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/* Kernel module help for PPC64.
Copyright (C) 2001, 2003 Rusty Russell IBM Corporation.
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/moduleloader.h>
#include <linux/err.h>
#include <linux/vmalloc.h>
#include <linux/bug.h>
#include <linux/uaccess.h>
#include <asm/module.h>
#include <asm/sections.h>
#include <asm/firmware.h>
#include <asm/code-patching.h>
#include <linux/sort.h>
#include "setup.h"
/* FIXME: We don't do .init separately. To do this, we'd need to have
a separate r2 value in the init and core section, and stub between
them, too.
Using a magic allocator which places modules within 32MB solves
this, and makes other things simpler. Anton?
--RR. */
#if 0
#define DEBUGP printk
#else
#define DEBUGP(fmt , ...)
#endif
/* There's actually a third entry here, but it's unused */
struct ppc64_opd_entry
{
unsigned long funcaddr;
unsigned long r2;
};
/* Like PPC32, we need little trampolines to do > 24-bit jumps (into
the kernel itself). But on PPC64, these need to be used for every
jump, actually, to reset r2 (TOC+0x8000). */
struct ppc64_stub_entry
{
/* 28 byte jump instruction sequence (7 instructions) */
unsigned char jump[28];
unsigned char unused[4];
/* Data for the above code */
struct ppc64_opd_entry opd;
};
/* We use a stub to fix up r2 (TOC ptr) and to jump to the (external)
function which may be more than 24-bits away. We could simply
patch the new r2 value and function pointer into the stub, but it's
significantly shorter to put these values at the end of the stub
code, and patch the stub address (32-bits relative to the TOC ptr,
r2) into the stub. */
static struct ppc64_stub_entry ppc64_stub =
{ .jump = {
0x3d, 0x82, 0x00, 0x00, /* addis r12,r2, <high> */
0x39, 0x8c, 0x00, 0x00, /* addi r12,r12, <low> */
/* Save current r2 value in magic place on the stack. */
0xf8, 0x41, 0x00, 0x28, /* std r2,40(r1) */
0xe9, 0x6c, 0x00, 0x20, /* ld r11,32(r12) */
0xe8, 0x4c, 0x00, 0x28, /* ld r2,40(r12) */
0x7d, 0x69, 0x03, 0xa6, /* mtctr r11 */
0x4e, 0x80, 0x04, 0x20 /* bctr */
} };
/* Count how many different 24-bit relocations (different symbol,
different addend) */
static unsigned int count_relocs(const Elf64_Rela *rela, unsigned int num)
{
unsigned int i, r_info, r_addend, _count_relocs;
/* FIXME: Only count external ones --RR */
_count_relocs = 0;
r_info = 0;
r_addend = 0;
for (i = 0; i < num; i++)
/* Only count 24-bit relocs, others don't need stubs */
if (ELF64_R_TYPE(rela[i].r_info) == R_PPC_REL24 &&
(r_info != ELF64_R_SYM(rela[i].r_info) ||
r_addend != rela[i].r_addend)) {
_count_relocs++;
r_info = ELF64_R_SYM(rela[i].r_info);
r_addend = rela[i].r_addend;
}
return _count_relocs;
}
static int relacmp(const void *_x, const void *_y)
{
const Elf64_Rela *x, *y;
y = (Elf64_Rela *)_x;
x = (Elf64_Rela *)_y;
/* Compare the entire r_info (as opposed to ELF64_R_SYM(r_info) only) to
* make the comparison cheaper/faster. It won't affect the sorting or
* the counting algorithms' performance
*/
if (x->r_info < y->r_info)
return -1;
else if (x->r_info > y->r_info)
return 1;
else if (x->r_addend < y->r_addend)
return -1;
else if (x->r_addend > y->r_addend)
return 1;
else
return 0;
}
static void relaswap(void *_x, void *_y, int size)
{
uint64_t *x, *y, tmp;
int i;
y = (uint64_t *)_x;
x = (uint64_t *)_y;
for (i = 0; i < sizeof(Elf64_Rela) / sizeof(uint64_t); i++) {
tmp = x[i];
x[i] = y[i];
y[i] = tmp;
}
}
/* Get size of potential trampolines required. */
static unsigned long get_stubs_size(const Elf64_Ehdr *hdr,
const Elf64_Shdr *sechdrs)
{
/* One extra reloc so it's always 0-funcaddr terminated */
unsigned long relocs = 1;
unsigned i;
/* Every relocated section... */
for (i = 1; i < hdr->e_shnum; i++) {
if (sechdrs[i].sh_type == SHT_RELA) {
DEBUGP("Found relocations in section %u\n", i);
DEBUGP("Ptr: %p. Number: %lu\n",
(void *)sechdrs[i].sh_addr,
sechdrs[i].sh_size / sizeof(Elf64_Rela));
/* Sort the relocation information based on a symbol and
* addend key. This is a stable O(n*log n) complexity
* alogrithm but it will reduce the complexity of
* count_relocs() to linear complexity O(n)
*/
sort((void *)sechdrs[i].sh_addr,
sechdrs[i].sh_size / sizeof(Elf64_Rela),
sizeof(Elf64_Rela), relacmp, relaswap);
relocs += count_relocs((void *)sechdrs[i].sh_addr,
sechdrs[i].sh_size
/ sizeof(Elf64_Rela));
}
}
DEBUGP("Looks like a total of %lu stubs, max\n", relocs);
return relocs * sizeof(struct ppc64_stub_entry);
}
static void dedotify_versions(struct modversion_info *vers,
unsigned long size)
{
struct modversion_info *end;
for (end = (void *)vers + size; vers < end; vers++)
if (vers->name[0] == '.')
memmove(vers->name, vers->name+1, strlen(vers->name));
}
/* Undefined symbols which refer to .funcname, hack to funcname */
static void dedotify(Elf64_Sym *syms, unsigned int numsyms, char *strtab)
{
unsigned int i;
for (i = 1; i < numsyms; i++) {
if (syms[i].st_shndx == SHN_UNDEF) {
char *name = strtab + syms[i].st_name;
if (name[0] == '.')
memmove(name, name+1, strlen(name));
}
}
}
int module_frob_arch_sections(Elf64_Ehdr *hdr,
Elf64_Shdr *sechdrs,
char *secstrings,
struct module *me)
{
unsigned int i;
/* Find .toc and .stubs sections, symtab and strtab */
for (i = 1; i < hdr->e_shnum; i++) {
char *p;
if (strcmp(secstrings + sechdrs[i].sh_name, ".stubs") == 0)
me->arch.stubs_section = i;
else if (strcmp(secstrings + sechdrs[i].sh_name, ".toc") == 0)
me->arch.toc_section = i;
else if (strcmp(secstrings+sechdrs[i].sh_name,"__versions")==0)
dedotify_versions((void *)hdr + sechdrs[i].sh_offset,
sechdrs[i].sh_size);
/* We don't handle .init for the moment: rename to _init */
while ((p = strstr(secstrings + sechdrs[i].sh_name, ".init")))
p[0] = '_';
if (sechdrs[i].sh_type == SHT_SYMTAB)
dedotify((void *)hdr + sechdrs[i].sh_offset,
sechdrs[i].sh_size / sizeof(Elf64_Sym),
(void *)hdr
+ sechdrs[sechdrs[i].sh_link].sh_offset);
}
if (!me->arch.stubs_section) {
printk("%s: doesn't contain .stubs.\n", <
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