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Commit 5d31d76e authored by qctecmdr's avatar qctecmdr Committed by Gerrit - the friendly Code Review server
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Merge "soc: qcom: ramdump: Abort user-space read if timed-out"

parents 3f43b0f2 c58293c6

drivers/soc/qcom/ramdump.c

+36 −3
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-only

/*

 * Copyright (c) 2011-2019, The Linux Foundation. All rights reserved.

 * Copyright (c) 2011-2020, The Linux Foundation. All rights reserved.

 */



#include <linux/kernel.h>
@@ -17,6 +17,7 @@ 
#include <linux/elf.h>

#include <linux/wait.h>

#include <linux/cdev.h>

#include <linux/srcu.h>

#include <linux/atomic.h>

#include <soc/qcom/ramdump.h>

#include <linux/dma-mapping.h>
@@ -61,6 +62,8 @@ struct ramdump_device { 
	char *elfcore_buf;

	unsigned long attrs;

	bool complete_ramdump;

	bool abort_ramdump;

	struct srcu_struct rd_srcu;

};



static int ramdump_open(struct inode *inode, struct file *filep)
@@ -160,15 +163,26 @@ static ssize_t ramdump_read(struct file *filep, char __user *buf, size_t count, 
	size_t copy_size = 0, alignsize;

	unsigned char *alignbuf = NULL, *finalbuf = NULL;

	int ret = 0;

	int srcu_idx;

	loff_t orig_pos = *pos;



	if ((filep->f_flags & O_NONBLOCK) && !entry->data_ready)

		return -EAGAIN;



	ret = wait_event_interruptible(rd_dev->dump_wait_q, entry->data_ready);

	ret = wait_event_interruptible(rd_dev->dump_wait_q,

				(entry->data_ready || rd_dev->abort_ramdump));

	if (ret)

		return ret;



	srcu_idx = srcu_read_lock(&rd_dev->rd_srcu);



	if (rd_dev->abort_ramdump) {

		pr_err("Ramdump(%s): Ramdump aborted\n", rd_dev->name);

		rd_dev->ramdump_status = -1;

		ret = -ETIME;

		goto ramdump_done;

	}



	if (*pos < rd_dev->elfcore_size) {

		copy_size = rd_dev->elfcore_size - *pos;

		copy_size = min(copy_size, count);
@@ -180,9 +194,11 @@ static ssize_t ramdump_read(struct file *filep, char __user *buf, size_t count, 
		*pos += copy_size;

		count -= copy_size;

		buf += copy_size;

		if (count == 0)

		if (count == 0) {

			srcu_read_unlock(&rd_dev->rd_srcu, srcu_idx);

			return copy_size;

		}

	}



	addr = offset_translate(*pos - rd_dev->elfcore_size, rd_dev,

				&data_left, &vaddr);
@@ -258,12 +274,15 @@ static ssize_t ramdump_read(struct file *filep, char __user *buf, size_t count, 
	pr_debug("Ramdump(%s): Read %zd bytes from address %lx.",

			rd_dev->name, copy_size, addr);



	srcu_read_unlock(&rd_dev->rd_srcu, srcu_idx);



	return *pos - orig_pos;



ramdump_done:

	if (!vaddr && origdevice_mem)

		dma_unremap(rd_dev->dev->parent, origdevice_mem, copy_size);



	srcu_read_unlock(&rd_dev->rd_srcu, srcu_idx);

	kfree(finalbuf);

	*pos = 0;

	reset_ramdump_entry(entry);
@@ -368,6 +387,7 @@ void *create_ramdump_device(const char *dev_name, struct device *parent) 


	mutex_init(&rd_dev->consumer_lock);

	atomic_set(&rd_dev->readers_left, 0);

	init_srcu_struct(&rd_dev->rd_srcu);

	cdev_init(&rd_dev->cdev, &ramdump_file_ops);



	ret = cdev_add(&rd_dev->cdev, MKDEV(MAJOR(ramdump_dev), minor), 1);
@@ -380,6 +400,7 @@ void *create_ramdump_device(const char *dev_name, struct device *parent) 
	return (void *)rd_dev;



fail_cdev_add:

	cleanup_srcu_struct(&rd_dev->rd_srcu);

	mutex_destroy(&rd_dev->consumer_lock);

	device_unregister(rd_dev->dev);

fail_return_minor:
@@ -400,6 +421,7 @@ void destroy_ramdump_device(void *dev) 


	cdev_del(&rd_dev->cdev);

	device_unregister(rd_dev->dev);

	cleanup_srcu_struct(&rd_dev->rd_srcu);

	ida_simple_remove(&rd_minor_id, minor);

	kfree(rd_dev);

}
@@ -480,6 +502,7 @@ static int _do_ramdump(void *handle, struct ramdump_segment *segments, 
	list_for_each_entry(entry, &rd_dev->consumer_list, list)

		entry->data_ready = true;

	rd_dev->ramdump_status = -1;

	rd_dev->abort_ramdump = false;



	reinit_completion(&rd_dev->ramdump_complete);

	atomic_set(&rd_dev->readers_left, rd_dev->consumers);
@@ -496,6 +519,11 @@ static int _do_ramdump(void *handle, struct ramdump_segment *segments, 
		pr_err("Ramdump(%s): Timed out waiting for userspace.\n",

			rd_dev->name);

		ret = -EPIPE;

		rd_dev->abort_ramdump = true;



		/* Wait for pending readers to complete (if any) */

		synchronize_srcu(&rd_dev->rd_srcu);



	} else

		ret = (rd_dev->ramdump_status == 0) ? 0 : -EPIPE;
@@ -609,6 +637,7 @@ static int _do_minidump(void *handle, struct ramdump_segment *segments, 
	list_for_each_entry(entry, &rd_dev->consumer_list, list)

		entry->data_ready = true;

	rd_dev->ramdump_status = -1;

	rd_dev->abort_ramdump = false;



	reinit_completion(&rd_dev->ramdump_complete);

	atomic_set(&rd_dev->readers_left, rd_dev->consumers);
@@ -625,6 +654,10 @@ static int _do_minidump(void *handle, struct ramdump_segment *segments, 
		pr_err("Ramdump(%s): Timed out waiting for userspace.\n",

		       rd_dev->name);

		ret = -EPIPE;

		rd_dev->abort_ramdump = true;



		/* Wait for pending readers to complete (if any) */

		synchronize_srcu(&rd_dev->rd_srcu);

	} else {

		ret = (rd_dev->ramdump_status == 0) ? 0 : -EPIPE;

	}