From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steven Rostedt Subject: [PATCH RT 1/8] random: Make it work on rt Date: Wed, 10 Oct 2012 09:34:07 -0400 Message-ID: <20121010133523.194434423@goodmis.org> References: <20121010133406.053812290@goodmis.org> Cc: Thomas Gleixner , Carsten Emde , John Kacur To: linux-kernel@vger.kernel.org, linux-rt-users Return-path: Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:23969 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754081Ab2JJNfZ (ORCPT ); Wed, 10 Oct 2012 09:35:25 -0400 Content-Disposition: inline; filename=0001-random-Make-it-work-on-rt.patch Sender: linux-rt-users-owner@vger.kernel.org List-ID: From: Thomas Gleixner Delegate the random insertion to the forced threaded interrupt handler. Store the return IP of the hard interrupt handler in the irq descriptor and feed it into the random generator as a source of entropy. Signed-off-by: Thomas Gleixner Cc: stable-rt@vger.kernel.org Signed-off-by: Steven Rostedt --- drivers/char/random.c | 10 ++++++---- include/linux/irqdesc.h | 1 + include/linux/random.h | 2 +- kernel/irq/handle.c | 7 +++++-- kernel/irq/manage.c | 6 ++++++ 5 files changed, 19 insertions(+), 7 deletions(-) diff --git a/drivers/char/random.c b/drivers/char/random.c index feae549..f786798 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -745,18 +745,16 @@ EXPORT_SYMBOL_GPL(add_input_randomness); static DEFINE_PER_CPU(struct fast_pool, irq_randomness); -void add_interrupt_randomness(int irq, int irq_flags) +void add_interrupt_randomness(int irq, int irq_flags, __u64 ip) { struct entropy_store *r; struct fast_pool *fast_pool = &__get_cpu_var(irq_randomness); - struct pt_regs *regs = get_irq_regs(); unsigned long now = jiffies; __u32 input[4], cycles = get_cycles(); input[0] = cycles ^ jiffies; input[1] = irq; - if (regs) { - __u64 ip = instruction_pointer(regs); + if (ip) { input[2] = ip; input[3] = ip >> 32; } @@ -770,7 +768,11 @@ void add_interrupt_randomness(int irq, int irq_flags) fast_pool->last = now; r = nonblocking_pool.initialized ? &input_pool : &nonblocking_pool; +#ifndef CONFIG_PREEMPT_RT_FULL __mix_pool_bytes(r, &fast_pool->pool, sizeof(fast_pool->pool), NULL); +#else + mix_pool_bytes(r, &fast_pool->pool, sizeof(fast_pool->pool), NULL); +#endif /* * If we don't have a valid cycle counter, and we see * back-to-back timer interrupts, then skip giving credit for diff --git a/include/linux/irqdesc.h b/include/linux/irqdesc.h index 9a323d1..5bf5add 100644 --- a/include/linux/irqdesc.h +++ b/include/linux/irqdesc.h @@ -52,6 +52,7 @@ struct irq_desc { unsigned int irq_count; /* For detecting broken IRQs */ unsigned long last_unhandled; /* Aging timer for unhandled count */ unsigned int irqs_unhandled; + u64 random_ip; raw_spinlock_t lock; struct cpumask *percpu_enabled; #ifdef CONFIG_SMP diff --git a/include/linux/random.h b/include/linux/random.h index ac621ce..9ae01e2 100644 --- a/include/linux/random.h +++ b/include/linux/random.h @@ -51,7 +51,7 @@ struct rnd_state { extern void add_device_randomness(const void *, unsigned int); extern void add_input_randomness(unsigned int type, unsigned int code, unsigned int value); -extern void add_interrupt_randomness(int irq, int irq_flags); +extern void add_interrupt_randomness(int irq, int irq_flags, __u64 ip); extern void get_random_bytes(void *buf, int nbytes); extern void get_random_bytes_arch(void *buf, int nbytes); diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c index 311c4e6..7f50c55 100644 --- a/kernel/irq/handle.c +++ b/kernel/irq/handle.c @@ -132,6 +132,8 @@ static void irq_wake_thread(struct irq_desc *desc, struct irqaction *action) irqreturn_t handle_irq_event_percpu(struct irq_desc *desc, struct irqaction *action) { + struct pt_regs *regs = get_irq_regs(); + u64 ip = regs ? instruction_pointer(regs) : 0; irqreturn_t retval = IRQ_NONE; unsigned int flags = 0, irq = desc->irq_data.irq; @@ -173,8 +175,9 @@ handle_irq_event_percpu(struct irq_desc *desc, struct irqaction *action) } while (action); #ifndef CONFIG_PREEMPT_RT_FULL - /* FIXME: Can we unbreak that ? */ - add_interrupt_randomness(irq, flags); + add_interrupt_randomness(irq, flags, ip); +#else + desc->random_ip = ip; #endif if (!noirqdebug) diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index ede56ac..90bf44a 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -814,6 +814,12 @@ static int irq_thread(void *data) if (!noirqdebug) note_interrupt(action->irq, desc, action_ret); +#ifdef CONFIG_PREEMPT_RT_FULL + migrate_disable(); + add_interrupt_randomness(action->irq, 0, + desc->random_ip ^ (u64) action); + migrate_enable(); +#endif wake_threads_waitq(desc); } -- 1.7.10.4