introduce generic sys_sigaltstack(), switch x86 and um to it
Conditional on CONFIG_GENERIC_SIGALTSTACK; architectures that do not
select it are completely unaffected
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 01ca0eb..f380614 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -111,6 +111,7 @@
select MODULES_USE_ELF_REL if X86_32
select MODULES_USE_ELF_RELA if X86_64
select CLONE_BACKWARDS if X86_32
+ select GENERIC_SIGALTSTACK
config INSTRUCTION_DECODER
def_bool y