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Commit 0c877142 authored by Jason A. Donenfeld's avatar Jason A. Donenfeld Committed by Greg Kroah-Hartman
Browse files

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: default avatarEric Biggers <ebiggers@google.com>
Reviewed-by: default avatarDominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: default avatarJason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 9d436efe

Documentation/sysctl/kernel.txt

+0 −9
Original line number Diff line number Diff line
@@ -808,15 +808,6 @@ 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

==================

drivers/char/random.c

+0 −40
Original line number Diff line number Diff line
@@ -241,8 +241,6 @@ 
#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. */
@@ -858,27 +856,6 @@ 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;
@@ -915,7 +892,6 @@ 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 &&
@@ -1623,22 +1599,6 @@ 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 */