Introduce lttng_copy_from_user_check_nofault

[lttng-modules.git] / lib / ringbuffer / backend.h

diff --git a/lib/ringbuffer/backend.h b/lib/ringbuffer/backend.h
index 0b75de8a65137aa1e7cd16a25afe26a280a5792d..46dcf1ccd9053443c4d00a743f5e1d19b2aa9ddb 100644 (file)
--- 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 <mathieu.desnoyers@efficios.com>
  *
- * 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 <linux/types.h>
 #include <linux/sched.h>
 #include <linux/timer.h>
@@ -34,7 +21,8 @@
 #include <linux/list.h>
 #include <linux/fs.h>
 #include <linux/mm.h>
-#include <linux/uaccess.h>
+#include <wrapper/uaccess.h>
+#include <probes/lttng-probe-user.h>
 
 /* Internal helpers */
 #include <wrapper/ringbuffer/backend_internal.h>
@@ -169,7 +157,7 @@ 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 = READ_ONCE(src[count]);
+               c = LTTNG_READ_ONCE(src[count]);
                if (!c)
                        break;
                lib_ring_buffer_do_copy(config, &dest[count], &c, 1);
@@ -290,7 +278,6 @@ void lib_ring_buffer_copy_from_user_inatomic(const struct lib_ring_buffer_config
        size_t offset = ctx->buf_offset;
        struct lib_ring_buffer_backend_pages *backend_pages;
        unsigned long ret;
-       mm_segment_t old_fs = get_fs();
 
        if (unlikely(!len))
                return;
@@ -300,9 +287,8 @@ void lib_ring_buffer_copy_from_user_inatomic(const struct lib_ring_buffer_config
        index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT;
        pagecpy = min_t(size_t, len, (-offset) & ~PAGE_MASK);
 
-       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)) {
@@ -317,19 +303,18 @@ void lib_ring_buffer_copy_from_user_inatomic(const struct lib_ring_buffer_config
                _lib_ring_buffer_copy_from_user_inatomic(bufb, offset, src, len, 0);
        }
        pagefault_enable();
-       set_fs(old_fs);
        ctx->buf_offset += len;
 
        return;
 
 fill_buffer:
        pagefault_enable();
-       set_fs(old_fs);
        /*
         * In the error path we call the slow path version to avoid
         * the pollution of static inline code.
         */
        _lib_ring_buffer_memset(bufb, offset, 0, len, 0);
+       ctx->buf_offset += len;
 }
 
 /**
@@ -360,7 +345,6 @@ void lib_ring_buffer_strcpy_from_user_inatomic(const struct lib_ring_buffer_conf
        size_t index, pagecpy;
        size_t offset = ctx->buf_offset;
        struct lib_ring_buffer_backend_pages *backend_pages;
-       mm_segment_t old_fs = get_fs();
 
        if (unlikely(!len))
                return;
@@ -370,9 +354,8 @@ void lib_ring_buffer_strcpy_from_user_inatomic(const struct lib_ring_buffer_conf
        index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT;
        pagecpy = min_t(size_t, len, (-offset) & ~PAGE_MASK);
 
-       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)) {
@@ -401,14 +384,12 @@ void lib_ring_buffer_strcpy_from_user_inatomic(const struct lib_ring_buffer_conf
                                        len, 0, pad);
        }
        pagefault_enable();
-       set_fs(old_fs);
        ctx->buf_offset += len;
 
        return;
 
 fill_buffer:
        pagefault_enable();
-       set_fs(old_fs);
        /*
         * In the error path we call the slow path version to avoid
         * the pollution of static inline code.
@@ -416,6 +397,7 @@ fill_buffer:
        _lib_ring_buffer_memset(bufb, offset, pad, len - 1, 0);
        offset += len - 1;
        _lib_ring_buffer_memset(bufb, offset, '\0', 1, 0);
+       ctx->buf_offset += len;
 }
 
 /*
@@ -459,18 +441,7 @@ 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 (!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;
+       return lttng_copy_from_user_check_nofault(dest, src, len);
 }
 
 #endif /* _LIB_RING_BUFFER_BACKEND_H */