X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=lib%2Fringbuffer%2Fbackend.h;h=da937f29d6f8cc3c8954ca4be7361e9f7e003139;hb=80bb26003945e96a8ade9c8788dab9b2e08cbc08;hp=aadc9c37b1d2b3f7870a2ad87f184ae736c0aafc;hpb=bfe529f90b1354246b5d8a18f49e30595c612041;p=lttng-modules.git diff --git a/lib/ringbuffer/backend.h b/lib/ringbuffer/backend.h index aadc9c37..da937f29 100644 --- a/lib/ringbuffer/backend.h +++ b/lib/ringbuffer/backend.h @@ -1,31 +1,18 @@ -#ifndef _LIB_RING_BUFFER_BACKEND_H -#define _LIB_RING_BUFFER_BACKEND_H - -/* +/* SPDX-License-Identifier: (GPL-2.0 OR LGPL-2.1) + * * lib/ringbuffer/backend.h * * Ring buffer backend (API). * * Copyright (C) 2010-2012 Mathieu Desnoyers * - * This library is free software; you can redistribute it and/or - * modify it under the terms of the GNU Lesser General Public - * License as published by the Free Software Foundation; only - * version 2.1 of the License. - * - * This library is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - * Lesser General Public License for more details. - * - * You should have received a copy of the GNU Lesser General Public - * License along with this library; if not, write to the Free Software - * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA - * * Credits to Steven Rostedt for proposing to use an extra-subbuffer owned by * the reader in flight recorder mode. */ +#ifndef _LIB_RING_BUFFER_BACKEND_H +#define _LIB_RING_BUFFER_BACKEND_H + #include #include #include @@ -34,11 +21,11 @@ #include #include #include -#include +#include /* Internal helpers */ -#include "../../wrapper/ringbuffer/backend_internal.h" -#include "../../wrapper/ringbuffer/frontend_internal.h" +#include +#include /* Ring buffer backend API */ @@ -54,8 +41,8 @@ extern int __lib_ring_buffer_copy_to_user(struct lib_ring_buffer_backend *bufb, extern int lib_ring_buffer_read_cstr(struct lib_ring_buffer_backend *bufb, size_t offset, void *dest, size_t len); -extern struct page ** -lib_ring_buffer_read_get_page(struct lib_ring_buffer_backend *bufb, size_t offset, +extern unsigned long * +lib_ring_buffer_read_get_pfn(struct lib_ring_buffer_backend *bufb, size_t offset, void ***virt); /* @@ -83,33 +70,27 @@ lib_ring_buffer_read_offset_address(struct lib_ring_buffer_backend *bufb, * backend-specific memcpy() operation. Calls the slow path (_ring_buffer_write) * if copy is crossing a page boundary. */ -static inline +static inline __attribute__((always_inline)) void lib_ring_buffer_write(const struct lib_ring_buffer_config *config, struct lib_ring_buffer_ctx *ctx, const void *src, size_t len) { struct lib_ring_buffer_backend *bufb = &ctx->buf->backend; struct channel_backend *chanb = &ctx->chan->backend; - size_t sbidx, index, pagecpy; + size_t index, pagecpy; size_t offset = ctx->buf_offset; - struct lib_ring_buffer_backend_pages *rpages; - unsigned long sb_bindex, id; + struct lib_ring_buffer_backend_pages *backend_pages; if (unlikely(!len)) return; + backend_pages = + lib_ring_buffer_get_backend_pages_from_ctx(config, ctx); offset &= chanb->buf_size - 1; - sbidx = offset >> chanb->subbuf_size_order; index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; pagecpy = min_t(size_t, len, (-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(ctx->chan, - config->mode == RING_BUFFER_OVERWRITE - && subbuffer_id_is_noref(config, id)); if (likely(pagecpy == len)) lib_ring_buffer_do_copy(config, - rpages->p[index].virt + backend_pages->p[index].virt + (offset & ~PAGE_MASK), src, len); else @@ -137,25 +118,19 @@ void lib_ring_buffer_memset(const struct lib_ring_buffer_config *config, struct lib_ring_buffer_backend *bufb = &ctx->buf->backend; struct channel_backend *chanb = &ctx->chan->backend; - size_t sbidx, index, pagecpy; + size_t index, pagecpy; size_t offset = ctx->buf_offset; - struct lib_ring_buffer_backend_pages *rpages; - unsigned long sb_bindex, id; + struct lib_ring_buffer_backend_pages *backend_pages; if (unlikely(!len)) return; + backend_pages = + lib_ring_buffer_get_backend_pages_from_ctx(config, ctx); offset &= chanb->buf_size - 1; - sbidx = offset >> chanb->subbuf_size_order; index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; pagecpy = min_t(size_t, len, (-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(ctx->chan, - config->mode == RING_BUFFER_OVERWRITE - && subbuffer_id_is_noref(config, id)); if (likely(pagecpy == len)) - lib_ring_buffer_do_memset(rpages->p[index].virt + lib_ring_buffer_do_memset(backend_pages->p[index].virt + (offset & ~PAGE_MASK), c, len); else @@ -168,7 +143,7 @@ void lib_ring_buffer_memset(const struct lib_ring_buffer_config *config, * terminating character is found in @src. Returns the number of bytes * copied. Does *not* terminate @dest with NULL terminating character. */ -static inline +static inline __attribute__((always_inline)) size_t lib_ring_buffer_do_strcpy(const struct lib_ring_buffer_config *config, char *dest, const char *src, size_t len) { @@ -181,7 +156,7 @@ size_t lib_ring_buffer_do_strcpy(const struct lib_ring_buffer_config *config, * Only read source character once, in case it is * modified concurrently. */ - c = ACCESS_ONCE(src[count]); + c = READ_ONCE(src[count]); if (!c) break; lib_ring_buffer_do_copy(config, &dest[count], &c, 1); @@ -199,7 +174,7 @@ size_t lib_ring_buffer_do_strcpy(const struct lib_ring_buffer_config *config, * directly without having the src pointer checked with access_ok() * previously. */ -static inline +static inline __attribute__((always_inline)) size_t lib_ring_buffer_do_strcpy_from_user_inatomic(const struct lib_ring_buffer_config *config, char *dest, const char __user *src, size_t len) { @@ -209,7 +184,7 @@ size_t lib_ring_buffer_do_strcpy_from_user_inatomic(const struct lib_ring_buffer int ret; char c; - ret = __get_user(c, &src[count]); + ret = __copy_from_user_inatomic(&c, src + count, 1); if (ret || !c) break; lib_ring_buffer_do_copy(config, &dest[count], &c, 1); @@ -240,28 +215,22 @@ void lib_ring_buffer_strcpy(const struct lib_ring_buffer_config *config, { struct lib_ring_buffer_backend *bufb = &ctx->buf->backend; struct channel_backend *chanb = &ctx->chan->backend; - size_t sbidx, index, pagecpy; + size_t index, pagecpy; size_t offset = ctx->buf_offset; - struct lib_ring_buffer_backend_pages *rpages; - unsigned long sb_bindex, id; + struct lib_ring_buffer_backend_pages *backend_pages; if (unlikely(!len)) return; + backend_pages = + lib_ring_buffer_get_backend_pages_from_ctx(config, ctx); offset &= chanb->buf_size - 1; - sbidx = offset >> chanb->subbuf_size_order; index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; pagecpy = min_t(size_t, len, (-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(ctx->chan, - config->mode == RING_BUFFER_OVERWRITE - && subbuffer_id_is_noref(config, id)); if (likely(pagecpy == len)) { size_t count; count = lib_ring_buffer_do_strcpy(config, - rpages->p[index].virt + backend_pages->p[index].virt + (offset & ~PAGE_MASK), src, len - 1); offset += count; @@ -269,13 +238,13 @@ void lib_ring_buffer_strcpy(const struct lib_ring_buffer_config *config, if (unlikely(count < len - 1)) { size_t pad_len = len - 1 - count; - lib_ring_buffer_do_memset(rpages->p[index].virt + lib_ring_buffer_do_memset(backend_pages->p[index].virt + (offset & ~PAGE_MASK), pad, pad_len); offset += pad_len; } /* Ending '\0' */ - lib_ring_buffer_do_memset(rpages->p[index].virt + lib_ring_buffer_do_memset(backend_pages->p[index].virt + (offset & ~PAGE_MASK), '\0', 1); } else { @@ -297,45 +266,38 @@ void lib_ring_buffer_strcpy(const struct lib_ring_buffer_config *config, * (_ring_buffer_write_from_user_inatomic) if copy is crossing a page boundary. * Disable the page fault handler to ensure we never try to take the mmap_sem. */ -static inline +static inline __attribute__((always_inline)) void lib_ring_buffer_copy_from_user_inatomic(const struct lib_ring_buffer_config *config, struct lib_ring_buffer_ctx *ctx, const void __user *src, size_t len) { struct lib_ring_buffer_backend *bufb = &ctx->buf->backend; struct channel_backend *chanb = &ctx->chan->backend; - size_t sbidx, index, pagecpy; + size_t index, pagecpy; size_t offset = ctx->buf_offset; - struct lib_ring_buffer_backend_pages *rpages; - unsigned long sb_bindex, id; + struct lib_ring_buffer_backend_pages *backend_pages; unsigned long ret; mm_segment_t old_fs = get_fs(); if (unlikely(!len)) return; + backend_pages = + lib_ring_buffer_get_backend_pages_from_ctx(config, ctx); offset &= chanb->buf_size - 1; - sbidx = offset >> chanb->subbuf_size_order; index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; pagecpy = min_t(size_t, len, (-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(ctx->chan, - config->mode == RING_BUFFER_OVERWRITE - && subbuffer_id_is_noref(config, id)); set_fs(KERNEL_DS); pagefault_disable(); - if (unlikely(!access_ok(VERIFY_READ, src, len))) + if (unlikely(!lttng_access_ok(VERIFY_READ, src, len))) goto fill_buffer; if (likely(pagecpy == len)) { ret = lib_ring_buffer_do_copy_from_user_inatomic( - rpages->p[index].virt + (offset & ~PAGE_MASK), + backend_pages->p[index].virt + (offset & ~PAGE_MASK), src, len); if (unlikely(ret > 0)) { - len -= (pagecpy - ret); - offset += (pagecpy - ret); + /* Copy failed. */ goto fill_buffer; } } else { @@ -382,35 +344,29 @@ void lib_ring_buffer_strcpy_from_user_inatomic(const struct lib_ring_buffer_conf { struct lib_ring_buffer_backend *bufb = &ctx->buf->backend; struct channel_backend *chanb = &ctx->chan->backend; - size_t sbidx, index, pagecpy; + size_t index, pagecpy; size_t offset = ctx->buf_offset; - struct lib_ring_buffer_backend_pages *rpages; - unsigned long sb_bindex, id; + struct lib_ring_buffer_backend_pages *backend_pages; mm_segment_t old_fs = get_fs(); if (unlikely(!len)) return; + backend_pages = + lib_ring_buffer_get_backend_pages_from_ctx(config, ctx); offset &= chanb->buf_size - 1; - sbidx = offset >> chanb->subbuf_size_order; index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; pagecpy = min_t(size_t, len, (-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(ctx->chan, - config->mode == RING_BUFFER_OVERWRITE - && subbuffer_id_is_noref(config, id)); set_fs(KERNEL_DS); pagefault_disable(); - if (unlikely(!access_ok(VERIFY_READ, src, len))) + if (unlikely(!lttng_access_ok(VERIFY_READ, src, len))) goto fill_buffer; if (likely(pagecpy == len)) { size_t count; count = lib_ring_buffer_do_strcpy_from_user_inatomic(config, - rpages->p[index].virt + backend_pages->p[index].virt + (offset & ~PAGE_MASK), src, len - 1); offset += count; @@ -418,13 +374,13 @@ void lib_ring_buffer_strcpy_from_user_inatomic(const struct lib_ring_buffer_conf if (unlikely(count < len - 1)) { size_t pad_len = len - 1 - count; - lib_ring_buffer_do_memset(rpages->p[index].virt + lib_ring_buffer_do_memset(backend_pages->p[index].virt + (offset & ~PAGE_MASK), pad, pad_len); offset += pad_len; } /* Ending '\0' */ - lib_ring_buffer_do_memset(rpages->p[index].virt + lib_ring_buffer_do_memset(backend_pages->p[index].virt + (offset & ~PAGE_MASK), '\0', 1); } else { @@ -479,4 +435,29 @@ unsigned long lib_ring_buffer_get_records_unread( return records_unread; } +/* + * We use __copy_from_user_inatomic to copy userspace data after + * checking with access_ok() and disabling page faults. + * + * Return 0 if OK, nonzero on error. + */ +static inline +unsigned long lib_ring_buffer_copy_from_user_check_nofault(void *dest, + const void __user *src, + unsigned long len) +{ + unsigned long ret; + mm_segment_t old_fs; + + if (!lttng_access_ok(VERIFY_READ, src, len)) + return 1; + old_fs = get_fs(); + set_fs(KERNEL_DS); + pagefault_disable(); + ret = __copy_from_user_inatomic(dest, src, len); + pagefault_enable(); + set_fs(old_fs); + return ret; +} + #endif /* _LIB_RING_BUFFER_BACKEND_H */