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-rw-r--r--arch/riscv/kernel/module.c459
1 files changed, 459 insertions, 0 deletions
diff --git a/arch/riscv/kernel/module.c b/arch/riscv/kernel/module.c
new file mode 100644
index 000000000..a331001e3
--- /dev/null
+++ b/arch/riscv/kernel/module.c
@@ -0,0 +1,459 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *
+ * Copyright (C) 2017 Zihao Yu
+ */
+
+#include <linux/elf.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/moduleloader.h>
+#include <linux/vmalloc.h>
+#include <linux/sizes.h>
+#include <linux/pgtable.h>
+#include <asm/alternative.h>
+#include <asm/sections.h>
+
+/*
+ * The auipc+jalr instruction pair can reach any PC-relative offset
+ * in the range [-2^31 - 2^11, 2^31 - 2^11)
+ */
+static bool riscv_insn_valid_32bit_offset(ptrdiff_t val)
+{
+#ifdef CONFIG_32BIT
+ return true;
+#else
+ return (-(1L << 31) - (1L << 11)) <= val && val < ((1L << 31) - (1L << 11));
+#endif
+}
+
+static int apply_r_riscv_32_rela(struct module *me, u32 *location, Elf_Addr v)
+{
+ if (v != (u32)v) {
+ pr_err("%s: value %016llx out of range for 32-bit field\n",
+ me->name, (long long)v);
+ return -EINVAL;
+ }
+ *location = v;
+ return 0;
+}
+
+static int apply_r_riscv_64_rela(struct module *me, u32 *location, Elf_Addr v)
+{
+ *(u64 *)location = v;
+ return 0;
+}
+
+static int apply_r_riscv_branch_rela(struct module *me, u32 *location,
+ Elf_Addr v)
+{
+ ptrdiff_t offset = (void *)v - (void *)location;
+ u32 imm12 = (offset & 0x1000) << (31 - 12);
+ u32 imm11 = (offset & 0x800) >> (11 - 7);
+ u32 imm10_5 = (offset & 0x7e0) << (30 - 10);
+ u32 imm4_1 = (offset & 0x1e) << (11 - 4);
+
+ *location = (*location & 0x1fff07f) | imm12 | imm11 | imm10_5 | imm4_1;
+ return 0;
+}
+
+static int apply_r_riscv_jal_rela(struct module *me, u32 *location,
+ Elf_Addr v)
+{
+ ptrdiff_t offset = (void *)v - (void *)location;
+ u32 imm20 = (offset & 0x100000) << (31 - 20);
+ u32 imm19_12 = (offset & 0xff000);
+ u32 imm11 = (offset & 0x800) << (20 - 11);
+ u32 imm10_1 = (offset & 0x7fe) << (30 - 10);
+
+ *location = (*location & 0xfff) | imm20 | imm19_12 | imm11 | imm10_1;
+ return 0;
+}
+
+static int apply_r_riscv_rvc_branch_rela(struct module *me, u32 *location,
+ Elf_Addr v)
+{
+ ptrdiff_t offset = (void *)v - (void *)location;
+ u16 imm8 = (offset & 0x100) << (12 - 8);
+ u16 imm7_6 = (offset & 0xc0) >> (6 - 5);
+ u16 imm5 = (offset & 0x20) >> (5 - 2);
+ u16 imm4_3 = (offset & 0x18) << (12 - 5);
+ u16 imm2_1 = (offset & 0x6) << (12 - 10);
+
+ *(u16 *)location = (*(u16 *)location & 0xe383) |
+ imm8 | imm7_6 | imm5 | imm4_3 | imm2_1;
+ return 0;
+}
+
+static int apply_r_riscv_rvc_jump_rela(struct module *me, u32 *location,
+ Elf_Addr v)
+{
+ ptrdiff_t offset = (void *)v - (void *)location;
+ u16 imm11 = (offset & 0x800) << (12 - 11);
+ u16 imm10 = (offset & 0x400) >> (10 - 8);
+ u16 imm9_8 = (offset & 0x300) << (12 - 11);
+ u16 imm7 = (offset & 0x80) >> (7 - 6);
+ u16 imm6 = (offset & 0x40) << (12 - 11);
+ u16 imm5 = (offset & 0x20) >> (5 - 2);
+ u16 imm4 = (offset & 0x10) << (12 - 5);
+ u16 imm3_1 = (offset & 0xe) << (12 - 10);
+
+ *(u16 *)location = (*(u16 *)location & 0xe003) |
+ imm11 | imm10 | imm9_8 | imm7 | imm6 | imm5 | imm4 | imm3_1;
+ return 0;
+}
+
+static int apply_r_riscv_pcrel_hi20_rela(struct module *me, u32 *location,
+ Elf_Addr v)
+{
+ ptrdiff_t offset = (void *)v - (void *)location;
+ s32 hi20;
+
+ if (!riscv_insn_valid_32bit_offset(offset)) {
+ pr_err(
+ "%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n",
+ me->name, (long long)v, location);
+ return -EINVAL;
+ }
+
+ hi20 = (offset + 0x800) & 0xfffff000;
+ *location = (*location & 0xfff) | hi20;
+ return 0;
+}
+
+static int apply_r_riscv_pcrel_lo12_i_rela(struct module *me, u32 *location,
+ Elf_Addr v)
+{
+ /*
+ * v is the lo12 value to fill. It is calculated before calling this
+ * handler.
+ */
+ *location = (*location & 0xfffff) | ((v & 0xfff) << 20);
+ return 0;
+}
+
+static int apply_r_riscv_pcrel_lo12_s_rela(struct module *me, u32 *location,
+ Elf_Addr v)
+{
+ /*
+ * v is the lo12 value to fill. It is calculated before calling this
+ * handler.
+ */
+ u32 imm11_5 = (v & 0xfe0) << (31 - 11);
+ u32 imm4_0 = (v & 0x1f) << (11 - 4);
+
+ *location = (*location & 0x1fff07f) | imm11_5 | imm4_0;
+ return 0;
+}
+
+static int apply_r_riscv_hi20_rela(struct module *me, u32 *location,
+ Elf_Addr v)
+{
+ s32 hi20;
+
+ if (IS_ENABLED(CONFIG_CMODEL_MEDLOW)) {
+ pr_err(
+ "%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n",
+ me->name, (long long)v, location);
+ return -EINVAL;
+ }
+
+ hi20 = ((s32)v + 0x800) & 0xfffff000;
+ *location = (*location & 0xfff) | hi20;
+ return 0;
+}
+
+static int apply_r_riscv_lo12_i_rela(struct module *me, u32 *location,
+ Elf_Addr v)
+{
+ /* Skip medlow checking because of filtering by HI20 already */
+ s32 hi20 = ((s32)v + 0x800) & 0xfffff000;
+ s32 lo12 = ((s32)v - hi20);
+ *location = (*location & 0xfffff) | ((lo12 & 0xfff) << 20);
+ return 0;
+}
+
+static int apply_r_riscv_lo12_s_rela(struct module *me, u32 *location,
+ Elf_Addr v)
+{
+ /* Skip medlow checking because of filtering by HI20 already */
+ s32 hi20 = ((s32)v + 0x800) & 0xfffff000;
+ s32 lo12 = ((s32)v - hi20);
+ u32 imm11_5 = (lo12 & 0xfe0) << (31 - 11);
+ u32 imm4_0 = (lo12 & 0x1f) << (11 - 4);
+ *location = (*location & 0x1fff07f) | imm11_5 | imm4_0;
+ return 0;
+}
+
+static int apply_r_riscv_got_hi20_rela(struct module *me, u32 *location,
+ Elf_Addr v)
+{
+ ptrdiff_t offset = (void *)v - (void *)location;
+ s32 hi20;
+
+ /* Always emit the got entry */
+ if (IS_ENABLED(CONFIG_MODULE_SECTIONS)) {
+ offset = module_emit_got_entry(me, v);
+ offset = (void *)offset - (void *)location;
+ } else {
+ pr_err(
+ "%s: can not generate the GOT entry for symbol = %016llx from PC = %p\n",
+ me->name, (long long)v, location);
+ return -EINVAL;
+ }
+
+ hi20 = (offset + 0x800) & 0xfffff000;
+ *location = (*location & 0xfff) | hi20;
+ return 0;
+}
+
+static int apply_r_riscv_call_plt_rela(struct module *me, u32 *location,
+ Elf_Addr v)
+{
+ ptrdiff_t offset = (void *)v - (void *)location;
+ u32 hi20, lo12;
+
+ if (!riscv_insn_valid_32bit_offset(offset)) {
+ /* Only emit the plt entry if offset over 32-bit range */
+ if (IS_ENABLED(CONFIG_MODULE_SECTIONS)) {
+ offset = module_emit_plt_entry(me, v);
+ offset = (void *)offset - (void *)location;
+ } else {
+ pr_err(
+ "%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n",
+ me->name, (long long)v, location);
+ return -EINVAL;
+ }
+ }
+
+ hi20 = (offset + 0x800) & 0xfffff000;
+ lo12 = (offset - hi20) & 0xfff;
+ *location = (*location & 0xfff) | hi20;
+ *(location + 1) = (*(location + 1) & 0xfffff) | (lo12 << 20);
+ return 0;
+}
+
+static int apply_r_riscv_call_rela(struct module *me, u32 *location,
+ Elf_Addr v)
+{
+ ptrdiff_t offset = (void *)v - (void *)location;
+ u32 hi20, lo12;
+
+ if (!riscv_insn_valid_32bit_offset(offset)) {
+ pr_err(
+ "%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n",
+ me->name, (long long)v, location);
+ return -EINVAL;
+ }
+
+ hi20 = (offset + 0x800) & 0xfffff000;
+ lo12 = (offset - hi20) & 0xfff;
+ *location = (*location & 0xfff) | hi20;
+ *(location + 1) = (*(location + 1) & 0xfffff) | (lo12 << 20);
+ return 0;
+}
+
+static int apply_r_riscv_relax_rela(struct module *me, u32 *location,
+ Elf_Addr v)
+{
+ return 0;
+}
+
+static int apply_r_riscv_align_rela(struct module *me, u32 *location,
+ Elf_Addr v)
+{
+ pr_err(
+ "%s: The unexpected relocation type 'R_RISCV_ALIGN' from PC = %p\n",
+ me->name, location);
+ return -EINVAL;
+}
+
+static int apply_r_riscv_add32_rela(struct module *me, u32 *location,
+ Elf_Addr v)
+{
+ *(u32 *)location += (u32)v;
+ return 0;
+}
+
+static int apply_r_riscv_add64_rela(struct module *me, u32 *location,
+ Elf_Addr v)
+{
+ *(u64 *)location += (u64)v;
+ return 0;
+}
+
+static int apply_r_riscv_sub32_rela(struct module *me, u32 *location,
+ Elf_Addr v)
+{
+ *(u32 *)location -= (u32)v;
+ return 0;
+}
+
+static int apply_r_riscv_sub64_rela(struct module *me, u32 *location,
+ Elf_Addr v)
+{
+ *(u64 *)location -= (u64)v;
+ return 0;
+}
+
+static int (*reloc_handlers_rela[]) (struct module *me, u32 *location,
+ Elf_Addr v) = {
+ [R_RISCV_32] = apply_r_riscv_32_rela,
+ [R_RISCV_64] = apply_r_riscv_64_rela,
+ [R_RISCV_BRANCH] = apply_r_riscv_branch_rela,
+ [R_RISCV_JAL] = apply_r_riscv_jal_rela,
+ [R_RISCV_RVC_BRANCH] = apply_r_riscv_rvc_branch_rela,
+ [R_RISCV_RVC_JUMP] = apply_r_riscv_rvc_jump_rela,
+ [R_RISCV_PCREL_HI20] = apply_r_riscv_pcrel_hi20_rela,
+ [R_RISCV_PCREL_LO12_I] = apply_r_riscv_pcrel_lo12_i_rela,
+ [R_RISCV_PCREL_LO12_S] = apply_r_riscv_pcrel_lo12_s_rela,
+ [R_RISCV_HI20] = apply_r_riscv_hi20_rela,
+ [R_RISCV_LO12_I] = apply_r_riscv_lo12_i_rela,
+ [R_RISCV_LO12_S] = apply_r_riscv_lo12_s_rela,
+ [R_RISCV_GOT_HI20] = apply_r_riscv_got_hi20_rela,
+ [R_RISCV_CALL_PLT] = apply_r_riscv_call_plt_rela,
+ [R_RISCV_CALL] = apply_r_riscv_call_rela,
+ [R_RISCV_RELAX] = apply_r_riscv_relax_rela,
+ [R_RISCV_ALIGN] = apply_r_riscv_align_rela,
+ [R_RISCV_ADD32] = apply_r_riscv_add32_rela,
+ [R_RISCV_ADD64] = apply_r_riscv_add64_rela,
+ [R_RISCV_SUB32] = apply_r_riscv_sub32_rela,
+ [R_RISCV_SUB64] = apply_r_riscv_sub64_rela,
+};
+
+int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
+ unsigned int symindex, unsigned int relsec,
+ struct module *me)
+{
+ Elf_Rela *rel = (void *) sechdrs[relsec].sh_addr;
+ int (*handler)(struct module *me, u32 *location, Elf_Addr v);
+ Elf_Sym *sym;
+ u32 *location;
+ unsigned int i, type;
+ Elf_Addr v;
+ int res;
+
+ pr_debug("Applying relocate section %u to %u\n", relsec,
+ sechdrs[relsec].sh_info);
+
+ for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
+ /* This is where to make the change */
+ location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
+ + rel[i].r_offset;
+ /* This is the symbol it is referring to */
+ sym = (Elf_Sym *)sechdrs[symindex].sh_addr
+ + ELF_RISCV_R_SYM(rel[i].r_info);
+ if (IS_ERR_VALUE(sym->st_value)) {
+ /* Ignore unresolved weak symbol */
+ if (ELF_ST_BIND(sym->st_info) == STB_WEAK)
+ continue;
+ pr_warn("%s: Unknown symbol %s\n",
+ me->name, strtab + sym->st_name);
+ return -ENOENT;
+ }
+
+ type = ELF_RISCV_R_TYPE(rel[i].r_info);
+
+ if (type < ARRAY_SIZE(reloc_handlers_rela))
+ handler = reloc_handlers_rela[type];
+ else
+ handler = NULL;
+
+ if (!handler) {
+ pr_err("%s: Unknown relocation type %u\n",
+ me->name, type);
+ return -EINVAL;
+ }
+
+ v = sym->st_value + rel[i].r_addend;
+
+ if (type == R_RISCV_PCREL_LO12_I || type == R_RISCV_PCREL_LO12_S) {
+ unsigned int j;
+
+ for (j = 0; j < sechdrs[relsec].sh_size / sizeof(*rel); j++) {
+ unsigned long hi20_loc =
+ sechdrs[sechdrs[relsec].sh_info].sh_addr
+ + rel[j].r_offset;
+ u32 hi20_type = ELF_RISCV_R_TYPE(rel[j].r_info);
+
+ /* Find the corresponding HI20 relocation entry */
+ if (hi20_loc == sym->st_value
+ && (hi20_type == R_RISCV_PCREL_HI20
+ || hi20_type == R_RISCV_GOT_HI20)) {
+ s32 hi20, lo12;
+ Elf_Sym *hi20_sym =
+ (Elf_Sym *)sechdrs[symindex].sh_addr
+ + ELF_RISCV_R_SYM(rel[j].r_info);
+ unsigned long hi20_sym_val =
+ hi20_sym->st_value
+ + rel[j].r_addend;
+
+ /* Calculate lo12 */
+ size_t offset = hi20_sym_val - hi20_loc;
+ if (IS_ENABLED(CONFIG_MODULE_SECTIONS)
+ && hi20_type == R_RISCV_GOT_HI20) {
+ offset = module_emit_got_entry(
+ me, hi20_sym_val);
+ offset = offset - hi20_loc;
+ }
+ hi20 = (offset + 0x800) & 0xfffff000;
+ lo12 = offset - hi20;
+ v = lo12;
+
+ break;
+ }
+ }
+ if (j == sechdrs[relsec].sh_size / sizeof(*rel)) {
+ pr_err(
+ "%s: Can not find HI20 relocation information\n",
+ me->name);
+ return -EINVAL;
+ }
+ }
+
+ res = handler(me, location, v);
+ if (res)
+ return res;
+ }
+
+ return 0;
+}
+
+#if defined(CONFIG_MMU) && defined(CONFIG_64BIT)
+void *module_alloc(unsigned long size)
+{
+ return __vmalloc_node_range(size, 1, MODULES_VADDR,
+ MODULES_END, GFP_KERNEL,
+ PAGE_KERNEL, VM_FLUSH_RESET_PERMS,
+ NUMA_NO_NODE,
+ __builtin_return_address(0));
+}
+#endif
+
+static const Elf_Shdr *find_section(const Elf_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;
+}
+
+int module_finalize(const Elf_Ehdr *hdr,
+ const Elf_Shdr *sechdrs,
+ struct module *me)
+{
+ const Elf_Shdr *s;
+
+ s = find_section(hdr, sechdrs, ".alternative");
+ if (s)
+ apply_module_alternatives((void *)s->sh_addr, s->sh_size);
+
+ return 0;
+}
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