diff options
| -rw-r--r-- | arch/riscv/Kconfig | 5 | ||||
| -rw-r--r-- | arch/riscv/Makefile | 5 | ||||
| -rw-r--r-- | arch/riscv/include/asm/module.h | 103 | ||||
| -rw-r--r-- | arch/riscv/kernel/Makefile | 1 | ||||
| -rw-r--r-- | arch/riscv/kernel/module-sections.c | 139 | ||||
| -rw-r--r-- | arch/riscv/kernel/module.lds | 7 |
6 files changed, 260 insertions, 0 deletions
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index 04807c7f64cc..90ff52059794 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -131,6 +131,10 @@ choice bool "medium any code model" endchoice +config MODULE_SECTIONS + bool + select HAVE_MOD_ARCH_SPECIFIC + choice prompt "Maximum Physical Memory" default MAXPHYSMEM_2GB if 32BIT @@ -141,6 +145,7 @@ choice bool "2GiB" config MAXPHYSMEM_128GB depends on 64BIT && CMODEL_MEDANY + select MODULE_SECTIONS if MODULES bool "128GiB" endchoice diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile index 6719dd30ec5b..c72d408c05c0 100644 --- a/arch/riscv/Makefile +++ b/arch/riscv/Makefile @@ -56,6 +56,11 @@ endif ifeq ($(CONFIG_CMODEL_MEDANY),y) KBUILD_CFLAGS += -mcmodel=medany endif +ifeq ($(CONFIG_MODULE_SECTIONS),y) + KBUILD_LDFLAGS_MODULE += -T $(srctree)/arch/riscv/kernel/module.lds +endif + +KBUILD_CFLAGS_MODULE += $(call cc-option,-mno-relax) # GCC versions that support the "-mstrict-align" option default to allowing # unaligned accesses. While unaligned accesses are explicitly allowed in the diff --git a/arch/riscv/include/asm/module.h b/arch/riscv/include/asm/module.h new file mode 100644 index 000000000000..e61d73f82d4d --- /dev/null +++ b/arch/riscv/include/asm/module.h @@ -0,0 +1,103 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* Copyright (C) 2017 Andes Technology Corporation */ + +#ifndef _ASM_RISCV_MODULE_H +#define _ASM_RISCV_MODULE_H + +#include <asm-generic/module.h> + +#define MODULE_ARCH_VERMAGIC "riscv" + +u64 module_emit_got_entry(struct module *mod, u64 val); +u64 module_emit_plt_entry(struct module *mod, u64 val); + +#ifdef CONFIG_MODULE_SECTIONS +struct mod_section { + struct elf64_shdr *shdr; + int num_entries; + int max_entries; +}; + +struct mod_arch_specific { + struct mod_section got; + struct mod_section plt; +}; + +struct got_entry { + u64 symbol_addr; /* the real variable address */ +}; + +static inline struct got_entry emit_got_entry(u64 val) +{ + return (struct got_entry) {val}; +} + +static inline struct got_entry *get_got_entry(u64 val, + const struct mod_section *sec) +{ + struct got_entry *got = (struct got_entry *)sec->shdr->sh_addr; + int i; + for (i = 0; i < sec->num_entries; i++) { + if (got[i].symbol_addr == val) + return &got[i]; + } + return NULL; +} + +struct plt_entry { + /* + * Trampoline code to real target address. The return address + * should be the original (pc+4) before entring plt entry. + * For 8 byte alignment of symbol_addr, + * don't pack structure to remove the padding. + */ + u32 insn_auipc; /* auipc t0, 0x0 */ + u32 insn_ld; /* ld t1, 0x10(t0) */ + u32 insn_jr; /* jr t1 */ + u64 symbol_addr; /* the real jump target address */ +}; + +#define OPC_AUIPC 0x0017 +#define OPC_LD 0x3003 +#define OPC_JALR 0x0067 +#define REG_T0 0x5 +#define REG_T1 0x6 +#define IMM_OFFSET 0x10 + +static inline struct plt_entry emit_plt_entry(u64 val) +{ + /* + * U-Type encoding: + * +------------+----------+----------+ + * | imm[31:12] | rd[11:7] | opc[6:0] | + * +------------+----------+----------+ + * + * I-Type encoding: + * +------------+------------+--------+----------+----------+ + * | imm[31:20] | rs1[19:15] | funct3 | rd[11:7] | opc[6:0] | + * +------------+------------+--------+----------+----------+ + * + */ + return (struct plt_entry) { + OPC_AUIPC | (REG_T0 << 7), + OPC_LD | (IMM_OFFSET << 20) | (REG_T0 << 15) | (REG_T1 << 7), + OPC_JALR | (REG_T1 << 15), + val + }; +} + +static inline struct plt_entry *get_plt_entry(u64 val, + const struct mod_section *sec) +{ + struct plt_entry *plt = (struct plt_entry *)sec->shdr->sh_addr; + int i; + for (i = 0; i < sec->num_entries; i++) { + if (plt[i].symbol_addr == val) + return &plt[i]; + } + return NULL; +} + +#endif /* CONFIG_MODULE_SECTIONS */ + +#endif /* _ASM_RISCV_MODULE_H */ diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile index 196f62ffc428..d355e3c18278 100644 --- a/arch/riscv/kernel/Makefile +++ b/arch/riscv/kernel/Makefile @@ -34,6 +34,7 @@ CFLAGS_setup.o := -mcmodel=medany obj-$(CONFIG_SMP) += smpboot.o obj-$(CONFIG_SMP) += smp.o obj-$(CONFIG_MODULES) += module.o +obj-$(CONFIG_MODULE_SECTIONS) += module-sections.o obj-$(CONFIG_FUNCTION_TRACER) += mcount.o obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += ftrace.o diff --git a/arch/riscv/kernel/module-sections.c b/arch/riscv/kernel/module-sections.c new file mode 100644 index 000000000000..94ba1551eac3 --- /dev/null +++ b/arch/riscv/kernel/module-sections.c @@ -0,0 +1,139 @@ +/* SPDX-License-Identifier: GPL-2.0 + * + * Copyright (C) 2014-2017 Linaro Ltd. <ard.biesheuvel@linaro.org> + * + * Copyright (C) 2018 Andes Technology Corporation <zong@andestech.com> + */ + +#include <linux/elf.h> +#include <linux/kernel.h> +#include <linux/module.h> + +u64 module_emit_got_entry(struct module *mod, u64 val) +{ + struct mod_section *got_sec = &mod->arch.got; + int i = got_sec->num_entries; + struct got_entry *got = get_got_entry(val, got_sec); + + if (got) + return (u64)got; + + /* There is no duplicate entry, create a new one */ + got = (struct got_entry *)got_sec->shdr->sh_addr; + got[i] = emit_got_entry(val); + + got_sec->num_entries++; + BUG_ON(got_sec->num_entries > got_sec->max_entries); + + return (u64)&got[i]; +} + +u64 module_emit_plt_entry(struct module *mod, u64 val) +{ + struct mod_section *plt_sec = &mod->arch.plt; + struct plt_entry *plt = get_plt_entry(val, plt_sec); + int i = plt_sec->num_entries; + + if (plt) + return (u64)plt; + + /* There is no duplicate entry, create a new one */ + plt = (struct plt_entry *)plt_sec->shdr->sh_addr; + plt[i] = emit_plt_entry(val); + + plt_sec->num_entries++; + BUG_ON(plt_sec->num_entries > plt_sec->max_entries); + + return (u64)&plt[i]; +} + +static int is_rela_equal(const Elf64_Rela *x, const Elf64_Rela *y) +{ + return x->r_info == y->r_info && x->r_addend == y->r_addend; +} + +static bool duplicate_rela(const Elf64_Rela *rela, int idx) +{ + int i; + for (i = 0; i < idx; i++) { + if (is_rela_equal(&rela[i], &rela[idx])) + return true; + } + return false; +} + +static void count_max_entries(Elf64_Rela *relas, int num, + unsigned int *plts, unsigned int *gots) +{ + unsigned int type, i; + + for (i = 0; i < num; i++) { + type = ELF64_R_TYPE(relas[i].r_info); + if (type == R_RISCV_CALL_PLT) { + if (!duplicate_rela(relas, i)) + (*plts)++; + } else if (type == R_RISCV_GOT_HI20) { + if (!duplicate_rela(relas, i)) + (*gots)++; + } + } +} + +int module_frob_arch_sections(Elf_Ehdr *ehdr, Elf_Shdr *sechdrs, + char *secstrings, struct module *mod) +{ + unsigned int num_plts = 0; + unsigned int num_gots = 0; + int i; + + /* + * Find the empty .got and .plt sections. + */ + for (i = 0; i < ehdr->e_shnum; i++) { + if (!strcmp(secstrings + sechdrs[i].sh_name, ".plt")) + mod->arch.plt.shdr = sechdrs + i; + else if (!strcmp(secstrings + sechdrs[i].sh_name, ".got")) + mod->arch.got.shdr = sechdrs + i; + } + + if (!mod->arch.plt.shdr) { + pr_err("%s: module PLT section(s) missing\n", mod->name); + return -ENOEXEC; + } + if (!mod->arch.got.shdr) { + pr_err("%s: module GOT section(s) missing\n", mod->name); + return -ENOEXEC; + } + + /* Calculate the maxinum number of entries */ + for (i = 0; i < ehdr->e_shnum; i++) { + Elf64_Rela *relas = (void *)ehdr + sechdrs[i].sh_offset; + int num_rela = sechdrs[i].sh_size / sizeof(Elf64_Rela); + Elf64_Shdr *dst_sec = sechdrs + sechdrs[i].sh_info; + + if (sechdrs[i].sh_type != SHT_RELA) + continue; + + /* ignore relocations that operate on non-exec sections */ + if (!(dst_sec->sh_flags & SHF_EXECINSTR)) + continue; + + count_max_entries(relas, num_rela, &num_plts, &num_gots); + } + + mod->arch.plt.shdr->sh_type = SHT_NOBITS; + mod->arch.plt.shdr->sh_flags = SHF_EXECINSTR | SHF_ALLOC; + mod->arch.plt.shdr->sh_addralign = L1_CACHE_BYTES; + mod->arch.plt.shdr->sh_size = (num_plts + 1) * sizeof(struct plt_entry); + mod->arch.plt.num_entries = 0; + mod->arch.plt.max_entries = num_plts; + + mod->arch.got.shdr->sh_type = SHT_NOBITS; + mod->arch.got.shdr->sh_flags = SHF_ALLOC; + mod->arch.got.shdr->sh_addralign = L1_CACHE_BYTES; + mod->arch.got.shdr->sh_size = (num_gots + 1) * sizeof(struct got_entry); + mod->arch.got.num_entries = 0; + mod->arch.got.max_entries = num_gots; + + return 0; +} diff --git a/arch/riscv/kernel/module.lds b/arch/riscv/kernel/module.lds new file mode 100644 index 000000000000..7ef580e62883 --- /dev/null +++ b/arch/riscv/kernel/module.lds @@ -0,0 +1,7 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* Copyright (C) 2017 Andes Technology Corporation */ + +SECTIONS { + .plt (NOLOAD) : { BYTE(0) } + .got (NOLOAD) : { BYTE(0) } +} |