When booting, initialize eh_frame for use in the DWARF unwinder. Do the
same for every coming module's info.
And destroy the information when a module is going away.
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
Cc: Jessica Yu <jeyu@xxxxxxxxxx>
Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
---
include/linux/module.h | 4 ++++
init/main.c | 3 +++
kernel/module.c | 32 +++++++++++++++++++++++++++++++-
3 files changed, 38 insertions(+), 1 deletion(-)
diff --git a/include/linux/module.h b/include/linux/module.h
index 21f56393602f..21f7a23f8004 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -257,6 +257,7 @@ extern const typeof(name) __mod_##type##__##name##_device_table \
* files require multiple MODULE_FIRMWARE() specifiers */
#define MODULE_FIRMWARE(_firmware) MODULE_INFO(firmware, _firmware)
+struct dwarf_table;
struct notifier_block;
#ifdef CONFIG_MODULES
@@ -393,6 +394,9 @@ struct module {
struct module_layout core_layout __module_layout_align;
struct module_layout init_layout;
+ /* The handle returned from dwarf_add_table. */
+ struct dwarf_table *dwarf_info;
+
/* Arch-specific module values */
struct mod_arch_specific arch;
diff --git a/init/main.c b/init/main.c
index cc48053bb39f..5acedeae355d 100644
--- a/init/main.c
+++ b/init/main.c
@@ -22,6 +22,7 @@
#include <linux/string.h>
#include <linux/ctype.h>
#include <linux/delay.h>
+#include <linux/dwarf.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/initrd.h>
@@ -490,6 +491,7 @@ asmlinkage __visible void __init start_kernel(void)
char *command_line;
char *after_dashes;
+ dwarf_init();
set_task_stack_end_magic(&init_task);
smp_setup_processor_id();
debug_objects_early_init();
@@ -514,6 +516,7 @@ asmlinkage __visible void __init start_kernel(void)
setup_arch(&command_line);
mm_init_cpumask(&init_mm);
setup_command_line(command_line);
+ dwarf_setup();
setup_nr_cpu_ids();
setup_per_cpu_areas();
boot_cpu_state_init();
diff --git a/kernel/module.c b/kernel/module.c
index 4a3665f8f837..3571328e41fe 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -38,6 +38,7 @@
#include <linux/capability.h>
#include <linux/cpu.h>
#include <linux/moduleparam.h>
+#include <linux/dwarf.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/vermagic.h>
@@ -314,7 +315,7 @@ struct load_info {
unsigned long mod_kallsyms_init_off;
#endif
struct {
- unsigned int sym, str, mod, vers, info, pcpu;
+ unsigned int sym, str, mod, vers, info, pcpu, dwarf;
} index;
};
@@ -753,6 +754,27 @@ bool __is_module_percpu_address(unsigned long addr, unsigned long *can_addr)
#endif /* CONFIG_SMP */
+static unsigned int find_dwarf(struct load_info *info)
+{
+ unsigned int section = 0;
+#ifdef ARCH_DWARF_SECTION_NAME
+ section = find_sec(info, ARCH_DWARF_SECTION_NAME);
+ if (section)
+ info->sechdrs[section].sh_flags |= SHF_ALLOC;
+#endif
+ return section;
+}
+
+static void add_dwarf_table(struct module *mod, struct load_info *info)
+{
+ int index = info->index.dwarf;
+
+ /* Size of section 0 is 0, so this is ok if there is no dwarf info. */
+ mod->dwarf_info = dwarf_add_table(mod,
+ (void *)info->sechdrs[index].sh_addr,
+ info->sechdrs[index].sh_size);
+}
+
#define MODINFO_ATTR(field) \
static void setup_modinfo_##field(struct module *mod, const char *s) \
{ \
@@ -2133,6 +2155,8 @@ static void free_module(struct module *mod)
/* Remove dynamic debug info */
ddebug_remove_module(mod->name);
+ dwarf_remove_table(mod->dwarf_info, false);
+
/* Arch-specific cleanup. */
module_arch_cleanup(mod);
@@ -2970,6 +2994,8 @@ static struct module *setup_load_info(struct load_info *info, int flags)
info->index.pcpu = find_pcpusec(info);
+ info->index.dwarf = find_dwarf(info);
+
/* Check module struct version now, before we try to use module. */
if (!check_modstruct_version(info->sechdrs, info->index.vers, mod))
return ERR_PTR(-ENOEXEC);
@@ -3459,6 +3485,7 @@ static noinline int do_init_module(struct module *mod)
/* Drop initial reference. */
module_put(mod);
trim_init_extable(mod);
+ dwarf_remove_table(mod->dwarf_info, true);
#ifdef CONFIG_KALLSYMS
/* Switch to core kallsyms now init is done: kallsyms may be walking! */
rcu_assign_pointer(mod->kallsyms, &mod->core_kallsyms);
@@ -3734,6 +3761,9 @@ static int load_module(struct load_info *info, const char __user *uargs,
goto sysfs_cleanup;
}
+ /* Initialize dwarf table */
+ add_dwarf_table(mod, info);
+
/* Get rid of temporary copy. */
free_copy(info);
--
2.12.2
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