Merge tag 'gcc-plugins-v4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull gcc plugins update from Kees Cook:
 "This adds a new gcc plugin named "latent_entropy". It is designed to
  extract as much possible uncertainty from a running system at boot
  time as possible, hoping to capitalize on any possible variation in
  CPU operation (due to runtime data differences, hardware differences,
  SMP ordering, thermal timing variation, cache behavior, etc).

  At the very least, this plugin is a much more comprehensive example
  for how to manipulate kernel code using the gcc plugin internals"

* tag 'gcc-plugins-v4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  latent_entropy: Mark functions with __latent_entropy
  gcc-plugins: Add latent_entropy plugin

1 files changed, 13 insertions, 2 deletions

diff --git a/include/linux/random.h b/include/linux/random.h
index f7bb7a355cf7..7bd2403e4fef 100644
--- a/include/linux/random.h
+++ b/include/linux/random.h
@@ -18,9 +18,20 @@ struct random_ready_callback {
 };
 
 extern void add_device_randomness(const void *, unsigned int);
+
+#if defined(CONFIG_GCC_PLUGIN_LATENT_ENTROPY) && !defined(__CHECKER__)
+static inline void add_latent_entropy(void)
+{
+        add_device_randomness((const void *)&latent_entropy,
+                              sizeof(latent_entropy));
+}
+#else
+static inline void add_latent_entropy(void) {}
+#endif
+
 extern void add_input_randomness(unsigned int type, unsigned int code,
-                                 unsigned int value);
-extern void add_interrupt_randomness(int irq, int irq_flags);
+                                 unsigned int value) __latent_entropy;
+extern void add_interrupt_randomness(int irq, int irq_flags) __latent_entropy;
 
 extern void get_random_bytes(void *buf, int nbytes);
 extern int add_random_ready_callback(struct random_ready_callback *rdy);