[Devel] [PATCH 27/39] kernel: add support for .init_array.* constructors

[Andrey Ryabinin]

From: Andrey Ryabinin <a.ryabinin at samsung.com>

commit 9ddf82521c86ae07af79dbe5a93c52890f2bab23 upstream.

KASan uses constructors for initializing redzones for global variables.
Globals instrumentation in GCC 4.9.2 produces constructors with priority
(.init_array.00099)

Currently kernel ignores such constructors.  Only constructors with
default priority supported (.init_array)

This patch adds support for constructors with priorities.  For kernel
image we put pointers to constructors between __ctors_start/__ctors_end
and do_ctors() will call them on start up.  For modules we merge
.init_array.* sections into resulting .init_array.  Module code properly
handles constructors in .init_array section.

Signed-off-by: Andrey Ryabinin <a.ryabinin at samsung.com>
Cc: Dmitry Vyukov <dvyukov at google.com>
Cc: Konstantin Serebryany <kcc at google.com>
Cc: Dmitry Chernenkov <dmitryc at google.com>
Signed-off-by: Andrey Konovalov <adech.fo at gmail.com>
Cc: Yuri Gribov <tetra2005 at gmail.com>
Cc: Konstantin Khlebnikov <koct9i at gmail.com>
Cc: Sasha Levin <sasha.levin at oracle.com>
Cc: Christoph Lameter <cl at linux.com>
Cc: Joonsoo Kim <iamjoonsoo.kim at lge.com>
Cc: Dave Hansen <dave.hansen at intel.com>
Cc: Andi Kleen <andi at firstfloor.org>
Cc: Ingo Molnar <mingo at elte.hu>
Cc: Thomas Gleixner <tglx at linutronix.de>
Cc: "H. Peter Anvin" <hpa at zytor.com>
Cc: Christoph Lameter <cl at linux.com>
Cc: Pekka Enberg <penberg at kernel.org>
Cc: David Rientjes <rientjes at google.com>
Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds at linux-foundation.org>
Signed-off-by: Andrey Ryabinin <aryabinin at odin.com>
---
 include/asm-generic/vmlinux.lds.h | 1 +
 scripts/module-common.lds         | 4 ++++
 2 files changed, 5 insertions(+)

diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index 72e4edc..5c90355 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -481,6 +481,7 @@
 #define KERNEL_CTORS()	. = ALIGN(8);			   \
 			VMLINUX_SYMBOL(__ctors_start) = .; \
 			*(.ctors)			   \
+			*(SORT(.init_array.*))		   \
 			*(.init_array)			   \
 			VMLINUX_SYMBOL(__ctors_end) = .;
 #else
diff --git a/scripts/module-common.lds b/scripts/module-common.lds
index 0865b3e..10fa8bf 100644
--- a/scripts/module-common.lds
+++ b/scripts/module-common.lds
@@ -16,4 +16,8 @@ SECTIONS {
 	__kcrctab_unused	: { *(SORT(___kcrctab_unused+*)) }
 	__kcrctab_unused_gpl	: { *(SORT(___kcrctab_unused_gpl+*)) }
 	__kcrctab_gpl_future	: { *(SORT(___kcrctab_gpl_future+*)) }
+
+
+	. = ALIGN(8);
+	.init_array		0 : { *(SORT(.init_array.*)) *(.init_array) }
 }
-- 
2.4.6