121 lines
3.9 KiB
Diff
121 lines
3.9 KiB
Diff
Subject: random: Make it work on rt
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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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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/3.14/patches-3.14.10-rt7.tar.xz
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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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[bwh:
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- Restore interrupt randomness dropped in 3.14.10-rt6]
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---
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drivers/char/random.c | 11 +++++++----
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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 | 8 +++++++-
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4 files changed, 16 insertions(+), 6 deletions(-)
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--- a/drivers/char/random.c
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+++ b/drivers/char/random.c
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@@ -832,21 +832,20 @@ 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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cycles_t cycles = random_get_entropy();
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__u32 input[4], c_high, j_high;
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- __u64 ip;
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c_high = (sizeof(cycles) > 4) ? cycles >> 32 : 0;
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j_high = (sizeof(now) > 4) ? now >> 32 : 0;
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input[0] = cycles ^ j_high ^ irq;
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input[1] = now ^ c_high;
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- ip = regs ? instruction_pointer(regs) : _RET_IP_;
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+ if (!ip)
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+ ip = _RET_IP_;
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input[2] = ip;
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input[3] = ip >> 32;
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@@ -858,7 +857,11 @@ void add_interrupt_randomness(int irq, i
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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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--- a/include/linux/irqdesc.h
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+++ b/include/linux/irqdesc.h
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@@ -56,6 +56,7 @@ struct irq_desc {
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unsigned int irqs_unhandled;
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atomic_t threads_handled;
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int threads_handled_last;
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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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--- a/include/linux/random.h
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+++ b/include/linux/random.h
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@@ -11,7 +11,7 @@
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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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--- a/kernel/irq/handle.c
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+++ b/kernel/irq/handle.c
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@@ -132,6 +132,8 @@ static void irq_wake_thread(struct irq_d
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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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@@ -172,7 +174,11 @@ handle_irq_event_percpu(struct irq_desc
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action = action->next;
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} while (action);
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- add_interrupt_randomness(irq, flags);
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+#ifndef CONFIG_PREEMPT_RT_FULL
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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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note_interrupt(irq, desc, retval);
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--- a/kernel/irq/manage.c
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+++ b/kernel/irq/manage.c
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@@ -942,6 +942,12 @@ static int irq_thread(void *data)
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if (action_ret == IRQ_HANDLED)
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atomic_inc(&desc->threads_handled);
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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 ^ (unsigned long) action);
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+ migrate_enable();
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+#endif
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wake_threads_waitq(desc);
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}
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