Merge git://git.kernel.org/pub/scm/linux/kernel/git/sam/kbuild-fix

* git://git.kernel.org/pub/scm/linux/kernel/git/sam/kbuild-fix:
  mm/slab: fix section mismatch warning
  mm: fix section mismatch warnings
  init/main: use __init_refok to fix section mismatch
  kbuild: introduce __init_refok/__initdata_refok to supress section mismatch warnings
  all-archs: consolidate .data section definition in asm-generic
  all-archs: consolidate .text section definition in asm-generic
  kbuild: add "Section mismatch" warning whitelist for powerpc
  kbuild: make better section mismatch reports on i386, arm and mips
  kbuild: make modpost section warnings clearer
  kconfig: search harder for curses library in check-lxdialog.sh
  kbuild: include limits.h in sumversion.c for PATH_MAX
  powerpc: Fix the MODALIAS generation in modpost for of devices

2 files changed, 25 insertions, 0 deletions

diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index f3806a74c478..8307b1bb337a 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -9,6 +9,11 @@
 /* Align . to a 8 byte boundary equals to maximum function alignment. */
 #define ALIGN_FUNCTION()  . = ALIGN(8)
 
+/* .data section */
+#define DATA_DATA							\
+	*(.data)							\
+	*(.data.init.refok)
+
 #define RODATA								\
 	. = ALIGN(4096);						\
 	.rodata           : AT(ADDR(.rodata) - LOAD_OFFSET) {		\
@@ -139,6 +144,13 @@
 		VMLINUX_SYMBOL(__security_initcall_end) = .;		\
 	}
 
+/* .text section. Map to function alignment to avoid address changes
+ * during second ld run in second ld pass when generating System.map */
+#define TEXT_TEXT							\
+		ALIGN_FUNCTION();					\
+		*(.text)						\
+		*(.text.init.refok)
+
 /* sched.text is aling to function alignment to secure we have same
  * address even at second ld pass when generating System.map */
 #define SCHED_TEXT							\
diff --git a/include/linux/init.h b/include/linux/init.h
index e007ae4dc41e..56ec4c62eee0 100644
--- a/include/linux/init.h
+++ b/include/linux/init.h
@@ -45,6 +45,19 @@
 #define __exitdata	__attribute__ ((__section__(".exit.data")))
 #define __exit_call	__attribute_used__ __attribute__ ((__section__ (".exitcall.exit")))
 
+/* modpost check for section mismatches during the kernel build.
+ * A section mismatch happens when there are references from a
+ * code or data section to an init section (both code or data).
+ * The init sections are (for most archs) discarded by the kernel
+ * when early init has completed so all such references are potential bugs.
+ * For exit sections the same issue exists.
+ * The following markers are used for the cases where the reference to
+ * the init/exit section (code or data) is valid and will teach modpost
+ * not to issue a warning.
+ * The markers follow same syntax rules as __init / __initdata. */
+#define __init_refok     noinline __attribute__ ((__section__ (".text.init.refok")))
+#define __initdata_refok          __attribute__ ((__section__ (".data.init.refok")))
+
 #ifdef MODULE
 #define __exit		__attribute__ ((__section__(".exit.text")))
 #else