um: Enable CONFIG_CONSTRUCTORS

We do need to call the constructors for *modules*, and
at least for KASAN in the future, we must call even the
kernel constructors only later when the kernel has been
initialized.

Instead of relying on libc to call them, emit an empty
section for libc and let the kernel's CONSTRUCTORS code
do the rest of the job.

Tested that it indeed doesn't work in modules, and does
work after the fixes in both, with a few functions with
__attribute__((constructor)) in both dynamic and static
builds.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

diff --git a/arch/um/include/asm/common.lds.S b/arch/um/include/asm/common.lds.S
index 4049f2c..d7086b9 100644 (file)
--- a/arch/um/include/asm/common.lds.S
+++ b/arch/um/include/asm/common.lds.S
@@ -83,8 +83,8 @@
        __preinit_array_end = .;
   }
   .init_array : {
+        /* dummy - we call this ourselves */
        __init_array_start = .;
-       *(.init_array)
        __init_array_end = .;
   }
   .fini_array : {

diff --git a/arch/um/kernel/dyn.lds.S b/arch/um/kernel/dyn.lds.S
index f500148..c69d69e 100644 (file)
--- a/arch/um/kernel/dyn.lds.S
+++ b/arch/um/kernel/dyn.lds.S
@@ -103,7 +103,6 @@ SECTIONS
      be empty, which isn't pretty.  */
   . = ALIGN(32 / 8);
   .preinit_array     : { *(.preinit_array) }
-  .init_array     : { *(.init_array) }
   .fini_array     : { *(.fini_array) }
   .data           : {
     INIT_TASK_DATA(KERNEL_STACK_SIZE)

diff --git a/init/Kconfig b/init/Kconfig
index bd7d650..81293d7 100644 (file)
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -48,7 +48,6 @@ config CC_DISABLE_WARN_MAYBE_UNINITIALIZED
 
 config CONSTRUCTORS
        bool
-       depends on !UML
 
 config IRQ_WORK
        bool

diff --git a/kernel/gcov/Kconfig b/kernel/gcov/Kconfig
index 3941a9c..060e8e7 100644 (file)
--- a/kernel/gcov/Kconfig
+++ b/kernel/gcov/Kconfig
@@ -4,7 +4,7 @@ menu "GCOV-based kernel profiling"
 config GCOV_KERNEL
        bool "Enable gcov-based kernel profiling"
        depends on DEBUG_FS
-       select CONSTRUCTORS if !UML
+       select CONSTRUCTORS
        default n
        ---help---
        This option enables gcov-based code profiling (e.g. for code coverage