;
/* Find this entry, or if that fails, the next avail. entry */
while (entry->jump[0]) {
if (entry_matches(entry, val)) return (uint32_t)entry;
entry++;
}
/* Stolen from Paul Mackerras as well... */
entry->jump[0] = 0x3d600000+((val+0x8000)>>16); /* lis r11,sym@ha */
entry->jump[1] = 0x396b0000 + (val&0xffff); /* addi r11,r11,sym@l*/
entry->jump[2] = 0x7d6903a6; /* mtctr r11 */
entry->jump[3] = 0x4e800420; /* bctr */
return (uint32_t)entry;
}
int apply_relocate_add(Elf32_Shdr *sechdrs,
const char *strtab,
unsigned int symindex,
unsigned int relsec,
struct module *module)
{
unsigned int i;
Elf32_Rela *rela = (void *)sechdrs[relsec].sh_offset;
Elf32_Sym *sym;
uint32_t *location;
uint32_t value;
DEBUGP("Applying ADD relocate section %u to %u\n", relsec,
sechdrs[relsec].sh_info);
for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) {
/* This is where to make the change */
location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_offset
+ rela[i].r_offset;
/* This is the symbol it is referring to */
sym = (Elf32_Sym *)sechdrs[symindex].sh_offset
+ ELF32_R_SYM(rela[i].r_info);
if (!sym->st_value) {
printk(KERN_WARNING "%s: Unknown symbol %s\n",
module->name, strtab + sym->st_name);
return -ENOENT;
}
/* `Everything is relative'. */
value = sym->st_value + rela[i].r_addend;
switch (ELF32_R_TYPE(rela[i].r_info)) {
case R_PPC_ADDR32:
/* Simply set it */
*(uint32_t *)location = value;
break;
case R_PPC_ADDR16_LO:
/* Low half of the symbol */
*(uint16_t *)location = value;
break;
case R_PPC_ADDR16_HA:
/* Sign-adjusted lower 16 bits: PPC ELF ABI says:
(((x >> 16) + ((x & 0x8000) ? 1 : 0))) & 0xFFFF.
This is the same, only sane.
*/
*(uint16_t *)location = (value + 0x8000) >> 16;
break;
case R_PPC_REL24:
if ((int)(value - (uint32_t)location) < -0x02000000
|| (int)(value - (uint32_t)location) >= 0x02000000)
value = do_plt_call(location, value, module);
/* Only replace bits 2 through 26 */
DEBUGP("REL24 value = %08X. location = %08X\n",
value, (uint32_t)location);
DEBUGP("Location before: %08X.\n",
*(uint32_t *)location);
*(uint32_t *)location
= (*(uint32_t *)location & ~0x03fffffc)
| ((value - (uint32_t)location)
& 0x03fffffc);
DEBUGP("Location after: %08X.\n",
*(uint32_t *)location);
DEBUGP("ie. jump to %08X+%08X = %08X\n",
*(uint32_t *)location & 0x03fffffc,
(uint32_t)location,
(*(uint32_t *)location & 0x03fffffc)
+ (uint32_t)location);
break;
case R_PPC_REL32:
/* 32-bit relative jump. */
*(uint32_t *)location = value - (uint32_t)location;
break;
default:
printk("%s: unknown ADD relocation: %u\n",
module->name,
ELF32_R_TYPE(rela[i].r_info));
return -ENOEXEC;
}
}
return 0;
}
/* FIXME: Sort exception table --RR */
int module_finalize(const Elf_Ehdr *hdr,
const Elf_Shdr *sechdrs,
struct module *me)
{
return 0;
}
......@@ -70,24 +70,29 @@ search_one_table(const struct exception_table_entry *first,
unsigned long
search_exception_table(unsigned long addr)
{
unsigned long ret;
unsigned long ret = 0;
#ifndef CONFIG_MODULES
/* There is only the kernel to search. */
ret = search_one_table(__start___ex_table, __stop___ex_table-1, addr);
if (ret) return ret;
#else
/* The kernel is the last "module" -- no need to treat it special. */
struct module *mp;
for (mp = module_list; mp != NULL; mp = mp->next) {
if (mp->ex_table_start == NULL)
unsigned long flags;
struct list_head *i;
/* The kernel is the last "module" -- no need to treat it special. */
spin_lock_irqsave(&modlist_lock, flags);
list_for_each(i, &extables) {
struct exception_table *ex
= list_entry(i, struct exception_table, list);
if (ex->num_entries == 0)
continue;
ret = search_one_table(mp->ex_table_start,
mp->ex_table_end - 1, addr);
ret = search_one_table(ex->entry,
ex->entry + ex->num_entries - 1, addr);
if (ret)
return ret;
break;
}
spin_unlock_irqrestore(&modlist_lock, flags);
#endif
return 0;
return ret;
}
#ifndef _ASM_PPC_MODULE_H
#define _ASM_PPC_MODULE_H
/*
* This file contains the PPC architecture specific module code.
*/
#define module_map(x) vmalloc(x)
#define module_unmap(x) vfree(x)
#define module_arch_init(x) (0)
#define arch_init_modules(x) do { } while (0)
/* Module stuff for PPC. (C) 2001 Rusty Russell */
/* Thanks to Paul M for explaining this.
PPC can only do rel jumps += 32MB, and often the kernel and other
modules are furthur away than this. So, we jump to a table of
trampolines attached to the module (the Procedure Linkage Table)
whenever that happens.
*/
struct ppc_plt_entry
{
/* 16 byte jump instruction sequence (4 instructions) */
unsigned int jump[4];
};
struct mod_arch_specific
{
/* How much of the core is actually taken up with core (then
we know the rest is for the PLT */
unsigned int core_plt_offset;
/* Same for init */
unsigned int init_plt_offset;
};
#define Elf_Shdr Elf32_Shdr
#define Elf_Sym Elf32_Sym
#define Elf_Ehdr Elf32_Ehdr
#endif /* _ASM_PPC_MODULE_H */
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