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-rw-r--r--arch/powerpc/kernel/module_32.c340
1 files changed, 340 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/module_32.c b/arch/powerpc/kernel/module_32.c
new file mode 100644
index 0000000000..816a63fd71
--- /dev/null
+++ b/arch/powerpc/kernel/module_32.c
@@ -0,0 +1,340 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Kernel module help for PPC.
+ Copyright (C) 2001 Rusty Russell.
+
+*/
+
+#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>
+#include <asm/code-patching.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;
+}
+
+/* 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") != NULL)
+ != is_init)
+ continue;
+
+ /* We don't want to look at debug sections. */
+ if (strstr(secstrings + sechdrs[i].sh_name, ".debug"))
+ 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
+ * algorithm 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, NULL);
+
+ 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] != PPC_RAW_LIS(_R12, PPC_HA(val)))
+ return 0;
+ if (entry->jump[1] != PPC_RAW_ADDI(_R12, _R12, PPC_LO(val)))
+ return 0;
+ return 1;
+}
+
+/* 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,
+ const 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 (within_module_core((unsigned long)location, mod))
+ 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++;
+ }
+
+ if (patch_instruction(&entry->jump[0], ppc_inst(PPC_RAW_LIS(_R12, PPC_HA(val)))))
+ return 0;
+ if (patch_instruction(&entry->jump[1], ppc_inst(PPC_RAW_ADDI(_R12, _R12, PPC_LO(val)))))
+ return 0;
+ if (patch_instruction(&entry->jump[2], ppc_inst(PPC_RAW_MTCTR(_R12))))
+ return 0;
+ if (patch_instruction(&entry->jump[3], ppc_inst(PPC_RAW_BCTR())))
+ return 0;
+
+ pr_debug("Initialized plt for 0x%x at %p\n", val, entry);
+ return (uint32_t)entry;
+}
+
+static int patch_location_16(uint32_t *loc, u16 value)
+{
+ loc = PTR_ALIGN_DOWN(loc, sizeof(u32));
+ return patch_instruction(loc, ppc_inst((*loc & 0xffff0000) | value));
+}
+
+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 */
+ if (patch_location_16(location, PPC_LO(value)))
+ return -EFAULT;
+ break;
+
+ case R_PPC_ADDR16_HI:
+ /* Higher half of the symbol */
+ if (patch_location_16(location, PPC_HI(value)))
+ return -EFAULT;
+ break;
+
+ case R_PPC_ADDR16_HA:
+ if (patch_location_16(location, PPC_HA(value)))
+ return -EFAULT;
+ 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);
+ if (!value)
+ return -EFAULT;
+ }
+
+ /* 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);
+ value = (*(uint32_t *)location & ~PPC_LI_MASK) |
+ PPC_LI(value - (uint32_t)location);
+
+ if (patch_instruction(location, ppc_inst(value)))
+ return -EFAULT;
+
+ pr_debug("Location after: %08X.\n",
+ *(uint32_t *)location);
+ pr_debug("ie. jump to %08X+%08X = %08X\n",
+ *(uint32_t *)PPC_LI((uint32_t)location), (uint32_t)location,
+ (*(uint32_t *)PPC_LI((uint32_t)location)) + (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;
+ }
+ }
+
+ return 0;
+}
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+notrace int module_trampoline_target(struct module *mod, unsigned long addr,
+ unsigned long *target)
+{
+ ppc_inst_t jmp[4];
+
+ /* Find where the trampoline jumps to */
+ if (copy_inst_from_kernel_nofault(jmp, (void *)addr))
+ return -EFAULT;
+ if (__copy_inst_from_kernel_nofault(jmp + 1, (void *)addr + 4))
+ return -EFAULT;
+ if (__copy_inst_from_kernel_nofault(jmp + 2, (void *)addr + 8))
+ return -EFAULT;
+ if (__copy_inst_from_kernel_nofault(jmp + 3, (void *)addr + 12))
+ return -EFAULT;
+
+ /* verify that this is what we expect it to be */
+ if ((ppc_inst_val(jmp[0]) & 0xffff0000) != PPC_RAW_LIS(_R12, 0))
+ return -EINVAL;
+ if ((ppc_inst_val(jmp[1]) & 0xffff0000) != PPC_RAW_ADDI(_R12, _R12, 0))
+ return -EINVAL;
+ if (ppc_inst_val(jmp[2]) != PPC_RAW_MTCTR(_R12))
+ return -EINVAL;
+ if (ppc_inst_val(jmp[3]) != PPC_RAW_BCTR())
+ return -EINVAL;
+
+ addr = (ppc_inst_val(jmp[1]) & 0xffff) | ((ppc_inst_val(jmp[0]) & 0xffff) << 16);
+ if (addr & 0x8000)
+ addr -= 0x10000;
+
+ *target = addr;
+
+ return 0;
+}
+
+int module_finalize_ftrace(struct module *module, const Elf_Shdr *sechdrs)
+{
+ module->arch.tramp = do_plt_call(module->mem[MOD_TEXT].base,
+ (unsigned long)ftrace_caller,
+ sechdrs, module);
+ if (!module->arch.tramp)
+ return -ENOENT;
+
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
+ module->arch.tramp_regs = do_plt_call(module->mem[MOD_TEXT].base,
+ (unsigned long)ftrace_regs_caller,
+ sechdrs, module);
+ if (!module->arch.tramp_regs)
+ return -ENOENT;
+#endif
+
+ return 0;
+}
+#endif