diff options
Diffstat (limited to 'kernel/trace/ring_buffer.c')
| -rw-r--r-- | kernel/trace/ring_buffer.c | 243 |
1 files changed, 157 insertions, 86 deletions
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index b0963ac6fd16..9c03a555a6ba 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -330,6 +330,14 @@ struct buffer_data_read_page { struct buffer_data_page *data; /* actual data, stored in this page */ }; +static __always_inline unsigned int rb_read_page_capacity(struct buffer_data_read_page *rpage) +{ + return (PAGE_SIZE << rpage->order) - BUF_PAGE_HDR_SIZE; +} + +/* The number of bits for static buffer ids */ +#define RB_STATIC_BITS 30 + /* * Note, the buffer_page list must be first. The buffer pages * are allocated in cache lines, which means that each buffer @@ -345,7 +353,7 @@ struct buffer_page { local_t entries; /* entries on this page */ unsigned long real_end; /* real end of data */ unsigned order; /* order of the page */ - u32 id:30; /* ID for external mapping */ + u32 id:RB_STATIC_BITS; /* ID for external mapping */ u32 range:1; /* Mapped via a range */ struct buffer_data_page *page; /* Actual data page */ }; @@ -652,6 +660,15 @@ static bool rb_is_static(struct ring_buffer_per_cpu *cpu_buffer) return cpu_buffer->user_mapped || cpu_buffer->remote || cpu_buffer->ring_meta; } +static unsigned long rb_static_max_pages(void) +{ + /* + * Static ring buffers are using bpage::id and must account for the + * reader page. + */ + return (1UL << RB_STATIC_BITS) - 1; +} + struct ring_buffer_iter { struct ring_buffer_per_cpu *cpu_buffer; unsigned long head; @@ -1669,7 +1686,7 @@ out_locked: * This is used to help find the next per cpu subbuffer within a mapped range. */ static unsigned long -rb_range_align_subbuf(unsigned long addr, int subbuf_size, int nr_subbufs) +rb_range_align_subbuf(unsigned long addr, unsigned int subbuf_size, unsigned long nr_subbufs) { addr += sizeof(struct ring_buffer_cpu_meta) + sizeof(int) * nr_subbufs; @@ -1679,13 +1696,12 @@ rb_range_align_subbuf(unsigned long addr, int subbuf_size, int nr_subbufs) /* * Return the ring_buffer_meta for a given @cpu. */ -static void *rb_range_meta(struct trace_buffer *buffer, int nr_pages, int cpu) +static void *rb_range_meta(struct trace_buffer *buffer, unsigned long nr_pages, int cpu) { - int subbuf_size = rb_subbuf_size(buffer); + unsigned int subbuf_size = rb_subbuf_size(buffer); struct ring_buffer_cpu_meta *meta; struct ring_buffer_meta *bmeta; - unsigned long ptr; - int nr_subbufs; + unsigned long ptr, nr_subbufs; bmeta = buffer->meta; if (!bmeta) @@ -1731,7 +1747,7 @@ static void *rb_range_meta(struct trace_buffer *buffer, int nr_pages, int cpu) /* Return the start of subbufs given the meta pointer */ static void *rb_subbufs_from_meta(struct ring_buffer_cpu_meta *meta) { - int subbuf_size = meta->subbuf_size; + unsigned int subbuf_size = meta->subbuf_size; unsigned long ptr; ptr = (unsigned long)meta; @@ -1743,11 +1759,11 @@ static void *rb_subbufs_from_meta(struct ring_buffer_cpu_meta *meta) /* * Return a specific sub-buffer for a given @cpu defined by @idx. */ -static void *rb_range_buffer(struct ring_buffer_per_cpu *cpu_buffer, int idx) +static void *rb_range_buffer(struct ring_buffer_per_cpu *cpu_buffer, unsigned long idx) { struct ring_buffer_cpu_meta *meta; + unsigned int subbuf_size; unsigned long ptr; - int subbuf_size; meta = rb_range_meta(cpu_buffer->buffer, 0, cpu_buffer->cpu); if (!meta) @@ -1763,7 +1779,7 @@ static void *rb_range_buffer(struct ring_buffer_per_cpu *cpu_buffer, int idx) ptr = (unsigned long)rb_subbufs_from_meta(meta); - ptr += subbuf_size * idx; + ptr += (unsigned long)subbuf_size * idx; if (ptr + subbuf_size > cpu_buffer->buffer->range_addr_end) return NULL; @@ -1840,13 +1856,12 @@ static bool rb_meta_init(struct trace_buffer *buffer, int scratch_size) * must be the same. */ static bool rb_cpu_meta_valid(struct ring_buffer_cpu_meta *meta, int cpu, - struct trace_buffer *buffer, int nr_pages, + struct trace_buffer *buffer, unsigned long nr_pages, unsigned long *subbuf_mask) { - int subbuf_size = PAGE_SIZE; unsigned long buffers_start; unsigned long buffers_end; - int i; + unsigned long i; if (!subbuf_mask) return false; @@ -1856,8 +1871,13 @@ static bool rb_cpu_meta_valid(struct ring_buffer_cpu_meta *meta, int cpu, return false; } + if (meta->nr_subbufs != nr_pages + 1) { + pr_info("Ring buffer boot meta [%d] invalid nr_subbufs\n", cpu); + return false; + } + buffers_start = meta->first_buffer; - buffers_end = meta->first_buffer + (subbuf_size * meta->nr_subbufs); + buffers_end = meta->first_buffer + (meta->nr_subbufs * PAGE_SIZE); /* Is the head and commit buffers within the range of buffers? */ if (meta->head_buffer < buffers_start || @@ -2095,8 +2115,8 @@ static void rb_meta_validate_events(struct ring_buffer_per_cpu *cpu_buffer) struct buffer_page *head_page, *orig_head, *orig_reader; struct rb_validation_state state = { 0 }; bool skip = false; + unsigned long i; int ret; - int i; if (!meta || !meta->head_buffer) return; @@ -2147,7 +2167,7 @@ static void rb_meta_validate_events(struct ring_buffer_per_cpu *cpu_buffer) rb_validate_buffer(head_page, cpu_buffer, meta, &state, 0, state.ts); } if (i) - pr_info("Ring buffer [%d] rewound %d pages\n", cpu_buffer->cpu, i); + pr_info("Ring buffer [%d] rewound %lu pages\n", cpu_buffer->cpu, i); /* The last rewound page must be skipped. */ if (head_page != orig_head) @@ -2231,7 +2251,8 @@ static void rb_meta_validate_events(struct ring_buffer_per_cpu *cpu_buffer) } } -static void rb_range_meta_init(struct trace_buffer *buffer, int nr_pages, int scratch_size) +static void rb_range_meta_init(struct trace_buffer *buffer, unsigned long nr_pages, + int scratch_size) { struct ring_buffer_cpu_meta *meta; unsigned long *subbuf_mask; @@ -2331,8 +2352,8 @@ static int rbm_show(struct seq_file *m, void *v) rb_meta_subbuf_idx(meta, (void *)meta->head_buffer)); seq_printf(m, "commit_buffer: %d\n", rb_meta_subbuf_idx(meta, (void *)meta->commit_buffer)); - seq_printf(m, "subbuf_size: %d\n", meta->subbuf_size); - seq_printf(m, "nr_subbufs: %d\n", meta->nr_subbufs); + seq_printf(m, "subbuf_size: %u\n", meta->subbuf_size); + seq_printf(m, "nr_subbufs: %u\n", meta->nr_subbufs); return 0; } @@ -2417,7 +2438,7 @@ static void *ring_buffer_desc_page(struct ring_buffer_desc *desc, unsigned int p } static int __rb_allocate_pages(struct ring_buffer_per_cpu *cpu_buffer, - long nr_pages, struct list_head *pages) + unsigned long nr_pages, struct list_head *pages) { struct trace_buffer *buffer = cpu_buffer->buffer; struct ring_buffer_cpu_meta *meta = NULL; @@ -2545,7 +2566,7 @@ static int rb_allocate_pages(struct ring_buffer_per_cpu *cpu_buffer, } static struct ring_buffer_per_cpu * -rb_allocate_cpu_buffer(struct trace_buffer *buffer, long nr_pages, int cpu) +rb_allocate_cpu_buffer(struct trace_buffer *buffer, unsigned long nr_pages, int cpu) { struct ring_buffer_per_cpu *cpu_buffer __free(kfree) = alloc_cpu_buffer(cpu); @@ -2600,8 +2621,8 @@ rb_allocate_cpu_buffer(struct trace_buffer *buffer, long nr_pages, int cpu) cpu_buffer->remote = buffer->remote; cpu_buffer->meta_page = (struct trace_buffer_meta *)(void *)desc->meta_va; cpu_buffer->nr_pages = nr_pages; - cpu_buffer->subbuf_ids = kcalloc(cpu_buffer->nr_pages + 1, - sizeof(*cpu_buffer->subbuf_ids), GFP_KERNEL); + cpu_buffer->subbuf_ids = kzalloc_objs(*cpu_buffer->subbuf_ids, + cpu_buffer->nr_pages + 1); if (!cpu_buffer->subbuf_ids) goto fail_free_reader; @@ -2702,8 +2723,8 @@ static void rb_test_inject_invalid_pages(struct trace_buffer *buffer) struct ring_buffer_cpu_meta *meta; struct buffer_data_page *dpage; unsigned long entry_bytes = 0; + unsigned int subbuf_size; unsigned long ptr; - int subbuf_size; int invalid = 0; int cpu; int i; @@ -2773,8 +2794,8 @@ static struct trace_buffer *alloc_buffer(unsigned long size, unsigned flags, struct ring_buffer_remote *remote) { struct trace_buffer *buffer __free(kfree) = NULL; - long nr_pages; - int subbuf_size; + unsigned int subbuf_size; + unsigned long nr_pages; int bsize; int cpu; int ret; @@ -2828,6 +2849,8 @@ static struct trace_buffer *alloc_buffer(unsigned long size, unsigned flags, size = end - buffers_start; size = size / nr_cpu_ids; + if (size < sizeof(struct ring_buffer_cpu_meta)) + goto fail_free_buffers; /* * The number of sub-buffers (nr_pages) is determined by the * total size allocated minus the meta data size. @@ -2837,6 +2860,10 @@ static struct trace_buffer *alloc_buffer(unsigned long size, unsigned flags, */ nr_pages = (size - sizeof(struct ring_buffer_cpu_meta)) / (subbuf_size + sizeof(int)); + + if (nr_pages > rb_static_max_pages()) + goto fail_free_buffers; + /* Need at least two pages plus the reader page */ if (nr_pages < 3) goto fail_free_buffers; @@ -2869,6 +2896,10 @@ static struct trace_buffer *alloc_buffer(unsigned long size, unsigned flags, /* The writer is remote. This ring-buffer is read-only */ atomic_inc(&buffer->record_disabled); nr_pages = desc->nr_page_va - 1; + + if (nr_pages > rb_static_max_pages()) + goto fail_free_buffers; + if (nr_pages < 2) goto fail_free_buffers; } else { @@ -5853,12 +5884,12 @@ __rb_get_reader_page_from_remote(struct ring_buffer_per_cpu *cpu_buffer) static struct buffer_page * __rb_get_reader_page(struct ring_buffer_per_cpu *cpu_buffer) { - int max_loops = cpu_buffer->ring_meta ? cpu_buffer->nr_pages : 3; + unsigned long max_loops = cpu_buffer->ring_meta ? cpu_buffer->nr_pages : 3; struct buffer_page *reader = NULL; + unsigned long nr_loops = 0; unsigned long overwrite; unsigned long flags; int missed_events = 0; - int nr_loops = 0; bool ret; local_irq_save(flags); @@ -6176,8 +6207,8 @@ rb_iter_peek(struct ring_buffer_iter *iter, u64 *ts) struct trace_buffer *buffer; struct ring_buffer_per_cpu *cpu_buffer; struct ring_buffer_event *event; - int nr_loops = 0; - int max_loops; + unsigned long nr_loops = 0; + unsigned long max_loops; if (ts) *ts = 0; @@ -6993,56 +7024,78 @@ EXPORT_SYMBOL_GPL(ring_buffer_swap_cpu); * ring_buffer_alloc_read_page - allocate a page to read from buffer * @buffer: the buffer to allocate for. * @cpu: the cpu buffer to allocate. + * @rpage: pointer to pass in an already allocated page (can be NULL) + * and returns the allocated page. * - * This function is used in conjunction with ring_buffer_read_page. + * This function is used in conjunction with ring_buffer_read_page(). * When reading a full page from the ring buffer, these functions * can be used to speed up the process. The calling function should * allocate a few pages first with this function. Then when it * needs to get pages from the ring buffer, it passes the result - * of this function into ring_buffer_read_page, which will swap + * of this function into ring_buffer_read_page(), which will swap * the page that was allocated, with the read page of the buffer. * + * If @rpage is provided, and it has a different order than the current + * subbuffer order, its payload will be freed and re-allocated. If it + * already matches the order, it is simply returned. + * * Returns: - * The page allocated, or ERR_PTR + * 0 on success, < 0 on error */ -struct buffer_data_read_page * -ring_buffer_alloc_read_page(struct trace_buffer *buffer, int cpu) +int ring_buffer_alloc_read_page(struct trace_buffer *buffer, int cpu, + struct buffer_data_read_page **rpage) { struct ring_buffer_per_cpu *cpu_buffer; - struct buffer_data_read_page *bpage = NULL; unsigned long flags; + unsigned int order; if (!cpumask_test_cpu(cpu, buffer->cpumask)) - return ERR_PTR(-ENODEV); + return -ENODEV; - bpage = kzalloc_obj(*bpage); - if (!bpage) - return ERR_PTR(-ENOMEM); + if (!rpage) + return -EINVAL; - bpage->order = buffer->subbuf_order; + order = READ_ONCE(buffer->subbuf_order); + + if (*rpage) { + if ((*rpage)->order == order) + return 0; + + /* We can reuse rpage, but we discard the payload */ + free_pages((unsigned long)(*rpage)->data, (*rpage)->order); + (*rpage)->data = NULL; + } else { + *rpage = kzalloc_obj(**rpage); + if (!*rpage) + return -ENOMEM; + } + + (*rpage)->order = order; cpu_buffer = buffer->buffers[cpu]; + local_irq_save(flags); arch_spin_lock(&cpu_buffer->lock); if (cpu_buffer->free_page.data) { - *bpage = cpu_buffer->free_page; + **rpage = cpu_buffer->free_page; cpu_buffer->free_page.data = NULL; } arch_spin_unlock(&cpu_buffer->lock); local_irq_restore(flags); - if (bpage->data) { - rb_init_data_page(bpage->data); + if ((*rpage)->data) { + rb_init_data_page((*rpage)->data); } else { - bpage->data = alloc_cpu_data(cpu, bpage->order); - if (!bpage->data) { - kfree(bpage); - return ERR_PTR(-ENOMEM); + (*rpage)->data = alloc_cpu_data(cpu, (*rpage)->order); + if (!(*rpage)->data) { + kfree(*rpage); + *rpage = NULL; + return -ENOMEM; } } - return bpage; + return 0; } EXPORT_SYMBOL_GPL(ring_buffer_alloc_read_page); @@ -7050,21 +7103,30 @@ EXPORT_SYMBOL_GPL(ring_buffer_alloc_read_page); * ring_buffer_free_read_page - free an allocated read page * @buffer: the buffer the page was allocate for * @cpu: the cpu buffer the page came from - * @data_page: the page to free + * @rpage: the buffer_data_read_page to free * * Free a page allocated from ring_buffer_alloc_read_page. */ void ring_buffer_free_read_page(struct trace_buffer *buffer, int cpu, - struct buffer_data_read_page *data_page) + struct buffer_data_read_page *rpage) { struct ring_buffer_per_cpu *cpu_buffer; - struct buffer_data_page *dpage = data_page->data; - struct page *page = virt_to_page(dpage); + struct buffer_data_page *dpage; unsigned long flags; + struct page *page; if (!buffer || !buffer->buffers || !buffer->buffers[cpu]) return; + if (!rpage) + return; + + dpage = rpage->data; + if (!dpage) + goto out; + + page = virt_to_page(dpage); + cpu_buffer = buffer->buffers[cpu]; /* @@ -7072,14 +7134,14 @@ void ring_buffer_free_read_page(struct trace_buffer *buffer, int cpu, * is different from the subbuffer order of the buffer - * we can't reuse it */ - if (page_ref_count(page) > 1 || data_page->order != buffer->subbuf_order) + if (page_ref_count(page) > 1 || rpage->order != READ_ONCE(buffer->subbuf_order)) goto out; local_irq_save(flags); arch_spin_lock(&cpu_buffer->lock); if (!cpu_buffer->free_page.data) { - cpu_buffer->free_page = *data_page; + cpu_buffer->free_page = *rpage; dpage = NULL; } @@ -7087,8 +7149,8 @@ void ring_buffer_free_read_page(struct trace_buffer *buffer, int cpu, local_irq_restore(flags); out: - free_pages((unsigned long)dpage, data_page->order); - kfree(data_page); + free_pages((unsigned long)dpage, rpage->order); + kfree(rpage); } EXPORT_SYMBOL_GPL(ring_buffer_free_read_page); @@ -7159,10 +7221,9 @@ int ring_buffer_read_page(struct trace_buffer *buffer, if (!dpage) return -1; - guard(raw_spinlock_irqsave)(&cpu_buffer->reader_lock); + len = min_t(size_t, len, rb_read_page_capacity(data_page)); - if (data_page->order != cpu_buffer->reader_page->order) - return -1; + guard(raw_spinlock_irqsave)(&cpu_buffer->reader_lock); reader = rb_get_reader_page(cpu_buffer); if (!reader) @@ -7177,31 +7238,26 @@ int ring_buffer_read_page(struct trace_buffer *buffer, /* Check if any events were dropped */ missed_events = cpu_buffer->lost_events; - /* - * If this page has been partially read or - * if len is not big enough to read the rest of the page or - * a writer is still on the page, then - * we must copy the data from the page to the buffer. - * Otherwise, we can simply swap the page with the one passed in. - */ + /* + * It is not possible to swap the reader page if: + * - It has been partially read + * - len is not big enough to read it entirely + * - A writer is still on it + * - The ring buffer is static + * - The order doesn't match + */ if (read || (len < (size - read)) || cpu_buffer->reader_page == cpu_buffer->commit_page || - rb_is_static(cpu_buffer)) { + rb_is_static(cpu_buffer) || + data_page->order != reader->order) { struct buffer_data_page *rpage = cpu_buffer->reader_page->page; unsigned int rpos = read; unsigned int pos = 0; unsigned int event_size; unsigned int flags = 0; - /* - * If a full page is expected, this can still be returned - * if there's been a previous partial read and the - * rest of the page can be read and the commit page is off - * the reader page. - */ - if (full && - (!read || (len < (size - read)) || - cpu_buffer->reader_page == cpu_buffer->commit_page)) + /* If a full page is requested, it cannot be the commit page */ + if (full && cpu_buffer->reader_page == cpu_buffer->commit_page) return -1; if (len > (size - read)) @@ -7287,7 +7343,7 @@ int ring_buffer_read_page(struct trace_buffer *buffer, * missed events, then record it there. */ if (missed_events > 0 && - rb_page_capacity(reader) - size >= sizeof(missed_events)) { + rb_read_page_capacity(data_page) - size >= sizeof(missed_events)) { memcpy(&dpage->data[size], &missed_events, sizeof(missed_events)); local_add(RB_MISSED_STORED, &dpage->commit); @@ -7307,8 +7363,8 @@ int ring_buffer_read_page(struct trace_buffer *buffer, /* * This page may be off to user land. Zero it out here. */ - if (size < rb_page_capacity(reader)) - memset(&dpage->data[size], 0, rb_page_capacity(reader) - size); + if (size < rb_read_page_capacity(data_page)) + memset(&dpage->data[size], 0, rb_read_page_capacity(data_page) - size); return read; } @@ -7327,6 +7383,18 @@ void *ring_buffer_read_page_data(struct buffer_data_read_page *page) EXPORT_SYMBOL_GPL(ring_buffer_read_page_data); /** + * ring_buffer_read_page_size - get size of the read page. + * @page: the page to get the size from + * + * Returns size of the page in bytes. + */ +unsigned int ring_buffer_read_page_size(struct buffer_data_read_page *rpage) +{ + return rpage ? PAGE_SIZE << rpage->order : 0; +} +EXPORT_SYMBOL_GPL(ring_buffer_read_page_size); + +/** * ring_buffer_subbuf_size_get - get size of the sub buffer. * @buffer: the buffer to get the sub buffer size from * @@ -7380,8 +7448,8 @@ int ring_buffer_subbuf_order_set(struct trace_buffer *buffer, int order) struct ring_buffer_per_cpu *cpu_buffer; struct buffer_page *bpage, *tmp; unsigned int old_capacity; + unsigned long nr_pages; int old_order; - int nr_pages; int psize; int err; int cpu; @@ -7411,7 +7479,7 @@ int ring_buffer_subbuf_order_set(struct trace_buffer *buffer, int order) /* Make sure all commits have finished */ synchronize_rcu(); - buffer->subbuf_order = order; + WRITE_ONCE(buffer->subbuf_order, order); /* Make sure all new buffers are allocated, before deleting the old ones */ for_each_buffer_cpu(buffer, cpu) { @@ -7515,7 +7583,7 @@ int ring_buffer_subbuf_order_set(struct trace_buffer *buffer, int order) return 0; error: - buffer->subbuf_order = old_order; + WRITE_ONCE(buffer->subbuf_order, old_order); atomic_dec(&buffer->record_disabled); @@ -7563,10 +7631,10 @@ static void rb_setup_ids_meta_page(struct ring_buffer_per_cpu *cpu_buffer, struct buffer_page **subbuf_ids) { struct trace_buffer_meta *meta = cpu_buffer->meta_page; - unsigned int nr_subbufs = cpu_buffer->nr_pages + 1; + unsigned long nr_subbufs = cpu_buffer->nr_pages + 1; struct buffer_page *first_subbuf, *subbuf; - int cnt = 0; - int id = 0; + unsigned int cnt = 0; + unsigned int id = 0; id = rb_page_id(cpu_buffer, cpu_buffer->reader_page, id); subbuf_ids[id++] = cpu_buffer->reader_page; @@ -7794,6 +7862,9 @@ int ring_buffer_map(struct trace_buffer *buffer, int cpu, /* prevent another thread from changing buffer/sub-buffer sizes */ guard(mutex)(&buffer->mutex); + if (cpu_buffer->nr_pages > rb_static_max_pages()) + return -E2BIG; + err = rb_alloc_meta_page(cpu_buffer); if (err) return err; |