Commit 90773bc1 authored by Hook, Gary's avatar Hook, Gary Committed by Herbert Xu
Browse files

crypto: ccp - module parameter to limit the number of enabled CCPs 



Provide the ability to constrain the total number of enabled devices in
the system. Once max_devs devices have been configured, subsequently
probed devices are ignored.

The max_devs parameter may be zero, in which case all CCPs are disabled.
PSPs are always enabled and active.

Disabling the CCPs also disables DMA and RNG registration.

Signed-off-by: default avatarGary R Hook <gary.hook@amd.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent c4a89279

drivers/crypto/ccp/ccp-dev.c

+17 −1
Original line number Diff line number Diff line
@@ -2,7 +2,7 @@ 
/*

 * AMD Cryptographic Coprocessor (CCP) driver

 *

 * Copyright (C) 2013,2017 Advanced Micro Devices, Inc.

 * Copyright (C) 2013,2019 Advanced Micro Devices, Inc.

 *

 * Author: Tom Lendacky <thomas.lendacky@amd.com>

 * Author: Gary R Hook <gary.hook@amd.com>
@@ -20,6 +20,7 @@ 
#include <linux/delay.h>

#include <linux/hw_random.h>

#include <linux/cpu.h>

#include <linux/atomic.h>

#ifdef CONFIG_X86

#include <asm/cpu_device_id.h>

#endif
@@ -27,11 +28,19 @@ 


#include "ccp-dev.h"



#define MAX_CCPS 32



/* Limit CCP use to a specifed number of queues per device */

static unsigned int nqueues = 0;

module_param(nqueues, uint, 0444);

MODULE_PARM_DESC(nqueues, "Number of queues per CCP (minimum 1; default: all available)");



/* Limit the maximum number of configured CCPs */

static atomic_t dev_count = ATOMIC_INIT(0);

static unsigned int max_devs = MAX_CCPS;

module_param(max_devs, uint, 0444);

MODULE_PARM_DESC(max_devs, "Maximum number of CCPs to enable (default: all; 0 disables all CCPs)");



struct ccp_tasklet_data {

	struct completion completion;

	struct ccp_cmd *cmd;
@@ -592,6 +601,13 @@ int ccp_dev_init(struct sp_device *sp) 
	struct ccp_device *ccp;

	int ret;



	/*

	 * Check how many we have so far, and stop after reaching

	 * that number

	 */

	if (atomic_inc_return(&dev_count) > max_devs)

		return 0; /* don't fail the load */



	ret = -ENOMEM;

	ccp = ccp_alloc_struct(sp);

	if (!ccp)

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