https://github.com/torvalds/linux
Revision a4412fdd49dc011bcc2c0d81ac4cab7457092650 authored by Steven Rostedt (Google) on 21 November 2022, 15:44:03 UTC, committed by Linus Torvalds on 01 December 2022, 21:14:21 UTC
The config to be able to inject error codes into any function annotated
with ALLOW_ERROR_INJECTION() is enabled when FUNCTION_ERROR_INJECTION is
enabled.  But unfortunately, this is always enabled on x86 when KPROBES
is enabled, and there's no way to turn it off.

As kprobes is useful for observability of the kernel, it is useful to
have it enabled in production environments.  But error injection should
be avoided.  Add a prompt to the config to allow it to be disabled even
when kprobes is enabled, and get rid of the "def_bool y".

This is a kernel debug feature (it's in Kconfig.debug), and should have
never been something enabled by default.

Cc: stable@vger.kernel.org
Fixes: 540adea3809f6 ("error-injection: Separate error-injection from kprobe")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 355479c
Raw File
Tip revision: a4412fdd49dc011bcc2c0d81ac4cab7457092650 authored by Steven Rostedt (Google) on 21 November 2022, 15:44:03 UTC
error-injection: Add prompt for function error injection
Tip revision: a4412fd
sysfs_slave.c
// SPDX-License-Identifier: GPL-2.0-only
// Copyright(c) 2015-2020 Intel Corporation.

#include <linux/device.h>
#include <linux/mod_devicetable.h>
#include <linux/slab.h>
#include <linux/sysfs.h>
#include <linux/soundwire/sdw.h>
#include <linux/soundwire/sdw_type.h>
#include "bus.h"
#include "sysfs_local.h"

/*
 * Slave sysfs
 */

/*
 * The sysfs for Slave reflects the MIPI description as given
 * in the MIPI DisCo spec.
 * status and device_number come directly from the MIPI SoundWire
 * 1.x specification.
 *
 * Base file is device
 *	|---- status
 *	|---- device_number
 *	|---- modalias
 *	|---- dev-properties
 *		|---- mipi_revision
 *		|---- wake_capable
 *		|---- test_mode_capable
 *		|---- clk_stop_mode1
 *		|---- simple_clk_stop_capable
 *		|---- clk_stop_timeout
 *		|---- ch_prep_timeout
 *		|---- reset_behave
 *		|---- high_PHY_capable
 *		|---- paging_support
 *		|---- bank_delay_support
 *		|---- p15_behave
 *		|---- master_count
 *		|---- source_ports
 *		|---- sink_ports
 *	|---- dp0
 *		|---- max_word
 *		|---- min_word
 *		|---- words
 *		|---- BRA_flow_controlled
 *		|---- simple_ch_prep_sm
 *		|---- imp_def_interrupts
 *	|---- dpN_<sink/src>
 *		|---- max_word
 *		|---- min_word
 *		|---- words
 *		|---- type
 *		|---- max_grouping
 *		|---- simple_ch_prep_sm
 *		|---- ch_prep_timeout
 *		|---- imp_def_interrupts
 *		|---- min_ch
 *		|---- max_ch
 *		|---- channels
 *		|---- ch_combinations
 *		|---- max_async_buffer
 *		|---- block_pack_mode
 *		|---- port_encoding
 *
 */

#define sdw_slave_attr(field, format_string)			\
static ssize_t field##_show(struct device *dev,			\
			    struct device_attribute *attr,	\
			    char *buf)				\
{								\
	struct sdw_slave *slave = dev_to_sdw_dev(dev);		\
	return sprintf(buf, format_string, slave->prop.field);	\
}								\
static DEVICE_ATTR_RO(field)

sdw_slave_attr(mipi_revision, "0x%x\n");
sdw_slave_attr(wake_capable, "%d\n");
sdw_slave_attr(test_mode_capable, "%d\n");
sdw_slave_attr(clk_stop_mode1, "%d\n");
sdw_slave_attr(simple_clk_stop_capable, "%d\n");
sdw_slave_attr(clk_stop_timeout, "%d\n");
sdw_slave_attr(ch_prep_timeout, "%d\n");
sdw_slave_attr(reset_behave, "%d\n");
sdw_slave_attr(high_PHY_capable, "%d\n");
sdw_slave_attr(paging_support, "%d\n");
sdw_slave_attr(bank_delay_support, "%d\n");
sdw_slave_attr(p15_behave, "%d\n");
sdw_slave_attr(master_count, "%d\n");
sdw_slave_attr(source_ports, "0x%x\n");
sdw_slave_attr(sink_ports, "0x%x\n");

static ssize_t modalias_show(struct device *dev,
			     struct device_attribute *attr, char *buf)
{
	struct sdw_slave *slave = dev_to_sdw_dev(dev);

	return sdw_slave_modalias(slave, buf, 256);
}
static DEVICE_ATTR_RO(modalias);

static struct attribute *slave_attrs[] = {
	&dev_attr_modalias.attr,
	NULL,
};
ATTRIBUTE_GROUPS(slave);

static struct attribute *slave_dev_attrs[] = {
	&dev_attr_mipi_revision.attr,
	&dev_attr_wake_capable.attr,
	&dev_attr_test_mode_capable.attr,
	&dev_attr_clk_stop_mode1.attr,
	&dev_attr_simple_clk_stop_capable.attr,
	&dev_attr_clk_stop_timeout.attr,
	&dev_attr_ch_prep_timeout.attr,
	&dev_attr_reset_behave.attr,
	&dev_attr_high_PHY_capable.attr,
	&dev_attr_paging_support.attr,
	&dev_attr_bank_delay_support.attr,
	&dev_attr_p15_behave.attr,
	&dev_attr_master_count.attr,
	&dev_attr_source_ports.attr,
	&dev_attr_sink_ports.attr,
	NULL,
};

/*
 * we don't use ATTRIBUTES_GROUP here since we want to add a subdirectory
 * for device-level properties
 */
static const struct attribute_group sdw_slave_dev_attr_group = {
	.attrs	= slave_dev_attrs,
	.name = "dev-properties",
};

/*
 * DP0 sysfs
 */

#define sdw_dp0_attr(field, format_string)				\
static ssize_t field##_show(struct device *dev,				\
			    struct device_attribute *attr,		\
			    char *buf)					\
{									\
	struct sdw_slave *slave = dev_to_sdw_dev(dev);			\
	return sprintf(buf, format_string, slave->prop.dp0_prop->field);\
}									\
static DEVICE_ATTR_RO(field)

sdw_dp0_attr(max_word, "%d\n");
sdw_dp0_attr(min_word, "%d\n");
sdw_dp0_attr(BRA_flow_controlled, "%d\n");
sdw_dp0_attr(simple_ch_prep_sm, "%d\n");
sdw_dp0_attr(imp_def_interrupts, "0x%x\n");

static ssize_t words_show(struct device *dev,
			  struct device_attribute *attr, char *buf)
{
	struct sdw_slave *slave = dev_to_sdw_dev(dev);
	ssize_t size = 0;
	int i;

	for (i = 0; i < slave->prop.dp0_prop->num_words; i++)
		size += sprintf(buf + size, "%d ",
				slave->prop.dp0_prop->words[i]);
	size += sprintf(buf + size, "\n");

	return size;
}
static DEVICE_ATTR_RO(words);

static struct attribute *dp0_attrs[] = {
	&dev_attr_max_word.attr,
	&dev_attr_min_word.attr,
	&dev_attr_words.attr,
	&dev_attr_BRA_flow_controlled.attr,
	&dev_attr_simple_ch_prep_sm.attr,
	&dev_attr_imp_def_interrupts.attr,
	NULL,
};

/*
 * we don't use ATTRIBUTES_GROUP here since we want to add a subdirectory
 * for dp0-level properties
 */
static const struct attribute_group dp0_group = {
	.attrs = dp0_attrs,
	.name = "dp0",
};

int sdw_slave_sysfs_init(struct sdw_slave *slave)
{
	int ret;

	ret = devm_device_add_groups(&slave->dev, slave_groups);
	if (ret < 0)
		return ret;

	ret = devm_device_add_group(&slave->dev, &sdw_slave_dev_attr_group);
	if (ret < 0)
		return ret;

	if (slave->prop.dp0_prop) {
		ret = devm_device_add_group(&slave->dev, &dp0_group);
		if (ret < 0)
			return ret;
	}

	if (slave->prop.source_ports || slave->prop.sink_ports) {
		ret = sdw_slave_sysfs_dpn_init(slave);
		if (ret < 0)
			return ret;
	}

	return 0;
}

/*
 * the status is shown in capital letters for UNATTACHED and RESERVED
 * on purpose, to highligh users to the fact that these status values
 * are not expected.
 */
static const char *const slave_status[] = {
	[SDW_SLAVE_UNATTACHED] =  "UNATTACHED",
	[SDW_SLAVE_ATTACHED] = "Attached",
	[SDW_SLAVE_ALERT] = "Alert",
	[SDW_SLAVE_RESERVED] = "RESERVED",
};

static ssize_t status_show(struct device *dev,
			   struct device_attribute *attr, char *buf)
{
	struct sdw_slave *slave = dev_to_sdw_dev(dev);

	return sprintf(buf, "%s\n", slave_status[slave->status]);
}
static DEVICE_ATTR_RO(status);

static ssize_t device_number_show(struct device *dev,
				  struct device_attribute *attr, char *buf)
{
	struct sdw_slave *slave = dev_to_sdw_dev(dev);

	if (slave->status == SDW_SLAVE_UNATTACHED)
		return sprintf(buf, "%s", "N/A");
	else
		return sprintf(buf, "%d", slave->dev_num);
}
static DEVICE_ATTR_RO(device_number);

static struct attribute *slave_status_attrs[] = {
	&dev_attr_status.attr,
	&dev_attr_device_number.attr,
	NULL,
};

/*
 * we don't use ATTRIBUTES_GROUP here since the group is used in a
 * separate file and can't be handled as a static.
 */
static const struct attribute_group sdw_slave_status_attr_group = {
	.attrs	= slave_status_attrs,
};

const struct attribute_group *sdw_slave_status_attr_groups[] = {
	&sdw_slave_status_attr_group,
	NULL
};
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