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-rw-r--r--arch/riscv/kernel/Makefile1
-rw-r--r--arch/riscv/kernel/module-sections.c156
-rw-r--r--arch/riscv/kernel/module.c179
-rw-r--r--arch/riscv/kernel/module.lds8
4 files changed, 338 insertions, 6 deletions
diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile
index d7bdf888f1ca..8586dd96c2f0 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-$(CONFIG_FUNCTION_TRACER) += mcount.o ftrace.o
obj-$(CONFIG_DYNAMIC_FTRACE) += mcount-dyn.o
diff --git a/arch/riscv/kernel/module-sections.c b/arch/riscv/kernel/module-sections.c
new file mode 100644
index 000000000000..bbbd26e19bfd
--- /dev/null
+++ b/arch/riscv/kernel/module-sections.c
@@ -0,0 +1,156 @@
+/* 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 *got_plt_sec = &mod->arch.got_plt;
+ struct got_entry *got_plt;
+ struct mod_section *plt_sec = &mod->arch.plt;
+ struct plt_entry *plt = get_plt_entry(val, plt_sec, got_plt_sec);
+ int i = plt_sec->num_entries;
+
+ if (plt)
+ return (u64)plt;
+
+ /* There is no duplicate entry, create a new one */
+ got_plt = (struct got_entry *)got_plt_sec->shdr->sh_addr;
+ got_plt[i] = emit_got_entry(val);
+ plt = (struct plt_entry *)plt_sec->shdr->sh_addr;
+ plt[i] = emit_plt_entry(val, (u64)&plt[i], (u64)&got_plt[i]);
+
+ plt_sec->num_entries++;
+ got_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;
+ else if (!strcmp(secstrings + sechdrs[i].sh_name, ".got.plt"))
+ mod->arch.got_plt.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;
+ }
+ if (!mod->arch.got_plt.shdr) {
+ pr_err("%s: module GOT.PLT 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;
+
+ mod->arch.got_plt.shdr->sh_type = SHT_NOBITS;
+ mod->arch.got_plt.shdr->sh_flags = SHF_ALLOC;
+ mod->arch.got_plt.shdr->sh_addralign = L1_CACHE_BYTES;
+ mod->arch.got_plt.shdr->sh_size = (num_plts + 1) * sizeof(struct got_entry);
+ mod->arch.got_plt.num_entries = 0;
+ mod->arch.got_plt.max_entries = num_plts;
+ return 0;
+}
diff --git a/arch/riscv/kernel/module.c b/arch/riscv/kernel/module.c
index e0f05034fc21..5dddba301d0a 100644
--- a/arch/riscv/kernel/module.c
+++ b/arch/riscv/kernel/module.c
@@ -49,6 +49,39 @@ static int apply_r_riscv_jal_rela(struct module *me, u32 *location,
return 0;
}
+static int apply_r_riscv_rcv_branch_rela(struct module *me, u32 *location,
+ Elf_Addr v)
+{
+ s64 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)
+{
+ s64 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)
{
@@ -92,6 +125,67 @@ static int apply_r_riscv_pcrel_lo12_s_rela(struct module *me, u32 *location,
return 0;
}
+static int apply_r_riscv_hi20_rela(struct module *me, u32 *location,
+ Elf_Addr v)
+{
+ s32 hi20;
+
+ if (IS_ENABLED(CMODEL_MEDLOW)) {
+ pr_err(
+ "%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n",
+ me->name, 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)
+{
+ s64 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, 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)
{
@@ -100,6 +194,33 @@ static int apply_r_riscv_call_plt_rela(struct module *me, u32 *location,
u32 hi20, lo12;
if (offset != fill_v) {
+ /* 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, 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)
+{
+ s64 offset = (void *)v - (void *)location;
+ s32 fill_v = offset;
+ u32 hi20, lo12;
+
+ if (offset != fill_v) {
pr_err(
"%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n",
me->name, v, location);
@@ -119,16 +240,49 @@ static int apply_r_riscv_relax_rela(struct module *me, u32 *location,
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_sub32_rela(struct module *me, u32 *location,
+ Elf_Addr v)
+{
+ *(u32 *)location -= (*(u32 *)v);
+ return 0;
+}
+
static int (*reloc_handlers_rela[]) (struct module *me, u32 *location,
Elf_Addr v) = {
[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_rcv_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_SUB32] = apply_r_riscv_sub32_rela,
};
int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
@@ -184,25 +338,38 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
u64 hi20_loc =
sechdrs[sechdrs[relsec].sh_info].sh_addr
+ rel[j].r_offset;
- /* Find the corresponding HI20 PC-relative relocation entry */
- if (hi20_loc == sym->st_value) {
+ 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);
u64 hi20_sym_val =
hi20_sym->st_value
+ rel[j].r_addend;
+
/* Calculate lo12 */
- s64 offset = hi20_sym_val - hi20_loc;
- s32 hi20 = (offset + 0x800) & 0xfffff000;
- s32 lo12 = offset - hi20;
+ u64 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 PC-relative relocation information\n",
+ "%s: Can not find HI20 relocation information\n",
me->name);
return -EINVAL;
}
diff --git a/arch/riscv/kernel/module.lds b/arch/riscv/kernel/module.lds
new file mode 100644
index 000000000000..295ecfb341a2
--- /dev/null
+++ b/arch/riscv/kernel/module.lds
@@ -0,0 +1,8 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (C) 2017 Andes Technology Corporation */
+
+SECTIONS {
+ .plt (NOLOAD) : { BYTE(0) }
+ .got (NOLOAD) : { BYTE(0) }
+ .got.plt (NOLOAD) : { BYTE(0) }
+}
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.