[PATCH v11 17/19] kernel: add support for .init_array.* constructors

[Andrey Ryabinin]

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@xxxxxxxxxxx>
---
 include/asm-generic/vmlinux.lds.h | 1 +
 scripts/module-common.lds         | 3 +++
 2 files changed, 4 insertions(+)

diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index bee5d68..ac78910 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -478,6 +478,7 @@
 #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..01c5849 100644
--- a/scripts/module-common.lds
+++ b/scripts/module-common.lds
@@ -16,4 +16,7 @@ SECTIONS {
 	__kcrctab_unused	: { *(SORT(___kcrctab_unused+*)) }
 	__kcrctab_unused_gpl	: { *(SORT(___kcrctab_unused_gpl+*)) }
 	__kcrctab_gpl_future	: { *(SORT(___kcrctab_gpl_future+*)) }
+
+	. = ALIGN(8);
+	.init_array		: { *(SORT(.init_array.*)) *(.init_array) }
 }
-- 
2.2.2

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