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authorJason A. Donenfeld <Jason@zx2c4.com>2022-02-10 16:35:24 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2022-06-25 11:49:05 +0200
commitf86bc7f7f1738c6b90f1f39ddb5473298a1f7cec (patch)
treef7ae59d0a0a64ed08fcb5a7bf4d26430ef595ed3
parent70a972688a67565484a795ffc8b2370937439216 (diff)
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random: remove ifdef'd out interrupt bench
commit 95e6060c20a7f5db60163274c5222a725ac118f9 upstream. With tools like kbench9000 giving more finegrained responses, and this basically never having been used ever since it was initially added, let's just get rid of this. There *is* still work to be done on the interrupt handler, but this really isn't the way it's being developed. Cc: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--Documentation/sysctl/kernel.txt9
-rw-r--r--drivers/char/random.c40
2 files changed, 0 insertions, 49 deletions
diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt
index 950b0d6a6307..5cbdff822e41 100644
--- a/Documentation/sysctl/kernel.txt
+++ b/Documentation/sysctl/kernel.txt
@@ -852,15 +852,6 @@ This is a directory, with the following entries:
are woken up. This file is writable for compatibility purposes, but
writing to it has no effect on any RNG behavior.
-If ``drivers/char/random.c`` is built with ``ADD_INTERRUPT_BENCH``
-defined, these additional entries are present:
-
-* ``add_interrupt_avg_cycles``: the average number of cycles between
- interrupts used to feed the pool;
-
-* ``add_interrupt_avg_deviation``: the standard deviation seen on the
- number of cycles between interrupts used to feed the pool.
-
randomize_va_space
==================
diff --git a/drivers/char/random.c b/drivers/char/random.c
index 9b7367d00560..511db57948c4 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -240,8 +240,6 @@
#define CREATE_TRACE_POINTS
#include <trace/events/random.h>
-/* #define ADD_INTERRUPT_BENCH */
-
enum {
POOL_BITS = BLAKE2S_HASH_SIZE * 8,
POOL_MIN_BITS = POOL_BITS /* No point in settling for less. */
@@ -806,27 +804,6 @@ EXPORT_SYMBOL_GPL(add_input_randomness);
static DEFINE_PER_CPU(struct fast_pool, irq_randomness);
-#ifdef ADD_INTERRUPT_BENCH
-static unsigned long avg_cycles, avg_deviation;
-
-#define AVG_SHIFT 8 /* Exponential average factor k=1/256 */
-#define FIXED_1_2 (1 << (AVG_SHIFT - 1))
-
-static void add_interrupt_bench(cycles_t start)
-{
- long delta = random_get_entropy() - start;
-
- /* Use a weighted moving average */
- delta = delta - ((avg_cycles + FIXED_1_2) >> AVG_SHIFT);
- avg_cycles += delta;
- /* And average deviation */
- delta = abs(delta) - ((avg_deviation + FIXED_1_2) >> AVG_SHIFT);
- avg_deviation += delta;
-}
-#else
-#define add_interrupt_bench(x)
-#endif
-
static u32 get_reg(struct fast_pool *f, struct pt_regs *regs)
{
u32 *ptr = (u32 *)regs;
@@ -863,7 +840,6 @@ void add_interrupt_randomness(int irq)
(sizeof(ip) > 4) ? ip >> 32 : get_reg(fast_pool, regs);
fast_mix(fast_pool);
- add_interrupt_bench(cycles);
if (unlikely(crng_init == 0)) {
if (fast_pool->count >= 64 &&
@@ -1571,22 +1547,6 @@ struct ctl_table random_table[] = {
.mode = 0444,
.proc_handler = proc_do_uuid,
},
-#ifdef ADD_INTERRUPT_BENCH
- {
- .procname = "add_interrupt_avg_cycles",
- .data = &avg_cycles,
- .maxlen = sizeof(avg_cycles),
- .mode = 0444,
- .proc_handler = proc_doulongvec_minmax,
- },
- {
- .procname = "add_interrupt_avg_deviation",
- .data = &avg_deviation,
- .maxlen = sizeof(avg_deviation),
- .mode = 0444,
- .proc_handler = proc_doulongvec_minmax,
- },
-#endif
{ }
};
#endif /* CONFIG_SYSCTL */