[RFC] MIPS: initial modules support
Antony Pavlov
antonynpavlov at gmail.com
Thu May 10 05:33:42 EDT 2012
This code does not work correctly.
insmod got unaligned access exception during apply_r_mips_32_rel
Signed-off-by: Antony Pavlov <antonynpavlov at gmail.com>
---
arch/mips/Kconfig | 1 +
arch/mips/include/asm/elf.h | 153 +++++++++++++++++++
arch/mips/include/asm/module.h | 17 ++-
arch/mips/lib/Makefile | 1 +
arch/mips/lib/module.c | 328 ++++++++++++++++++++++++++++++++++++++++
5 files changed, 499 insertions(+), 1 deletion(-)
create mode 100644 arch/mips/lib/module.c
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 50d5c67..55c5d3b 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -6,6 +6,7 @@ config MIPS
select HAS_KALLSYMS
select HAVE_CONFIGURABLE_MEMORY_LAYOUT
select HAVE_CONFIGURABLE_TEXT_BASE
+ select HAS_MODULES
default y
config SYS_SUPPORTS_BIG_ENDIAN
diff --git a/arch/mips/include/asm/elf.h b/arch/mips/include/asm/elf.h
index b8b8219..9375508 100644
--- a/arch/mips/include/asm/elf.h
+++ b/arch/mips/include/asm/elf.h
@@ -15,6 +15,159 @@
#ifndef _ASM_MIPS_ELF_H
#define _ASM_MIPS_ELF_H
+/* ELF header e_flags defines. */
+/* MIPS architecture level. */
+#define EF_MIPS_ARCH_1 0x00000000 /* -mips1 code. */
+#define EF_MIPS_ARCH_2 0x10000000 /* -mips2 code. */
+#define EF_MIPS_ARCH_3 0x20000000 /* -mips3 code. */
+#define EF_MIPS_ARCH_4 0x30000000 /* -mips4 code. */
+#define EF_MIPS_ARCH_5 0x40000000 /* -mips5 code. */
+#define EF_MIPS_ARCH_32 0x50000000 /* MIPS32 code. */
+#define EF_MIPS_ARCH_64 0x60000000 /* MIPS64 code. */
+#define EF_MIPS_ARCH_32R2 0x70000000 /* MIPS32 R2 code. */
+#define EF_MIPS_ARCH_64R2 0x80000000 /* MIPS64 R2 code. */
+
+/* The ABI of a file. */
+#define EF_MIPS_ABI_O32 0x00001000 /* O32 ABI. */
+#define EF_MIPS_ABI_O64 0x00002000 /* O32 extended for 64 bit. */
+
+#define PT_MIPS_REGINFO 0x70000000
+#define PT_MIPS_RTPROC 0x70000001
+#define PT_MIPS_OPTIONS 0x70000002
+
+/* Flags in the e_flags field of the header */
+#define EF_MIPS_NOREORDER 0x00000001
+#define EF_MIPS_PIC 0x00000002
+#define EF_MIPS_CPIC 0x00000004
+#define EF_MIPS_ABI2 0x00000020
+#define EF_MIPS_OPTIONS_FIRST 0x00000080
+#define EF_MIPS_32BITMODE 0x00000100
+#define EF_MIPS_ABI 0x0000f000
+#define EF_MIPS_ARCH 0xf0000000
+
+#define DT_MIPS_RLD_VERSION 0x70000001
+#define DT_MIPS_TIME_STAMP 0x70000002
+#define DT_MIPS_ICHECKSUM 0x70000003
+#define DT_MIPS_IVERSION 0x70000004
+#define DT_MIPS_FLAGS 0x70000005
+ #define RHF_NONE 0x00000000
+ #define RHF_HARDWAY 0x00000001
+ #define RHF_NOTPOT 0x00000002
+ #define RHF_SGI_ONLY 0x00000010
+#define DT_MIPS_BASE_ADDRESS 0x70000006
+#define DT_MIPS_CONFLICT 0x70000008
+#define DT_MIPS_LIBLIST 0x70000009
+#define DT_MIPS_LOCAL_GOTNO 0x7000000a
+#define DT_MIPS_CONFLICTNO 0x7000000b
+#define DT_MIPS_LIBLISTNO 0x70000010
+#define DT_MIPS_SYMTABNO 0x70000011
+#define DT_MIPS_UNREFEXTNO 0x70000012
+#define DT_MIPS_GOTSYM 0x70000013
+#define DT_MIPS_HIPAGENO 0x70000014
+#define DT_MIPS_RLD_MAP 0x70000016
+
+#define R_MIPS_NONE 0
+#define R_MIPS_16 1
+#define R_MIPS_32 2
+#define R_MIPS_REL32 3
+#define R_MIPS_26 4
+#define R_MIPS_HI16 5
+#define R_MIPS_LO16 6
+#define R_MIPS_GPREL16 7
+#define R_MIPS_LITERAL 8
+#define R_MIPS_GOT16 9
+#define R_MIPS_PC16 10
+#define R_MIPS_CALL16 11
+#define R_MIPS_GPREL32 12
+/* The remaining relocs are defined on Irix, although they are not
+ in the MIPS ELF ABI. */
+#define R_MIPS_UNUSED1 13
+#define R_MIPS_UNUSED2 14
+#define R_MIPS_UNUSED3 15
+#define R_MIPS_SHIFT5 16
+#define R_MIPS_SHIFT6 17
+#define R_MIPS_64 18
+#define R_MIPS_GOT_DISP 19
+#define R_MIPS_GOT_PAGE 20
+#define R_MIPS_GOT_OFST 21
+/*
+ * The following two relocation types are specified in the MIPS ABI
+ * conformance guide version 1.2 but not yet in the psABI.
+ */
+#define R_MIPS_GOTHI16 22
+#define R_MIPS_GOTLO16 23
+#define R_MIPS_SUB 24
+#define R_MIPS_INSERT_A 25
+#define R_MIPS_INSERT_B 26
+#define R_MIPS_DELETE 27
+#define R_MIPS_HIGHER 28
+#define R_MIPS_HIGHEST 29
+/*
+ * The following two relocation types are specified in the MIPS ABI
+ * conformance guide version 1.2 but not yet in the psABI.
+ */
+#define R_MIPS_CALLHI16 30
+#define R_MIPS_CALLLO16 31
+/*
+ * This range is reserved for vendor specific relocations.
+ */
+#define R_MIPS_LOVENDOR 100
+#define R_MIPS_HIVENDOR 127
+
+#define SHN_MIPS_ACCOMON 0xff00 /* Allocated common symbols */
+#define SHN_MIPS_TEXT 0xff01 /* Allocated test symbols. */
+#define SHN_MIPS_DATA 0xff02 /* Allocated data symbols. */
+#define SHN_MIPS_SCOMMON 0xff03 /* Small common symbols */
+#define SHN_MIPS_SUNDEFINED 0xff04 /* Small undefined symbols */
+
+#define SHT_MIPS_LIST 0x70000000
+#define SHT_MIPS_CONFLICT 0x70000002
+#define SHT_MIPS_GPTAB 0x70000003
+#define SHT_MIPS_UCODE 0x70000004
+#define SHT_MIPS_DEBUG 0x70000005
+#define SHT_MIPS_REGINFO 0x70000006
+#define SHT_MIPS_PACKAGE 0x70000007
+#define SHT_MIPS_PACKSYM 0x70000008
+#define SHT_MIPS_RELD 0x70000009
+#define SHT_MIPS_IFACE 0x7000000b
+#define SHT_MIPS_CONTENT 0x7000000c
+#define SHT_MIPS_OPTIONS 0x7000000d
+#define SHT_MIPS_SHDR 0x70000010
+#define SHT_MIPS_FDESC 0x70000011
+#define SHT_MIPS_EXTSYM 0x70000012
+#define SHT_MIPS_DENSE 0x70000013
+#define SHT_MIPS_PDESC 0x70000014
+#define SHT_MIPS_LOCSYM 0x70000015
+#define SHT_MIPS_AUXSYM 0x70000016
+#define SHT_MIPS_OPTSYM 0x70000017
+#define SHT_MIPS_LOCSTR 0x70000018
+#define SHT_MIPS_LINE 0x70000019
+#define SHT_MIPS_RFDESC 0x7000001a
+#define SHT_MIPS_DELTASYM 0x7000001b
+#define SHT_MIPS_DELTAINST 0x7000001c
+#define SHT_MIPS_DELTACLASS 0x7000001d
+#define SHT_MIPS_DWARF 0x7000001e
+#define SHT_MIPS_DELTADECL 0x7000001f
+#define SHT_MIPS_SYMBOL_LIB 0x70000020
+#define SHT_MIPS_EVENTS 0x70000021
+#define SHT_MIPS_TRANSLATE 0x70000022
+#define SHT_MIPS_PIXIE 0x70000023
+#define SHT_MIPS_XLATE 0x70000024
+#define SHT_MIPS_XLATE_DEBUG 0x70000025
+#define SHT_MIPS_WHIRL 0x70000026
+#define SHT_MIPS_EH_REGION 0x70000027
+#define SHT_MIPS_XLATE_OLD 0x70000028
+#define SHT_MIPS_PDR_EXCEPTION 0x70000029
+
+#define SHF_MIPS_GPREL 0x10000000
+#define SHF_MIPS_MERGE 0x20000000
+#define SHF_MIPS_ADDR 0x40000000
+#define SHF_MIPS_STRING 0x80000000
+#define SHF_MIPS_NOSTRIP 0x08000000
+#define SHF_MIPS_LOCAL 0x04000000
+#define SHF_MIPS_NAMES 0x02000000
+#define SHF_MIPS_NODUPES 0x01000000
+
#ifndef ELF_ARCH
#ifdef CONFIG_32BIT
diff --git a/arch/mips/include/asm/module.h b/arch/mips/include/asm/module.h
index 3046220..d423ced 100644
--- a/arch/mips/include/asm/module.h
+++ b/arch/mips/include/asm/module.h
@@ -19,6 +19,21 @@
#ifndef _ASM_MIPS_MODULE_H_
#define _ASM_MIPS_MODULE_H_
-/* nothing special yet */
+struct mod_arch_specific
+{
+};
+
+#ifdef CONFIG_32BIT
+#define Elf_Shdr Elf32_Shdr
+#define Elf_Sym Elf32_Sym
+#define Elf_Ehdr Elf32_Ehdr
+#define Elf_Addr Elf32_Addr
+
+#define Elf_Mips_Rel Elf32_Rel
+#define Elf_Mips_Rela Elf32_Rela
+
+#define ELF_MIPS_R_SYM(rel) ELF32_R_SYM(rel.r_info)
+#define ELF_MIPS_R_TYPE(rel) ELF32_R_TYPE(rel.r_info)
+#endif
#endif /* _ASM_MIPS_MODULE_H_ */
diff --git a/arch/mips/lib/Makefile b/arch/mips/lib/Makefile
index 45fe920..8a043a6 100644
--- a/arch/mips/lib/Makefile
+++ b/arch/mips/lib/Makefile
@@ -6,3 +6,4 @@ obj-y += ashrdi3.o
obj-y += memory.o
obj-$(CONFIG_CMD_MIPS_CPUINFO) += cpuinfo.o
+obj-$(CONFIG_MODULES) += module.o
diff --git a/arch/mips/lib/module.c b/arch/mips/lib/module.c
new file mode 100644
index 0000000..924d138
--- /dev/null
+++ b/arch/mips/lib/module.c
@@ -0,0 +1,328 @@
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ * Copyright (C) 2001 Rusty Russell.
+ * Copyright (C) 2003, 2004 Ralf Baechle (ralf at linux-mips.org)
+ * Copyright (C) 2005 Thiemo Seufer
+ */
+
+#undef DEBUG
+#define DEBUG
+
+#include <common.h>
+#include <elf.h>
+#include <module.h>
+#include <errno.h>
+#include <malloc.h>
+#include <linux/barebox-wrapper.h>
+#include <linux/err.h>
+
+struct mips_hi16 {
+ struct mips_hi16 *next;
+ Elf_Addr *addr;
+ Elf_Addr value;
+};
+
+static struct mips_hi16 *mips_hi16_list;
+
+static int apply_r_mips_none(struct module *me, u32 *location, Elf_Addr v)
+{
+ return 0;
+}
+
+static int apply_r_mips_32_rel(struct module *me, u32 *location, Elf_Addr v)
+{
+ pr_debug("apply_r_mips_32_rel: locatio = %p, v = %08x\n", location, v);
+
+ *location += v;
+
+ return 0;
+}
+
+static int apply_r_mips_32_rela(struct module *me, u32 *location, Elf_Addr v)
+{
+ *location = v;
+
+ return 0;
+}
+
+static int apply_r_mips_26_rel(struct module *me, u32 *location, Elf_Addr v)
+{
+ if (v % 4) {
+ pr_err("module %s: dangerous R_MIPS_26 REL relocation\n",
+ me->name);
+ return -ENOEXEC;
+ }
+
+ if ((v & 0xf0000000) != (((unsigned long)location + 4) & 0xf0000000)) {
+ printk(KERN_ERR
+ "module %s: relocation overflow\n",
+ me->name);
+ return -ENOEXEC;
+ }
+
+ *location = (*location & ~0x03ffffff) |
+ ((*location + (v >> 2)) & 0x03ffffff);
+
+ return 0;
+}
+
+static int apply_r_mips_26_rela(struct module *me, u32 *location, Elf_Addr v)
+{
+ if (v % 4) {
+ pr_err("module %s: dangerous R_MIPS_26 RELArelocation\n",
+ me->name);
+ return -ENOEXEC;
+ }
+
+ if ((v & 0xf0000000) != (((unsigned long)location + 4) & 0xf0000000)) {
+ printk(KERN_ERR
+ "module %s: relocation overflow\n",
+ me->name);
+ return -ENOEXEC;
+ }
+
+ *location = (*location & ~0x03ffffff) | ((v >> 2) & 0x03ffffff);
+
+ return 0;
+}
+
+static int apply_r_mips_hi16_rel(struct module *me, u32 *location, Elf_Addr v)
+{
+ struct mips_hi16 *n;
+
+ /*
+ * We cannot relocate this one now because we don't know the value of
+ * the carry we need to add. Save the information, and let LO16 do the
+ * actual relocation.
+ */
+ n = kmalloc(sizeof *n, GFP_KERNEL);
+ if (!n)
+ return -ENOMEM;
+
+ n->addr = (Elf_Addr *)location;
+ n->value = v;
+ n->next = mips_hi16_list;
+ mips_hi16_list = n;
+
+ return 0;
+}
+
+static int apply_r_mips_hi16_rela(struct module *me, u32 *location, Elf_Addr v)
+{
+ *location = (*location & 0xffff0000) |
+ ((((long long) v + 0x8000LL) >> 16) & 0xffff);
+
+ return 0;
+}
+
+static int apply_r_mips_lo16_rel(struct module *me, u32 *location, Elf_Addr v)
+{
+ unsigned long insnlo = *location;
+ Elf_Addr val, vallo;
+
+ /* Sign extend the addend we extract from the lo insn. */
+ vallo = ((insnlo & 0xffff) ^ 0x8000) - 0x8000;
+
+ if (mips_hi16_list != NULL) {
+ struct mips_hi16 *l;
+
+ l = mips_hi16_list;
+ while (l != NULL) {
+ struct mips_hi16 *next;
+ unsigned long insn;
+
+ /*
+ * The value for the HI16 had best be the same.
+ */
+ if (v != l->value)
+ goto out_danger;
+
+ /*
+ * Do the HI16 relocation. Note that we actually don't
+ * need to know anything about the LO16 itself, except
+ * where to find the low 16 bits of the addend needed
+ * by the LO16.
+ */
+ insn = *l->addr;
+ val = ((insn & 0xffff) << 16) + vallo;
+ val += v;
+
+ /*
+ * Account for the sign extension that will happen in
+ * the low bits.
+ */
+ val = ((val >> 16) + ((val & 0x8000) != 0)) & 0xffff;
+
+ insn = (insn & ~0xffff) | val;
+ *l->addr = insn;
+
+ next = l->next;
+ kfree(l);
+ l = next;
+ }
+
+ mips_hi16_list = NULL;
+ }
+
+ /*
+ * Ok, we're done with the HI16 relocs. Now deal with the LO16.
+ */
+ val = v + vallo;
+ insnlo = (insnlo & ~0xffff) | (val & 0xffff);
+ *location = insnlo;
+
+ return 0;
+
+out_danger:
+ pr_err("module %s: dangerous R_MIPS_LO16 REL relocation\n", me->name);
+
+ return -ENOEXEC;
+}
+
+static int apply_r_mips_lo16_rela(struct module *me, u32 *location, Elf_Addr v)
+{
+ *location = (*location & 0xffff0000) | (v & 0xffff);
+
+ return 0;
+}
+
+static int apply_r_mips_64_rela(struct module *me, u32 *location, Elf_Addr v)
+{
+ *(Elf_Addr *)location = v;
+
+ return 0;
+}
+
+static int apply_r_mips_higher_rela(struct module *me, u32 *location,
+ Elf_Addr v)
+{
+ *location = (*location & 0xffff0000) |
+ ((((long long) v + 0x80008000LL) >> 32) & 0xffff);
+
+ return 0;
+}
+
+static int apply_r_mips_highest_rela(struct module *me, u32 *location,
+ Elf_Addr v)
+{
+ *location = (*location & 0xffff0000) |
+ ((((long long) v + 0x800080008000LL) >> 48) & 0xffff);
+
+ return 0;
+}
+
+static int (*reloc_handlers_rel[]) (struct module *me, u32 *location,
+ Elf_Addr v) = {
+ [R_MIPS_NONE] = apply_r_mips_none,
+ [R_MIPS_32] = apply_r_mips_32_rel,
+ [R_MIPS_26] = apply_r_mips_26_rel,
+ [R_MIPS_HI16] = apply_r_mips_hi16_rel,
+ [R_MIPS_LO16] = apply_r_mips_lo16_rel
+};
+
+static int (*reloc_handlers_rela[]) (struct module *me, u32 *location,
+ Elf_Addr v) = {
+ [R_MIPS_NONE] = apply_r_mips_none,
+ [R_MIPS_32] = apply_r_mips_32_rela,
+ [R_MIPS_26] = apply_r_mips_26_rela,
+ [R_MIPS_HI16] = apply_r_mips_hi16_rela,
+ [R_MIPS_LO16] = apply_r_mips_lo16_rela,
+ [R_MIPS_64] = apply_r_mips_64_rela,
+ [R_MIPS_HIGHER] = apply_r_mips_higher_rela,
+ [R_MIPS_HIGHEST] = apply_r_mips_highest_rela
+};
+
+int apply_relocate(Elf_Shdr *sechdrs, const char *strtab,
+ unsigned int symindex, unsigned int relsec,
+ struct module *me)
+{
+ Elf_Mips_Rel *rel = (void *) sechdrs[relsec].sh_addr;
+ Elf_Sym *sym;
+ u32 *location;
+ unsigned int i;
+ 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_MIPS_R_SYM(rel[i]);
+ if (IS_ERR_VALUE(sym->st_value)) {
+ /* Ignore unresolved weak symbol */
+ if (ELF_ST_BIND(sym->st_info) == STB_WEAK)
+ continue;
+ printk(KERN_WARNING "%s: Unknown symbol %s\n",
+ me->name, strtab + sym->st_name);
+ return -ENOENT;
+ }
+
+ v = sym->st_value;
+
+ printk(KERN_ERR "%s: location=%p, v=%08x\n",
+ me->name, location, v);
+ res = reloc_handlers_rel[ELF_MIPS_R_TYPE(rel[i])](me, location, v);
+ if (res)
+ return res;
+ }
+
+ return 0;
+}
+
+int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
+ unsigned int symindex, unsigned int relsec,
+ struct module *me)
+{
+ Elf_Mips_Rela *rel = (void *) sechdrs[relsec].sh_addr;
+ Elf_Sym *sym;
+ u32 *location;
+ unsigned int i;
+ 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_MIPS_R_SYM(rel[i]);
+ if (IS_ERR_VALUE(sym->st_value)) {
+ /* Ignore unresolved weak symbol */
+ if (ELF_ST_BIND(sym->st_info) == STB_WEAK)
+ continue;
+ printk(KERN_WARNING "%s: Unknown symbol %s\n",
+ me->name, strtab + sym->st_name);
+ return -ENOENT;
+ }
+
+ v = sym->st_value + rel[i].r_addend;
+
+ res = reloc_handlers_rela[ELF_MIPS_R_TYPE(rel[i])](me, location, v);
+ if (res)
+ return res;
+ }
+
+ return 0;
+}
--
1.7.10
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