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- // SPDX-License-Identifier: GPL-2.0-only
- /*
- * linux/arch/arm/kernel/module.c
- *
- * Copyright (C) 2002 Russell King.
- * Modified for nommu by Hyok S. Choi
- *
- * Module allocation method suggested by Andi Kleen.
- */
- #include <linux/module.h>
- #include <linux/moduleloader.h>
- #include <linux/kernel.h>
- #include <linux/mm.h>
- #include <linux/elf.h>
- #include <linux/vmalloc.h>
- #include <linux/fs.h>
- #include <linux/string.h>
- #include <linux/gfp.h>
- #include <asm/sections.h>
- #include <asm/smp_plat.h>
- #include <asm/unwind.h>
- #include <asm/opcodes.h>
- #ifdef CONFIG_XIP_KERNEL
- /*
- * The XIP kernel text is mapped in the module area for modules and
- * some other stuff to work without any indirect relocations.
- * MODULES_VADDR is redefined here and not in asm/memory.h to avoid
- * recompiling the whole kernel when CONFIG_XIP_KERNEL is turned on/off.
- */
- #undef MODULES_VADDR
- #define MODULES_VADDR (((unsigned long)_exiprom + ~PMD_MASK) & PMD_MASK)
- #endif
- #ifdef CONFIG_MMU
- void *module_alloc(unsigned long size)
- {
- gfp_t gfp_mask = GFP_KERNEL;
- void *p;
- /* Silence the initial allocation */
- if (IS_ENABLED(CONFIG_ARM_MODULE_PLTS))
- gfp_mask |= __GFP_NOWARN;
- p = __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END,
- gfp_mask, PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE,
- __builtin_return_address(0));
- if (!IS_ENABLED(CONFIG_ARM_MODULE_PLTS) || p)
- return p;
- return __vmalloc_node_range(size, 1, VMALLOC_START, VMALLOC_END,
- GFP_KERNEL, PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE,
- __builtin_return_address(0));
- }
- #endif
- bool module_init_section(const char *name)
- {
- return strstarts(name, ".init") ||
- strstarts(name, ".ARM.extab.init") ||
- strstarts(name, ".ARM.exidx.init");
- }
- bool module_exit_section(const char *name)
- {
- return strstarts(name, ".exit") ||
- strstarts(name, ".ARM.extab.exit") ||
- strstarts(name, ".ARM.exidx.exit");
- }
- #ifdef CONFIG_ARM_HAS_GROUP_RELOCS
- /*
- * This implements the partitioning algorithm for group relocations as
- * documented in the ARM AArch32 ELF psABI (IHI 0044).
- *
- * A single PC-relative symbol reference is divided in up to 3 add or subtract
- * operations, where the final one could be incorporated into a load/store
- * instruction with immediate offset. E.g.,
- *
- * ADD Rd, PC, #... or ADD Rd, PC, #...
- * ADD Rd, Rd, #... ADD Rd, Rd, #...
- * LDR Rd, [Rd, #...] ADD Rd, Rd, #...
- *
- * The latter has a guaranteed range of only 16 MiB (3x8 == 24 bits), so it is
- * of limited use in the kernel. However, the ADD/ADD/LDR combo has a range of
- * -/+ 256 MiB, (2x8 + 12 == 28 bits), which means it has sufficient range for
- * any in-kernel symbol reference (unless module PLTs are being used).
- *
- * The main advantage of this approach over the typical pattern using a literal
- * load is that literal loads may miss in the D-cache, and generally lead to
- * lower cache efficiency for variables that are referenced often from many
- * different places in the code.
- */
- static u32 get_group_rem(u32 group, u32 *offset)
- {
- u32 val = *offset;
- u32 shift;
- do {
- shift = val ? (31 - __fls(val)) & ~1 : 32;
- *offset = val;
- if (!val)
- break;
- val &= 0xffffff >> shift;
- } while (group--);
- return shift;
- }
- #endif
- int
- apply_relocate(Elf32_Shdr *sechdrs, const char *strtab, unsigned int symindex,
- unsigned int relindex, struct module *module)
- {
- Elf32_Shdr *symsec = sechdrs + symindex;
- Elf32_Shdr *relsec = sechdrs + relindex;
- Elf32_Shdr *dstsec = sechdrs + relsec->sh_info;
- Elf32_Rel *rel = (void *)relsec->sh_addr;
- unsigned int i;
- for (i = 0; i < relsec->sh_size / sizeof(Elf32_Rel); i++, rel++) {
- unsigned long loc;
- Elf32_Sym *sym;
- const char *symname;
- #ifdef CONFIG_ARM_HAS_GROUP_RELOCS
- u32 shift, group = 1;
- #endif
- s32 offset;
- u32 tmp;
- #ifdef CONFIG_THUMB2_KERNEL
- u32 upper, lower, sign, j1, j2;
- #endif
- offset = ELF32_R_SYM(rel->r_info);
- if (offset < 0 || offset > (symsec->sh_size / sizeof(Elf32_Sym))) {
- pr_err("%s: section %u reloc %u: bad relocation sym offset\n",
- module->name, relindex, i);
- return -ENOEXEC;
- }
- sym = ((Elf32_Sym *)symsec->sh_addr) + offset;
- symname = strtab + sym->st_name;
- if (rel->r_offset < 0 || rel->r_offset > dstsec->sh_size - sizeof(u32)) {
- pr_err("%s: section %u reloc %u sym '%s': out of bounds relocation, offset %d size %u\n",
- module->name, relindex, i, symname,
- rel->r_offset, dstsec->sh_size);
- return -ENOEXEC;
- }
- loc = dstsec->sh_addr + rel->r_offset;
- switch (ELF32_R_TYPE(rel->r_info)) {
- case R_ARM_NONE:
- /* ignore */
- break;
- case R_ARM_ABS32:
- case R_ARM_TARGET1:
- *(u32 *)loc += sym->st_value;
- break;
- case R_ARM_PC24:
- case R_ARM_CALL:
- case R_ARM_JUMP24:
- if (sym->st_value & 3) {
- pr_err("%s: section %u reloc %u sym '%s': unsupported interworking call (ARM -> Thumb)\n",
- module->name, relindex, i, symname);
- return -ENOEXEC;
- }
- offset = __mem_to_opcode_arm(*(u32 *)loc);
- offset = (offset & 0x00ffffff) << 2;
- if (offset & 0x02000000)
- offset -= 0x04000000;
- offset += sym->st_value - loc;
- /*
- * Route through a PLT entry if 'offset' exceeds the
- * supported range. Note that 'offset + loc + 8'
- * contains the absolute jump target, i.e.,
- * @sym + addend, corrected for the +8 PC bias.
- */
- if (IS_ENABLED(CONFIG_ARM_MODULE_PLTS) &&
- (offset <= (s32)0xfe000000 ||
- offset >= (s32)0x02000000))
- offset = get_module_plt(module, loc,
- offset + loc + 8)
- - loc - 8;
- if (offset <= (s32)0xfe000000 ||
- offset >= (s32)0x02000000) {
- pr_err("%s: section %u reloc %u sym '%s': relocation %u out of range (%#lx -> %#x)\n",
- module->name, relindex, i, symname,
- ELF32_R_TYPE(rel->r_info), loc,
- sym->st_value);
- return -ENOEXEC;
- }
- offset >>= 2;
- offset &= 0x00ffffff;
- *(u32 *)loc &= __opcode_to_mem_arm(0xff000000);
- *(u32 *)loc |= __opcode_to_mem_arm(offset);
- break;
- case R_ARM_V4BX:
- /* Preserve Rm and the condition code. Alter
- * other bits to re-code instruction as
- * MOV PC,Rm.
- */
- *(u32 *)loc &= __opcode_to_mem_arm(0xf000000f);
- *(u32 *)loc |= __opcode_to_mem_arm(0x01a0f000);
- break;
- case R_ARM_PREL31:
- offset = (*(s32 *)loc << 1) >> 1; /* sign extend */
- offset += sym->st_value - loc;
- if (offset >= 0x40000000 || offset < -0x40000000) {
- pr_err("%s: section %u reloc %u sym '%s': relocation %u out of range (%#lx -> %#x)\n",
- module->name, relindex, i, symname,
- ELF32_R_TYPE(rel->r_info), loc,
- sym->st_value);
- return -ENOEXEC;
- }
- *(u32 *)loc &= 0x80000000;
- *(u32 *)loc |= offset & 0x7fffffff;
- break;
- case R_ARM_REL32:
- *(u32 *)loc += sym->st_value - loc;
- break;
- case R_ARM_MOVW_ABS_NC:
- case R_ARM_MOVT_ABS:
- case R_ARM_MOVW_PREL_NC:
- case R_ARM_MOVT_PREL:
- offset = tmp = __mem_to_opcode_arm(*(u32 *)loc);
- offset = ((offset & 0xf0000) >> 4) | (offset & 0xfff);
- offset = (offset ^ 0x8000) - 0x8000;
- offset += sym->st_value;
- if (ELF32_R_TYPE(rel->r_info) == R_ARM_MOVT_PREL ||
- ELF32_R_TYPE(rel->r_info) == R_ARM_MOVW_PREL_NC)
- offset -= loc;
- if (ELF32_R_TYPE(rel->r_info) == R_ARM_MOVT_ABS ||
- ELF32_R_TYPE(rel->r_info) == R_ARM_MOVT_PREL)
- offset >>= 16;
- tmp &= 0xfff0f000;
- tmp |= ((offset & 0xf000) << 4) |
- (offset & 0x0fff);
- *(u32 *)loc = __opcode_to_mem_arm(tmp);
- break;
- #ifdef CONFIG_ARM_HAS_GROUP_RELOCS
- case R_ARM_ALU_PC_G0_NC:
- group = 0;
- fallthrough;
- case R_ARM_ALU_PC_G1_NC:
- tmp = __mem_to_opcode_arm(*(u32 *)loc);
- offset = ror32(tmp & 0xff, (tmp & 0xf00) >> 7);
- if (tmp & BIT(22))
- offset = -offset;
- offset += sym->st_value - loc;
- if (offset < 0) {
- offset = -offset;
- tmp = (tmp & ~BIT(23)) | BIT(22); // SUB opcode
- } else {
- tmp = (tmp & ~BIT(22)) | BIT(23); // ADD opcode
- }
- shift = get_group_rem(group, &offset);
- if (shift < 24) {
- offset >>= 24 - shift;
- offset |= (shift + 8) << 7;
- }
- *(u32 *)loc = __opcode_to_mem_arm((tmp & ~0xfff) | offset);
- break;
- case R_ARM_LDR_PC_G2:
- tmp = __mem_to_opcode_arm(*(u32 *)loc);
- offset = tmp & 0xfff;
- if (~tmp & BIT(23)) // U bit cleared?
- offset = -offset;
- offset += sym->st_value - loc;
- if (offset < 0) {
- offset = -offset;
- tmp &= ~BIT(23); // clear U bit
- } else {
- tmp |= BIT(23); // set U bit
- }
- get_group_rem(2, &offset);
- if (offset > 0xfff) {
- pr_err("%s: section %u reloc %u sym '%s': relocation %u out of range (%#lx -> %#x)\n",
- module->name, relindex, i, symname,
- ELF32_R_TYPE(rel->r_info), loc,
- sym->st_value);
- return -ENOEXEC;
- }
- *(u32 *)loc = __opcode_to_mem_arm((tmp & ~0xfff) | offset);
- break;
- #endif
- #ifdef CONFIG_THUMB2_KERNEL
- case R_ARM_THM_CALL:
- case R_ARM_THM_JUMP24:
- /*
- * For function symbols, only Thumb addresses are
- * allowed (no interworking).
- *
- * For non-function symbols, the destination
- * has no specific ARM/Thumb disposition, so
- * the branch is resolved under the assumption
- * that interworking is not required.
- */
- if (ELF32_ST_TYPE(sym->st_info) == STT_FUNC &&
- !(sym->st_value & 1)) {
- pr_err("%s: section %u reloc %u sym '%s': unsupported interworking call (Thumb -> ARM)\n",
- module->name, relindex, i, symname);
- return -ENOEXEC;
- }
- upper = __mem_to_opcode_thumb16(*(u16 *)loc);
- lower = __mem_to_opcode_thumb16(*(u16 *)(loc + 2));
- /*
- * 25 bit signed address range (Thumb-2 BL and B.W
- * instructions):
- * S:I1:I2:imm10:imm11:0
- * where:
- * S = upper[10] = offset[24]
- * I1 = ~(J1 ^ S) = offset[23]
- * I2 = ~(J2 ^ S) = offset[22]
- * imm10 = upper[9:0] = offset[21:12]
- * imm11 = lower[10:0] = offset[11:1]
- * J1 = lower[13]
- * J2 = lower[11]
- */
- sign = (upper >> 10) & 1;
- j1 = (lower >> 13) & 1;
- j2 = (lower >> 11) & 1;
- offset = (sign << 24) | ((~(j1 ^ sign) & 1) << 23) |
- ((~(j2 ^ sign) & 1) << 22) |
- ((upper & 0x03ff) << 12) |
- ((lower & 0x07ff) << 1);
- if (offset & 0x01000000)
- offset -= 0x02000000;
- offset += sym->st_value - loc;
- /*
- * Route through a PLT entry if 'offset' exceeds the
- * supported range.
- */
- if (IS_ENABLED(CONFIG_ARM_MODULE_PLTS) &&
- (offset <= (s32)0xff000000 ||
- offset >= (s32)0x01000000))
- offset = get_module_plt(module, loc,
- offset + loc + 4)
- - loc - 4;
- if (offset <= (s32)0xff000000 ||
- offset >= (s32)0x01000000) {
- pr_err("%s: section %u reloc %u sym '%s': relocation %u out of range (%#lx -> %#x)\n",
- module->name, relindex, i, symname,
- ELF32_R_TYPE(rel->r_info), loc,
- sym->st_value);
- return -ENOEXEC;
- }
- sign = (offset >> 24) & 1;
- j1 = sign ^ (~(offset >> 23) & 1);
- j2 = sign ^ (~(offset >> 22) & 1);
- upper = (u16)((upper & 0xf800) | (sign << 10) |
- ((offset >> 12) & 0x03ff));
- lower = (u16)((lower & 0xd000) |
- (j1 << 13) | (j2 << 11) |
- ((offset >> 1) & 0x07ff));
- *(u16 *)loc = __opcode_to_mem_thumb16(upper);
- *(u16 *)(loc + 2) = __opcode_to_mem_thumb16(lower);
- break;
- case R_ARM_THM_MOVW_ABS_NC:
- case R_ARM_THM_MOVT_ABS:
- case R_ARM_THM_MOVW_PREL_NC:
- case R_ARM_THM_MOVT_PREL:
- upper = __mem_to_opcode_thumb16(*(u16 *)loc);
- lower = __mem_to_opcode_thumb16(*(u16 *)(loc + 2));
- /*
- * MOVT/MOVW instructions encoding in Thumb-2:
- *
- * i = upper[10]
- * imm4 = upper[3:0]
- * imm3 = lower[14:12]
- * imm8 = lower[7:0]
- *
- * imm16 = imm4:i:imm3:imm8
- */
- offset = ((upper & 0x000f) << 12) |
- ((upper & 0x0400) << 1) |
- ((lower & 0x7000) >> 4) | (lower & 0x00ff);
- offset = (offset ^ 0x8000) - 0x8000;
- offset += sym->st_value;
- if (ELF32_R_TYPE(rel->r_info) == R_ARM_THM_MOVT_PREL ||
- ELF32_R_TYPE(rel->r_info) == R_ARM_THM_MOVW_PREL_NC)
- offset -= loc;
- if (ELF32_R_TYPE(rel->r_info) == R_ARM_THM_MOVT_ABS ||
- ELF32_R_TYPE(rel->r_info) == R_ARM_THM_MOVT_PREL)
- offset >>= 16;
- upper = (u16)((upper & 0xfbf0) |
- ((offset & 0xf000) >> 12) |
- ((offset & 0x0800) >> 1));
- lower = (u16)((lower & 0x8f00) |
- ((offset & 0x0700) << 4) |
- (offset & 0x00ff));
- *(u16 *)loc = __opcode_to_mem_thumb16(upper);
- *(u16 *)(loc + 2) = __opcode_to_mem_thumb16(lower);
- break;
- #endif
- default:
- pr_err("%s: unknown relocation: %u\n",
- module->name, ELF32_R_TYPE(rel->r_info));
- return -ENOEXEC;
- }
- }
- return 0;
- }
- struct mod_unwind_map {
- const Elf_Shdr *unw_sec;
- const Elf_Shdr *txt_sec;
- };
- static const Elf_Shdr *find_mod_section(const Elf32_Ehdr *hdr,
- const Elf_Shdr *sechdrs, const char *name)
- {
- const Elf_Shdr *s, *se;
- const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
- for (s = sechdrs, se = sechdrs + hdr->e_shnum; s < se; s++)
- if (strcmp(name, secstrs + s->sh_name) == 0)
- return s;
- return NULL;
- }
- extern void fixup_pv_table(const void *, unsigned long);
- extern void fixup_smp(const void *, unsigned long);
- int module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs,
- struct module *mod)
- {
- const Elf_Shdr *s = NULL;
- #ifdef CONFIG_ARM_UNWIND
- const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
- const Elf_Shdr *sechdrs_end = sechdrs + hdr->e_shnum;
- struct list_head *unwind_list = &mod->arch.unwind_list;
- INIT_LIST_HEAD(unwind_list);
- mod->arch.init_table = NULL;
- for (s = sechdrs; s < sechdrs_end; s++) {
- const char *secname = secstrs + s->sh_name;
- const char *txtname;
- const Elf_Shdr *txt_sec;
- if (!(s->sh_flags & SHF_ALLOC) ||
- s->sh_type != ELF_SECTION_UNWIND)
- continue;
- if (!strcmp(".ARM.exidx", secname))
- txtname = ".text";
- else
- txtname = secname + strlen(".ARM.exidx");
- txt_sec = find_mod_section(hdr, sechdrs, txtname);
- if (txt_sec) {
- struct unwind_table *table =
- unwind_table_add(s->sh_addr,
- s->sh_size,
- txt_sec->sh_addr,
- txt_sec->sh_size);
- list_add(&table->mod_list, unwind_list);
- /* save init table for module_arch_freeing_init */
- if (strcmp(".ARM.exidx.init.text", secname) == 0)
- mod->arch.init_table = table;
- }
- }
- #endif
- #ifdef CONFIG_ARM_PATCH_PHYS_VIRT
- s = find_mod_section(hdr, sechdrs, ".pv_table");
- if (s)
- fixup_pv_table((void *)s->sh_addr, s->sh_size);
- #endif
- s = find_mod_section(hdr, sechdrs, ".alt.smp.init");
- if (s && !is_smp())
- #ifdef CONFIG_SMP_ON_UP
- fixup_smp((void *)s->sh_addr, s->sh_size);
- #else
- return -EINVAL;
- #endif
- return 0;
- }
- void
- module_arch_cleanup(struct module *mod)
- {
- #ifdef CONFIG_ARM_UNWIND
- struct unwind_table *tmp;
- struct unwind_table *n;
- list_for_each_entry_safe(tmp, n,
- &mod->arch.unwind_list, mod_list) {
- list_del(&tmp->mod_list);
- unwind_table_del(tmp);
- }
- mod->arch.init_table = NULL;
- #endif
- }
- void __weak module_arch_freeing_init(struct module *mod)
- {
- #ifdef CONFIG_ARM_UNWIND
- struct unwind_table *init = mod->arch.init_table;
- if (init) {
- mod->arch.init_table = NULL;
- list_del(&init->mod_list);
- unwind_table_del(init);
- }
- #endif
- }
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