forked from rrcarlosr/Jetpack
148 lines
4.7 KiB
Diff
148 lines
4.7 KiB
Diff
From 8a88c62139ea7ea68b9dac5a2f3da47d518ecd3b 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 278/352] 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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---
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drivers/char/random.c | 11 +++++------
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drivers/hv/vmbus_drv.c | 4 +++-
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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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6 files changed, 23 insertions(+), 9 deletions(-)
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diff --git a/drivers/char/random.c b/drivers/char/random.c
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index 74300e8..002f686 100644
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--- a/drivers/char/random.c
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+++ b/drivers/char/random.c
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@@ -1183,28 +1183,27 @@ static __u32 get_reg(struct fast_pool *f, struct pt_regs *regs)
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return *ptr;
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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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diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
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index 0276d2e..8868045 100644
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--- a/drivers/hv/vmbus_drv.c
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+++ b/drivers/hv/vmbus_drv.c
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@@ -761,6 +761,8 @@ static void vmbus_isr(void)
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void *page_addr;
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struct hv_message *msg;
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union hv_synic_event_flags *event;
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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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bool handled = false;
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page_addr = hv_context.synic_event_page[cpu];
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@@ -808,7 +810,7 @@ static void vmbus_isr(void)
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tasklet_schedule(hv_context.msg_dpc[cpu]);
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}
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- add_interrupt_randomness(HYPERVISOR_CALLBACK_VECTOR, 0);
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+ add_interrupt_randomness(HYPERVISOR_CALLBACK_VECTOR, 0, ip);
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}
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diff --git a/include/linux/irqdesc.h b/include/linux/irqdesc.h
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index c9be579..eeeb540 100644
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--- a/include/linux/irqdesc.h
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+++ b/include/linux/irqdesc.h
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@@ -66,6 +66,7 @@ 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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const struct cpumask *percpu_affinity;
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diff --git a/include/linux/random.h b/include/linux/random.h
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index 16ab429..9d0fecb 100644
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--- a/include/linux/random.h
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+++ b/include/linux/random.h
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@@ -31,7 +31,7 @@ static inline void add_latent_entropy(void) {}
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extern void add_input_randomness(unsigned int type, unsigned int code,
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unsigned int value) __latent_entropy;
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-extern void add_interrupt_randomness(int irq, int irq_flags) __latent_entropy;
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+extern void add_interrupt_randomness(int irq, int irq_flags, __u64 ip) __latent_entropy;
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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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diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c
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index d3f2490..f87aa8f 100644
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--- a/kernel/irq/handle.c
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+++ b/kernel/irq/handle.c
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@@ -181,10 +181,16 @@ irqreturn_t handle_irq_event_percpu(struct irq_desc *desc)
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{
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irqreturn_t retval;
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unsigned int flags = 0;
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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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retval = __handle_irq_event_percpu(desc, &flags);
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- add_interrupt_randomness(desc->irq_data.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(desc->irq_data.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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diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
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index 8867672..4e0f709 100644
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--- a/kernel/irq/manage.c
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+++ b/kernel/irq/manage.c
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@@ -1027,6 +1027,12 @@ 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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--
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2.7.4
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