151 lines
4.7 KiB
Diff
151 lines
4.7 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/4.19/older/patches-4.19.1-rt3.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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drivers/hv/hv.c | 4 +++-
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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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7 files changed, 26 insertions(+), 10 deletions(-)
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--- a/drivers/char/random.c
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+++ b/drivers/char/random.c
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@@ -1229,28 +1229,27 @@ static __u32 get_reg(struct fast_pool *f
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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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--- a/drivers/hv/hv.c
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+++ b/drivers/hv/hv.c
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@@ -112,10 +112,12 @@ int hv_post_message(union hv_connection_
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static void hv_stimer0_isr(void)
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{
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struct hv_per_cpu_context *hv_cpu;
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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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hv_cpu = this_cpu_ptr(hv_context.cpu_context);
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hv_cpu->clk_evt->event_handler(hv_cpu->clk_evt);
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- add_interrupt_randomness(stimer0_vector, 0);
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+ add_interrupt_randomness(stimer0_vector, 0, ip);
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}
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static int hv_ce_set_next_event(unsigned long delta,
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--- a/drivers/hv/vmbus_drv.c
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+++ b/drivers/hv/vmbus_drv.c
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@@ -991,6 +991,8 @@ static void vmbus_isr(void)
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void *page_addr = hv_cpu->synic_event_page;
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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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if (unlikely(page_addr == NULL))
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@@ -1034,7 +1036,7 @@ static void vmbus_isr(void)
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tasklet_schedule(&hv_cpu->msg_dpc);
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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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/*
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--- a/include/linux/irqdesc.h
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+++ b/include/linux/irqdesc.h
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@@ -70,6 +70,7 @@ 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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--- a/include/linux/random.h
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+++ b/include/linux/random.h
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@@ -32,7 +32,7 @@ static inline void add_latent_entropy(vo
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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 wait_for_random_bytes(void);
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--- a/kernel/irq/handle.c
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+++ b/kernel/irq/handle.c
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@@ -185,10 +185,16 @@ irqreturn_t handle_irq_event_percpu(stru
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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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--- a/kernel/irq/manage.c
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+++ b/kernel/irq/manage.c
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@@ -1072,6 +1072,12 @@ 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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