--- /dev/null
+/* SPDX-License-Identifier: (GPL-2.0-only OR LGPL-2.1-only)
+ *
+ * ring_buffer_backend.c
+ *
+ * Copyright (C) 2005-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ */
+
+#include <linux/stddef.h>
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/bitops.h>
+#include <linux/delay.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/cpu.h>
+#include <linux/mm.h>
+#include <linux/vmalloc.h>
+
+#include <wrapper/mm.h>
+#include <wrapper/vmalloc.h> /* for wrapper_vmalloc_sync_mappings() */
+#include <ringbuffer/config.h>
+#include <ringbuffer/backend.h>
+#include <ringbuffer/frontend.h>
+
+/**
+ * lib_ring_buffer_backend_allocate - allocate a channel buffer
+ * @config: ring buffer instance configuration
+ * @buf: the buffer struct
+ * @size: total size of the buffer
+ * @num_subbuf: number of subbuffers
+ * @extra_reader_sb: need extra subbuffer for reader
+ */
+static
+int lib_ring_buffer_backend_allocate(const struct lib_ring_buffer_config *config,
+ struct lib_ring_buffer_backend *bufb,
+ size_t size, size_t num_subbuf,
+ int extra_reader_sb)
+{
+ struct channel_backend *chanb = &bufb->chan->backend;
+ unsigned long j, num_pages, num_pages_per_subbuf, page_idx = 0;
+ unsigned long subbuf_size, mmap_offset = 0;
+ unsigned long num_subbuf_alloc;
+ struct page **pages;
+ unsigned long i;
+
+ num_pages = size >> PAGE_SHIFT;
+
+ /*
+ * Verify that there is enough free pages available on the system for
+ * the current allocation request.
+ * wrapper_check_enough_free_pages uses si_mem_available() if available
+ * and returns if there should be enough free pages based on the
+ * current estimate.
+ */
+ if (!wrapper_check_enough_free_pages(num_pages))
+ goto not_enough_pages;
+
+ /*
+ * Set the current user thread as the first target of the OOM killer.
+ * If the estimate received by si_mem_available() was off, and we do
+ * end up running out of memory because of this buffer allocation, we
+ * want to kill the offending app first.
+ */
+ wrapper_set_current_oom_origin();
+
+ num_pages_per_subbuf = num_pages >> get_count_order(num_subbuf);
+ subbuf_size = chanb->subbuf_size;
+ num_subbuf_alloc = num_subbuf;
+
+ if (extra_reader_sb) {
+ num_pages += num_pages_per_subbuf; /* Add pages for reader */
+ num_subbuf_alloc++;
+ }
+
+ pages = vmalloc_node(ALIGN(sizeof(*pages) * num_pages,
+ 1 << INTERNODE_CACHE_SHIFT),
+ cpu_to_node(max(bufb->cpu, 0)));
+ if (unlikely(!pages))
+ goto pages_error;
+
+ bufb->array = lttng_kvmalloc_node(ALIGN(sizeof(*bufb->array)
+ * num_subbuf_alloc,
+ 1 << INTERNODE_CACHE_SHIFT),
+ GFP_KERNEL | __GFP_NOWARN,
+ cpu_to_node(max(bufb->cpu, 0)));
+ if (unlikely(!bufb->array))
+ goto array_error;
+
+ for (i = 0; i < num_pages; i++) {
+ pages[i] = alloc_pages_node(cpu_to_node(max(bufb->cpu, 0)),
+ GFP_KERNEL | __GFP_NOWARN | __GFP_ZERO, 0);
+ if (unlikely(!pages[i]))
+ goto depopulate;
+ }
+ bufb->num_pages_per_subbuf = num_pages_per_subbuf;
+
+ /* Allocate backend pages array elements */
+ for (i = 0; i < num_subbuf_alloc; i++) {
+ bufb->array[i] =
+ lttng_kvzalloc_node(ALIGN(
+ sizeof(struct lib_ring_buffer_backend_pages) +
+ sizeof(struct lib_ring_buffer_backend_page)
+ * num_pages_per_subbuf,
+ 1 << INTERNODE_CACHE_SHIFT),
+ GFP_KERNEL | __GFP_NOWARN,
+ cpu_to_node(max(bufb->cpu, 0)));
+ if (!bufb->array[i])
+ goto free_array;
+ }
+
+ /* Allocate write-side subbuffer table */
+ bufb->buf_wsb = lttng_kvzalloc_node(ALIGN(
+ sizeof(struct lib_ring_buffer_backend_subbuffer)
+ * num_subbuf,
+ 1 << INTERNODE_CACHE_SHIFT),
+ GFP_KERNEL | __GFP_NOWARN,
+ cpu_to_node(max(bufb->cpu, 0)));
+ if (unlikely(!bufb->buf_wsb))
+ goto free_array;
+
+ for (i = 0; i < num_subbuf; i++)
+ bufb->buf_wsb[i].id = subbuffer_id(config, 0, 1, i);
+
+ /* Assign read-side subbuffer table */
+ if (extra_reader_sb)
+ bufb->buf_rsb.id = subbuffer_id(config, 0, 1,
+ num_subbuf_alloc - 1);
+ else
+ bufb->buf_rsb.id = subbuffer_id(config, 0, 1, 0);
+
+ /* Allocate subbuffer packet counter table */
+ bufb->buf_cnt = lttng_kvzalloc_node(ALIGN(
+ sizeof(struct lib_ring_buffer_backend_counts)
+ * num_subbuf,
+ 1 << INTERNODE_CACHE_SHIFT),
+ GFP_KERNEL | __GFP_NOWARN,
+ cpu_to_node(max(bufb->cpu, 0)));
+ if (unlikely(!bufb->buf_cnt))
+ goto free_wsb;
+
+ /* Assign pages to page index */
+ for (i = 0; i < num_subbuf_alloc; i++) {
+ for (j = 0; j < num_pages_per_subbuf; j++) {
+ CHAN_WARN_ON(chanb, page_idx > num_pages);
+ bufb->array[i]->p[j].virt = page_address(pages[page_idx]);
+ bufb->array[i]->p[j].pfn = page_to_pfn(pages[page_idx]);
+ page_idx++;
+ }
+ if (config->output == RING_BUFFER_MMAP) {
+ bufb->array[i]->mmap_offset = mmap_offset;
+ mmap_offset += subbuf_size;
+ }
+ }
+
+ /*
+ * If kmalloc ever uses vmalloc underneath, make sure the buffer pages
+ * will not fault.
+ */
+ wrapper_vmalloc_sync_mappings();
+ wrapper_clear_current_oom_origin();
+ vfree(pages);
+ return 0;
+
+free_wsb:
+ lttng_kvfree(bufb->buf_wsb);
+free_array:
+ for (i = 0; (i < num_subbuf_alloc && bufb->array[i]); i++)
+ lttng_kvfree(bufb->array[i]);
+depopulate:
+ /* Free all allocated pages */
+ for (i = 0; (i < num_pages && pages[i]); i++)
+ __free_page(pages[i]);
+ lttng_kvfree(bufb->array);
+array_error:
+ vfree(pages);
+pages_error:
+ wrapper_clear_current_oom_origin();
+not_enough_pages:
+ return -ENOMEM;
+}
+
+int lib_ring_buffer_backend_create(struct lib_ring_buffer_backend *bufb,
+ struct channel_backend *chanb, int cpu)
+{
+ const struct lib_ring_buffer_config *config = &chanb->config;
+
+ bufb->chan = container_of(chanb, struct channel, backend);
+ bufb->cpu = cpu;
+
+ return lib_ring_buffer_backend_allocate(config, bufb, chanb->buf_size,
+ chanb->num_subbuf,
+ chanb->extra_reader_sb);
+}
+
+void lib_ring_buffer_backend_free(struct lib_ring_buffer_backend *bufb)
+{
+ struct channel_backend *chanb = &bufb->chan->backend;
+ unsigned long i, j, num_subbuf_alloc;
+
+ num_subbuf_alloc = chanb->num_subbuf;
+ if (chanb->extra_reader_sb)
+ num_subbuf_alloc++;
+
+ lttng_kvfree(bufb->buf_wsb);
+ lttng_kvfree(bufb->buf_cnt);
+ for (i = 0; i < num_subbuf_alloc; i++) {
+ for (j = 0; j < bufb->num_pages_per_subbuf; j++)
+ __free_page(pfn_to_page(bufb->array[i]->p[j].pfn));
+ lttng_kvfree(bufb->array[i]);
+ }
+ lttng_kvfree(bufb->array);
+ bufb->allocated = 0;
+}
+
+void lib_ring_buffer_backend_reset(struct lib_ring_buffer_backend *bufb)
+{
+ struct channel_backend *chanb = &bufb->chan->backend;
+ const struct lib_ring_buffer_config *config = &chanb->config;
+ unsigned long num_subbuf_alloc;
+ unsigned int i;
+
+ num_subbuf_alloc = chanb->num_subbuf;
+ if (chanb->extra_reader_sb)
+ num_subbuf_alloc++;
+
+ for (i = 0; i < chanb->num_subbuf; i++)
+ bufb->buf_wsb[i].id = subbuffer_id(config, 0, 1, i);
+ if (chanb->extra_reader_sb)
+ bufb->buf_rsb.id = subbuffer_id(config, 0, 1,
+ num_subbuf_alloc - 1);
+ else
+ bufb->buf_rsb.id = subbuffer_id(config, 0, 1, 0);
+
+ for (i = 0; i < num_subbuf_alloc; i++) {
+ /* Don't reset mmap_offset */
+ v_set(config, &bufb->array[i]->records_commit, 0);
+ v_set(config, &bufb->array[i]->records_unread, 0);
+ bufb->array[i]->data_size = 0;
+ /* Don't reset backend page and virt addresses */
+ }
+ /* Don't reset num_pages_per_subbuf, cpu, allocated */
+ v_set(config, &bufb->records_read, 0);
+}
+
+/*
+ * The frontend is responsible for also calling ring_buffer_backend_reset for
+ * each buffer when calling channel_backend_reset.
+ */
+void channel_backend_reset(struct channel_backend *chanb)
+{
+ struct channel *chan = container_of(chanb, struct channel, backend);
+ const struct lib_ring_buffer_config *config = &chanb->config;
+
+ /*
+ * Don't reset buf_size, subbuf_size, subbuf_size_order,
+ * num_subbuf_order, buf_size_order, extra_reader_sb, num_subbuf,
+ * priv, notifiers, config, cpumask and name.
+ */
+ chanb->start_tsc = config->cb.ring_buffer_clock_read(chan);
+}
+
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0))
+
+/*
+ * No need to implement a "dead" callback to do a buffer switch here,
+ * because it will happen when tracing is stopped, or will be done by
+ * switch timer CPU DEAD callback.
+ * We don't free buffers when CPU go away, because it would make trace
+ * data vanish, which is unwanted.
+ */
+int lttng_cpuhp_rb_backend_prepare(unsigned int cpu,
+ struct lttng_cpuhp_node *node)
+{
+ struct channel_backend *chanb = container_of(node,
+ struct channel_backend, cpuhp_prepare);
+ const struct lib_ring_buffer_config *config = &chanb->config;
+ struct lib_ring_buffer *buf;
+ int ret;
+
+ CHAN_WARN_ON(chanb, config->alloc == RING_BUFFER_ALLOC_GLOBAL);
+
+ buf = per_cpu_ptr(chanb->buf, cpu);
+ ret = lib_ring_buffer_create(buf, chanb, cpu);
+ if (ret) {
+ printk(KERN_ERR
+ "ring_buffer_cpu_hp_callback: cpu %d "
+ "buffer creation failed\n", cpu);
+ return ret;
+ }
+ return 0;
+}
+EXPORT_SYMBOL_GPL(lttng_cpuhp_rb_backend_prepare);
+
+#else /* #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */
+
+#ifdef CONFIG_HOTPLUG_CPU
+
+/**
+ * lib_ring_buffer_cpu_hp_callback - CPU hotplug callback
+ * @nb: notifier block
+ * @action: hotplug action to take
+ * @hcpu: CPU number
+ *
+ * Returns the success/failure of the operation. (%NOTIFY_OK, %NOTIFY_BAD)
+ */
+static
+int lib_ring_buffer_cpu_hp_callback(struct notifier_block *nb,
+ unsigned long action,
+ void *hcpu)
+{
+ unsigned int cpu = (unsigned long)hcpu;
+ struct channel_backend *chanb = container_of(nb, struct channel_backend,
+ cpu_hp_notifier);
+ const struct lib_ring_buffer_config *config = &chanb->config;
+ struct lib_ring_buffer *buf;
+ int ret;
+
+ CHAN_WARN_ON(chanb, config->alloc == RING_BUFFER_ALLOC_GLOBAL);
+
+ switch (action) {
+ case CPU_UP_PREPARE:
+ case CPU_UP_PREPARE_FROZEN:
+ buf = per_cpu_ptr(chanb->buf, cpu);
+ ret = lib_ring_buffer_create(buf, chanb, cpu);
+ if (ret) {
+ printk(KERN_ERR
+ "ring_buffer_cpu_hp_callback: cpu %d "
+ "buffer creation failed\n", cpu);
+ return NOTIFY_BAD;
+ }
+ break;
+ case CPU_DEAD:
+ case CPU_DEAD_FROZEN:
+ /* No need to do a buffer switch here, because it will happen
+ * when tracing is stopped, or will be done by switch timer CPU
+ * DEAD callback. */
+ break;
+ }
+ return NOTIFY_OK;
+}
+
+#endif
+
+#endif /* #else #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */
+
+/**
+ * channel_backend_init - initialize a channel backend
+ * @chanb: channel backend
+ * @name: channel name
+ * @config: client ring buffer configuration
+ * @priv: client private data
+ * @parent: dentry of parent directory, %NULL for root directory
+ * @subbuf_size: size of sub-buffers (> PAGE_SIZE, power of 2)
+ * @num_subbuf: number of sub-buffers (power of 2)
+ *
+ * Returns channel pointer if successful, %NULL otherwise.
+ *
+ * Creates per-cpu channel buffers using the sizes and attributes
+ * specified. The created channel buffer files will be named
+ * name_0...name_N-1. File permissions will be %S_IRUSR.
+ *
+ * Called with CPU hotplug disabled.
+ */
+int channel_backend_init(struct channel_backend *chanb,
+ const char *name,
+ const struct lib_ring_buffer_config *config,
+ void *priv, size_t subbuf_size, size_t num_subbuf)
+{
+ struct channel *chan = container_of(chanb, struct channel, backend);
+ unsigned int i;
+ int ret;
+
+ if (!name)
+ return -EPERM;
+
+ /* Check that the subbuffer size is larger than a page. */
+ if (subbuf_size < PAGE_SIZE)
+ return -EINVAL;
+
+ /*
+ * Make sure the number of subbuffers and subbuffer size are
+ * power of 2 and nonzero.
+ */
+ if (!subbuf_size || (subbuf_size & (subbuf_size - 1)))
+ return -EINVAL;
+ if (!num_subbuf || (num_subbuf & (num_subbuf - 1)))
+ return -EINVAL;
+ /*
+ * Overwrite mode buffers require at least 2 subbuffers per
+ * buffer.
+ */
+ if (config->mode == RING_BUFFER_OVERWRITE && num_subbuf < 2)
+ return -EINVAL;
+
+ ret = subbuffer_id_check_index(config, num_subbuf);
+ if (ret)
+ return ret;
+
+ chanb->priv = priv;
+ chanb->buf_size = num_subbuf * subbuf_size;
+ chanb->subbuf_size = subbuf_size;
+ chanb->buf_size_order = get_count_order(chanb->buf_size);
+ chanb->subbuf_size_order = get_count_order(subbuf_size);
+ chanb->num_subbuf_order = get_count_order(num_subbuf);
+ chanb->extra_reader_sb =
+ (config->mode == RING_BUFFER_OVERWRITE) ? 1 : 0;
+ chanb->num_subbuf = num_subbuf;
+ strlcpy(chanb->name, name, NAME_MAX);
+ memcpy(&chanb->config, config, sizeof(chanb->config));
+
+ if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) {
+ if (!zalloc_cpumask_var(&chanb->cpumask, GFP_KERNEL))
+ return -ENOMEM;
+ }
+
+ if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) {
+ /* Allocating the buffer per-cpu structures */
+ chanb->buf = alloc_percpu(struct lib_ring_buffer);
+ if (!chanb->buf)
+ goto free_cpumask;
+
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0))
+ chanb->cpuhp_prepare.component = LTTNG_RING_BUFFER_BACKEND;
+ ret = cpuhp_state_add_instance(lttng_rb_hp_prepare,
+ &chanb->cpuhp_prepare.node);
+ if (ret)
+ goto free_bufs;
+#else /* #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */
+
+ {
+ /*
+ * In case of non-hotplug cpu, if the ring-buffer is allocated
+ * in early initcall, it will not be notified of secondary cpus.
+ * In that off case, we need to allocate for all possible cpus.
+ */
+#ifdef CONFIG_HOTPLUG_CPU
+ /*
+ * buf->backend.allocated test takes care of concurrent CPU
+ * hotplug.
+ * Priority higher than frontend, so we create the ring buffer
+ * before we start the timer.
+ */
+ chanb->cpu_hp_notifier.notifier_call =
+ lib_ring_buffer_cpu_hp_callback;
+ chanb->cpu_hp_notifier.priority = 5;
+ register_hotcpu_notifier(&chanb->cpu_hp_notifier);
+
+ get_online_cpus();
+ for_each_online_cpu(i) {
+ ret = lib_ring_buffer_create(per_cpu_ptr(chanb->buf, i),
+ chanb, i);
+ if (ret)
+ goto free_bufs; /* cpu hotplug locked */
+ }
+ put_online_cpus();
+#else
+ for_each_possible_cpu(i) {
+ ret = lib_ring_buffer_create(per_cpu_ptr(chanb->buf, i),
+ chanb, i);
+ if (ret)
+ goto free_bufs;
+ }
+#endif
+ }
+#endif /* #else #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */
+ } else {
+ chanb->buf = kzalloc(sizeof(struct lib_ring_buffer), GFP_KERNEL);
+ if (!chanb->buf)
+ goto free_cpumask;
+ ret = lib_ring_buffer_create(chanb->buf, chanb, -1);
+ if (ret)
+ goto free_bufs;
+ }
+ chanb->start_tsc = config->cb.ring_buffer_clock_read(chan);
+
+ return 0;
+
+free_bufs:
+ if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) {
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0))
+ /*
+ * Teardown of lttng_rb_hp_prepare instance
+ * on "add" error is handled within cpu hotplug,
+ * no teardown to do from the caller.
+ */
+#else /* #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */
+#ifdef CONFIG_HOTPLUG_CPU
+ put_online_cpus();
+ unregister_hotcpu_notifier(&chanb->cpu_hp_notifier);
+#endif
+#endif /* #else #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */
+ for_each_possible_cpu(i) {
+ struct lib_ring_buffer *buf =
+ per_cpu_ptr(chanb->buf, i);
+
+ if (!buf->backend.allocated)
+ continue;
+ lib_ring_buffer_free(buf);
+ }
+ free_percpu(chanb->buf);
+ } else
+ kfree(chanb->buf);
+free_cpumask:
+ if (config->alloc == RING_BUFFER_ALLOC_PER_CPU)
+ free_cpumask_var(chanb->cpumask);
+ return -ENOMEM;
+}
+
+/**
+ * channel_backend_unregister_notifiers - unregister notifiers
+ * @chan: the channel
+ *
+ * Holds CPU hotplug.
+ */
+void channel_backend_unregister_notifiers(struct channel_backend *chanb)
+{
+ const struct lib_ring_buffer_config *config = &chanb->config;
+
+ if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) {
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0))
+ int ret;
+
+ ret = cpuhp_state_remove_instance(lttng_rb_hp_prepare,
+ &chanb->cpuhp_prepare.node);
+ WARN_ON(ret);
+#else /* #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */
+ unregister_hotcpu_notifier(&chanb->cpu_hp_notifier);
+#endif /* #else #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */
+ }
+}
+
+/**
+ * channel_backend_free - destroy the channel
+ * @chan: the channel
+ *
+ * Destroy all channel buffers and frees the channel.
+ */
+void channel_backend_free(struct channel_backend *chanb)
+{
+ const struct lib_ring_buffer_config *config = &chanb->config;
+ unsigned int i;
+
+ if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) {
+ for_each_possible_cpu(i) {
+ struct lib_ring_buffer *buf = per_cpu_ptr(chanb->buf, i);
+
+ if (!buf->backend.allocated)
+ continue;
+ lib_ring_buffer_free(buf);
+ }
+ free_cpumask_var(chanb->cpumask);
+ free_percpu(chanb->buf);
+ } else {
+ struct lib_ring_buffer *buf = chanb->buf;
+
+ CHAN_WARN_ON(chanb, !buf->backend.allocated);
+ lib_ring_buffer_free(buf);
+ kfree(buf);
+ }
+}
+
+/**
+ * lib_ring_buffer_write - write data to a ring_buffer buffer.
+ * @bufb : buffer backend
+ * @offset : offset within the buffer
+ * @src : source address
+ * @len : length to write
+ * @pagecpy : page size copied so far
+ */
+void _lib_ring_buffer_write(struct lib_ring_buffer_backend *bufb, size_t offset,
+ const void *src, size_t len, size_t pagecpy)
+{
+ struct channel_backend *chanb = &bufb->chan->backend;
+ const struct lib_ring_buffer_config *config = &chanb->config;
+ size_t sbidx, index;
+ struct lib_ring_buffer_backend_pages *rpages;
+ unsigned long sb_bindex, id;
+
+ do {
+ len -= pagecpy;
+ src += pagecpy;
+ offset += pagecpy;
+ sbidx = offset >> chanb->subbuf_size_order;
+ index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT;
+
+ /*
+ * Underlying layer should never ask for writes across
+ * subbuffers.
+ */
+ CHAN_WARN_ON(chanb, offset >= chanb->buf_size);
+
+ pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK));
+ id = bufb->buf_wsb[sbidx].id;
+ sb_bindex = subbuffer_id_get_index(config, id);
+ rpages = bufb->array[sb_bindex];
+ CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE
+ && subbuffer_id_is_noref(config, id));
+ lib_ring_buffer_do_copy(config,
+ rpages->p[index].virt
+ + (offset & ~PAGE_MASK),
+ src, pagecpy);
+ } while (unlikely(len != pagecpy));
+}
+EXPORT_SYMBOL_GPL(_lib_ring_buffer_write);
+
+
+/**
+ * lib_ring_buffer_memset - write len bytes of c to a ring_buffer buffer.
+ * @bufb : buffer backend
+ * @offset : offset within the buffer
+ * @c : the byte to write
+ * @len : length to write
+ * @pagecpy : page size copied so far
+ */
+void _lib_ring_buffer_memset(struct lib_ring_buffer_backend *bufb,
+ size_t offset,
+ int c, size_t len, size_t pagecpy)
+{
+ struct channel_backend *chanb = &bufb->chan->backend;
+ const struct lib_ring_buffer_config *config = &chanb->config;
+ size_t sbidx, index;
+ struct lib_ring_buffer_backend_pages *rpages;
+ unsigned long sb_bindex, id;
+
+ do {
+ len -= pagecpy;
+ offset += pagecpy;
+ sbidx = offset >> chanb->subbuf_size_order;
+ index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT;
+
+ /*
+ * Underlying layer should never ask for writes across
+ * subbuffers.
+ */
+ CHAN_WARN_ON(chanb, offset >= chanb->buf_size);
+
+ pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK));
+ id = bufb->buf_wsb[sbidx].id;
+ sb_bindex = subbuffer_id_get_index(config, id);
+ rpages = bufb->array[sb_bindex];
+ CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE
+ && subbuffer_id_is_noref(config, id));
+ lib_ring_buffer_do_memset(rpages->p[index].virt
+ + (offset & ~PAGE_MASK),
+ c, pagecpy);
+ } while (unlikely(len != pagecpy));
+}
+EXPORT_SYMBOL_GPL(_lib_ring_buffer_memset);
+
+/**
+ * lib_ring_buffer_strcpy - write string data to a ring_buffer buffer.
+ * @bufb : buffer backend
+ * @offset : offset within the buffer
+ * @src : source address
+ * @len : length to write
+ * @pagecpy : page size copied so far
+ * @pad : character to use for padding
+ */
+void _lib_ring_buffer_strcpy(struct lib_ring_buffer_backend *bufb,
+ size_t offset, const char *src, size_t len,
+ size_t pagecpy, int pad)
+{
+ struct channel_backend *chanb = &bufb->chan->backend;
+ const struct lib_ring_buffer_config *config = &chanb->config;
+ size_t sbidx, index;
+ struct lib_ring_buffer_backend_pages *rpages;
+ unsigned long sb_bindex, id;
+ int src_terminated = 0;
+
+ CHAN_WARN_ON(chanb, !len);
+ offset += pagecpy;
+ do {
+ len -= pagecpy;
+ if (!src_terminated)
+ src += pagecpy;
+ sbidx = offset >> chanb->subbuf_size_order;
+ index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT;
+
+ /*
+ * Underlying layer should never ask for writes across
+ * subbuffers.
+ */
+ CHAN_WARN_ON(chanb, offset >= chanb->buf_size);
+
+ pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK));
+ id = bufb->buf_wsb[sbidx].id;
+ sb_bindex = subbuffer_id_get_index(config, id);
+ rpages = bufb->array[sb_bindex];
+ CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE
+ && subbuffer_id_is_noref(config, id));
+
+ if (likely(!src_terminated)) {
+ size_t count, to_copy;
+
+ to_copy = pagecpy;
+ if (pagecpy == len)
+ to_copy--; /* Final '\0' */
+ count = lib_ring_buffer_do_strcpy(config,
+ rpages->p[index].virt
+ + (offset & ~PAGE_MASK),
+ src, to_copy);
+ offset += count;
+ /* Padding */
+ if (unlikely(count < to_copy)) {
+ size_t pad_len = to_copy - count;
+
+ /* Next pages will have padding */
+ src_terminated = 1;
+ lib_ring_buffer_do_memset(rpages->p[index].virt
+ + (offset & ~PAGE_MASK),
+ pad, pad_len);
+ offset += pad_len;
+ }
+ } else {
+ size_t pad_len;
+
+ pad_len = pagecpy;
+ if (pagecpy == len)
+ pad_len--; /* Final '\0' */
+ lib_ring_buffer_do_memset(rpages->p[index].virt
+ + (offset & ~PAGE_MASK),
+ pad, pad_len);
+ offset += pad_len;
+ }
+ } while (unlikely(len != pagecpy));
+ /* Ending '\0' */
+ lib_ring_buffer_do_memset(rpages->p[index].virt + (offset & ~PAGE_MASK),
+ '\0', 1);
+}
+EXPORT_SYMBOL_GPL(_lib_ring_buffer_strcpy);
+
+/**
+ * lib_ring_buffer_copy_from_user_inatomic - write user data to a ring_buffer buffer.
+ * @bufb : buffer backend
+ * @offset : offset within the buffer
+ * @src : source address
+ * @len : length to write
+ * @pagecpy : page size copied so far
+ *
+ * This function deals with userspace pointers, it should never be called
+ * directly without having the src pointer checked with access_ok()
+ * previously.
+ */
+void _lib_ring_buffer_copy_from_user_inatomic(struct lib_ring_buffer_backend *bufb,
+ size_t offset,
+ const void __user *src, size_t len,
+ size_t pagecpy)
+{
+ struct channel_backend *chanb = &bufb->chan->backend;
+ const struct lib_ring_buffer_config *config = &chanb->config;
+ size_t sbidx, index;
+ struct lib_ring_buffer_backend_pages *rpages;
+ unsigned long sb_bindex, id;
+ int ret;
+
+ do {
+ len -= pagecpy;
+ src += pagecpy;
+ offset += pagecpy;
+ sbidx = offset >> chanb->subbuf_size_order;
+ index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT;
+
+ /*
+ * Underlying layer should never ask for writes across
+ * subbuffers.
+ */
+ CHAN_WARN_ON(chanb, offset >= chanb->buf_size);
+
+ pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK));
+ id = bufb->buf_wsb[sbidx].id;
+ sb_bindex = subbuffer_id_get_index(config, id);
+ rpages = bufb->array[sb_bindex];
+ CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE
+ && subbuffer_id_is_noref(config, id));
+ ret = lib_ring_buffer_do_copy_from_user_inatomic(rpages->p[index].virt
+ + (offset & ~PAGE_MASK),
+ src, pagecpy) != 0;
+ if (ret > 0) {
+ /* Copy failed. */
+ _lib_ring_buffer_memset(bufb, offset, 0, len, 0);
+ break; /* stop copy */
+ }
+ } while (unlikely(len != pagecpy));
+}
+EXPORT_SYMBOL_GPL(_lib_ring_buffer_copy_from_user_inatomic);
+
+/**
+ * lib_ring_buffer_strcpy_from_user_inatomic - write userspace string data to a ring_buffer buffer.
+ * @bufb : buffer backend
+ * @offset : offset within the buffer
+ * @src : source address
+ * @len : length to write
+ * @pagecpy : page size copied so far
+ * @pad : character to use for padding
+ *
+ * This function deals with userspace pointers, it should never be called
+ * directly without having the src pointer checked with access_ok()
+ * previously.
+ */
+void _lib_ring_buffer_strcpy_from_user_inatomic(struct lib_ring_buffer_backend *bufb,
+ size_t offset, const char __user *src, size_t len,
+ size_t pagecpy, int pad)
+{
+ struct channel_backend *chanb = &bufb->chan->backend;
+ const struct lib_ring_buffer_config *config = &chanb->config;
+ size_t sbidx, index;
+ struct lib_ring_buffer_backend_pages *rpages;
+ unsigned long sb_bindex, id;
+ int src_terminated = 0;
+
+ offset += pagecpy;
+ do {
+ len -= pagecpy;
+ if (!src_terminated)
+ src += pagecpy;
+ sbidx = offset >> chanb->subbuf_size_order;
+ index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT;
+
+ /*
+ * Underlying layer should never ask for writes across
+ * subbuffers.
+ */
+ CHAN_WARN_ON(chanb, offset >= chanb->buf_size);
+
+ pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK));
+ id = bufb->buf_wsb[sbidx].id;
+ sb_bindex = subbuffer_id_get_index(config, id);
+ rpages = bufb->array[sb_bindex];
+ CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE
+ && subbuffer_id_is_noref(config, id));
+
+ if (likely(!src_terminated)) {
+ size_t count, to_copy;
+
+ to_copy = pagecpy;
+ if (pagecpy == len)
+ to_copy--; /* Final '\0' */
+ count = lib_ring_buffer_do_strcpy_from_user_inatomic(config,
+ rpages->p[index].virt
+ + (offset & ~PAGE_MASK),
+ src, to_copy);
+ offset += count;
+ /* Padding */
+ if (unlikely(count < to_copy)) {
+ size_t pad_len = to_copy - count;
+
+ /* Next pages will have padding */
+ src_terminated = 1;
+ lib_ring_buffer_do_memset(rpages->p[index].virt
+ + (offset & ~PAGE_MASK),
+ pad, pad_len);
+ offset += pad_len;
+ }
+ } else {
+ size_t pad_len;
+
+ pad_len = pagecpy;
+ if (pagecpy == len)
+ pad_len--; /* Final '\0' */
+ lib_ring_buffer_do_memset(rpages->p[index].virt
+ + (offset & ~PAGE_MASK),
+ pad, pad_len);
+ offset += pad_len;
+ }
+ } while (unlikely(len != pagecpy));
+ /* Ending '\0' */
+ lib_ring_buffer_do_memset(rpages->p[index].virt + (offset & ~PAGE_MASK),
+ '\0', 1);
+}
+EXPORT_SYMBOL_GPL(_lib_ring_buffer_strcpy_from_user_inatomic);
+
+/**
+ * lib_ring_buffer_read - read data from ring_buffer_buffer.
+ * @bufb : buffer backend
+ * @offset : offset within the buffer
+ * @dest : destination address
+ * @len : length to copy to destination
+ *
+ * Should be protected by get_subbuf/put_subbuf.
+ * Returns the length copied.
+ */
+size_t lib_ring_buffer_read(struct lib_ring_buffer_backend *bufb, size_t offset,
+ void *dest, size_t len)
+{
+ struct channel_backend *chanb = &bufb->chan->backend;
+ const struct lib_ring_buffer_config *config = &chanb->config;
+ size_t index, pagecpy, orig_len;
+ struct lib_ring_buffer_backend_pages *rpages;
+ unsigned long sb_bindex, id;
+
+ orig_len = len;
+ offset &= chanb->buf_size - 1;
+ index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT;
+ if (unlikely(!len))
+ return 0;
+ for (;;) {
+ pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK));
+ id = bufb->buf_rsb.id;
+ sb_bindex = subbuffer_id_get_index(config, id);
+ rpages = bufb->array[sb_bindex];
+ CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE
+ && subbuffer_id_is_noref(config, id));
+ memcpy(dest, rpages->p[index].virt + (offset & ~PAGE_MASK),
+ pagecpy);
+ len -= pagecpy;
+ if (likely(!len))
+ break;
+ dest += pagecpy;
+ offset += pagecpy;
+ index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT;
+ /*
+ * Underlying layer should never ask for reads across
+ * subbuffers.
+ */
+ CHAN_WARN_ON(chanb, offset >= chanb->buf_size);
+ }
+ return orig_len;
+}
+EXPORT_SYMBOL_GPL(lib_ring_buffer_read);
+
+/**
+ * __lib_ring_buffer_copy_to_user - read data from ring_buffer to userspace
+ * @bufb : buffer backend
+ * @offset : offset within the buffer
+ * @dest : destination userspace address
+ * @len : length to copy to destination
+ *
+ * Should be protected by get_subbuf/put_subbuf.
+ * access_ok() must have been performed on dest addresses prior to call this
+ * function.
+ * Returns -EFAULT on error, 0 if ok.
+ */
+int __lib_ring_buffer_copy_to_user(struct lib_ring_buffer_backend *bufb,
+ size_t offset, void __user *dest, size_t len)
+{
+ struct channel_backend *chanb = &bufb->chan->backend;
+ const struct lib_ring_buffer_config *config = &chanb->config;
+ size_t index;
+ ssize_t pagecpy;
+ struct lib_ring_buffer_backend_pages *rpages;
+ unsigned long sb_bindex, id;
+
+ offset &= chanb->buf_size - 1;
+ index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT;
+ if (unlikely(!len))
+ return 0;
+ for (;;) {
+ pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK));
+ id = bufb->buf_rsb.id;
+ sb_bindex = subbuffer_id_get_index(config, id);
+ rpages = bufb->array[sb_bindex];
+ CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE
+ && subbuffer_id_is_noref(config, id));
+ if (__copy_to_user(dest,
+ rpages->p[index].virt + (offset & ~PAGE_MASK),
+ pagecpy))
+ return -EFAULT;
+ len -= pagecpy;
+ if (likely(!len))
+ break;
+ dest += pagecpy;
+ offset += pagecpy;
+ index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT;
+ /*
+ * Underlying layer should never ask for reads across
+ * subbuffers.
+ */
+ CHAN_WARN_ON(chanb, offset >= chanb->buf_size);
+ }
+ return 0;
+}
+EXPORT_SYMBOL_GPL(__lib_ring_buffer_copy_to_user);
+
+/**
+ * lib_ring_buffer_read_cstr - read a C-style string from ring_buffer.
+ * @bufb : buffer backend
+ * @offset : offset within the buffer
+ * @dest : destination address
+ * @len : destination's length
+ *
+ * Return string's length, or -EINVAL on error.
+ * Should be protected by get_subbuf/put_subbuf.
+ * Destination length should be at least 1 to hold '\0'.
+ */
+int lib_ring_buffer_read_cstr(struct lib_ring_buffer_backend *bufb, size_t offset,
+ void *dest, size_t len)
+{
+ struct channel_backend *chanb = &bufb->chan->backend;
+ const struct lib_ring_buffer_config *config = &chanb->config;
+ size_t index;
+ ssize_t pagecpy, pagelen, strpagelen, orig_offset;
+ char *str;
+ struct lib_ring_buffer_backend_pages *rpages;
+ unsigned long sb_bindex, id;
+
+ offset &= chanb->buf_size - 1;
+ index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT;
+ orig_offset = offset;
+ if (unlikely(!len))
+ return -EINVAL;
+ for (;;) {
+ id = bufb->buf_rsb.id;
+ sb_bindex = subbuffer_id_get_index(config, id);
+ rpages = bufb->array[sb_bindex];
+ CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE
+ && subbuffer_id_is_noref(config, id));
+ str = (char *)rpages->p[index].virt + (offset & ~PAGE_MASK);
+ pagelen = PAGE_SIZE - (offset & ~PAGE_MASK);
+ strpagelen = strnlen(str, pagelen);
+ if (len) {
+ pagecpy = min_t(size_t, len, strpagelen);
+ if (dest) {
+ memcpy(dest, str, pagecpy);
+ dest += pagecpy;
+ }
+ len -= pagecpy;
+ }
+ offset += strpagelen;
+ index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT;
+ if (strpagelen < pagelen)
+ break;
+ /*
+ * Underlying layer should never ask for reads across
+ * subbuffers.
+ */
+ CHAN_WARN_ON(chanb, offset >= chanb->buf_size);
+ }
+ if (dest && len)
+ ((char *)dest)[0] = 0;
+ return offset - orig_offset;
+}
+EXPORT_SYMBOL_GPL(lib_ring_buffer_read_cstr);
+
+/**
+ * lib_ring_buffer_read_get_pfn - Get a page frame number to read from
+ * @bufb : buffer backend
+ * @offset : offset within the buffer
+ * @virt : pointer to page address (output)
+ *
+ * Should be protected by get_subbuf/put_subbuf.
+ * Returns the pointer to the page frame number unsigned long.
+ */
+unsigned long *lib_ring_buffer_read_get_pfn(struct lib_ring_buffer_backend *bufb,
+ size_t offset, void ***virt)
+{
+ size_t index;
+ struct lib_ring_buffer_backend_pages *rpages;
+ struct channel_backend *chanb = &bufb->chan->backend;
+ const struct lib_ring_buffer_config *config = &chanb->config;
+ unsigned long sb_bindex, id;
+
+ offset &= chanb->buf_size - 1;
+ index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT;
+ id = bufb->buf_rsb.id;
+ sb_bindex = subbuffer_id_get_index(config, id);
+ rpages = bufb->array[sb_bindex];
+ CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE
+ && subbuffer_id_is_noref(config, id));
+ *virt = &rpages->p[index].virt;
+ return &rpages->p[index].pfn;
+}
+EXPORT_SYMBOL_GPL(lib_ring_buffer_read_get_pfn);
+
+/**
+ * lib_ring_buffer_read_offset_address - get address of a buffer location
+ * @bufb : buffer backend
+ * @offset : offset within the buffer.
+ *
+ * Return the address where a given offset is located (for read).
+ * Should be used to get the current subbuffer header pointer. Given we know
+ * it's never on a page boundary, it's safe to read/write directly
+ * from/to this address, as long as the read/write is never bigger than a
+ * page size.
+ */
+void *lib_ring_buffer_read_offset_address(struct lib_ring_buffer_backend *bufb,
+ size_t offset)
+{
+ size_t index;
+ struct lib_ring_buffer_backend_pages *rpages;
+ struct channel_backend *chanb = &bufb->chan->backend;
+ const struct lib_ring_buffer_config *config = &chanb->config;
+ unsigned long sb_bindex, id;
+
+ offset &= chanb->buf_size - 1;
+ index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT;
+ id = bufb->buf_rsb.id;
+ sb_bindex = subbuffer_id_get_index(config, id);
+ rpages = bufb->array[sb_bindex];
+ CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE
+ && subbuffer_id_is_noref(config, id));
+ return rpages->p[index].virt + (offset & ~PAGE_MASK);
+}
+EXPORT_SYMBOL_GPL(lib_ring_buffer_read_offset_address);
+
+/**
+ * lib_ring_buffer_offset_address - get address of a location within the buffer
+ * @bufb : buffer backend
+ * @offset : offset within the buffer.
+ *
+ * Return the address where a given offset is located.
+ * Should be used to get the current subbuffer header pointer. Given we know
+ * it's always at the beginning of a page, it's safe to write directly to this
+ * address, as long as the write is never bigger than a page size.
+ */
+void *lib_ring_buffer_offset_address(struct lib_ring_buffer_backend *bufb,
+ size_t offset)
+{
+ size_t sbidx, index;
+ struct lib_ring_buffer_backend_pages *rpages;
+ struct channel_backend *chanb = &bufb->chan->backend;
+ const struct lib_ring_buffer_config *config = &chanb->config;
+ unsigned long sb_bindex, id;
+
+ offset &= chanb->buf_size - 1;
+ sbidx = offset >> chanb->subbuf_size_order;
+ index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT;
+ id = bufb->buf_wsb[sbidx].id;
+ sb_bindex = subbuffer_id_get_index(config, id);
+ rpages = bufb->array[sb_bindex];
+ CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE
+ && subbuffer_id_is_noref(config, id));
+ return rpages->p[index].virt + (offset & ~PAGE_MASK);
+}
+EXPORT_SYMBOL_GPL(lib_ring_buffer_offset_address);
projects / lttng-modules.git / blobdiff