fix: sublevel version overflow in LINUX_VERSION_CODE

[lttng-modules.git] / include / lttng / kernel-version.h

diff --git a/include/lttng/kernel-version.h b/include/lttng/kernel-version.h
index a97cc024222d3c0eee2bf1ef2a2226ba11d8a73d..38b47cc34e424fc92fb47d82a624b42832461b00 100644 (file)
--- a/include/lttng/kernel-version.h
+++ b/include/lttng/kernel-version.h
@@ -2,7 +2,7 @@
  *
  * lttng/kernel-version.h
  *
- * Contains helpers to check more complex kernel version conditions.
+ * Contains helpers to check kernel version conditions.
  *
  * Copyright (C) 2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  */
@@ -13,22 +13,68 @@
 #include <linux/version.h>
 #include <generated/utsrelease.h>
 
+#define LTTNG_KERNEL_VERSION(a, b, c) KERNEL_VERSION(a, b, c)
+#define LTTNG_LINUX_VERSION_CODE LINUX_VERSION_CODE
+
+/*
+ * The following defines are extracted from the toplevel Linux Makefile and
+ * passed on the command line -with '-D'.
+ */
+
+#ifndef LTTNG_LINUX_MAJOR
+#define LTTNG_LINUX_MAJOR 0
+#endif
+
+#ifndef LTTNG_LINUX_MINOR
+#define LTTNG_LINUX_MINOR 0
+#endif
+
+#ifndef LTTNG_LINUX_PATCH
+#define LTTNG_LINUX_PATCH 0
+#endif
+
+/*
+ * Some stable releases have overflowed the 8bits allocated to the sublevel in
+ * the version code. To determine if the current kernel is affected, use the
+ * sublevel version from the Makefile. This is currently true for the 4.4.256
+ * and 4.9.256 stable releases.
+ *
+ * When the sublevel has overflowed, use the values from the Makefile instead
+ * of LINUX_VERSION_CODE from the kernel headers and allocate 16bits.
+ * Otherwise, keep using the version code from the headers to minimise the
+ * behavior change and avoid regressions.
+ */
+#if (LTTNG_LINUX_PATCH >= 256)
+
+#define LTTNG_KERNEL_VERSION(a, b, c) \
+       (((a) << 24) + ((b) << 16) + (c))
+
+#define LTTNG_LINUX_VERSION_CODE \
+       LTTNG_KERNEL_VERSION(LTTNG_LINUX_MAJOR, LTTNG_LINUX_MINOR, LTTNG_LINUX_PATCH)
+
+#else
+
+#define LTTNG_KERNEL_VERSION(a, b, c) KERNEL_VERSION(a, b, c)
+#define LTTNG_LINUX_VERSION_CODE LINUX_VERSION_CODE
+
+#endif
+
 /*
  * This macro checks if the kernel version is between the two specified
  * versions (lower limit inclusive, upper limit exclusive).
  */
 #define LTTNG_KERNEL_RANGE(a_low, b_low, c_low, a_high, b_high, c_high) \
-       (LINUX_VERSION_CODE >= KERNEL_VERSION(a_low, b_low, c_low) && \
-        LINUX_VERSION_CODE < KERNEL_VERSION(a_high, b_high, c_high))
+       (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(a_low, b_low, c_low) && \
+        LTTNG_LINUX_VERSION_CODE < LTTNG_KERNEL_VERSION(a_high, b_high, c_high))
 
 /* Ubuntu */
 
 #define LTTNG_UBUNTU_KERNEL_VERSION(a, b, c, d) \
-       (((a) << 24) + ((b) << 16) + ((c) << 8) + (d))
+       (((LTTNG_KERNEL_VERSION(a, b, c)) << 8) + (d))
 
 #ifdef UTS_UBUNTU_RELEASE_ABI
 #define LTTNG_UBUNTU_VERSION_CODE \
-       ((LINUX_VERSION_CODE << 8) + UTS_UBUNTU_RELEASE_ABI)
+       ((LTTNG_LINUX_VERSION_CODE << 8) + UTS_UBUNTU_RELEASE_ABI)
 #else
 #define LTTNG_UBUNTU_VERSION_CODE      0
 #endif
@@ -43,11 +89,11 @@
 /* Debian */
 
 #define LTTNG_DEBIAN_KERNEL_VERSION(a, b, c, d, e, f) \
-       (((((a) << 16) + ((b) << 8) + (c)) * 1000000ULL) + ((d) * 10000) + ((e) * 100) + (f))
+       (((LTTNG_KERNEL_VERSION(a, b, c)) * 1000000ULL) + ((d) * 10000) + ((e) * 100) + (f))
 
 #ifdef DEBIAN_API_VERSION
 #define LTTNG_DEBIAN_VERSION_CODE \
-       ((LINUX_VERSION_CODE * 1000000ULL) + DEBIAN_API_VERSION)
+       ((LTTNG_LINUX_VERSION_CODE * 1000000ULL) + DEBIAN_API_VERSION)
 #else
 #define LTTNG_DEBIAN_VERSION_CODE      0
 #endif
@@ -59,14 +105,14 @@
                LTTNG_DEBIAN_VERSION_CODE < \
                LTTNG_DEBIAN_KERNEL_VERSION(a_high, b_high, c_high, d_high, e_high, f_high))
 
-#define LTTNG_RHEL_KERNEL_VERSION(a, b, c, d, e, f) \
-       (((((a) << 16) + ((b) << 8) + (c)) * 10000000ULL) + ((d) * 10000) + ((e) * 100) + (f))
-
 /* RHEL */
 
+#define LTTNG_RHEL_KERNEL_VERSION(a, b, c, d, e, f) \
+       (((LTTNG_KERNEL_VERSION(a, b, c)) * 10000000ULL) + ((d) * 10000) + ((e) * 100) + (f))
+
 #ifdef RHEL_API_VERSION
 #define LTTNG_RHEL_VERSION_CODE \
-       ((LINUX_VERSION_CODE * 10000000ULL) + RHEL_API_VERSION)
+       ((LTTNG_LINUX_VERSION_CODE * 10000000ULL) + RHEL_API_VERSION)
 #else
 #define LTTNG_RHEL_VERSION_CODE                0
 #endif
@@ -81,11 +127,11 @@
 /* SUSE Linux enterprise */
 
 #define LTTNG_SLE_KERNEL_VERSION(a, b, c, d, e, f) \
-       (((((a) << 16) + ((b) << 8) + (c)) * 10000000ULL) + ((d) * 10000) + ((e) * 100) + (f))
+       (((LTTNG_KERNEL_VERSION(a, b, c)) * 10000000ULL) + ((d) * 10000) + ((e) * 100) + (f))
 
 #ifdef SLE_API_VERSION
 #define LTTNG_SLE_VERSION_CODE \
-       ((LINUX_VERSION_CODE * 10000000ULL) + SLE_API_VERSION)
+       ((LTTNG_LINUX_VERSION_CODE * 10000000ULL) + SLE_API_VERSION)
 #else
 #define LTTNG_SLE_VERSION_CODE         0
 #endif
@@ -100,11 +146,11 @@
 /* Fedora */
 
 #define LTTNG_FEDORA_KERNEL_VERSION(a, b, c, d) \
-        (((((a) << 16) + ((b) << 8) + (c)) * 10000ULL) + (d))
+        (((LTTNG_KERNEL_VERSION(a, b, c)) * 10000ULL) + (d))
 
 #ifdef FEDORA_REVISION_VERSION
 #define LTTNG_FEDORA_VERSION_CODE \
-        ((LINUX_VERSION_CODE * 10000ULL) + FEDORA_REVISION_VERSION)
+        ((LTTNG_LINUX_VERSION_CODE * 10000ULL) + FEDORA_REVISION_VERSION)
 #else
 #define LTTNG_FEDORA_VERSION_CODE         0
 #endif
@@ -119,11 +165,11 @@
 /* RT patch */
 
 #define LTTNG_RT_KERNEL_VERSION(a, b, c, d) \
-       (((a) << 24) + ((b) << 16) + ((c) << 8) + (d))
+       (((LTTNG_KERNEL_VERSION(a, b, c)) << 8) + (d))
 
 #ifdef RT_PATCH_VERSION
 #define LTTNG_RT_VERSION_CODE \
-       ((LINUX_VERSION_CODE << 8) + RT_PATCH_VERSION)
+       ((LTTNG_LINUX_VERSION_CODE << 8) + RT_PATCH_VERSION)
 #else
 #define LTTNG_RT_VERSION_CODE  0
 #endif