[PATCH RFC 1/2] livepatch: add klp-convert tool and integrate with module build

From: Josh Poimboeuf
Date: Thu Oct 27 2016 - 10:36:25 EST

This still needs to be split up into several patches. It does several
things:

- Create a klp_module_reloc struct and KLP_MODULE_RELOC macro which
gives livepatch modules a way to specify which local and unexported
symbols they need.

- Create a klp-convert tool which reads the klp_module_reloc structs
from the ".klp.module_relocs.*" sections and converts the relevant
symbols and relocations to their klp counterparts.

- Integrate klp-convert with the module build so that it automatically
converts any kernel modules with the 'livepatch' modinfo to real
livepatch modules.

Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
---
Makefile | 2 +-
include/linux/livepatch.h | 1 +
include/uapi/linux/Kbuild | 1 +
include/uapi/linux/livepatch.h | 37 +++
kernel/livepatch/core.c | 4 +-
scripts/Makefile | 1 +
scripts/Makefile.modpost | 18 +-
scripts/livepatch/.gitignore | 1 +
scripts/livepatch/Makefile | 7 +
scripts/livepatch/elf.c | 717 ++++++++++++++++++++++++++++++++++++++++
scripts/livepatch/elf.h | 88 +++++
scripts/livepatch/klp-convert.c | 181 ++++++++++
scripts/livepatch/list.h | 381 +++++++++++++++++++++
scripts/mod/modpost.c | 9 +-
scripts/mod/modpost.h | 1 +
15 files changed, 1443 insertions(+), 6 deletions(-)
create mode 100644 include/uapi/linux/livepatch.h
create mode 100644 scripts/livepatch/.gitignore
create mode 100644 scripts/livepatch/Makefile
create mode 100644 scripts/livepatch/elf.c
create mode 100644 scripts/livepatch/elf.h
create mode 100644 scripts/livepatch/klp-convert.c
create mode 100644 scripts/livepatch/list.h

diff --git a/Makefile b/Makefile
index 93beca4..5114e99 100644
--- a/Makefile
+++ b/Makefile
@@ -555,7 +555,7 @@ ifeq ($(KBUILD_EXTMOD),)
# in parallel
PHONY += scripts
scripts: scripts_basic include/config/auto.conf include/config/tristate.conf \
- asm-generic gcc-plugins
+ asm-generic gcc-plugins headers_install
$(Q)$(MAKE) $(build)=$(@)

# Objects we will link into vmlinux / subdirs we need to visit
diff --git a/include/linux/livepatch.h b/include/linux/livepatch.h
index 9072f04..0537eb9 100644
--- a/include/linux/livepatch.h
+++ b/include/linux/livepatch.h
@@ -23,6 +23,7 @@

#include <linux/module.h>
#include <linux/ftrace.h>
+#include <uapi/linux/livepatch.h>

#if IS_ENABLED(CONFIG_LIVEPATCH)

diff --git a/include/uapi/linux/Kbuild b/include/uapi/linux/Kbuild
index bc2ef9f..5500312 100644
--- a/include/uapi/linux/Kbuild
+++ b/include/uapi/linux/Kbuild
@@ -250,6 +250,7 @@ header-y += l2tp.h
header-y += libc-compat.h
header-y += lirc.h
header-y += limits.h
+header-y += livepatch.h
header-y += llc.h
header-y += loop.h
header-y += lp.h
diff --git a/include/uapi/linux/livepatch.h b/include/uapi/linux/livepatch.h
new file mode 100644
index 0000000..41184f9
--- /dev/null
+++ b/include/uapi/linux/livepatch.h
@@ -0,0 +1,37 @@
+/*
+ * livepatch.h - Kernel Live Patching Core
+ *
+ * Copyright (C) 2016 Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
+ *
+ * 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef _UAPI_LIVEPATCH_H
+#define _UAPI_LIVEPATCH_H
+
+#include <linux/types.h>
+
+#define KLP_RELA_PREFIX ".klp.rela."
+#define KLP_SYM_PREFIX ".klp.sym."
+
+struct klp_module_reloc {
+ void *sym;
+ unsigned int sympos;
+} __attribute__((packed));
+
+#define KLP_MODULE_RELOC(obj) \
+ klp_module_reloc \
+ __attribute__((__section__(".klp.module_relocs." #obj)))
+
+#endif /* _UAPI_LIVEPATCH_H */
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index af46438..e451345 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -240,7 +240,7 @@ static int klp_resolve_symbols(Elf_Shdr *relasec, struct module *pmod)

/* Format: .klp.sym.objname.symname,sympos */
cnt = sscanf(strtab + sym->st_name,
- ".klp.sym.%55[^.].%127[^,],%lu",
+ KLP_SYM_PREFIX "%55[^.].%127[^,],%lu",
objname, symname, &sympos);
if (cnt != 3) {
pr_err("symbol %s has an incorrectly formatted name",
@@ -286,7 +286,7 @@ static int klp_write_object_relocations(struct module *pmod,
* See comment in klp_resolve_symbols() for an explanation
* of the selected field width value.
*/
- cnt = sscanf(secname, ".klp.rela.%55[^.]", sec_objname);
+ cnt = sscanf(secname, KLP_RELA_PREFIX "%55[^.]", sec_objname);
if (cnt != 1) {
pr_err("section %s has an incorrectly formatted name",
secname);
diff --git a/scripts/Makefile b/scripts/Makefile
index 1d80897..2cc2b8a 100644
--- a/scripts/Makefile
+++ b/scripts/Makefile
@@ -45,6 +45,7 @@ subdir-y += mod
subdir-$(CONFIG_SECURITY_SELINUX) += selinux
subdir-$(CONFIG_DTC) += dtc
subdir-$(CONFIG_GDB_SCRIPTS) += gdb
+subdir-$(CONFIG_LIVEPATCH) += livepatch

# Let clean descend into subdirs
subdir- += basic kconfig package gcc-plugins
diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost
index 16923ba..916dd34 100644
--- a/scripts/Makefile.modpost
+++ b/scripts/Makefile.modpost
@@ -123,10 +123,24 @@ quiet_cmd_ld_ko_o = LD [M] $@
$(LD) -r $(LDFLAGS) \
$(KBUILD_LDFLAGS_MODULE) $(LDFLAGS_MODULE) \
-o $@ $(filter-out FORCE,$^) ; \
- $(if $(ARCH_POSTLINK), $(MAKE) -f $(ARCH_POSTLINK) $@, true)
+ $(if $(ARCH_POSTLINK), $(MAKE) -f $(ARCH_POSTLINK) $@, true) ;
+
+ifdef CONFIG_LIVEPATCH
+KLP_CONVERT = scripts/livepatch/klp-convert
+ cmd_klp_convert = \
+ if [[ -n "`modinfo -F livepatch $@`" ]]; then \
+ mv $@ $(@:.ko=.klp.o); \
+ $(KLP_CONVERT) $(@:.ko=.klp.o) $@; \
+ fi ;
+endif
+
+define rule_link_module
+ $(call echo-cmd,ld_ko_o) $(cmd_ld_ko_o) \
+ $(cmd_klp_convert)
+endef

$(modules): %.ko :%.o %.mod.o FORCE
- +$(call if_changed,ld_ko_o)
+ +$(call if_changed_rule,link_module)

targets += $(modules)

diff --git a/scripts/livepatch/.gitignore b/scripts/livepatch/.gitignore
new file mode 100644
index 0000000..dc22fe4
--- /dev/null
+++ b/scripts/livepatch/.gitignore
@@ -0,0 +1 @@
+klp-convert
diff --git a/scripts/livepatch/Makefile b/scripts/livepatch/Makefile
new file mode 100644
index 0000000..221829b
--- /dev/null
+++ b/scripts/livepatch/Makefile
@@ -0,0 +1,7 @@
+hostprogs-y := klp-convert
+always := $(hostprogs-y)
+
+klp-convert-objs := klp-convert.o elf.o
+
+HOSTCFLAGS := -g -I$(INSTALL_HDR_PATH)/include -Wall
+HOSTLDFLAGS := -lelf
diff --git a/scripts/livepatch/elf.c b/scripts/livepatch/elf.c
new file mode 100644
index 0000000..bbf1b76
--- /dev/null
+++ b/scripts/livepatch/elf.c
@@ -0,0 +1,717 @@
+/*
+ * elf.c - ELF access library
+ *
+ * Adapted from kpatch (https://github.com/dynup/kpatch):
+ * Copyright (C) 2013-2016 Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
+ * Copyright (C) 2014 Seth Jennings <sjenning@xxxxxxxxxx>
+ *
+ * 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "elf.h"
+
+#define WARN(format, ...) \
+ fprintf(stderr, "%s: " format "\n", elf->name, ##__VA_ARGS__)
+
+/*
+ * Fallback for systems without this "read, mmaping if possible" cmd.
+ */
+#ifndef ELF_C_READ_MMAP
+#define ELF_C_READ_MMAP ELF_C_READ
+#endif
+
+bool is_rela_section(struct section *sec)
+{
+ return (sec->sh.sh_type == SHT_RELA);
+}
+
+struct section *find_section_by_name(struct elf *elf, const char *name)
+{
+ struct section *sec;
+
+ list_for_each_entry(sec, &elf->sections, list)
+ if (!strcmp(sec->name, name))
+ return sec;
+
+ return NULL;
+}
+
+static struct section *find_section_by_index(struct elf *elf,
+ unsigned int idx)
+{
+ struct section *sec;
+
+ list_for_each_entry(sec, &elf->sections, list)
+ if (sec->idx == idx)
+ return sec;
+
+ return NULL;
+}
+
+static struct symbol *find_symbol_by_index(struct elf *elf, unsigned int idx)
+{
+ struct symbol *sym;
+
+ list_for_each_entry(sym, &elf->symbols, list)
+ if (sym->idx == idx)
+ return sym;
+
+ return NULL;
+}
+
+struct rela *find_rela_by_dest_range(struct section *sec, unsigned long offset,
+ unsigned int len)
+{
+ struct rela *rela;
+ unsigned long o;
+
+ if (!sec->rela)
+ return NULL;
+
+ for (o = offset; o < offset + len; o++)
+ list_for_each_entry(rela, &sec->rela->relas, list)
+ if (rela->offset == o)
+ return rela;
+
+ return NULL;
+}
+
+struct rela *find_rela_by_dest(struct section *sec, unsigned long offset)
+{
+ return find_rela_by_dest_range(sec, offset, 1);
+}
+
+static int read_sections(struct elf *elf)
+{
+ Elf_Scn *s = NULL;
+ struct section *sec;
+ size_t shstrndx, sections_nr;
+ int i;
+
+ if (elf_getshdrnum(elf->elf, &sections_nr)) {
+ perror("elf_getshdrnum");
+ return -1;
+ }
+
+ if (elf_getshdrstrndx(elf->elf, &shstrndx)) {
+ perror("elf_getshdrstrndx");
+ return -1;
+ }
+
+ for (i = 0; i < sections_nr; i++) {
+ sec = malloc(sizeof(*sec));
+ if (!sec) {
+ perror("malloc");
+ return -1;
+ }
+ memset(sec, 0, sizeof(*sec));
+
+ INIT_LIST_HEAD(&sec->relas);
+
+ list_add_tail(&sec->list, &elf->sections);
+
+ s = elf_getscn(elf->elf, i);
+ if (!s) {
+ perror("elf_getscn");
+ return -1;
+ }
+
+ sec->idx = elf_ndxscn(s);
+
+ if (!gelf_getshdr(s, &sec->sh)) {
+ perror("gelf_getshdr");
+ return -1;
+ }
+
+ sec->name = elf_strptr(elf->elf, shstrndx, sec->sh.sh_name);
+ if (!sec->name) {
+ perror("elf_strptr");
+ return -1;
+ }
+
+ sec->elf_data = elf_getdata(s, NULL);
+ if (!sec->elf_data) {
+ perror("elf_getdata");
+ return -1;
+ }
+
+ if (sec->elf_data->d_off != 0 ||
+ sec->elf_data->d_size != sec->sh.sh_size) {
+ WARN("unexpected data attributes for %s", sec->name);
+ return -1;
+ }
+
+ sec->data = sec->elf_data->d_buf;
+ sec->size = sec->elf_data->d_size;
+ }
+
+ /* sanity check, one more call to elf_nextscn() should return NULL */
+ if (elf_nextscn(elf->elf, s)) {
+ WARN("section entry mismatch");
+ return -1;
+ }
+
+ return 0;
+}
+
+static int read_symbols(struct elf *elf)
+{
+ struct section *symtab;
+ struct symbol *sym;
+ int symbols_nr, i;
+
+ symtab = find_section_by_name(elf, ".symtab");
+ if (!symtab) {
+ WARN("missing symbol table");
+ return -1;
+ }
+
+ symbols_nr = symtab->sh.sh_size / symtab->sh.sh_entsize;
+
+ for (i = 0; i < symbols_nr; i++) {
+ sym = malloc(sizeof(*sym));
+ if (!sym) {
+ perror("malloc");
+ return -1;
+ }
+ memset(sym, 0, sizeof(*sym));
+
+ sym->idx = i;
+
+ if (!gelf_getsym(symtab->elf_data, i, &sym->sym)) {
+ perror("gelf_getsym");
+ goto err;
+ }
+
+ sym->name = elf_strptr(elf->elf, symtab->sh.sh_link,
+ sym->sym.st_name);
+ if (!sym->name) {
+ perror("elf_strptr");
+ goto err;
+ }
+
+ sym->type = GELF_ST_TYPE(sym->sym.st_info);
+ sym->bind = GELF_ST_BIND(sym->sym.st_info);
+
+ if (sym->sym.st_shndx > SHN_UNDEF &&
+ sym->sym.st_shndx < SHN_LORESERVE) {
+ sym->sec = find_section_by_index(elf,
+ sym->sym.st_shndx);
+ if (!sym->sec) {
+ WARN("couldn't find section for symbol %s",
+ sym->name);
+ goto err;
+ }
+ if (sym->type == STT_SECTION) {
+ sym->name = sym->sec->name;
+ sym->sec->sym = sym;
+ }
+ }
+
+ sym->offset = sym->sym.st_value;
+ sym->size = sym->sym.st_size;
+
+ list_add_tail(&sym->list, &elf->symbols);
+ }
+
+ return 0;
+
+err:
+ free(sym);
+ return -1;
+}
+
+static int read_relas(struct elf *elf)
+{
+ struct section *sec;
+ struct rela *rela;
+ int i;
+ unsigned int symndx;
+
+ list_for_each_entry(sec, &elf->sections, list) {
+ if (sec->sh.sh_type != SHT_RELA)
+ continue;
+
+ sec->base = find_section_by_name(elf, sec->name + 5);
+ if (!sec->base) {
+ WARN("can't find base section for rela section %s",
+ sec->name);
+ return -1;
+ }
+
+ sec->base->rela = sec;
+
+ for (i = 0; i < sec->sh.sh_size / sec->sh.sh_entsize; i++) {
+ rela = malloc(sizeof(*rela));
+ if (!rela) {
+ perror("malloc");
+ return -1;
+ }
+ memset(rela, 0, sizeof(*rela));
+
+ if (!gelf_getrela(sec->elf_data, i, &rela->rela)) {
+ perror("gelf_getrela");
+ return -1;
+ }
+
+ rela->type = GELF_R_TYPE(rela->rela.r_info);
+ rela->addend = rela->rela.r_addend;
+ rela->offset = rela->rela.r_offset;
+ symndx = GELF_R_SYM(rela->rela.r_info);
+ rela->sym = find_symbol_by_index(elf, symndx);
+ if (!rela->sym) {
+ WARN("can't find rela entry symbol %d for %s",
+ symndx, sec->name);
+ return -1;
+ }
+
+ list_add_tail(&rela->list, &sec->relas);
+ }
+ }
+
+ return 0;
+}
+
+struct section *create_rela_section(struct elf *elf, const char *name,
+ struct section *base)
+{
+ struct section *sec;
+
+ sec = malloc(sizeof(*sec));
+ if (!sec) {
+ WARN("malloc failed");
+ return NULL;
+ }
+ memset(sec, 0, sizeof(*sec));
+ INIT_LIST_HEAD(&sec->relas);
+
+ sec->base = base;
+ sec->name = strdup(name);
+ sec->sh.sh_name = -1;
+ sec->sh.sh_type = SHT_RELA;
+ sec->sh.sh_entsize = sizeof(GElf_Rela);
+ sec->sh.sh_addralign = 8;
+ sec->sh.sh_flags = SHF_ALLOC;
+
+ sec->elf_data = malloc(sizeof(*sec->elf_data));
+ if (!sec->elf_data) {
+ WARN("malloc failed");
+ return NULL;
+ }
+ memset(sec->elf_data, 0, sizeof(*sec->elf_data));
+ sec->elf_data->d_type = ELF_T_RELA;
+
+ list_add_tail(&sec->list, &elf->sections);
+
+ return sec;
+}
+
+static int update_shstrtab(struct elf *elf)
+{
+ struct section *shstrtab, *sec;
+ size_t orig_size, new_size = 0, offset, len;
+ char *buf;
+
+ shstrtab = find_section_by_name(elf, ".shstrtab");
+ if (!shstrtab) {
+ WARN("can't find .shstrtab");
+ return -1;
+ }
+
+ orig_size = new_size = shstrtab->size;
+
+ list_for_each_entry(sec, &elf->sections, list) {
+ if (sec->sh.sh_name != -1)
+ continue;
+ new_size += strlen(sec->name) + 1;
+ }
+
+ if (new_size == orig_size)
+ return 0;
+
+ buf = malloc(new_size);
+ if (!buf) {
+ WARN("malloc failed");
+ return -1;
+ }
+ memcpy(buf, (void *)shstrtab->data, orig_size);
+
+ offset = orig_size;
+ list_for_each_entry(sec, &elf->sections, list) {
+ if (sec->sh.sh_name != -1)
+ continue;
+ sec->sh.sh_name = offset;
+ len = strlen(sec->name) + 1;
+ memcpy(buf + offset, sec->name, len);
+ offset += len;
+ }
+
+ shstrtab->elf_data->d_buf = shstrtab->data = buf;
+ shstrtab->elf_data->d_size = shstrtab->size = new_size;
+ shstrtab->sh.sh_size = new_size;
+
+ return 0;
+}
+
+static int update_strtab(struct elf *elf)
+{
+ struct section *strtab;
+ struct symbol *sym;
+ size_t orig_size, new_size = 0, offset, len;
+ char *buf;
+
+ strtab = find_section_by_name(elf, ".strtab");
+ if (!strtab) {
+ WARN("can't find .strtab");
+ return -1;
+ }
+
+ orig_size = new_size = strtab->size;
+
+ list_for_each_entry(sym, &elf->symbols, list) {
+ if (sym->sym.st_name != -1)
+ continue;
+ new_size += strlen(sym->name) + 1;
+ }
+
+ if (new_size == orig_size)
+ return 0;
+
+ buf = malloc(new_size);
+ if (!buf) {
+ WARN("malloc failed");
+ return -1;
+ }
+ memcpy(buf, (void *)strtab->data, orig_size);
+
+ offset = orig_size;
+ list_for_each_entry(sym, &elf->symbols, list) {
+ if (sym->sym.st_name != -1)
+ continue;
+ sym->sym.st_name = offset;
+ len = strlen(sym->name) + 1;
+ memcpy(buf + offset, sym->name, len);
+ offset += len;
+ }
+
+ strtab->elf_data->d_buf = strtab->data = buf;
+ strtab->elf_data->d_size = strtab->size = new_size;
+ strtab->sh.sh_size = new_size;
+
+ return 0;
+}
+
+static int update_symtab(struct elf *elf)
+{
+ struct section *symtab, *sec;
+ struct symbol *sym;
+ char *buf;
+ size_t size;
+ int nr_syms = 0, offset = 0, nr_locals = 0, idx;
+
+ idx = 0;
+ list_for_each_entry(sec, &elf->sections, list)
+ sec->idx = idx++;
+
+ idx = 0;
+ list_for_each_entry(sym, &elf->symbols, list) {
+ sym->idx = idx++;
+ if (sym->sec)
+ sym->sym.st_shndx = sym->sec->idx;
+ }
+
+ symtab = find_section_by_name(elf, ".symtab");
+ if (!symtab) {
+ WARN("can't find symtab");
+ return -1;
+ }
+
+ symtab->sh.sh_link = find_section_by_name(elf, ".strtab")->idx;
+
+ /* count symbols */
+ list_for_each_entry(sym, &elf->symbols, list)
+ nr_syms++;
+
+ /* create new symtab buffer */
+ size = nr_syms * symtab->sh.sh_entsize;
+ buf = malloc(size);
+ if (!buf) {
+ WARN("malloc failed");
+ return -1;
+ }
+ memset(buf, 0, size);
+
+ offset = 0;
+ list_for_each_entry(sym, &elf->symbols, list) {
+ memcpy(buf + offset, &sym->sym, symtab->sh.sh_entsize);
+ offset += symtab->sh.sh_entsize;
+
+ if (sym->bind == STB_LOCAL)
+ nr_locals++;
+ }
+
+ symtab->elf_data->d_buf = symtab->data = buf;
+ symtab->elf_data->d_size = symtab->size = size;
+ symtab->sh.sh_size = size;
+
+ /* update symtab section header */
+ symtab->sh.sh_info = nr_locals;
+
+ return 0;
+}
+
+static int update_relas(struct elf *elf)
+{
+ struct section *sec, *symtab;
+ struct rela *rela;
+ int nr_relas, idx, size;
+ GElf_Rela *relas;
+
+ symtab = find_section_by_name(elf, ".symtab");
+
+ list_for_each_entry(sec, &elf->sections, list) {
+ if (!is_rela_section(sec))
+ continue;
+
+ sec->sh.sh_link = symtab->idx;
+ if (sec->base)
+ sec->sh.sh_info = sec->base->idx;
+
+ nr_relas = 0;
+ list_for_each_entry(rela, &sec->relas, list)
+ nr_relas++;
+
+ size = nr_relas * sizeof(*relas);
+ relas = malloc(size);
+ if (!relas) {
+ WARN("malloc failed");
+ return -1;
+ }
+
+ sec->elf_data->d_buf = sec->data = relas;
+ sec->elf_data->d_size = sec->size = size;
+ sec->sh.sh_size = size;
+
+ idx = 0;
+ list_for_each_entry(rela, &sec->relas, list) {
+ relas[idx].r_offset = rela->offset;
+ relas[idx].r_addend = rela->addend;
+ relas[idx].r_info = GELF_R_INFO(rela->sym->idx,
+ rela->type);
+ idx++;
+ }
+ }
+
+ return 0;
+}
+
+static int write_file(struct elf *elf, const char *file)
+{
+ int fd;
+ Elf *e;
+ GElf_Ehdr eh, ehout;
+ Elf_Scn *scn;
+ Elf_Data *data;
+ GElf_Shdr sh;
+ struct section *sec;
+
+ fd = creat(file, 0664);
+ if (fd == -1) {
+ WARN("couldn't create %s", file);
+ return -1;
+ }
+
+ e = elf_begin(fd, ELF_C_WRITE, NULL);
+ if (!e) {
+ WARN("elf_begin failed");
+ return -1;
+ }
+
+ if (!gelf_newehdr(e, gelf_getclass(elf->elf))) {
+ WARN("gelf_newehdr failed");
+ return -1;
+ }
+
+ if (!gelf_getehdr(e, &ehout)) {
+ WARN("gelf_getehdr failed");
+ return -1;
+ }
+
+ if (!gelf_getehdr(elf->elf, &eh)) {
+ WARN("gelf_getehdr failed");
+ return -1;
+ }
+
+ memset(&ehout, 0, sizeof(ehout));
+ ehout.e_ident[EI_DATA] = eh.e_ident[EI_DATA];
+ ehout.e_machine = eh.e_machine;
+ ehout.e_type = eh.e_type;
+ ehout.e_version = EV_CURRENT;
+ ehout.e_shstrndx = find_section_by_name(elf, ".shstrtab")->idx;
+
+ list_for_each_entry(sec, &elf->sections, list) {
+ if (!sec->idx)
+ continue;
+ scn = elf_newscn(e);
+ if (!scn) {
+ WARN("elf_newscn failed");
+ return -1;
+ }
+
+ data = elf_newdata(scn);
+ if (!data) {
+ WARN("elf_newdata failed");
+ return -1;
+ }
+
+ if (!elf_flagdata(data, ELF_C_SET, ELF_F_DIRTY)) {
+ WARN("elf_flagdata failed");
+ return -1;
+ }
+
+ data->d_type = sec->elf_data->d_type;
+ data->d_buf = sec->elf_data->d_buf;
+ data->d_size = sec->elf_data->d_size;
+
+ if(!gelf_getshdr(scn, &sh)) {
+ WARN("gelf_getshdr failed");
+ return -1;
+ }
+
+ sh = sec->sh;
+
+ if (!gelf_update_shdr(scn, &sh)) {
+ WARN("gelf_update_shdr failed");
+ return -1;
+ }
+ }
+
+ if (!gelf_update_ehdr(e, &ehout)) {
+ WARN("gelf_update_ehdr failed");
+ return -1;
+ }
+
+ if (elf_update(e, ELF_C_WRITE) < 0) {
+ fprintf(stderr, "%s\n",elf_errmsg(-1));
+ WARN("elf_update failed");
+ return -1;
+ }
+
+ return 0;
+}
+
+int elf_write_file(struct elf *elf, const char *file)
+{
+ int ret;
+
+ ret = update_shstrtab(elf);
+ if (ret)
+ return ret;
+
+ ret = update_strtab(elf);
+ if (ret)
+ return ret;
+
+ ret = update_symtab(elf);
+ if (ret)
+ return ret;
+
+ ret = update_relas(elf);
+ if (ret)
+ return ret;
+
+ return write_file(elf, file);
+}
+
+struct elf *elf_open(const char *name)
+{
+ struct elf *elf;
+
+ elf_version(EV_CURRENT);
+
+ elf = malloc(sizeof(*elf));
+ if (!elf) {
+ perror("malloc");
+ return NULL;
+ }
+ memset(elf, 0, sizeof(*elf));
+
+ INIT_LIST_HEAD(&elf->sections);
+ INIT_LIST_HEAD(&elf->symbols);
+
+ elf->fd = open(name, O_RDONLY);
+ if (elf->fd == -1) {
+ perror("open");
+ goto err;
+ }
+
+ elf->elf = elf_begin(elf->fd, ELF_C_READ_MMAP, NULL);
+ if (!elf->elf) {
+ perror("elf_begin");
+ goto err;
+ }
+
+ if (!gelf_getehdr(elf->elf, &elf->ehdr)) {
+ perror("gelf_getehdr");
+ goto err;
+ }
+
+ if (read_sections(elf))
+ goto err;
+
+ if (read_symbols(elf))
+ goto err;
+
+ if (read_relas(elf))
+ goto err;
+
+ return elf;
+
+err:
+ elf_close(elf);
+ return NULL;
+}
+
+void elf_close(struct elf *elf)
+{
+ struct section *sec, *tmpsec;
+ struct symbol *sym, *tmpsym;
+ struct rela *rela, *tmprela;
+
+ list_for_each_entry_safe(sym, tmpsym, &elf->symbols, list) {
+ list_del(&sym->list);
+ free(sym);
+ }
+ list_for_each_entry_safe(sec, tmpsec, &elf->sections, list) {
+ list_for_each_entry_safe(rela, tmprela, &sec->relas, list) {
+ list_del(&rela->list);
+ free(rela);
+ }
+ list_del(&sec->list);
+ free(sec);
+ }
+ if (elf->fd > 0)
+ close(elf->fd);
+ if (elf->elf)
+ elf_end(elf->elf);
+ free(elf);
+}
diff --git a/scripts/livepatch/elf.h b/scripts/livepatch/elf.h
new file mode 100644
index 0000000..f7bc676
--- /dev/null
+++ b/scripts/livepatch/elf.h
@@ -0,0 +1,88 @@
+/*
+ * Copyright (C) 2015-2016 Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
+ *
+ * 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef _KLP_MODPOST_ELF_H
+#define _KLP_MODPOST_ELF_H
+
+#include <stdio.h>
+#include <stdbool.h>
+#include <gelf.h>
+#include "list.h"
+
+#ifdef LIBELF_USE_DEPRECATED
+# define elf_getshdrnum elf_getshnum
+# define elf_getshdrstrndx elf_getshstrndx
+#endif
+
+struct section {
+ struct list_head list;
+ GElf_Shdr sh;
+ struct section *base, *rela;
+ struct list_head relas;
+ struct symbol *sym;
+ Elf_Data *elf_data;
+ char *name;
+ int idx;
+ void *data;
+ unsigned int size;
+};
+
+struct symbol {
+ struct list_head list;
+ GElf_Sym sym;
+ struct section *sec;
+ char *name;
+ unsigned int idx;
+ unsigned char bind, type;
+ unsigned long offset;
+ unsigned int size;
+};
+
+struct rela {
+ struct list_head list;
+ GElf_Rela rela;
+ struct symbol *sym;
+ unsigned int type;
+ unsigned long offset;
+ int addend;
+};
+
+struct elf {
+ Elf *elf;
+ GElf_Ehdr ehdr;
+ int fd;
+ char *name;
+ struct list_head sections;
+ struct list_head symbols;
+};
+
+
+struct elf *elf_open(const char *name);
+bool is_rela_section(struct section *sec);
+struct section *find_section_by_name(struct elf *elf, const char *name);
+struct rela *find_rela_by_dest(struct section *sec, unsigned long offset);
+struct rela *find_rela_by_dest_range(struct section *sec, unsigned long offset,
+ unsigned int len);
+
+struct section *create_rela_section(struct elf *elf, const char *name,
+ struct section *base);
+
+void elf_close(struct elf *elf);
+int elf_write_file(struct elf *elf, const char *file);
+
+
+#endif /* _KLP_MODPOST_ELF_H */
diff --git a/scripts/livepatch/klp-convert.c b/scripts/livepatch/klp-convert.c
new file mode 100644
index 0000000..28a7282
--- /dev/null
+++ b/scripts/livepatch/klp-convert.c
@@ -0,0 +1,181 @@
+/*
+ * Copyright (C) 2016 Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
+ *
+ * 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include "elf.h"
+#include <linux/livepatch.h>
+
+#define WARN(format, ...) \
+ fprintf(stderr, "%s: " format "\n", elf->name, ##__VA_ARGS__)
+
+#define MODULE_NAME_LEN (64 - sizeof(GElf_Addr))
+
+#define SHN_LIVEPATCH 0xff20
+#define SHF_RELA_LIVEPATCH 0x00100000
+
+static const char usage_string[] =
+ "klp-convert <input.ko> <output.ko>";
+
+struct elf *elf;
+
+static struct section *find_or_create_klp_rela_section(char *objname,
+ struct section *oldsec)
+{
+ char name[256];
+ struct section *sec;
+
+ if (snprintf(name, 256, KLP_RELA_PREFIX "%s.%s", objname,
+ oldsec->base->name) >= 256) {
+ WARN("section name too long (%s)", oldsec->base->name);
+ return NULL;
+ }
+
+ sec = find_section_by_name(elf, name);
+ if (sec)
+ return sec;
+
+ sec = create_rela_section(elf, name, oldsec->base);
+ if (!sec)
+ return NULL;
+
+ sec->sh.sh_flags |= SHF_RELA_LIVEPATCH;
+ return sec;
+}
+
+static int rename_klp_symbols(struct section *sec, char *objname)
+{
+ struct section *relasec;
+ struct rela *rela, *tmprela;
+ struct klp_module_reloc *reloc;
+ int nr_entries, i;
+ char name[256];
+
+ relasec = sec->rela;
+ if (!relasec) {
+ WARN("section %s doesn't have a corresponding rela section",
+ sec->name);
+ return -1;
+ }
+
+ if (list_empty(&relasec->relas)) {
+ WARN("section %s is empty", relasec->name);
+ return -1;
+ }
+
+ reloc = sec->data;
+ nr_entries = sec->size / sizeof(*reloc);
+
+ i = 0;
+ list_for_each_entry_safe(rela, tmprela, &relasec->relas, list) {
+
+ if (snprintf(name, 256, KLP_SYM_PREFIX "%s.%s,%d", objname,
+ rela->sym->name, reloc[i].sympos) >= 256) {
+ WARN("symbol name too long (%s)", rela->sym->name);
+ return -1;
+ }
+
+ rela->sym->name = strdup(name);
+ rela->sym->sym.st_name = -1;
+ rela->sym->sec = NULL;
+ rela->sym->sym.st_shndx = SHN_LIVEPATCH;
+
+ list_del(&rela->list);
+ i++;
+ }
+
+ if (i != nr_entries) {
+ WARN("nr_entries mismatch (%d != %d) for %s\n",
+ i, nr_entries, relasec->name);
+ return -1;
+ }
+
+ list_del(&relasec->list);
+ list_del(&sec->list);
+ list_del(&sec->sym->list);
+
+ return 0;
+}
+
+static int migrate_klp_rela(struct section *oldsec, struct rela *rela)
+{
+ char objname[MODULE_NAME_LEN];
+ struct section *newsec;
+
+ if (sscanf(rela->sym->name, KLP_SYM_PREFIX "%55[^.]", objname) != 1) {
+ WARN("bad format for klp rela %s", rela->sym->name);
+ return -1;
+ }
+
+ newsec = find_or_create_klp_rela_section(objname, oldsec);
+ if (!newsec)
+ return -1;
+
+ list_del(&rela->list);
+ list_add_tail(&rela->list, &newsec->relas);
+
+ return 0;
+}
+
+int main(int argc, const char **argv)
+{
+ const char *in_name, *out_name;
+ struct section *sec, *tmpsec;
+ char objname[MODULE_NAME_LEN];
+ struct rela *rela, *tmprela;
+
+ if (argc != 3) {
+ fprintf(stderr, "Usage: %s\n", usage_string);
+ return 1;
+ }
+
+ in_name = argv[1];
+ out_name = argv[2];
+
+ elf = elf_open(in_name);
+ if (!elf) {
+ fprintf(stderr, "error reading elf file %s\b", in_name);
+ return 1;
+ }
+
+ list_for_each_entry_safe(sec, tmpsec, &elf->sections, list) {
+ if (sscanf(sec->name, ".klp.module_relocs.%55s", objname) != 1)
+ continue;
+ if (rename_klp_symbols(sec, objname))
+ return 1;
+ }
+
+ list_for_each_entry(sec, &elf->sections, list) {
+ if (!is_rela_section(sec))
+ continue;
+ if (!strncmp(sec->name, KLP_RELA_PREFIX,
+ strlen(KLP_RELA_PREFIX)))
+ continue;
+ list_for_each_entry_safe(rela, tmprela, &sec->relas, list) {
+ if (strncmp(rela->sym->name, KLP_SYM_PREFIX,
+ strlen(KLP_SYM_PREFIX)))
+ continue;
+ if (migrate_klp_rela(sec, rela))
+ return 1;
+ }
+ }
+
+ if (elf_write_file(elf, out_name))
+ return 1;
+
+ return 0;
+}
diff --git a/scripts/livepatch/list.h b/scripts/livepatch/list.h
new file mode 100644
index 0000000..7f27e64
--- /dev/null
+++ b/scripts/livepatch/list.h
@@ -0,0 +1,381 @@
+#ifndef _LINUX_LIST_H
+#define _LINUX_LIST_H
+
+/*
+ * Simple doubly linked list implementation.
+ *
+ * Some of the internal functions ("__xxx") are useful when
+ * manipulating whole lists rather than single entries, as
+ * sometimes we already know the next/prev entries and we can
+ * generate better code by using them directly rather than
+ * using the generic single-entry routines.
+ */
+
+#define WRITE_ONCE(a, b) a = b
+#define READ_ONCE(a) a
+
+#undef offsetof
+#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
+
+/**
+ * container_of - cast a member of a structure out to the containing structure
+ * @ptr: the pointer to the member.
+ * @type: the type of the container struct this is embedded in.
+ * @member: the name of the member within the struct.
+ *
+ */
+#define container_of(ptr, type, member) ({ \
+ const typeof( ((type *)0)->member ) *__mptr = (ptr); \
+ (type *)( (char *)__mptr - offsetof(type,member) );})
+
+struct list_head {
+ struct list_head *next, *prev;
+};
+
+#define LIST_HEAD_INIT(name) { &(name), &(name) }
+
+#define LIST_HEAD(name) \
+ struct list_head name = LIST_HEAD_INIT(name)
+
+static inline void INIT_LIST_HEAD(struct list_head *list)
+{
+ WRITE_ONCE(list->next, list);
+ list->prev = list;
+}
+
+/*
+ * Insert a new entry between two known consecutive entries.
+ *
+ * This is only for internal list manipulation where we know
+ * the prev/next entries already!
+ */
+static inline void __list_add(struct list_head *new,
+ struct list_head *prev,
+ struct list_head *next)
+{
+ next->prev = new;
+ new->next = next;
+ new->prev = prev;
+ WRITE_ONCE(prev->next, new);
+}
+
+/**
+ * list_add - add a new entry
+ * @new: new entry to be added
+ * @head: list head to add it after
+ *
+ * Insert a new entry after the specified head.
+ * This is good for implementing stacks.
+ */
+static inline void list_add(struct list_head *new, struct list_head *head)
+{
+ __list_add(new, head, head->next);
+}
+
+
+/**
+ * list_add_tail - add a new entry
+ * @new: new entry to be added
+ * @head: list head to add it before
+ *
+ * Insert a new entry before the specified head.
+ * This is useful for implementing queues.
+ */
+static inline void list_add_tail(struct list_head *new, struct list_head *head)
+{
+ __list_add(new, head->prev, head);
+}
+
+/*
+ * Delete a list entry by making the prev/next entries
+ * point to each other.
+ *
+ * This is only for internal list manipulation where we know
+ * the prev/next entries already!
+ */
+static inline void __list_del(struct list_head * prev, struct list_head * next)
+{
+ next->prev = prev;
+ WRITE_ONCE(prev->next, next);
+}
+
+/**
+ * list_del - deletes entry from list.
+ * @entry: the element to delete from the list.
+ * Note: list_empty() on entry does not return true after this, the entry is
+ * in an undefined state.
+ */
+static inline void __list_del_entry(struct list_head *entry)
+{
+ __list_del(entry->prev, entry->next);
+}
+
+static inline void list_del(struct list_head *entry)
+{
+ __list_del(entry->prev, entry->next);
+}
+
+/**
+ * list_is_last - tests whether @list is the last entry in list @head
+ * @list: the entry to test
+ * @head: the head of the list
+ */
+static inline int list_is_last(const struct list_head *list,
+ const struct list_head *head)
+{
+ return list->next == head;
+}
+
+/**
+ * list_empty - tests whether a list is empty
+ * @head: the list to test.
+ */
+static inline int list_empty(const struct list_head *head)
+{
+ return READ_ONCE(head->next) == head;
+}
+
+/**
+ * list_entry - get the struct for this entry
+ * @ptr: the &struct list_head pointer.
+ * @type: the type of the struct this is embedded in.
+ * @member: the name of the list_head within the struct.
+ */
+#define list_entry(ptr, type, member) \
+ container_of(ptr, type, member)
+
+/**
+ * list_first_entry - get the first element from a list
+ * @ptr: the list head to take the element from.
+ * @type: the type of the struct this is embedded in.
+ * @member: the name of the list_head within the struct.
+ *
+ * Note, that list is expected to be not empty.
+ */
+#define list_first_entry(ptr, type, member) \
+ list_entry((ptr)->next, type, member)
+
+/**
+ * list_last_entry - get the last element from a list
+ * @ptr: the list head to take the element from.
+ * @type: the type of the struct this is embedded in.
+ * @member: the name of the list_head within the struct.
+ *
+ * Note, that list is expected to be not empty.
+ */
+#define list_last_entry(ptr, type, member) \
+ list_entry((ptr)->prev, type, member)
+
+/**
+ * list_first_entry_or_null - get the first element from a list
+ * @ptr: the list head to take the element from.
+ * @type: the type of the struct this is embedded in.
+ * @member: the name of the list_head within the struct.
+ *
+ * Note that if the list is empty, it returns NULL.
+ */
+#define list_first_entry_or_null(ptr, type, member) \
+ (!list_empty(ptr) ? list_first_entry(ptr, type, member) : NULL)
+
+/**
+ * list_next_entry - get the next element in list
+ * @pos: the type * to cursor
+ * @member: the name of the list_head within the struct.
+ */
+#define list_next_entry(pos, member) \
+ list_entry((pos)->member.next, typeof(*(pos)), member)
+
+/**
+ * list_prev_entry - get the prev element in list
+ * @pos: the type * to cursor
+ * @member: the name of the list_head within the struct.
+ */
+#define list_prev_entry(pos, member) \
+ list_entry((pos)->member.prev, typeof(*(pos)), member)
+
+/**
+ * list_for_each - iterate over a list
+ * @pos: the &struct list_head to use as a loop cursor.
+ * @head: the head for your list.
+ */
+#define list_for_each(pos, head) \
+ for (pos = (head)->next; pos != (head); pos = pos->next)
+
+/**
+ * list_for_each_prev - iterate over a list backwards
+ * @pos: the &struct list_head to use as a loop cursor.
+ * @head: the head for your list.
+ */
+#define list_for_each_prev(pos, head) \
+ for (pos = (head)->prev; pos != (head); pos = pos->prev)
+
+/**
+ * list_for_each_safe - iterate over a list safe against removal of list entry
+ * @pos: the &struct list_head to use as a loop cursor.
+ * @n: another &struct list_head to use as temporary storage
+ * @head: the head for your list.
+ */
+#define list_for_each_safe(pos, n, head) \
+ for (pos = (head)->next, n = pos->next; pos != (head); \
+ pos = n, n = pos->next)
+
+/**
+ * list_for_each_prev_safe - iterate over a list backwards safe against removal of list entry
+ * @pos: the &struct list_head to use as a loop cursor.
+ * @n: another &struct list_head to use as temporary storage
+ * @head: the head for your list.
+ */
+#define list_for_each_prev_safe(pos, n, head) \
+ for (pos = (head)->prev, n = pos->prev; \
+ pos != (head); \
+ pos = n, n = pos->prev)
+
+/**
+ * list_for_each_entry - iterate over list of given type
+ * @pos: the type * to use as a loop cursor.
+ * @head: the head for your list.
+ * @member: the name of the list_head within the struct.
+ */
+#define list_for_each_entry(pos, head, member) \
+ for (pos = list_first_entry(head, typeof(*pos), member); \
+ &pos->member != (head); \
+ pos = list_next_entry(pos, member))
+
+/**
+ * list_for_each_entry_reverse - iterate backwards over list of given type.
+ * @pos: the type * to use as a loop cursor.
+ * @head: the head for your list.
+ * @member: the name of the list_head within the struct.
+ */
+#define list_for_each_entry_reverse(pos, head, member) \
+ for (pos = list_last_entry(head, typeof(*pos), member); \
+ &pos->member != (head); \
+ pos = list_prev_entry(pos, member))
+
+/**
+ * list_prepare_entry - prepare a pos entry for use in list_for_each_entry_continue()
+ * @pos: the type * to use as a start point
+ * @head: the head of the list
+ * @member: the name of the list_head within the struct.
+ *
+ * Prepares a pos entry for use as a start point in list_for_each_entry_continue().
+ */
+#define list_prepare_entry(pos, head, member) \
+ ((pos) ? : list_entry(head, typeof(*pos), member))
+
+/**
+ * list_for_each_entry_continue - continue iteration over list of given type
+ * @pos: the type * to use as a loop cursor.
+ * @head: the head for your list.
+ * @member: the name of the list_head within the struct.
+ *
+ * Continue to iterate over list of given type, continuing after
+ * the current position.
+ */
+#define list_for_each_entry_continue(pos, head, member) \
+ for (pos = list_next_entry(pos, member); \
+ &pos->member != (head); \
+ pos = list_next_entry(pos, member))
+
+/**
+ * list_for_each_entry_continue_reverse - iterate backwards from the given point
+ * @pos: the type * to use as a loop cursor.
+ * @head: the head for your list.
+ * @member: the name of the list_head within the struct.
+ *
+ * Start to iterate over list of given type backwards, continuing after
+ * the current position.
+ */
+#define list_for_each_entry_continue_reverse(pos, head, member) \
+ for (pos = list_prev_entry(pos, member); \
+ &pos->member != (head); \
+ pos = list_prev_entry(pos, member))
+
+/**
+ * list_for_each_entry_from - iterate over list of given type from the current point
+ * @pos: the type * to use as a loop cursor.
+ * @head: the head for your list.
+ * @member: the name of the list_head within the struct.
+ *
+ * Iterate over list of given type, continuing from current position.
+ */
+#define list_for_each_entry_from(pos, head, member) \
+ for (; &pos->member != (head); \
+ pos = list_next_entry(pos, member))
+
+/**
+ * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry
+ * @pos: the type * to use as a loop cursor.
+ * @n: another type * to use as temporary storage
+ * @head: the head for your list.
+ * @member: the name of the list_head within the struct.
+ */
+#define list_for_each_entry_safe(pos, n, head, member) \
+ for (pos = list_first_entry(head, typeof(*pos), member), \
+ n = list_next_entry(pos, member); \
+ &pos->member != (head); \
+ pos = n, n = list_next_entry(n, member))
+
+/**
+ * list_for_each_entry_safe_continue - continue list iteration safe against removal
+ * @pos: the type * to use as a loop cursor.
+ * @n: another type * to use as temporary storage
+ * @head: the head for your list.
+ * @member: the name of the list_head within the struct.
+ *
+ * Iterate over list of given type, continuing after current point,
+ * safe against removal of list entry.
+ */
+#define list_for_each_entry_safe_continue(pos, n, head, member) \
+ for (pos = list_next_entry(pos, member), \
+ n = list_next_entry(pos, member); \
+ &pos->member != (head); \
+ pos = n, n = list_next_entry(n, member))
+
+/**
+ * list_for_each_entry_safe_from - iterate over list from current point safe against removal
+ * @pos: the type * to use as a loop cursor.
+ * @n: another type * to use as temporary storage
+ * @head: the head for your list.
+ * @member: the name of the list_head within the struct.
+ *
+ * Iterate over list of given type from current point, safe against
+ * removal of list entry.
+ */
+#define list_for_each_entry_safe_from(pos, n, head, member) \
+ for (n = list_next_entry(pos, member); \
+ &pos->member != (head); \
+ pos = n, n = list_next_entry(n, member))
+
+/**
+ * list_for_each_entry_safe_reverse - iterate backwards over list safe against removal
+ * @pos: the type * to use as a loop cursor.
+ * @n: another type * to use as temporary storage
+ * @head: the head for your list.
+ * @member: the name of the list_head within the struct.
+ *
+ * Iterate backwards over list of given type, safe against removal
+ * of list entry.
+ */
+#define list_for_each_entry_safe_reverse(pos, n, head, member) \
+ for (pos = list_last_entry(head, typeof(*pos), member), \
+ n = list_prev_entry(pos, member); \
+ &pos->member != (head); \
+ pos = n, n = list_prev_entry(n, member))
+
+/**
+ * list_safe_reset_next - reset a stale list_for_each_entry_safe loop
+ * @pos: the loop cursor used in the list_for_each_entry_safe loop
+ * @n: temporary storage used in list_for_each_entry_safe
+ * @member: the name of the list_head within the struct.
+ *
+ * list_safe_reset_next is not safe to use in general if the list may be
+ * modified concurrently (eg. the lock is dropped in the loop body). An
+ * exception to this is if the cursor element (pos) is pinned in the list,
+ * and list_safe_reset_next is called after re-taking the lock and before
+ * completing the current iteration of the loop body.
+ */
+#define list_safe_reset_next(pos, n, member) \
+ n = list_next_entry(pos, member)
+
+#endif
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index bd83497..f1a9bbc 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -1960,6 +1960,13 @@ static void read_symbols(char *modname)
"license", license);
}

+ /*
+ * For livepatch modules, any unresolved symbols will get resolved
+ * after linking by klp-convert.
+ */
+ if (get_modinfo(info.modinfo, info.modinfo_len, "livepatch"))
+ mod->livepatch = 1;
+
for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
symname = remove_dot(info.strtab + sym->st_name);

@@ -2153,7 +2160,7 @@ static int add_versions(struct buffer *b, struct module *mod)
for (s = mod->unres; s; s = s->next) {
exp = find_symbol(s->name);
if (!exp || exp->module == mod) {
- if (have_vmlinux && !s->weak) {
+ if (have_vmlinux && !s->weak && !mod->livepatch) {
if (warn_unresolved) {
warn("\"%s\" [%s.ko] undefined!\n",
s->name, mod->name);
diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h
index 6a5e151..dcb32a5 100644
--- a/scripts/mod/modpost.h
+++ b/scripts/mod/modpost.h
@@ -117,6 +117,7 @@ struct module {
int skip;
int has_init;
int has_cleanup;
+ int livepatch;
struct buffer dev_table_buf;
char srcversion[25];
int is_dot_o;
--
2.7.4