[PATCH v13 02/12] livepatch: Helper macros to define livepatch structures

Petr Mladek
2018-10-15T12:37:34Z

The definition of struct klp_func might be a bit confusing.
The original function is defined by name as a string.
The new function is defined by name as a function pointer
casted to unsigned long.

This patch adds helper macros that hide the different types.
The functions are defined just by the name. For example:

static struct klp_func funcs[] = {
{
.old_name = "function_A",
.new_addr = (unsigned long)livepatch_function_A,
}, {
.old_name = "function_B",
.new_addr = (unsigned long)livepatch_function_B,
}, { }
};

can be defined as:

static struct klp_func funcs[] = {
KLP_FUNC(function_A,
livepatch_function_A),
KLP_FUNC(function_B,
livepatch_function_B),
KLP_FUNC_END
};

Just for completeness, this patch adds similar macros to define
struct klp_object. For example,

static struct klp_object objs[] = {
{
/* name being NULL means vmlinux */
.funcs = funcs_vmlinux,
}, {
.name = "module_A",
.funcs = funcs_module_A,
}, {
.name = "module_B",
.funcs = funcs_module_B,
}, { }
};

can be defined as:

static struct klp_object objs[] = {
KLP_VMLINUX(funcs_vmlinux),
KLP_OBJECT(module_A,
funcs_module_A),
KLP_OBJECT(module_B,
funcs_module_B),
KLP_OBJECT_END
};

Signed-off-by: Petr Mladek <pmladek@suse.com>
---
include/linux/livepatch.h | 40 ++++++++++++++++++++
samples/livepatch/livepatch-callbacks-demo.c | 55 +++++++++++-----------------
samples/livepatch/livepatch-sample.c | 13 +++----
samples/livepatch/livepatch-shadow-fix1.c | 20 ++++------
samples/livepatch/livepatch-shadow-fix2.c | 20 ++++------
5 files changed, 83 insertions(+), 65 deletions(-)

diff --git a/include/linux/livepatch.h b/include/linux/livepatch.h
index 817a737b49e8..1163742b27c0 100644
--- a/include/linux/livepatch.h
+++ b/include/linux/livepatch.h
@@ -152,6 +152,46 @@ struct klp_patch {
struct completion finish;
};

+#define KLP_FUNC(_old_func, _new_func) { \
+ .old_name = #_old_func, \
+ .new_addr = (unsigned long)(_new_func), \
+ }
+#define KLP_FUNC_POS(_old_func, _new_func, _sympos) { \
+ .old_name = #_old_func, \
+ .new_addr = (unsigned long)_new_func, \
+ .sympos = _sympos, \
+ }
+#define KLP_FUNC_END { }
+
+#define KLP_OBJECT(_obj, _funcs) { \
+ .name = #_obj, \
+ .funcs = _funcs, \
+ }
+#define KLP_OBJECT_CALLBACKS(_obj, _funcs, \
+ _pre_patch, _post_patch, \
+ _pre_unpatch, _post_unpatch) { \
+ .name = #_obj, \
+ .funcs = _funcs, \
+ .callbacks.pre_patch = _pre_patch, \
+ .callbacks.post_patch = _post_patch, \
+ .callbacks.pre_unpatch = _pre_unpatch, \
+ .callbacks.post_unpatch = _post_unpatch, \
+ }
+/* name being NULL means vmlinux */
+#define KLP_VMLINUX(_funcs) { \
+ .funcs = _funcs, \
+ }
+#define KLP_VMLINUX_CALLBACKS(_funcs, \
+ _pre_patch, _post_patch, \
+ _pre_unpatch, _post_unpatch) { \
+ .funcs = _funcs, \
+ .callbacks.pre_patch = _pre_patch, \
+ .callbacks.post_patch = _post_patch, \
+ .callbacks.pre_unpatch = _pre_unpatch, \
+ .callbacks.post_unpatch = _post_unpatch, \
+ }
+#define KLP_OBJECT_END { }
+
#define klp_for_each_object(patch, obj) \
for (obj = patch->objs; obj->funcs || obj->name; obj++)

diff --git a/samples/livepatch/livepatch-callbacks-demo.c b/samples/livepatch/livepatch-callbacks-demo.c
index 4b1aec474bb7..001a0c672251 100644
--- a/samples/livepatch/livepatch-callbacks-demo.c
+++ b/samples/livepatch/livepatch-callbacks-demo.c
@@ -147,45 +147,34 @@ static void patched_work_func(struct work_struct *work)
}

static struct klp_func no_funcs[] = {
- { }
+ KLP_FUNC_END
};

static struct klp_func busymod_funcs[] = {
- {
- .old_name = "busymod_work_func",
- .new_addr = (unsigned long)patched_work_func,
- }, { }
+ KLP_FUNC(busymod_work_func,
+ patched_work_func),
+ KLP_FUNC_END
};

static struct klp_object objs[] = {
- {
- .name = NULL, /* vmlinux */
- .funcs = no_funcs,
- .callbacks = {
- .pre_patch = pre_patch_callback,
- .post_patch = post_patch_callback,
- .pre_unpatch = pre_unpatch_callback,
- .post_unpatch = post_unpatch_callback,
- },
- }, {
- .name = "livepatch_callbacks_mod",
- .funcs = no_funcs,
- .callbacks = {
- .pre_patch = pre_patch_callback,
- .post_patch = post_patch_callback,
- .pre_unpatch = pre_unpatch_callback,
- .post_unpatch = post_unpatch_callback,
- },
- }, {
- .name = "livepatch_callbacks_busymod",
- .funcs = busymod_funcs,
- .callbacks = {
- .pre_patch = pre_patch_callback,
- .post_patch = post_patch_callback,
- .pre_unpatch = pre_unpatch_callback,
- .post_unpatch = post_unpatch_callback,
- },
- }, { }
+ KLP_VMLINUX_CALLBACKS(no_funcs,
+ pre_patch_callback,
+ post_patch_callback,
+ pre_unpatch_callback,
+ post_unpatch_callback),
+ KLP_OBJECT_CALLBACKS(livepatch_callbacks_mod,
+ no_funcs,
+ pre_patch_callback,
+ post_patch_callback,
+ pre_unpatch_callback,
+ post_unpatch_callback),
+ KLP_OBJECT_CALLBACKS(livepatch_callbacks_busymod,
+ busymod_funcs,
+ pre_patch_callback,
+ post_patch_callback,
+ pre_unpatch_callback,
+ post_unpatch_callback),
+ KLP_OBJECT_END
};

static struct klp_patch patch = {
diff --git a/samples/livepatch/livepatch-sample.c b/samples/livepatch/livepatch-sample.c
index e470a052fb77..de30d1ba4791 100644
--- a/samples/livepatch/livepatch-sample.c
+++ b/samples/livepatch/livepatch-sample.c
@@ -49,17 +49,14 @@ static int livepatch_cmdline_proc_show(struct seq_file *m, void *v)
}

static struct klp_func funcs[] = {
- {
- .old_name = "cmdline_proc_show",
- .new_addr = (unsigned long)livepatch_cmdline_proc_show,
- }, { }
+ KLP_FUNC(cmdline_proc_show,
+ livepatch_cmdline_proc_show),
+ KLP_FUNC_END
};

static struct klp_object objs[] = {
- {
- /* name being NULL means vmlinux */
- .funcs = funcs,
- }, { }
+ KLP_VMLINUX(funcs),
+ KLP_OBJECT_END
};

static struct klp_patch patch = {
diff --git a/samples/livepatch/livepatch-shadow-fix1.c b/samples/livepatch/livepatch-shadow-fix1.c
index ede0de7abe40..8f337b4a9108 100644
--- a/samples/livepatch/livepatch-shadow-fix1.c
+++ b/samples/livepatch/livepatch-shadow-fix1.c
@@ -128,21 +128,17 @@ void livepatch_fix1_dummy_free(struct dummy *d)
}

static struct klp_func funcs[] = {
- {
- .old_name = "dummy_alloc",
- .new_addr = (unsigned long)livepatch_fix1_dummy_alloc,
- },
- {
- .old_name = "dummy_free",
- .new_addr = (unsigned long)livepatch_fix1_dummy_free,
- }, { }
+ KLP_FUNC(dummy_alloc,
+ livepatch_fix1_dummy_alloc),
+ KLP_FUNC(dummy_free,
+ livepatch_fix1_dummy_free),
+ KLP_FUNC_END
};

static struct klp_object objs[] = {
- {
- .name = "livepatch_shadow_mod",
- .funcs = funcs,
- }, { }
+ KLP_OBJECT(livepatch_shadow_mod,
+ funcs),
+ KLP_OBJECT_END
};

static struct klp_patch patch = {
diff --git a/samples/livepatch/livepatch-shadow-fix2.c b/samples/livepatch/livepatch-shadow-fix2.c
index 035ee0ef387f..e8c0c0467bc0 100644
--- a/samples/livepatch/livepatch-shadow-fix2.c
+++ b/samples/livepatch/livepatch-shadow-fix2.c
@@ -105,21 +105,17 @@ void livepatch_fix2_dummy_free(struct dummy *d)
}

static struct klp_func funcs[] = {
- {
- .old_name = "dummy_check",
- .new_addr = (unsigned long)livepatch_fix2_dummy_check,
- },
- {
- .old_name = "dummy_free",
- .new_addr = (unsigned long)livepatch_fix2_dummy_free,
- }, { }
+ KLP_FUNC(dummy_check,
+ livepatch_fix2_dummy_check),
+ KLP_FUNC(dummy_free,
+ livepatch_fix2_dummy_free),
+ KLP_FUNC_END
};

static struct klp_object objs[] = {
- {
- .name = "livepatch_shadow_mod",
- .funcs = funcs,
- }, { }
+ KLP_OBJECT(livepatch_shadow_mod,
+ funcs),
+ KLP_OBJECT_END
};

static struct klp_patch patch = {
--
2.13.7