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Commit ceb18132 authored by Luis R. Rodriguez's avatar Luis R. Rodriguez Committed by Greg Kroah-Hartman
Browse files

firmware: enable run time change of forcing fallback loader 



Currently one requires to test four kernel configurations to test the
firmware API completely:

0)
  CONFIG_FW_LOADER=y

1)
  o CONFIG_FW_LOADER=y
  o CONFIG_FW_LOADER_USER_HELPER=y

2)
  o CONFIG_FW_LOADER=y
  o CONFIG_FW_LOADER_USER_HELPER=y
  o CONFIG_FW_LOADER_USER_HELPER_FALLBACK=y

3) When CONFIG_FW_LOADER=m the built-in stuff is disabled, we have
   no current tests for this.

We can reduce the requirements to three kernel configurations by making
fw_config.force_sysfs_fallback a proc knob we flip on off. For kernels that
disable CONFIG_IKCONFIG_PROC this can also enable one to inspect if
CONFIG_FW_LOADER_USER_HELPER_FALLBACK was enabled at build time by checking
the proc value at boot time.

Acked-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarLuis R. Rodriguez <mcgrof@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 5d6d1ddd

drivers/base/firmware_loader/fallback.c

+1 −0
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ 
#include <linux/security.h>

#include <linux/highmem.h>

#include <linux/umh.h>

#include <linux/sysctl.h>



#include "fallback.h"

#include "firmware.h"

drivers/base/firmware_loader/fallback.h

+3 −1
Original line number Diff line number Diff line
@@ -12,12 +12,14 @@ 
 *

 * @force_sysfs_fallback: force the sysfs fallback mechanism to be used

 * 	as if one had enabled CONFIG_FW_LOADER_USER_HELPER_FALLBACK=y.

 * 	Useful to help debug a CONFIG_FW_LOADER_USER_HELPER_FALLBACK=y

 * 	functionality on a kernel where that config entry has been disabled.

 * @old_timeout: for internal use

 * @loading_timeout: the timeout to wait for the fallback mechanism before

 * 	giving up, in seconds.

 */

struct firmware_fallback_config {

	const bool force_sysfs_fallback;

	unsigned int force_sysfs_fallback;

	int old_timeout;

	int loading_timeout;

};

drivers/base/firmware_loader/fallback_table.c

+17 −0
Original line number Diff line number Diff line
@@ -19,6 +19,9 @@ 
/* Module or buit-in */

#ifdef CONFIG_FW_LOADER_USER_HELPER



static unsigned int zero;

static unsigned int one = 1;



struct firmware_fallback_config fw_fallback_config = {

	.force_sysfs_fallback = IS_ENABLED(CONFIG_FW_LOADER_USER_HELPER_FALLBACK),

	.loading_timeout = 60,
@@ -26,4 +29,18 @@ struct firmware_fallback_config fw_fallback_config = { 
};

EXPORT_SYMBOL_GPL(fw_fallback_config);



struct ctl_table firmware_config_table[] = {

	{

		.procname	= "force_sysfs_fallback",

		.data		= &fw_fallback_config.force_sysfs_fallback,

		.maxlen         = sizeof(unsigned int),

		.mode           = 0644,

		.proc_handler   = proc_douintvec_minmax,

		.extra1		= &zero,

		.extra2		= &one,

	},

	{ }

};

EXPORT_SYMBOL_GPL(firmware_config_table);



#endif

kernel/sysctl.c

+11 −0
Original line number Diff line number Diff line
@@ -253,6 +253,10 @@ extern struct ctl_table random_table[]; 
extern struct ctl_table epoll_table[];

#endif



#ifdef CONFIG_FW_LOADER_USER_HELPER

extern struct ctl_table firmware_config_table[];

#endif



#ifdef HAVE_ARCH_PICK_MMAP_LAYOUT

int sysctl_legacy_va_layout;

#endif
@@ -748,6 +752,13 @@ static struct ctl_table kern_table[] = { 
		.mode		= 0555,

		.child		= usermodehelper_table,

	},

#ifdef CONFIG_FW_LOADER_USER_HELPER

	{

		.procname	= "firmware_config",

		.mode		= 0555,

		.child		= firmware_config_table,

	},

#endif

	{

		.procname	= "overflowuid",

		.data		= &overflowuid,