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Diffstat (limited to 'arch/powerpc/kernel/module_32.c')
-rw-r--r--arch/powerpc/kernel/module_32.c304
1 files changed, 304 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/module_32.c b/arch/powerpc/kernel/module_32.c
new file mode 100644
index 000000000..c94d2e018
--- /dev/null
+++ b/arch/powerpc/kernel/module_32.c
@@ -0,0 +1,304 @@
+/* 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
+*/
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/moduleloader.h>
+#include <linux/elf.h>
+#include <linux/vmalloc.h>
+#include <linux/fs.h>
+#include <linux/string.h>
+#include <linux/kernel.h>
+#include <linux/ftrace.h>
+#include <linux/cache.h>
+#include <linux/bug.h>
+#include <linux/sort.h>
+#include <asm/setup.h>
+
+/* Count how many different relocations (different symbol, different
+ addend) */
+static unsigned int count_relocs(const Elf32_Rela *rela, unsigned int num)
+{
+ unsigned int i, r_info, r_addend, _count_relocs;
+
+ _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 (ELF32_R_TYPE(rela[i].r_info) == R_PPC_REL24 &&
+ (r_info != ELF32_R_SYM(rela[i].r_info) ||
+ r_addend != rela[i].r_addend)) {
+ _count_relocs++;
+ r_info = ELF32_R_SYM(rela[i].r_info);
+ r_addend = rela[i].r_addend;
+ }
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+ _count_relocs++; /* add one for ftrace_caller */
+#endif
+ return _count_relocs;
+}
+
+static int relacmp(const void *_x, const void *_y)
+{
+ const Elf32_Rela *x, *y;
+
+ y = (Elf32_Rela *)_x;
+ x = (Elf32_Rela *)_y;
+
+ /* Compare the entire r_info (as opposed to ELF32_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)
+{
+ uint32_t *x, *y, tmp;
+ int i;
+
+ y = (uint32_t *)_x;
+ x = (uint32_t *)_y;
+
+ for (i = 0; i < sizeof(Elf32_Rela) / sizeof(uint32_t); i++) {
+ tmp = x[i];
+ x[i] = y[i];
+ y[i] = tmp;
+ }
+}
+
+/* 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;
+
+ /* We don't want to look at debug sections. */
+ if (strstr(secstrings + sechdrs[i].sh_name, ".debug") != 0)
+ continue;
+
+ if (sechdrs[i].sh_type == SHT_RELA) {
+ pr_debug("Found relocations in section %u\n", i);
+ pr_debug("Ptr: %p. Number: %u\n",
+ (void *)hdr + sechdrs[i].sh_offset,
+ sechdrs[i].sh_size / sizeof(Elf32_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 *)hdr + sechdrs[i].sh_offset,
+ sechdrs[i].sh_size / sizeof(Elf32_Rela),
+ sizeof(Elf32_Rela), relacmp, relaswap);
+
+ ret += count_relocs((void *)hdr
+ + sechdrs[i].sh_offset,
+ sechdrs[i].sh_size
+ / sizeof(Elf32_Rela))
+ * sizeof(struct ppc_plt_entry);
+ }
+ }
+
+ return ret;
+}
+
+int module_frob_arch_sections(Elf32_Ehdr *hdr,
+ Elf32_Shdr *sechdrs,
+ char *secstrings,
+ struct module *me)
+{
+ unsigned int i;
+
+ /* Find .plt and .init.plt sections */
+ for (i = 0; i < hdr->e_shnum; i++) {
+ if (strcmp(secstrings + sechdrs[i].sh_name, ".init.plt") == 0)
+ me->arch.init_plt_section = i;
+ else if (strcmp(secstrings + sechdrs[i].sh_name, ".plt") == 0)
+ me->arch.core_plt_section = i;
+ }
+ if (!me->arch.core_plt_section || !me->arch.init_plt_section) {
+ pr_err("Module doesn't contain .plt or .init.plt sections.\n");
+ return -ENOEXEC;
+ }
+
+ /* Override their sizes */
+ sechdrs[me->arch.core_plt_section].sh_size
+ = get_plt_size(hdr, sechdrs, secstrings, 0);
+ sechdrs[me->arch.init_plt_section].sh_size
+ = get_plt_size(hdr, sechdrs, secstrings, 1);
+ return 0;
+}
+
+static inline int entry_matches(struct ppc_plt_entry *entry, Elf32_Addr val)
+{
+ if (entry->jump[0] == 0x3d800000 + ((val + 0x8000) >> 16)
+ && entry->jump[1] == 0x398c0000 + (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,
+ Elf32_Shdr *sechdrs,
+ struct module *mod)
+{
+ struct ppc_plt_entry *entry;
+
+ pr_debug("Doing plt for call to 0x%x at 0x%x\n", val, (unsigned int)location);
+ /* Init, or core PLT? */
+ if (location >= mod->module_core
+ && location < mod->module_core + mod->core_size)
+ entry = (void *)sechdrs[mod->arch.core_plt_section].sh_addr;
+ else
+ entry = (void *)sechdrs[mod->arch.init_plt_section].sh_addr;
+
+ /* 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++;
+ }
+
+ entry->jump[0] = 0x3d800000+((val+0x8000)>>16); /* lis r12,sym@ha */
+ entry->jump[1] = 0x398c0000 + (val&0xffff); /* addi r12,r12,sym@l*/
+ entry->jump[2] = 0x7d8903a6; /* mtctr r12 */
+ entry->jump[3] = 0x4e800420; /* bctr */
+
+ pr_debug("Initialized plt for 0x%x at %p\n", val, entry);
+ 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_addr;
+ Elf32_Sym *sym;
+ uint32_t *location;
+ uint32_t value;
+
+ pr_debug("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. Note that all
+ undefined symbols have been resolved. */
+ sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
+ + ELF32_R_SYM(rela[i].r_info);
+ /* `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_HI:
+ /* Higher half of the symbol */
+ *(uint16_t *)location = (value >> 16);
+ 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,
+ sechdrs, module);
+
+ /* Only replace bits 2 through 26 */
+ pr_debug("REL24 value = %08X. location = %08X\n",
+ value, (uint32_t)location);
+ pr_debug("Location before: %08X.\n",
+ *(uint32_t *)location);
+ *(uint32_t *)location
+ = (*(uint32_t *)location & ~0x03fffffc)
+ | ((value - (uint32_t)location)
+ & 0x03fffffc);
+ pr_debug("Location after: %08X.\n",
+ *(uint32_t *)location);
+ pr_debug("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:
+ pr_err("%s: unknown ADD relocation: %u\n",
+ module->name,
+ ELF32_R_TYPE(rela[i].r_info));
+ return -ENOEXEC;
+ }
+ }
+#ifdef CONFIG_DYNAMIC_FTRACE
+ module->arch.tramp =
+ do_plt_call(module->module_core,
+ (unsigned long)ftrace_caller,
+ sechdrs, module);
+#endif
+ return 0;
+}
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