[RFC 4/7] Add kernel module support for linux-kernel target

Philipp Rudo
2017-01-12T13:02:27Z

This patch implements module support for the new linux-kernel target by
adding a target_so_ops. In addition this patch adds handling for kernel
virtual addresses. This is necessary because kernel modules, unlike
task_structs, live in kernel virtual address space. Thus addresses need
to be translated before they can be read from. We achieve this by adding
an implementation for the targets to_xfer_partial hook, which translates
the addresses before passing them down to the target beneath.

gdb/ChangeLog:

* lk-modules.h: New file.
* lk-modules.c: New file.
* lk-low.h (lk_hook_is_kvaddr, lk_hook_vtop)
(lk_hook_get_module_text_offset): New arch dependent hooks.
(sturct lk_private_hooks): Add new hooks.
(LK_MODULES_NAME_LEN, LK_UTS_NAME_LEN): New define.
* lk-low.c (lk-modules.h): New include.
(lk_kvtop, restore_current_target, lk_xfer_partial): New functions.
(lk_init_private_data): Declare needed debug symbols.
(lk_try_push_target): Assert for new hooks and set solib_ops.
(init_linux_kernel_ops): Add implementation for to_xfer_partial.
* solib.c (get_solib_search_path): New function.
* solib.h (get_solib_search_path): New export.
* Makefile.in (SFILES, ALLDEPFILES): Add lk-modules.c.
(HFILES_NO_SRCDIR): Add lk-modules.h.
(COMMON_OBS): Add lk-modules.o.
---
gdb/Makefile.in | 4 +
gdb/lk-low.c | 101 ++++++++++++++
gdb/lk-low.h | 29 +++-
gdb/lk-modules.c | 412 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
gdb/lk-modules.h | 29 ++++
gdb/solib.c | 8 ++
gdb/solib.h | 5 +
7 files changed, 586 insertions(+), 2 deletions(-)
create mode 100644 gdb/lk-modules.c
create mode 100644 gdb/lk-modules.h

diff --git a/gdb/Makefile.in b/gdb/Makefile.in
index fef5c2e..be8a91d 100644
--- a/gdb/Makefile.in
+++ b/gdb/Makefile.in
@@ -1094,6 +1094,7 @@ SFILES = \
linespec.c \
lk-lists.c \
lk-low.c \
+ lk-modules.c \
location.c \
m2-exp.y \
m2-lang.c \
@@ -1342,6 +1343,7 @@ HFILES_NO_SRCDIR = \
linux-tdep.h \
lk-lists.h \
lk-low.h \
+ lk-modules.h \
location.h \
m2-lang.h \
m32r-tdep.h \
@@ -1701,6 +1703,7 @@ COMMON_OBS = $(DEPFILES) $(CONFIG_OBS) $(YYOBJ) \
language.o \
linespec.o \
lk-lists.o \
+ lk-modules.o \
location.o \
m2-lang.o \
m2-typeprint.o \
@@ -2534,6 +2537,7 @@ ALLDEPFILES = \
linux-tdep.c \
lk-lists.c \
lk-low.c \
+ lk-modules.c \
lm32-tdep.c \
m32r-linux-nat.c \
m32r-linux-tdep.c \
diff --git a/gdb/lk-low.c b/gdb/lk-low.c
index ee753a4..81ff61c 100644
--- a/gdb/lk-low.c
+++ b/gdb/lk-low.c
@@ -29,6 +29,7 @@
#include "inferior.h"
#include "lk-lists.h"
#include "lk-low.h"
+#include "lk-modules.h"
#include "objfiles.h"
#include "observer.h"
#include "solib.h"
@@ -564,6 +565,46 @@ lk_thread_name (struct target_ops *target, struct thread_info *ti)
return buf;
}

+/* Translate a kernel virtual address ADDR to a physical address. */
+
+CORE_ADDR
+lk_kvtop (CORE_ADDR addr)
+{
+ CORE_ADDR pgd = lk_read_addr (LK_ADDR (init_mm)
+ + LK_OFFSET (mm_struct, pgd));
+ return LK_HOOK->vtop (pgd, addr);
+}
+
+/* Restore current_target to TARGET. */
+static void
+restore_current_target (void *target)
+{
+ current_target.beneath = (struct target_ops *) target;
+}
+
+/* Function for targets to_xfer_partial hook. */
+
+enum target_xfer_status
+lk_xfer_partial (struct target_ops *ops, enum target_object object,
+ const char *annex, gdb_byte *readbuf,
+ const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
+ ULONGEST *xfered_len)
+{
+ enum target_xfer_status ret_val;
+ struct cleanup *old_chain = make_cleanup (restore_current_target, ops);
+
+ current_target.beneath = ops->beneath;
+
+ if (LK_HOOK->is_kvaddr (offset))
+ offset = lk_kvtop (offset);
+
+ ret_val = ops->beneath->to_xfer_partial (ops->beneath, object, annex,
+ readbuf, writebuf, offset, len,
+ xfered_len);
+ do_cleanups (old_chain);
+ return ret_val;
+}
+
/* Functions to initialize and free target_ops and its private data. As well
as functions for targets to_open/close/detach hooks. */

@@ -599,6 +640,9 @@ lk_init_private ()
/* Initialize architecture independent private data. Must be called
_after_ symbol tables were initialized. */

+/* FIXME: throw error more fine-grained. */
+/* FIXME: make independent of compile options. */
+
static void
lk_init_private_data ()
{
@@ -619,10 +663,61 @@ lk_init_private_data ()

LK_DECLARE_FIELD (cpumask, bits);

+ LK_DECLARE_FIELD (mm_struct, pgd);
+
+ LK_DECLARE_FIELD (pgd_t, pgd);
+
+ LK_DECLARE_FIELD (module, list);
+ LK_DECLARE_FIELD (module, name);
+ LK_DECLARE_FIELD (module, source_list);
+ LK_DECLARE_FIELD (module, arch);
+ LK_DECLARE_FIELD (module, init);
+ LK_DECLARE_FIELD (module, percpu);
+ LK_DECLARE_FIELD (module, percpu_size);
+
+ /* Module offset moved to new struct module_layout with linux 4.5.
+ It must be checked in code which of this fields exist. */
+ if (LK_DECLARE_FIELD_SILENT (module_layout, base)) /* linux 4.5+ */
+ {
+ LK_DECLARE_FIELD (module, init_layout);
+ LK_DECLARE_FIELD (module, core_layout);
+
+ LK_DECLARE_FIELD (module_layout, size);
+ LK_DECLARE_FIELD (module_layout, text_size);
+ LK_DECLARE_FIELD (module_layout, ro_size);
+ }
+ else if (LK_DECLARE_FIELD_SILENT (module, module_core)) /* linux -4.4 */
+ {
+ LK_DECLARE_FIELD (module, init_size);
+ LK_DECLARE_FIELD (module, core_size);
+
+ LK_DECLARE_FIELD (module, core_text_size);
+ LK_DECLARE_FIELD (module, core_ro_size);
+ }
+ else
+ {
+ error (_("Could not find module base. Abort."));
+ }
+
+ LK_DECLARE_FIELD (module_use, source_list);
+ LK_DECLARE_FIELD (module_use, source);
+
+ LK_DECLARE_FIELD (uts_namespace, name);
+
+ LK_DECLARE_STRUCT_ALIAS (new_utsname, utsname);
+ LK_DECLARE_STRUCT_ALIAS (old_utsname, utsname);
+ LK_DECLARE_STRUCT_ALIAS (oldold_utsname, utsname);
+ if (LK_STRUCT (utsname) == NULL)
+ error (_("Could not find struct utsname. Abort."));
+ LK_DECLARE_FIELD (utsname, version);
+ LK_DECLARE_FIELD (utsname, release);
+
LK_DECLARE_ADDR (init_task);
LK_DECLARE_ADDR (runqueues);
LK_DECLARE_ADDR (__per_cpu_offset);
LK_DECLARE_ADDR (init_mm);
+ LK_DECLARE_ADDR (modules);
+ LK_DECLARE_ADDR (init_uts_ns);

LK_DECLARE_ADDR_ALIAS (__cpu_online_mask, cpu_online_mask); /* linux 4.5+ */
LK_DECLARE_ADDR_ALIAS (cpu_online_bits, cpu_online_mask); /* linux -4.4 */
@@ -720,12 +815,17 @@ lk_try_push_target ()
gdbarch_lk_init_private (gdbarch);
/* Check for required arch hooks. */
gdb_assert (LK_HOOK->get_registers);
+ gdb_assert (LK_HOOK->is_kvaddr);
+ gdb_assert (LK_HOOK->vtop);
+ gdb_assert (LK_HOOK->get_module_text_offset);

lk_init_ptid_map ();
lk_update_thread_list (linux_kernel_ops);

if (!target_is_pushed (linux_kernel_ops))
push_target (linux_kernel_ops);
+
+ set_solib_ops (gdbarch, lk_modules_so_ops);
}

/* Function for targets to_open hook. */
@@ -838,6 +938,7 @@ init_linux_kernel_ops (void)
t->to_update_thread_list = lk_update_thread_list;
t->to_pid_to_str = lk_pid_to_str;
t->to_thread_name = lk_thread_name;
+ t->to_xfer_partial = lk_xfer_partial;

t->to_stratum = thread_stratum;
t->to_magic = OPS_MAGIC;
diff --git a/gdb/lk-low.h b/gdb/lk-low.h
index 57b7bf4..cde78b6 100644
--- a/gdb/lk-low.h
+++ b/gdb/lk-low.h
@@ -27,6 +27,8 @@ extern struct target_ops *linux_kernel_ops;
/* Copy constants defined in Linux kernel. */
#define LK_TASK_COMM_LEN 16
#define LK_BITS_PER_BYTE 8
+#define LK_MODULE_NAME_LEN 56
+#define LK_UTS_NAME_LEN 64

/* Private data structs for this target. */
/* Forward declarations. */
@@ -200,13 +202,27 @@ typedef void (*lk_hook_get_registers) (CORE_ADDR task,
struct regcache *regcache,
int regnum);

+/* Hook to check if address ADDR is a kernel virtual address.
+ NOTE: This hook is called in the context of target beneath. */
+typedef int (*lk_hook_is_kvaddr) (CORE_ADDR addr);
+
+/* Hook to translate virtual adress ADDR to a pysical address using page
+ table located at PGD.
+ NOTE: This hook is called in the context of target beneath. */
+typedef CORE_ADDR (*lk_hook_vtop) (CORE_ADDR addr, CORE_ADDR pgd);
+
+/* Hook to get the offset between a modules base and the start of its
+ .text section. */
+
+typedef CORE_ADDR (*lk_hook_get_module_text_offset) (CORE_ADDR mod);
+
/* Hook to return the per_cpu_offset of cpu CPU. Only architectures that
do not use the __per_cpu_offset array to determin the offset have to
supply this hook. */
typedef CORE_ADDR (*lk_hook_get_percpu_offset) (int cpu);

-/* Hook to map a running task to a logical CPU. Required if the target beneath
- uses a different PID as struct rq. */
+/* Hook to map a running task to a logical CPU. Required if the target
+ beneath uses a different PID as struct rq. */
typedef int (*lk_hook_map_running_task_to_cpu) (struct thread_info *ti);

struct lk_private_hooks
@@ -214,6 +230,15 @@ struct lk_private_hooks
/* required */
lk_hook_get_registers get_registers;

+ /* required */
+ lk_hook_is_kvaddr is_kvaddr;
+
+ /* required */
+ lk_hook_vtop vtop;
+
+ /* reqired */
+ lk_hook_get_module_text_offset get_module_text_offset;
+
/* optional, required if __per_cpu_offset array is not used to determine
offset. */
lk_hook_get_percpu_offset get_percpu_offset;
diff --git a/gdb/lk-modules.c b/gdb/lk-modules.c
new file mode 100644
index 0000000..8bb04d6
--- /dev/null
+++ b/gdb/lk-modules.c
@@ -0,0 +1,412 @@
+/* Handle Linux kernel modules as shared libraries.
+
+ Copyright (C) 2016 Free Software Foundation, Inc.
+
+ This file is part of GDB.
+
+ 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 3 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 "defs.h"
+
+#include "common/filestuff.h"
+#include "filenames.h"
+#include "gdbcmd.h"
+#include "gdbcore.h"
+#include "gdb_regex.h"
+#include "lk-lists.h"
+#include "lk-low.h"
+#include "lk-modules.h"
+#include "objfiles.h"
+#include "observer.h"
+#include "readline/readline.h"
+#include "solib.h"
+#include "solist.h"
+#include "utils.h"
+
+#include <unordered_map>
+#include <string>
+
+struct target_so_ops *lk_modules_so_ops = NULL;
+
+/* Info for single section type. */
+
+struct lm_info_sec
+{
+ CORE_ADDR start;
+ CORE_ADDR offset;
+ unsigned int size;
+};
+
+/* Link map info to include in an allocated so_list entry. */
+
+struct lm_info
+{
+ CORE_ADDR base;
+ unsigned int size;
+
+ struct lm_info_sec text;
+ struct lm_info_sec init_text;
+ struct lm_info_sec ro_data;
+ struct lm_info_sec rw_data;
+ struct lm_info_sec percpu;
+};
+
+/* Check if debug info for module NAME are loaded. */
+
+bool
+lk_modules_debug_info_loaded (const std::string &name)
+{
+ struct so_list *so;
+
+ for (so = master_so_list (); so; so = so->next)
+ {
+ if (name == so->so_original_name)
+ return (so->symbols_loaded && objfile_has_symbols (so->objfile));
+ }
+
+ return false;
+}
+
+/* Replace tags, like '$release', with corresponding data in
+ solib_search_path.
+
+ Known tags:
+ $release Linux kernel release, same as 'uname -r'
+
+ Returns the expanded path. */
+
+static std::string
+lk_modules_expand_search_path ()
+{
+ char release[LK_UTS_NAME_LEN + 1];
+ CORE_ADDR utsname;
+
+ utsname = LK_ADDR (init_uts_ns) + LK_OFFSET (uts_namespace, name);
+ read_memory_string (utsname + LK_OFFSET (utsname, release),
+ release, LK_UTS_NAME_LEN);
+ release[LK_UTS_NAME_LEN] = '\0';
+
+ std::string search_path = get_solib_search_path ();
+ substitute_path_component (search_path, "$release", release);
+
+ return search_path;
+}
+
+/* With kernel modules there is the problem that the kernel only stores
+ the modules name but not the path from wich it was loaded from.
+ Thus we need to map the name to a path GDB can read from. We use file
+ modules.order to do so. It is created by kbuild containing the order in
+ which the modules appear in the Makefile and is also used by modprobe.
+ The drawback of this method is that it needs the modules.order file and
+ all relative paths, starting from <solib-search-path>, must be exactly the
+ same as decribed in it. */
+
+/* Open file <solib-search-path>/modules.order and return its file
+ pointer. */
+
+FILE *
+lk_modules_open_mod_order ()
+{
+ FILE *mod_order;
+ std::string filename = concat_path (lk_modules_expand_search_path (),
+ "modules.order");
+ mod_order = gdb_fopen_cloexec (filename.c_str (), "r");
+
+ if (!mod_order)
+ {
+ error (_("\
+Can not find file module.order at %s \
+to load module symbol files.\n\
+Please check if solib-search-path is set correctly."),
+ filename.c_str ());
+ }
+
+ return mod_order;
+}
+
+/* Build map between module name and path to binary file by reading file
+ modules.order. Returns unordered_map with module name as key and its
+ path as value. */
+
+std::unordered_map<std::string, std::string>
+lk_modules_build_path_map ()
+{
+ std::unordered_map<std::string, std::string> umap;
+ FILE *mod_order;
+ struct cleanup *old_chain;
+ char line[SO_NAME_MAX_PATH_SIZE + 1];
+
+ mod_order = lk_modules_open_mod_order ();
+ old_chain = make_cleanup_fclose (mod_order);
+
+ line[SO_NAME_MAX_PATH_SIZE] = '\0';
+ std::string search_path = lk_modules_expand_search_path ();
+ while (fgets (line, SO_NAME_MAX_PATH_SIZE, mod_order))
+ {
+ /* Remove trailing newline. */
+ line[strlen (line) - 1] = '\0';
+
+ std::string name = lbasename (line);
+
+ /* 3 = strlen (".ko"). */
+ if (!endswith (name, ".ko")
+ || name.length () >= LK_MODULE_NAME_LEN + 3)
+ continue;
+
+ name = name.substr (0, name.length () - 3);
+
+ /* Kernel modules are named after the files they are stored in with
+ all minus '-' replaced by underscore '_'. Do the same to enable
+ mapping. */
+ for (size_t p = name.find('-'); p != std::string::npos;
+ p = name.find ('-', p + 1))
+ name[p] = '_';
+
+ umap[name] = concat_path(search_path, line);
+ }
+
+ do_cleanups (old_chain);
+ return umap;
+}
+
+/* Allocate and fill a copy of struct lm_info for module at address MOD. */
+
+struct lm_info *
+lk_modules_read_lm_info (CORE_ADDR mod)
+{
+ struct lm_info *lmi = XNEW (struct lm_info);
+ struct cleanup *old_chain = make_cleanup (xfree, lmi);
+
+ if (LK_FIELD (module, module_core)) /* linux -4.4 */
+ {
+ lmi->base = lk_read_addr (mod + LK_OFFSET (module, module_core));
+ lmi->size = lk_read_addr (mod + LK_OFFSET (module, core_size));
+
+ lmi->text.start = lmi->base;
+ lmi->text.offset = LK_HOOK->get_module_text_offset (mod);
+ lmi->text.size = lk_read_uint (mod + LK_OFFSET (module, core_text_size));
+
+ lmi->ro_data.start = lmi->base + lmi->text.size;
+ lmi->ro_data.offset = 0;
+ lmi->ro_data.size = lk_read_uint (mod + LK_OFFSET (module,
+ core_ro_size));
+ }
+ else /* linux 4.5+ */
+ {
+ CORE_ADDR mod_core = mod + LK_OFFSET (module, core_layout);
+
+ lmi->base = lk_read_addr (mod_core
+ + LK_OFFSET (module_layout, base));
+ lmi->size = lk_read_uint (mod_core
+ + LK_OFFSET (module_layout, size));
+
+ lmi->text.start = lmi->base;
+ lmi->text.offset = LK_HOOK->get_module_text_offset (mod);
+ lmi->text.size = lk_read_uint (mod_core
+ + LK_OFFSET (module_layout, text_size));
+
+ lmi->ro_data.start = lmi->base + lmi->text.size;
+ lmi->ro_data.offset = 0;
+ lmi->ro_data.size = lk_read_uint (mod_core
+ + LK_OFFSET (module_layout, ro_size));
+ }
+
+ lmi->rw_data.start = lmi->base + lmi->ro_data.size;
+ lmi->rw_data.offset = 0;
+ lmi->rw_data.size = lmi->size - lmi->ro_data.size;
+
+ lmi->init_text.start = lk_read_addr (mod + LK_OFFSET (module, init));
+ lmi->init_text.offset = 0;
+
+ lmi->percpu.start = lk_read_addr (mod + LK_OFFSET (module, percpu));
+ lmi->percpu.size = lk_read_uint (mod + LK_OFFSET (module, percpu_size));
+ lmi->percpu.offset = 0;
+
+ discard_cleanups (old_chain);
+ return lmi;
+}
+
+/* Function for current_sos hook. */
+
+struct so_list *
+lk_modules_current_sos (void)
+{
+ CORE_ADDR modules, next;
+ FILE *mod_order;
+ struct so_list *list = NULL;
+ std::unordered_map<std::string, std::string> umap;
+
+ umap = lk_modules_build_path_map ();
+ modules = LK_ADDR (modules);
+ lk_list_for_each (next, modules, module, list)
+ {
+ char name[LK_MODULE_NAME_LEN];
+ CORE_ADDR mod, name_addr;
+
+ mod = LK_CONTAINER_OF (next, module, list);
+ name_addr = mod + LK_OFFSET (module, name);
+ read_memory_string (name_addr, name, LK_MODULE_NAME_LEN);
+
+ if (umap.count (name))
+ {
+ struct so_list *newso = XCNEW (struct so_list);
+
+ newso->next = list;
+ list = newso;
+ newso->lm_info = lk_modules_read_lm_info (mod);
+ strncpy (newso->so_original_name, name, SO_NAME_MAX_PATH_SIZE);
+ strncpy (newso->so_name, umap[name].c_str (), SO_NAME_MAX_PATH_SIZE);
+ newso->pspace = current_program_space;
+ }
+ }
+
+ return list;
+}
+
+/* Relocate target_section SEC to section type LMI_SEC. Helper function for
+ lk_modules_relocate_section_addresses. */
+
+void
+lk_modules_relocate_sec (struct target_section *sec,
+ struct lm_info_sec *lmi_sec)
+{
+ unsigned int alignment = 1;
+
+ alignment = 1 << sec->the_bfd_section->alignment_power;
+
+ /* Adjust offset to section alignment. */
+ if (lmi_sec->offset % alignment != 0)
+ lmi_sec->offset += alignment - (lmi_sec->offset % alignment);
+
+ sec->addr += lmi_sec->start + lmi_sec->offset;
+ sec->endaddr += lmi_sec->start + lmi_sec->offset;
+ lmi_sec->offset += sec->endaddr - sec->addr;
+}
+
+/* Function for relocate_section_addresses hook. */
+
+void
+lk_modules_relocate_section_addresses (struct so_list *so,
+ struct target_section *sec)
+{
+ struct lm_info *lmi = so->lm_info;
+ unsigned int flags = sec->the_bfd_section->flags;
+ const char *name = sec->the_bfd_section->name;
+
+ if (streq (name, ".modinfo") || streq (name, "__versions"))
+ return;
+
+ /* FIXME: Make dependent on module state, i.e. only map .init sections if
+ * state is MODULE_STATE_COMING. */
+ if (startswith (name, ".init"))
+ lk_modules_relocate_sec (sec, &lmi->init_text);
+ else if (endswith (name, ".percpu"))
+ lk_modules_relocate_sec (sec, &lmi->percpu);
+ else if (flags & SEC_CODE)
+ lk_modules_relocate_sec (sec, &lmi->text);
+ else if (flags & SEC_READONLY)
+ lk_modules_relocate_sec (sec, &lmi->ro_data);
+ else if (flags & SEC_ALLOC)
+ lk_modules_relocate_sec (sec, &lmi->rw_data);
+
+ /* Set address range to be displayed with info shared.
+ size = text + (ro + rw) data without .init sections. */
+ if (so->addr_low == so->addr_high)
+ {
+ so->addr_low = lmi->base;
+ so->addr_high = lmi->base + lmi->size;
+ }
+}
+
+/* Function for free_so hook. */
+
+void
+lk_modules_free_so (struct so_list *so)
+{
+ xfree (so->lm_info);
+}
+
+/* Function for clear_so hook. */
+
+void
+lk_modules_clear_so (struct so_list *so)
+{
+ if (so->lm_info != NULL)
+ memset (so->lm_info, 0, sizeof (struct lm_info));
+}
+
+/* Function for clear_solib hook. */
+
+void
+lk_modules_clear_solib ()
+{
+ /* Nothing to do. */
+}
+
+/* Function for clear_create_inferior_hook hook. */
+
+void
+lk_modules_create_inferior_hook (int from_tty)
+{
+ /* Nothing to do. */
+}
+
+/* Function for clear_create_inferior_hook hook. */
+
+int
+lk_modules_in_dynsym_resolve_code (CORE_ADDR pc)
+{
+ return 0;
+}
+
+/* Function for same hook. */
+
+int
+lk_modules_same (struct so_list *gdb, struct so_list *inf)
+{
+ return streq (gdb->so_name, inf->so_name);
+}
+
+/* Initialize linux modules solib target. */
+
+void
+init_lk_modules_so_ops (void)
+{
+ struct target_so_ops *t;
+
+ if (lk_modules_so_ops != NULL)
+ return;
+
+ t = XCNEW (struct target_so_ops);
+ t->relocate_section_addresses = lk_modules_relocate_section_addresses;
+ t->free_so = lk_modules_free_so;
+ t->clear_so = lk_modules_clear_so;
+ t->clear_solib = lk_modules_clear_solib;
+ t->solib_create_inferior_hook = lk_modules_create_inferior_hook;
+ t->current_sos = lk_modules_current_sos;
+ t->bfd_open = solib_bfd_open;
+ t->in_dynsym_resolve_code = lk_modules_in_dynsym_resolve_code;
+ t->same = lk_modules_same;
+
+ lk_modules_so_ops = t;
+}
+
+/* Provide a prototype to silence -Wmissing-prototypes. */
+extern initialize_file_ftype _initialize_lk_modules;
+
+void
+_initialize_lk_modules (void)
+{
+ init_lk_modules_so_ops ();
+}
diff --git a/gdb/lk-modules.h b/gdb/lk-modules.h
new file mode 100644
index 0000000..47e6dde
--- /dev/null
+++ b/gdb/lk-modules.h
@@ -0,0 +1,29 @@
+/* Handle kernel modules as shared libraries.
+
+ Copyright (C) 2016 Free Software Foundation, Inc.
+
+ This file is part of GDB.
+
+ 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 3 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 __LK_MODULES_H__
+#define __LK_MODULES_H__
+
+extern struct target_so_ops *lk_modules_so_ops;
+
+/* Check if debug info for module NAME are loaded. Needed by lsmod command. */
+
+extern bool lk_modules_debug_info_loaded (const std::string &name);
+
+#endif /* __LK_MODULES_H__ */
diff --git a/gdb/solib.c b/gdb/solib.c
index fc45133..595828a 100644
--- a/gdb/solib.c
+++ b/gdb/solib.c
@@ -107,6 +107,14 @@ show_solib_search_path (struct ui_file *file, int from_tty,
value);
}

+/* see solib.h. */
+
+const char *
+get_solib_search_path ()
+{
+ return solib_search_path ? solib_search_path : "";
+}
+
/* Same as HAVE_DOS_BASED_FILE_SYSTEM, but useable as an rvalue. */
#if (HAVE_DOS_BASED_FILE_SYSTEM)
# define DOS_BASED_FILE_SYSTEM 1
diff --git a/gdb/solib.h b/gdb/solib.h
index dd07636..99b5cda 100644
--- a/gdb/solib.h
+++ b/gdb/solib.h
@@ -28,6 +28,11 @@ struct program_space;

#include "symfile-add-flags.h"

+/* Returns the solib_search_path. The returned string is malloc'ed and must be
+ freed by the caller. */
+
+extern const char *get_solib_search_path ();
+
/* Called when we free all symtabs, to free the shared library information
as well. */

--
2.8.4