126 lines
4.4 KiB
Diff
126 lines
4.4 KiB
Diff
From 993d4add01527a662c9506544257031b5a46b7ba Mon Sep 17 00:00:00 2001
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From: Thomas Gleixner <tglx@linutronix.de>
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Date: Tue, 21 Aug 2012 20:38:50 +0200
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Subject: [PATCH 279/298] random: Make it work on rt
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Delegate the random insertion to the forced threaded interrupt
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handler. Store the return IP of the hard interrupt handler in the irq
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descriptor and feed it into the random generator as a source of
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entropy.
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Cc: stable-rt@vger.kernel.org
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Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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---
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drivers/char/random.c | 10 ++++++----
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include/linux/irqdesc.h | 1 +
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include/linux/random.h | 2 +-
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kernel/irq/handle.c | 7 +++++--
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kernel/irq/manage.c | 6 ++++++
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5 files changed, 19 insertions(+), 7 deletions(-)
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diff --git a/drivers/char/random.c b/drivers/char/random.c
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index d38af32..66c8a0f9 100644
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--- a/drivers/char/random.c
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+++ b/drivers/char/random.c
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@@ -767,18 +767,16 @@ EXPORT_SYMBOL_GPL(add_input_randomness);
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static DEFINE_PER_CPU(struct fast_pool, irq_randomness);
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-void add_interrupt_randomness(int irq, int irq_flags)
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+void add_interrupt_randomness(int irq, int irq_flags, __u64 ip)
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{
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struct entropy_store *r;
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struct fast_pool *fast_pool = &__get_cpu_var(irq_randomness);
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- struct pt_regs *regs = get_irq_regs();
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unsigned long now = jiffies;
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__u32 input[4], cycles = get_cycles();
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input[0] = cycles ^ jiffies;
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input[1] = irq;
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- if (regs) {
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- __u64 ip = instruction_pointer(regs);
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+ if (ip) {
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input[2] = ip;
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input[3] = ip >> 32;
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}
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@@ -792,7 +790,11 @@ void add_interrupt_randomness(int irq, int irq_flags)
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fast_pool->last = now;
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r = nonblocking_pool.initialized ? &input_pool : &nonblocking_pool;
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+#ifndef CONFIG_PREEMPT_RT_FULL
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__mix_pool_bytes(r, &fast_pool->pool, sizeof(fast_pool->pool), NULL);
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+#else
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+ mix_pool_bytes(r, &fast_pool->pool, sizeof(fast_pool->pool), NULL);
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+#endif
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/*
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* If we don't have a valid cycle counter, and we see
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* back-to-back timer interrupts, then skip giving credit for
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diff --git a/include/linux/irqdesc.h b/include/linux/irqdesc.h
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index f1e2527..5f4f091 100644
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--- a/include/linux/irqdesc.h
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+++ b/include/linux/irqdesc.h
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@@ -53,6 +53,7 @@ struct irq_desc {
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unsigned int irq_count; /* For detecting broken IRQs */
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unsigned long last_unhandled; /* Aging timer for unhandled count */
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unsigned int irqs_unhandled;
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+ u64 random_ip;
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raw_spinlock_t lock;
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struct cpumask *percpu_enabled;
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#ifdef CONFIG_SMP
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diff --git a/include/linux/random.h b/include/linux/random.h
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index 29e217a..3995b33 100644
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--- a/include/linux/random.h
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+++ b/include/linux/random.h
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@@ -53,7 +53,7 @@ extern void rand_initialize_irq(int irq);
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extern void add_device_randomness(const void *, unsigned int);
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extern void add_input_randomness(unsigned int type, unsigned int code,
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unsigned int value);
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-extern void add_interrupt_randomness(int irq, int irq_flags);
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+extern void add_interrupt_randomness(int irq, int irq_flags, __u64 ip);
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extern void get_random_bytes(void *buf, int nbytes);
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extern void get_random_bytes_arch(void *buf, int nbytes);
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diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c
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index a768885..f6b91bc 100644
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--- a/kernel/irq/handle.c
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+++ b/kernel/irq/handle.c
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@@ -116,6 +116,8 @@ static void irq_wake_thread(struct irq_desc *desc, struct irqaction *action)
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irqreturn_t
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handle_irq_event_percpu(struct irq_desc *desc, struct irqaction *action)
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{
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+ struct pt_regs *regs = get_irq_regs();
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+ u64 ip = regs ? instruction_pointer(regs) : 0;
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irqreturn_t retval = IRQ_NONE;
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unsigned int flags = 0, irq = desc->irq_data.irq;
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@@ -157,8 +159,9 @@ handle_irq_event_percpu(struct irq_desc *desc, struct irqaction *action)
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} while (action);
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#ifndef CONFIG_PREEMPT_RT_FULL
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- /* FIXME: Can we unbreak that ? */
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- add_interrupt_randomness(irq, flags);
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+ add_interrupt_randomness(irq, flags, ip);
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+#else
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+ desc->random_ip = ip;
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#endif
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if (!noirqdebug)
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diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
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index f52263a..ff7bb89 100644
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--- a/kernel/irq/manage.c
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+++ b/kernel/irq/manage.c
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@@ -825,6 +825,12 @@ static int irq_thread(void *data)
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action_ret = handler_fn(desc, action);
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if (!noirqdebug)
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note_interrupt(action->irq, desc, action_ret);
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+#ifdef CONFIG_PREEMPT_RT_FULL
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+ migrate_disable();
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+ add_interrupt_randomness(action->irq, 0,
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+ desc->random_ip ^ (u64) action);
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+ migrate_enable();
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+#endif
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}
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wake = atomic_dec_and_test(&desc->threads_active);
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