Merge tag 'v4.0-rc2' into timers/core, to refresh the tree before pulling more changes

9 files changed, 505 insertions, 18 deletions

diff --git a/samples/Kconfig b/samples/Kconfig
index 6181c2cc9ca0..224ebb46bed5 100644
--- a/samples/Kconfig
+++ b/samples/Kconfig
@@ -63,4 +63,11 @@ config SAMPLE_RPMSG_CLIENT
           to communicate with an AMP-configured remote processor over
           the rpmsg bus.
 
+config SAMPLE_LIVEPATCH
+        tristate "Build live patching sample -- loadable modules only"
+        depends on LIVEPATCH && m
+        help
+          Builds a sample live patch that replaces the procfs handler
+          for /proc/cmdline to print "this has been live patched".
+
 endif # SAMPLES
diff --git a/samples/Makefile b/samples/Makefile
index 1a60c62e2045..f00257bcc5a7 100644
--- a/samples/Makefile
+++ b/samples/Makefile
@@ -1,4 +1,4 @@
 # Makefile for Linux samples code
 
-obj-$(CONFIG_SAMPLES)   += kobject/ kprobes/ trace_events/ \
+obj-$(CONFIG_SAMPLES)   += kobject/ kprobes/ trace_events/ livepatch/ \
                            hw_breakpoint/ kfifo/ kdb/ hidraw/ rpmsg/ seccomp/
diff --git a/samples/bpf/test_maps.c b/samples/bpf/test_maps.c
index e286b42307f3..6299ee95cd11 100644
--- a/samples/bpf/test_maps.c
+++ b/samples/bpf/test_maps.c
@@ -69,9 +69,9 @@ static void test_hashmap_sanity(int i, void *data)
 
         /* iterate over two elements */
         assert(bpf_get_next_key(map_fd, &key, &next_key) == 0 &&
-               next_key == 2);
+               (next_key == 1 || next_key == 2));
         assert(bpf_get_next_key(map_fd, &next_key, &next_key) == 0 &&
-               next_key == 1);
+               (next_key == 1 || next_key == 2));
         assert(bpf_get_next_key(map_fd, &next_key, &next_key) == -1 &&
                errno == ENOENT);
 
diff --git a/samples/livepatch/Makefile b/samples/livepatch/Makefile
new file mode 100644
index 000000000000..10319d7ea0b1
--- /dev/null
+++ b/samples/livepatch/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_SAMPLE_LIVEPATCH) += livepatch-sample.o
diff --git a/samples/livepatch/livepatch-sample.c b/samples/livepatch/livepatch-sample.c
new file mode 100644
index 000000000000..fb8c8614e728
--- /dev/null
+++ b/samples/livepatch/livepatch-sample.c
@@ -0,0 +1,91 @@
+/*
+ * livepatch-sample.c - Kernel Live Patching Sample Module
+ *
+ * Copyright (C) 2014 Seth Jennings <sjenning@redhat.com>
+ *
+ * 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 <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/livepatch.h>
+
+/*
+ * This (dumb) live patch overrides the function that prints the
+ * kernel boot cmdline when /proc/cmdline is read.
+ *
+ * Example:
+ *
+ * $ cat /proc/cmdline
+ * <your cmdline>
+ *
+ * $ insmod livepatch-sample.ko
+ * $ cat /proc/cmdline
+ * this has been live patched
+ *
+ * $ echo 0 > /sys/kernel/livepatch/livepatch_sample/enabled
+ * $ cat /proc/cmdline
+ * <your cmdline>
+ */
+
+#include <linux/seq_file.h>
+static int livepatch_cmdline_proc_show(struct seq_file *m, void *v)
+{
+        seq_printf(m, "%s\n", "this has been live patched");
+        return 0;
+}
+
+static struct klp_func funcs[] = {
+        {
+                .old_name = "cmdline_proc_show",
+                .new_func = livepatch_cmdline_proc_show,
+        }, { }
+};
+
+static struct klp_object objs[] = {
+        {
+                /* name being NULL means vmlinux */
+                .funcs = funcs,
+        }, { }
+};
+
+static struct klp_patch patch = {
+        .mod = THIS_MODULE,
+        .objs = objs,
+};
+
+static int livepatch_init(void)
+{
+        int ret;
+
+        ret = klp_register_patch(&patch);
+        if (ret)
+                return ret;
+        ret = klp_enable_patch(&patch);
+        if (ret) {
+                WARN_ON(klp_unregister_patch(&patch));
+                return ret;
+        }
+        return 0;
+}
+
+static void livepatch_exit(void)
+{
+        WARN_ON(klp_disable_patch(&patch));
+        WARN_ON(klp_unregister_patch(&patch));
+}
+
+module_init(livepatch_init);
+module_exit(livepatch_exit);
+MODULE_LICENSE("GPL");
diff --git a/samples/seccomp/bpf-fancy.c b/samples/seccomp/bpf-fancy.c
index 8eb483aaec46..e8b24f443709 100644
--- a/samples/seccomp/bpf-fancy.c
+++ b/samples/seccomp/bpf-fancy.c
@@ -25,7 +25,9 @@
 
 int main(int argc, char **argv)
 {
-        struct bpf_labels l;
+        struct bpf_labels l = {
+                .count = 0,
+        };
         static const char msg1[] = "Please type something: ";
         static const char msg2[] = "You typed: ";
         char buf[256];
diff --git a/samples/seccomp/bpf-helper.c b/samples/seccomp/bpf-helper.c
index 579cfe331886..05cb4d5ff9f5 100644
--- a/samples/seccomp/bpf-helper.c
+++ b/samples/seccomp/bpf-helper.c
@@ -10,6 +10,7 @@
  */
 
 #include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 
 #include "bpf-helper.h"
@@ -63,6 +64,11 @@ __u32 seccomp_bpf_label(struct bpf_labels *labels, const char *label)
 {
         struct __bpf_label *begin = labels->labels, *end;
         int id;
+
+        if (labels->count == BPF_LABELS_MAX) {
+                fprintf(stderr, "Too many labels\n");
+                exit(1);
+        }
         if (labels->count == 0) {
                 begin->label = label;
                 begin->location = 0xffffffff;
diff --git a/samples/trace_events/trace-events-sample.c b/samples/trace_events/trace-events-sample.c
index aabc4e970911..880a7d1d27d2 100644
--- a/samples/trace_events/trace-events-sample.c
+++ b/samples/trace_events/trace-events-sample.c
@@ -10,12 +10,38 @@
 #define CREATE_TRACE_POINTS
 #include "trace-events-sample.h"
 
+static const char *random_strings[] = {
+        "Mother Goose",
+        "Snoopy",
+        "Gandalf",
+        "Frodo",
+        "One ring to rule them all"
+};
 
 static void simple_thread_func(int cnt)
 {
+        int array[6];
+        int len = cnt % 5;
+        int i;
+
         set_current_state(TASK_INTERRUPTIBLE);
         schedule_timeout(HZ);
-        trace_foo_bar("hello", cnt);
+
+        for (i = 0; i < len; i++)
+                array[i] = i + 1;
+        array[i] = 0;
+
+        /* Silly tracepoints */
+        trace_foo_bar("hello", cnt, array, random_strings[len],
+                      tsk_cpus_allowed(current));
+
+        trace_foo_with_template_simple("HELLO", cnt);
+
+        trace_foo_bar_with_cond("Some times print", cnt);
+
+        trace_foo_with_template_cond("prints other times", cnt);
+
+        trace_foo_with_template_print("I have to be different", cnt);
 }
 
 static int simple_thread(void *arg)
@@ -29,6 +55,53 @@ static int simple_thread(void *arg)
 }
 
 static struct task_struct *simple_tsk;
+static struct task_struct *simple_tsk_fn;
+
+static void simple_thread_func_fn(int cnt)
+{
+        set_current_state(TASK_INTERRUPTIBLE);
+        schedule_timeout(HZ);
+
+        /* More silly tracepoints */
+        trace_foo_bar_with_fn("Look at me", cnt);
+        trace_foo_with_template_fn("Look at me too", cnt);
+}
+
+static int simple_thread_fn(void *arg)
+{
+        int cnt = 0;
+
+        while (!kthread_should_stop())
+                simple_thread_func_fn(cnt++);
+
+        return 0;
+}
+
+static DEFINE_MUTEX(thread_mutex);
+
+void foo_bar_reg(void)
+{
+        pr_info("Starting thread for foo_bar_fn\n");
+        /*
+         * We shouldn't be able to start a trace when the module is
+         * unloading (there's other locks to prevent that). But
+         * for consistency sake, we still take the thread_mutex.
+         */
+        mutex_lock(&thread_mutex);
+        simple_tsk_fn = kthread_run(simple_thread_fn, NULL, "event-sample-fn");
+        mutex_unlock(&thread_mutex);
+}
+
+void foo_bar_unreg(void)
+{
+        pr_info("Killing thread for foo_bar_fn\n");
+        /* protect against module unloading */
+        mutex_lock(&thread_mutex);
+        if (simple_tsk_fn)
+                kthread_stop(simple_tsk_fn);
+        simple_tsk_fn = NULL;
+        mutex_unlock(&thread_mutex);
+}
 
 static int __init trace_event_init(void)
 {
@@ -42,6 +115,11 @@ static int __init trace_event_init(void)
 static void __exit trace_event_exit(void)
 {
         kthread_stop(simple_tsk);
+        mutex_lock(&thread_mutex);
+        if (simple_tsk_fn)
+                kthread_stop(simple_tsk_fn);
+        simple_tsk_fn = NULL;
+        mutex_unlock(&thread_mutex);
 }
 
 module_init(trace_event_init);
diff --git a/samples/trace_events/trace-events-sample.h b/samples/trace_events/trace-events-sample.h
index 476429281389..a2c8b02b6359 100644
--- a/samples/trace_events/trace-events-sample.h
+++ b/samples/trace_events/trace-events-sample.h
@@ -1,6 +1,6 @@
 /*
  * If TRACE_SYSTEM is defined, that will be the directory created
- * in the ftrace directory under /sys/kernel/debug/tracing/events/<system>
+ * in the ftrace directory under /sys/kernel/tracing/events/<system>
  *
  * The define_trace.h below will also look for a file name of
  * TRACE_SYSTEM.h where TRACE_SYSTEM is what is defined here.
@@ -54,45 +54,347 @@
  *    Here it is simply "foo, bar".
  *
  * struct:  This defines the way the data will be stored in the ring buffer.
- *    There are currently two types of elements. __field and __array.
- *    a __field is broken up into (type, name). Where type can be any
- *    primitive type (integer, long or pointer). __field_struct() can
- *    be any static complex data value (struct, union, but not an array).
- *    For an array. there are three fields. (type, name, size). The
- *    type of elements in the array, the name of the field and the size
- *    of the array.
+ *          The items declared here become part of a special structure
+ *          called "__entry", which can be used in the fast_assign part of the
+ *          TRACE_EVENT macro.
+ *
+ *      Here are the currently defined types you can use:
+ *
+ *   __field : Is broken up into type and name. Where type can be any
+ *         primitive type (integer, long or pointer).
+ *
+ *        __field(int, foo)
+ *
+ *        __entry->foo = 5;
+ *
+ *   __field_struct : This can be any static complex data type (struct, union
+ *         but not an array). Be careful using complex types, as each
+ *         event is limited in size, and copying large amounts of data
+ *         into the ring buffer can slow things down.
+ *
+ *         __field_struct(struct bar, foo)
+ *
+ *         __entry->bar.x = y;
+
+ *   __array: There are three fields (type, name, size). The type is the
+ *         type of elements in teh array, the name is the name of the array.
+ *         size is the number of items in the array (not the total size).
+ *
+ *         __array( char, foo, 10) is the same as saying: char foo[10];
+ *
+ *         Assigning arrays can be done like any array:
+ *
+ *         __entry->foo[0] = 'a';
+ *
+ *         memcpy(__entry->foo, bar, 10);
+ *
+ *   __dynamic_array: This is similar to array, but can vary is size from
+ *         instance to instance of the tracepoint being called.
+ *         Like __array, this too has three elements (type, name, size);
+ *         type is the type of the element, name is the name of the array.
+ *         The size is different than __array. It is not a static number,
+ *         but the algorithm to figure out the length of the array for the
+ *         specific instance of tracepoint. Again, size is the numebr of
+ *         items in the array, not the total length in bytes.
+ *
+ *         __dynamic_array( int, foo, bar) is similar to: int foo[bar];
+ *
+ *         Note, unlike arrays, you must use the __get_dynamic_array() macro
+ *         to access the array.
+ *
+ *         memcpy(__get_dynamic_array(foo), bar, 10);
+ *
+ *         Notice, that "__entry" is not needed here.
+ *
+ *   __string: This is a special kind of __dynamic_array. It expects to
+ *         have a nul terminated character array passed to it (it allows
+ *         for NULL too, which would be converted into "(null)"). __string
+ *         takes two paramenter (name, src), where name is the name of
+ *         the string saved, and src is the string to copy into the
+ *         ring buffer.
+ *
+ *         __string(foo, bar)  is similar to:  strcpy(foo, bar)
+ *
+ *         To assign a string, use the helper macro __assign_str().
+ *
+ *         __assign_str(foo, bar);
+ *
+ *         In most cases, the __assign_str() macro will take the same
+ *         parameters as the __string() macro had to declare the string.
+ *
+ *   __bitmask: This is another kind of __dynamic_array, but it expects
+ *         an array of longs, and the number of bits to parse. It takes
+ *         two parameters (name, nr_bits), where name is the name of the
+ *         bitmask to save, and the nr_bits is the number of bits to record.
+ *
+ *         __bitmask(target_cpu, nr_cpumask_bits)
+ *
+ *         To assign a bitmask, use the __assign_bitmask() helper macro.
+ *
+ *         __assign_bitmask(target_cpus, cpumask_bits(bar), nr_cpumask_bits);
  *
- *    __array( char, foo, 10) is the same as saying   char foo[10].
  *
  * fast_assign: This is a C like function that is used to store the items
- *    into the ring buffer.
+ *    into the ring buffer. A special variable called "__entry" will be the
+ *    structure that points into the ring buffer and has the same fields as
+ *    described by the struct part of TRACE_EVENT above.
  *
  * printk: This is a way to print out the data in pretty print. This is
  *    useful if the system crashes and you are logging via a serial line,
  *    the data can be printed to the console using this "printk" method.
+ *    This is also used to print out the data from the trace files.
+ *    Again, the __entry macro is used to access the data from the ring buffer.
+ *
+ *    Note, __dynamic_array, __string, and __bitmask require special helpers
+ *       to access the data.
+ *
+ *      For __dynamic_array(int, foo, bar) use __get_dynamic_array(foo)
+ *            Use __get_dynamic_array_len(foo) to get the length of the array
+ *            saved.
+ *
+ *      For __string(foo, bar) use __get_str(foo)
+ *
+ *      For __bitmask(target_cpus, nr_cpumask_bits) use __get_bitmask(target_cpus)
+ *
  *
  * Note, that for both the assign and the printk, __entry is the handler
  * to the data structure in the ring buffer, and is defined by the
  * TP_STRUCT__entry.
  */
+
+/*
+ * It is OK to have helper functions in the file, but they need to be protected
+ * from being defined more than once. Remember, this file gets included more
+ * than once.
+ */
+#ifndef __TRACE_EVENT_SAMPLE_HELPER_FUNCTIONS
+#define __TRACE_EVENT_SAMPLE_HELPER_FUNCTIONS
+static inline int __length_of(const int *list)
+{
+        int i;
+
+        if (!list)
+                return 0;
+
+        for (i = 0; list[i]; i++)
+                ;
+        return i;
+}
+#endif
+
 TRACE_EVENT(foo_bar,
 
-        TP_PROTO(char *foo, int bar),
+        TP_PROTO(const char *foo, int bar, const int *lst,
+                 const char *string, const struct cpumask *mask),
 
-        TP_ARGS(foo, bar),
+        TP_ARGS(foo, bar, lst, string, mask),
 
         TP_STRUCT__entry(
                 __array(        char,   foo,    10              )
                 __field(        int,    bar                     )
+                __dynamic_array(int,    list,   __length_of(lst))
+                __string(       str,    string                  )
+                __bitmask(      cpus,   num_possible_cpus()     )
         ),
 
         TP_fast_assign(
                 strlcpy(__entry->foo, foo, 10);
                 __entry->bar    = bar;
+                memcpy(__get_dynamic_array(list), lst,
+                       __length_of(lst) * sizeof(int));
+                __assign_str(str, string);
+                __assign_bitmask(cpus, cpumask_bits(mask), num_possible_cpus());
+        ),
+
+        TP_printk("foo %s %d %s %s (%s)", __entry->foo, __entry->bar,
+                  __print_array(__get_dynamic_array(list),
+                                __get_dynamic_array_len(list),
+                                sizeof(int)),
+                  __get_str(str), __get_bitmask(cpus))
+);
+
+/*
+ * There may be a case where a tracepoint should only be called if
+ * some condition is set. Otherwise the tracepoint should not be called.
+ * But to do something like:
+ *
+ *  if (cond)
+ *     trace_foo();
+ *
+ * Would cause a little overhead when tracing is not enabled, and that
+ * overhead, even if small, is not something we want. As tracepoints
+ * use static branch (aka jump_labels), where no branch is taken to
+ * skip the tracepoint when not enabled, and a jmp is placed to jump
+ * to the tracepoint code when it is enabled, having a if statement
+ * nullifies that optimization. It would be nice to place that
+ * condition within the static branch. This is where TRACE_EVENT_CONDITION
+ * comes in.
+ *
+ * TRACE_EVENT_CONDITION() is just like TRACE_EVENT, except it adds another
+ * parameter just after args. Where TRACE_EVENT has:
+ *
+ * TRACE_EVENT(name, proto, args, struct, assign, printk)
+ *
+ * the CONDITION version has:
+ *
+ * TRACE_EVENT_CONDITION(name, proto, args, cond, struct, assign, printk)
+ *
+ * Everything is the same as TRACE_EVENT except for the new cond. Think
+ * of the cond variable as:
+ *
+ *   if (cond)
+ *      trace_foo_bar_with_cond();
+ *
+ * Except that the logic for the if branch is placed after the static branch.
+ * That is, the if statement that processes the condition will not be
+ * executed unless that traecpoint is enabled. Otherwise it still remains
+ * a nop.
+ */
+TRACE_EVENT_CONDITION(foo_bar_with_cond,
+
+        TP_PROTO(const char *foo, int bar),
+
+        TP_ARGS(foo, bar),
+
+        TP_CONDITION(!(bar % 10)),
+
+        TP_STRUCT__entry(
+                __string(       foo,    foo             )
+                __field(        int,    bar                     )
+        ),
+
+        TP_fast_assign(
+                __assign_str(foo, foo);
+                __entry->bar    = bar;
+        ),
+
+        TP_printk("foo %s %d", __get_str(foo), __entry->bar)
+);
+
+void foo_bar_reg(void);
+void foo_bar_unreg(void);
+
+/*
+ * Now in the case that some function needs to be called when the
+ * tracepoint is enabled and/or when it is disabled, the
+ * TRACE_EVENT_FN() serves this purpose. This is just like TRACE_EVENT()
+ * but adds two more parameters at the end:
+ *
+ * TRACE_EVENT_FN( name, proto, args, struct, assign, printk, reg, unreg)
+ *
+ * reg and unreg are functions with the prototype of:
+ *
+ *    void reg(void)
+ *
+ * The reg function gets called before the tracepoint is enabled, and
+ * the unreg function gets called after the tracepoint is disabled.
+ *
+ * Note, reg and unreg are allowed to be NULL. If you only need to
+ * call a function before enabling, or after disabling, just set one
+ * function and pass in NULL for the other parameter.
+ */
+TRACE_EVENT_FN(foo_bar_with_fn,
+
+        TP_PROTO(const char *foo, int bar),
+
+        TP_ARGS(foo, bar),
+
+        TP_STRUCT__entry(
+                __string(       foo,    foo             )
+                __field(        int,    bar             )
+        ),
+
+        TP_fast_assign(
+                __assign_str(foo, foo);
+                __entry->bar    = bar;
+        ),
+
+        TP_printk("foo %s %d", __get_str(foo), __entry->bar),
+
+        foo_bar_reg, foo_bar_unreg
+);
+
+/*
+ * Each TRACE_EVENT macro creates several helper functions to produce
+ * the code to add the tracepoint, create the files in the trace
+ * directory, hook it to perf, assign the values and to print out
+ * the raw data from the ring buffer. To prevent too much bloat,
+ * if there are more than one tracepoint that uses the same format
+ * for the proto, args, struct, assign and printk, and only the name
+ * is different, it is highly recommended to use the DECLARE_EVENT_CLASS
+ *
+ * DECLARE_EVENT_CLASS() macro creates most of the functions for the
+ * tracepoint. Then DEFINE_EVENT() is use to hook a tracepoint to those
+ * functions. This DEFINE_EVENT() is an instance of the class and can
+ * be enabled and disabled separately from other events (either TRACE_EVENT
+ * or other DEFINE_EVENT()s).
+ *
+ * Note, TRACE_EVENT() itself is simply defined as:
+ *
+ * #define TRACE_EVENT(name, proto, args, tstruct, assign, printk)  \
+ *  DEFINE_EVENT_CLASS(name, proto, args, tstruct, assign, printk); \
+ *  DEFINE_EVENT(name, name, proto, args)
+ *
+ * The DEFINE_EVENT() also can be declared with conditions and reg functions:
+ *
+ * DEFINE_EVENT_CONDITION(template, name, proto, args, cond);
+ * DEFINE_EVENT_FN(template, name, proto, args, reg, unreg);
+ */
+DECLARE_EVENT_CLASS(foo_template,
+
+        TP_PROTO(const char *foo, int bar),
+
+        TP_ARGS(foo, bar),
+
+        TP_STRUCT__entry(
+                __string(       foo,    foo             )
+                __field(        int,    bar             )
+        ),
+
+        TP_fast_assign(
+                __assign_str(foo, foo);
+                __entry->bar    = bar;
         ),
 
-        TP_printk("foo %s %d", __entry->foo, __entry->bar)
+        TP_printk("foo %s %d", __get_str(foo), __entry->bar)
 );
+
+/*
+ * Here's a better way for the previous samples (except, the first
+ * exmaple had more fields and could not be used here).
+ */
+DEFINE_EVENT(foo_template, foo_with_template_simple,
+        TP_PROTO(const char *foo, int bar),
+        TP_ARGS(foo, bar));
+
+DEFINE_EVENT_CONDITION(foo_template, foo_with_template_cond,
+        TP_PROTO(const char *foo, int bar),
+        TP_ARGS(foo, bar),
+        TP_CONDITION(!(bar % 8)));
+
+
+DEFINE_EVENT_FN(foo_template, foo_with_template_fn,
+        TP_PROTO(const char *foo, int bar),
+        TP_ARGS(foo, bar),
+        foo_bar_reg, foo_bar_unreg);
+
+/*
+ * Anytime two events share basically the same values and have
+ * the same output, use the DECLARE_EVENT_CLASS() and DEFINE_EVENT()
+ * when ever possible.
+ */
+
+/*
+ * If the event is similar to the DECLARE_EVENT_CLASS, but you need
+ * to have a different output, then use DEFINE_EVENT_PRINT() which
+ * lets you override the TP_printk() of the class.
+ */
+
+DEFINE_EVENT_PRINT(foo_template, foo_with_template_print,
+        TP_PROTO(const char *foo, int bar),
+        TP_ARGS(foo, bar),
+        TP_printk("bar %s %d", __get_str(foo), __entry->bar));
+
 #endif
 
 /***** NOTICE! The #if protection ends here. *****/