devcoredump.h

  1/* SPDX-License-Identifier: GPL-2.0-only */
  2/*
  3 * Copyright(c) 2015 Intel Deutschland GmbH
  4 */
  5#ifndef __DEVCOREDUMP_H
  6#define __DEVCOREDUMP_H
  7
  8#include <linux/device.h>
  9#include <linux/module.h>
 10#include <linux/vmalloc.h>
 11
 12#include <linux/scatterlist.h>
 13#include <linux/slab.h>
 14
 15/* if data isn't read by userspace after 5 minutes then delete it */
 16#define DEVCD_TIMEOUT	(HZ * 60 * 5)
 17
 18/*
 19 * _devcd_free_sgtable - free all the memory of the given scatterlist table
 20 * (i.e. both pages and scatterlist instances)
 21 * NOTE: if two tables allocated and chained using the sg_chain function then
 22 * this function should be called only once on the first table
 23 * @table: pointer to sg_table to free
 24 */
 25static inline void _devcd_free_sgtable(struct scatterlist *table)
 26{
 27	int i;
 28	struct page *page;
 29	struct scatterlist *iter;
 30	struct scatterlist *delete_iter;
 31
 32	/* free pages */
 33	iter = table;
 34	for_each_sg(table, iter, sg_nents(table), i) {
 35		page = sg_page(iter);
 36		if (page)
 37			__free_page(page);
 38	}
 39
 40	/* then free all chained tables */
 41	iter = table;
 42	delete_iter = table;	/* always points on a head of a table */
 43	while (!sg_is_last(iter)) {
 44		iter++;
 45		if (sg_is_chain(iter)) {
 46			iter = sg_chain_ptr(iter);
 47			kfree(delete_iter);
 48			delete_iter = iter;
 49		}
 50	}
 51
 52	/* free the last table */
 53	kfree(delete_iter);
 54}
 55
 56#ifdef CONFIG_DEV_COREDUMP
 57void dev_coredumpv(struct device *dev, void *data, size_t datalen,
 58		   gfp_t gfp);
 59
 60void dev_coredumpm_timeout(struct device *dev, struct module *owner,
 61			   void *data, size_t datalen, gfp_t gfp,
 62			   ssize_t (*read)(char *buffer, loff_t offset,
 63					   size_t count, void *data,
 64					   size_t datalen),
 65			   void (*free)(void *data),
 66			   unsigned long timeout);
 67
 68void dev_coredumpsg(struct device *dev, struct scatterlist *table,
 69		    size_t datalen, gfp_t gfp);
 70
 71void dev_coredump_put(struct device *dev);
 72#else
 73static inline void dev_coredumpv(struct device *dev, void *data,
 74				 size_t datalen, gfp_t gfp)
 75{
 76	vfree(data);
 77}
 78
 79static inline void
 80dev_coredumpm_timeout(struct device *dev, struct module *owner,
 81		      void *data, size_t datalen, gfp_t gfp,
 82		      ssize_t (*read)(char *buffer, loff_t offset,
 83				      size_t count, void *data,
 84				      size_t datalen),
 85		      void (*free)(void *data),
 86		      unsigned long timeout)
 87{
 88	free(data);
 89}
 90
 91static inline void dev_coredumpsg(struct device *dev, struct scatterlist *table,
 92				  size_t datalen, gfp_t gfp)
 93{
 94	_devcd_free_sgtable(table);
 95}
 96static inline void dev_coredump_put(struct device *dev)
 97{
 98}
 99#endif /* CONFIG_DEV_COREDUMP */
100
101/**
102 * dev_coredumpm - create device coredump with read/free methods
103 * @dev: the struct device for the crashed device
104 * @owner: the module that contains the read/free functions, use %THIS_MODULE
105 * @data: data cookie for the @read/@free functions
106 * @datalen: length of the data
107 * @gfp: allocation flags
108 * @read: function to read from the given buffer
109 * @free: function to free the given buffer
110 *
111 * Creates a new device coredump for the given device. If a previous one hasn't
112 * been read yet, the new coredump is discarded. The data lifetime is determined
113 * by the device coredump framework and when it is no longer needed the @free
114 * function will be called to free the data.
115 */
116static inline void dev_coredumpm(struct device *dev, struct module *owner,
117				 void *data, size_t datalen, gfp_t gfp,
118				 ssize_t (*read)(char *buffer, loff_t offset, size_t count,
119						 void *data, size_t datalen),
120				void (*free)(void *data))
121{
122	dev_coredumpm_timeout(dev, owner, data, datalen, gfp, read, free,
123			      DEVCD_TIMEOUT);
124}
125
126#endif /* __DEVCOREDUMP_H */