[PATCH v3 1/6] include: split out uaccess instrumentation into a separate header

[Peter Collingbourne]

In an upcoming change we are going to add uaccess instrumentation
that uses inline access to struct task_struct from the
instrumentation routines. Because instrumentation.h is included
from many places including (recursively) from sched.h this would
otherwise lead to a circular dependency. Break the dependency by
moving uaccess instrumentation routines into a separate header,
instrumentation-uaccess.h.

Link: https://linux-review.googlesource.com/id/I625728db0c8db374e13e4ebc54985ac5c79ace7d
Signed-off-by: Peter Collingbourne <pcc at google.com>
---
 include/linux/instrumented-uaccess.h | 49 ++++++++++++++++++++++++++++
 include/linux/instrumented.h         | 34 -------------------
 include/linux/uaccess.h              |  2 +-
 lib/iov_iter.c                       |  2 +-
 lib/usercopy.c                       |  2 +-
 5 files changed, 52 insertions(+), 37 deletions(-)
 create mode 100644 include/linux/instrumented-uaccess.h

diff --git a/include/linux/instrumented-uaccess.h b/include/linux/instrumented-uaccess.h
new file mode 100644
index 000000000000..ece549088e50
--- /dev/null
+++ b/include/linux/instrumented-uaccess.h
@@ -0,0 +1,49 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/*
+ * This header provides generic wrappers for memory access instrumentation for
+ * uaccess routines that the compiler cannot emit for: KASAN, KCSAN.
+ */
+#ifndef _LINUX_INSTRUMENTED_UACCESS_H
+#define _LINUX_INSTRUMENTED_UACCESS_H
+
+#include <linux/compiler.h>
+#include <linux/kasan-checks.h>
+#include <linux/kcsan-checks.h>
+#include <linux/types.h>
+
+/**
+ * instrument_copy_to_user - instrument reads of copy_to_user
+ *
+ * Instrument reads from kernel memory, that are due to copy_to_user (and
+ * variants). The instrumentation must be inserted before the accesses.
+ *
+ * @to destination address
+ * @from source address
+ * @n number of bytes to copy
+ */
+static __always_inline void
+instrument_copy_to_user(void __user *to, const void *from, unsigned long n)
+{
+	kasan_check_read(from, n);
+	kcsan_check_read(from, n);
+}
+
+/**
+ * instrument_copy_from_user - instrument writes of copy_from_user
+ *
+ * Instrument writes to kernel memory, that are due to copy_from_user (and
+ * variants). The instrumentation should be inserted before the accesses.
+ *
+ * @to destination address
+ * @from source address
+ * @n number of bytes to copy
+ */
+static __always_inline void
+instrument_copy_from_user(const void *to, const void __user *from, unsigned long n)
+{
+	kasan_check_write(to, n);
+	kcsan_check_write(to, n);
+}
+
+#endif /* _LINUX_INSTRUMENTED_UACCESS_H */
diff --git a/include/linux/instrumented.h b/include/linux/instrumented.h
index 42faebbaa202..b68f415510c7 100644
--- a/include/linux/instrumented.h
+++ b/include/linux/instrumented.h
@@ -102,38 +102,4 @@ static __always_inline void instrument_atomic_read_write(const volatile void *v,
 	kcsan_check_atomic_read_write(v, size);
 }
 
-/**
- * instrument_copy_to_user - instrument reads of copy_to_user
- *
- * Instrument reads from kernel memory, that are due to copy_to_user (and
- * variants). The instrumentation must be inserted before the accesses.
- *
- * @to destination address
- * @from source address
- * @n number of bytes to copy
- */
-static __always_inline void
-instrument_copy_to_user(void __user *to, const void *from, unsigned long n)
-{
-	kasan_check_read(from, n);
-	kcsan_check_read(from, n);
-}
-
-/**
- * instrument_copy_from_user - instrument writes of copy_from_user
- *
- * Instrument writes to kernel memory, that are due to copy_from_user (and
- * variants). The instrumentation should be inserted before the accesses.
- *
- * @to destination address
- * @from source address
- * @n number of bytes to copy
- */
-static __always_inline void
-instrument_copy_from_user(const void *to, const void __user *from, unsigned long n)
-{
-	kasan_check_write(to, n);
-	kcsan_check_write(to, n);
-}
-
 #endif /* _LINUX_INSTRUMENTED_H */
diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h
index ac0394087f7d..c0c467e39657 100644
--- a/include/linux/uaccess.h
+++ b/include/linux/uaccess.h
@@ -3,7 +3,7 @@
 #define __LINUX_UACCESS_H__
 
 #include <linux/fault-inject-usercopy.h>
-#include <linux/instrumented.h>
+#include <linux/instrumented-uaccess.h>
 #include <linux/minmax.h>
 #include <linux/sched.h>
 #include <linux/thread_info.h>
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index 66a740e6e153..3f9dc6df7102 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -12,7 +12,7 @@
 #include <linux/compat.h>
 #include <net/checksum.h>
 #include <linux/scatterlist.h>
-#include <linux/instrumented.h>
+#include <linux/instrumented-uaccess.h>
 
 #define PIPE_PARANOIA /* for now */
 
diff --git a/lib/usercopy.c b/lib/usercopy.c
index 7413dd300516..1cd188e62d06 100644
--- a/lib/usercopy.c
+++ b/lib/usercopy.c
@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 #include <linux/bitops.h>
 #include <linux/fault-inject-usercopy.h>
-#include <linux/instrumented.h>
+#include <linux/instrumented-uaccess.h>
 #include <linux/uaccess.h>
 
 /* out-of-line parts */
-- 
2.34.1.173.g76aa8bc2d0-goog