117 lines
3.7 KiB
Diff
117 lines
3.7 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/4.4/patches-4.4.3-rt9.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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---
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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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kernel/irq/manage.c | 6 ++++++
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5 files changed, 20 insertions(+), 8 deletions(-)
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--- a/drivers/char/random.c
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+++ b/drivers/char/random.c
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@@ -888,28 +888,27 @@ static __u32 get_reg(struct fast_pool *f
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return *(ptr + f->reg_idx++);
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}
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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 = this_cpu_ptr(&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 c_high, j_high;
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- __u64 ip;
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unsigned long seed;
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int credit = 0;
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if (cycles == 0)
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- cycles = get_reg(fast_pool, regs);
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+ cycles = get_reg(fast_pool, NULL);
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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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fast_pool->pool[0] ^= cycles ^ j_high ^ irq;
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fast_pool->pool[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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fast_pool->pool[2] ^= ip;
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fast_pool->pool[3] ^= (sizeof(ip) > 4) ? ip >> 32 :
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- get_reg(fast_pool, regs);
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+ get_reg(fast_pool, NULL);
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fast_mix(fast_pool);
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add_interrupt_bench(cycles);
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--- a/include/linux/irqdesc.h
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+++ b/include/linux/irqdesc.h
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@@ -61,6 +61,7 @@ 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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@@ -20,7 +20,7 @@ struct random_ready_callback {
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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 int add_random_ready_callback(struct random_ready_callback *rdy);
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--- a/kernel/irq/handle.c
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+++ b/kernel/irq/handle.c
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@@ -134,6 +134,8 @@ void __irq_wake_thread(struct irq_desc *
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irqreturn_t handle_irq_event_percpu(struct irq_desc *desc)
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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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struct irqaction *action = desc->action;
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@@ -176,7 +178,11 @@ irqreturn_t handle_irq_event_percpu(stru
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action = action->next;
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}
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- add_interrupt_randomness(irq, flags);
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+#ifdef CONFIG_PREEMPT_RT_FULL
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+ desc->random_ip = ip;
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+#else
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+ add_interrupt_randomness(irq, flags, ip);
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+#endif
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if (!noirqdebug)
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note_interrupt(desc, retval);
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--- a/kernel/irq/manage.c
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+++ b/kernel/irq/manage.c
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@@ -1045,6 +1045,12 @@ static int irq_thread(void *data)
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if (action_ret == IRQ_WAKE_THREAD)
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irq_wake_secondary(desc, action);
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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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