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Diffstat (limited to 'arch/powerpc/kernel/module_64.c')
-rw-r--r--arch/powerpc/kernel/module_64.c455
1 files changed, 455 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/module_64.c b/arch/powerpc/kernel/module_64.c
new file mode 100644
index 0000000..928b858
--- /dev/null
+++ b/arch/powerpc/kernel/module_64.c
@@ -0,0 +1,455 @@
+/* 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 <asm/module.h>
+#include <asm/uaccess.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, j, ret = 0;
+
+ /* FIXME: Only count external ones --RR */
+ /* Sure, this is order(n^2), but it's usually short, and not
+ time critical */
+ 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)
+ continue;
+ for (j = 0; j < i; j++) {
+ /* If this addend appeared before, it's
+ already been counted */
+ if (rela[i].r_info == rela[j].r_info
+ && rela[i].r_addend == rela[j].r_addend)
+ break;
+ }
+ if (j == i) ret++;
+ }
+ return ret;
+}
+
+void *module_alloc(unsigned long size)
+{
+ if (size == 0)
+ return NULL;
+
+ return vmalloc_exec(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. */
+}
+
+/* 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));
+ 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 || !me->arch.toc_section) {
+ printk("%s: doesn't contain .toc or .stubs.\n", me->name);
+ return -ENOEXEC;
+ }
+
+ /* Override the stubs size */
+ sechdrs[me->arch.stubs_section].sh_size = get_stubs_size(hdr, sechdrs);
+ return 0;
+}
+
+int apply_relocate(Elf64_Shdr *sechdrs,
+ const char *strtab,
+ unsigned int symindex,
+ unsigned int relsec,
+ struct module *me)
+{
+ printk(KERN_ERR "%s: Non-ADD RELOCATION unsupported\n", me->name);
+ return -ENOEXEC;
+}
+
+/* r2 is the TOC pointer: it actually points 0x8000 into the TOC (this
+ gives the value maximum span in an instruction which uses a signed
+ offset) */
+static inline unsigned long my_r2(Elf64_Shdr *sechdrs, struct module *me)
+{
+ return sechdrs[me->arch.toc_section].sh_addr + 0x8000;
+}
+
+/* Both low and high 16 bits are added as SIGNED additions, so if low
+ 16 bits has high bit set, high 16 bits must be adjusted. These
+ macros do that (stolen from binutils). */
+#define PPC_LO(v) ((v) & 0xffff)
+#define PPC_HI(v) (((v) >> 16) & 0xffff)
+#define PPC_HA(v) PPC_HI ((v) + 0x8000)
+
+/* Patch stub to reference function and correct r2 value. */
+static inline int create_stub(Elf64_Shdr *sechdrs,
+ struct ppc64_stub_entry *entry,
+ struct ppc64_opd_entry *opd,
+ struct module *me)
+{
+ Elf64_Half *loc1, *loc2;
+ long reladdr;
+
+ *entry = ppc64_stub;
+
+ loc1 = (Elf64_Half *)&entry->jump[2];
+ loc2 = (Elf64_Half *)&entry->jump[6];
+
+ /* Stub uses address relative to r2. */
+ reladdr = (unsigned long)entry - my_r2(sechdrs, me);
+ if (reladdr > 0x7FFFFFFF || reladdr < -(0x80000000L)) {
+ printk("%s: Address %p of stub out of range of %p.\n",
+ me->name, (void *)reladdr, (void *)my_r2);
+ return 0;
+ }
+ DEBUGP("Stub %p get data from reladdr %li\n", entry, reladdr);
+
+ *loc1 = PPC_HA(reladdr);
+ *loc2 = PPC_LO(reladdr);
+ entry->opd.funcaddr = opd->funcaddr;
+ entry->opd.r2 = opd->r2;
+ return 1;
+}
+
+/* Create stub to jump to function described in this OPD: we need the
+ stub to set up the TOC ptr (r2) for the function. */
+static unsigned long stub_for_addr(Elf64_Shdr *sechdrs,
+ unsigned long opdaddr,
+ struct module *me)
+{
+ struct ppc64_stub_entry *stubs;
+ struct ppc64_opd_entry *opd = (void *)opdaddr;
+ unsigned int i, num_stubs;
+
+ num_stubs = sechdrs[me->arch.stubs_section].sh_size / sizeof(*stubs);
+
+ /* Find this stub, or if that fails, the next avail. entry */
+ stubs = (void *)sechdrs[me->arch.stubs_section].sh_addr;
+ for (i = 0; stubs[i].opd.funcaddr; i++) {
+ BUG_ON(i >= num_stubs);
+
+ if (stubs[i].opd.funcaddr == opd->funcaddr)
+ return (unsigned long)&stubs[i];
+ }
+
+ if (!create_stub(sechdrs, &stubs[i], opd, me))
+ return 0;
+
+ return (unsigned long)&stubs[i];
+}
+
+/* We expect a noop next: if it is, replace it with instruction to
+ restore r2. */
+static int restore_r2(u32 *instruction, struct module *me)
+{
+ if (*instruction != 0x60000000) {
+ printk("%s: Expect noop after relocate, got %08x\n",
+ me->name, *instruction);
+ return 0;
+ }
+ *instruction = 0xe8410028; /* ld r2,40(r1) */
+ return 1;
+}
+
+int apply_relocate_add(Elf64_Shdr *sechdrs,
+ const char *strtab,
+ unsigned int symindex,
+ unsigned int relsec,
+ struct module *me)
+{
+ unsigned int i;
+ Elf64_Rela *rela = (void *)sechdrs[relsec].sh_addr;
+ Elf64_Sym *sym;
+ unsigned long *location;
+ unsigned long 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_addr
+ + rela[i].r_offset;
+ /* This is the symbol it is referring to */
+ sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
+ + ELF64_R_SYM(rela[i].r_info);
+
+ DEBUGP("RELOC at %p: %li-type as %s (%lu) + %li\n",
+ location, (long)ELF64_R_TYPE(rela[i].r_info),
+ strtab + sym->st_name, (unsigned long)sym->st_value,
+ (long)rela[i].r_addend);
+
+ /* `Everything is relative'. */
+ value = sym->st_value + rela[i].r_addend;
+
+ switch (ELF64_R_TYPE(rela[i].r_info)) {
+ case R_PPC64_ADDR32:
+ /* Simply set it */
+ *(u32 *)location = value;
+ break;
+
+ case R_PPC64_ADDR64:
+ /* Simply set it */
+ *(unsigned long *)location = value;
+ break;
+
+ case R_PPC64_TOC:
+ *(unsigned long *)location = my_r2(sechdrs, me);
+ break;
+
+ case R_PPC64_TOC16:
+ /* Subtact TOC pointer */
+ value -= my_r2(sechdrs, me);
+ if (value + 0x8000 > 0xffff) {
+ printk("%s: bad TOC16 relocation (%lu)\n",
+ me->name, value);
+ return -ENOEXEC;
+ }
+ *((uint16_t *) location)
+ = (*((uint16_t *) location) & ~0xffff)
+ | (value & 0xffff);
+ break;
+
+ case R_PPC64_TOC16_DS:
+ /* Subtact TOC pointer */
+ value -= my_r2(sechdrs, me);
+ if ((value & 3) != 0 || value + 0x8000 > 0xffff) {
+ printk("%s: bad TOC16_DS relocation (%lu)\n",
+ me->name, value);
+ return -ENOEXEC;
+ }
+ *((uint16_t *) location)
+ = (*((uint16_t *) location) & ~0xfffc)
+ | (value & 0xfffc);
+ break;
+
+ case R_PPC_REL24:
+ /* FIXME: Handle weak symbols here --RR */
+ if (sym->st_shndx == SHN_UNDEF) {
+ /* External: go via stub */
+ value = stub_for_addr(sechdrs, value, me);
+ if (!value)
+ return -ENOENT;
+ if (!restore_r2((u32 *)location + 1, me))
+ return -ENOEXEC;
+ }
+
+ /* Convert value to relative */
+ value -= (unsigned long)location;
+ if (value + 0x2000000 > 0x3ffffff || (value & 3) != 0){
+ printk("%s: REL24 %li out of range!\n",
+ me->name, (long int)value);
+ return -ENOEXEC;
+ }
+
+ /* Only replace bits 2 through 26 */
+ *(uint32_t *)location
+ = (*(uint32_t *)location & ~0x03fffffc)
+ | (value & 0x03fffffc);
+ break;
+
+ default:
+ printk("%s: Unknown ADD relocation: %lu\n",
+ me->name,
+ (unsigned long)ELF64_R_TYPE(rela[i].r_info));
+ return -ENOEXEC;
+ }
+ }
+
+ return 0;
+}
+
+LIST_HEAD(module_bug_list);
+
+int module_finalize(const Elf_Ehdr *hdr,
+ const Elf_Shdr *sechdrs, struct module *me)
+{
+ char *secstrings;
+ unsigned int i;
+
+ me->arch.bug_table = NULL;
+ me->arch.num_bugs = 0;
+
+ /* Find the __bug_table section, if present */
+ secstrings = (char *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
+ for (i = 1; i < hdr->e_shnum; i++) {
+ if (strcmp(secstrings+sechdrs[i].sh_name, "__bug_table"))
+ continue;
+ me->arch.bug_table = (void *) sechdrs[i].sh_addr;
+ me->arch.num_bugs = sechdrs[i].sh_size / sizeof(struct bug_entry);
+ break;
+ }
+
+ /*
+ * Strictly speaking this should have a spinlock to protect against
+ * traversals, but since we only traverse on BUG()s, a spinlock
+ * could potentially lead to deadlock and thus be counter-productive.
+ */
+ list_add(&me->arch.bug_list, &module_bug_list);
+
+ return 0;
+}
+
+void module_arch_cleanup(struct module *mod)
+{
+ list_del(&mod->arch.bug_list);
+}
+
+struct bug_entry *module_find_bug(unsigned long bugaddr)
+{
+ struct mod_arch_specific *mod;
+ unsigned int i;
+ struct bug_entry *bug;
+
+ list_for_each_entry(mod, &module_bug_list, bug_list) {
+ bug = mod->bug_table;
+ for (i = 0; i < mod->num_bugs; ++i, ++bug)
+ if (bugaddr == bug->bug_addr)
+ return bug;
+ }
+ return NULL;
+}
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