91 lines
2.7 KiB
Diff
91 lines
2.7 KiB
Diff
From b925c782d8d87378293a10e02bde34c2806644e4 Mon Sep 17 00:00:00 2001
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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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Date: Fri, 12 May 2017 15:46:17 +0200
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Subject: [PATCH 276/365] random: avoid preempt_disable()ed section
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extract_crng() will use sleeping locks while in a preempt_disable()
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section due to get_cpu_var().
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Work around it with local_locks.
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Cc: stable-rt@vger.kernel.org # where it applies to
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Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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---
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drivers/char/random.c | 20 +++++++++++++++-----
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1 file changed, 15 insertions(+), 5 deletions(-)
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diff --git a/drivers/char/random.c b/drivers/char/random.c
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index 3777a8ff637e..c033135f2a67 100644
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--- a/drivers/char/random.c
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+++ b/drivers/char/random.c
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@@ -263,6 +263,7 @@
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#include <linux/syscalls.h>
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#include <linux/completion.h>
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#include <linux/uuid.h>
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+#include <linux/locallock.h>
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#include <crypto/chacha20.h>
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#include <asm/processor.h>
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@@ -1664,7 +1665,7 @@ void get_random_bytes_arch(void *buf, int nbytes)
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if (!arch_get_random_long(&v))
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break;
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-
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+
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memcpy(p, &v, chunk);
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p += chunk;
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nbytes -= chunk;
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@@ -2118,18 +2119,22 @@ struct batched_entropy {
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* the goal of being quite fast and not depleting entropy.
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*/
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static DEFINE_PER_CPU(struct batched_entropy, batched_entropy_long);
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+static DEFINE_LOCAL_IRQ_LOCK(batched_entropy_long_lock);
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unsigned long get_random_long(void)
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{
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unsigned long ret;
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struct batched_entropy *batch;
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- batch = &get_cpu_var(batched_entropy_long);
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+ if (arch_get_random_long(&ret))
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+ return ret;
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+
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+ batch = &get_locked_var(batched_entropy_long_lock, batched_entropy_long);
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if (batch->position % ARRAY_SIZE(batch->entropy_long) == 0) {
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extract_crng((u8 *)batch->entropy_long);
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batch->position = 0;
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}
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ret = batch->entropy_long[batch->position++];
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- put_cpu_var(batched_entropy_long);
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+ put_locked_var(batched_entropy_long_lock, batched_entropy_long);
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return ret;
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}
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EXPORT_SYMBOL(get_random_long);
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@@ -2141,18 +2146,23 @@ unsigned int get_random_int(void)
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}
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#else
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static DEFINE_PER_CPU(struct batched_entropy, batched_entropy_int);
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+static DEFINE_LOCAL_IRQ_LOCK(batched_entropy_int_lock);
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+
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unsigned int get_random_int(void)
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{
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unsigned int ret;
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struct batched_entropy *batch;
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- batch = &get_cpu_var(batched_entropy_int);
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+ if (arch_get_random_int(&ret))
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+ return ret;
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+
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+ batch = &get_locked_var(batched_entropy_int_lock, batched_entropy_int);
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if (batch->position % ARRAY_SIZE(batch->entropy_int) == 0) {
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extract_crng((u8 *)batch->entropy_int);
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batch->position = 0;
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}
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ret = batch->entropy_int[batch->position++];
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- put_cpu_var(batched_entropy_int);
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+ put_locked_var(batched_entropy_int_lock, batched_entropy_int);
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return ret;
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}
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#endif
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--
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2.28.0
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