latent_entropy: Mark functions with __latent_entropy

The __latent_entropy gcc attribute can be used only on functions and
variables.  If it is on a function then the plugin will instrument it for
gathering control-flow entropy. If the attribute is on a variable then
the plugin will initialize it with random contents.  The variable must
be an integer, an integer array type or a structure with integer fields.

These specific functions have been selected because they are init
functions (to help gather boot-time entropy), are called at unpredictable
times, or they have variable loops, each of which provide some level of
latent entropy.

Signed-off-by: Emese Revfy <re.emese@gmail.com>
[kees: expanded commit message]
Signed-off-by: Kees Cook <keescook@chromium.org>

2 files changed, 2 insertions, 2 deletions

diff --git a/lib/irq_poll.c b/lib/irq_poll.c
index 836f7db4e548..63be7495dbb2 100644
--- a/lib/irq_poll.c
+++ b/lib/irq_poll.c
@@ -74,7 +74,7 @@ void irq_poll_complete(struct irq_poll *iop)
 }
 EXPORT_SYMBOL(irq_poll_complete);
 
-static void irq_poll_softirq(struct softirq_action *h)
+static void __latent_entropy irq_poll_softirq(struct softirq_action *h)
 {
         struct list_head *list = this_cpu_ptr(&blk_cpu_iopoll);
         int rearm = 0, budget = irq_poll_budget;
diff --git a/lib/random32.c b/lib/random32.c
index 69ed593aab07..a30923573676 100644
--- a/lib/random32.c
+++ b/lib/random32.c
@@ -47,7 +47,7 @@ static inline void prandom_state_selftest(void)
 }
 #endif
 
-static DEFINE_PER_CPU(struct rnd_state, net_rand_state);
+static DEFINE_PER_CPU(struct rnd_state, net_rand_state) __latent_entropy;
 
 /**
  *      prandom_u32_state - seeded pseudo-random number generator.