arm: add initjmp()

Implement initjmp() for Arm. a non-standard extension to setjmp()/
longjmp() allowing to initialize a jump buffer with a function pointer
and a stack pointer. This will be useful to later introduce threads.
With this new function it becomes possible to longjmp() to a particular
function pointer (rather than to a point previously reached during
program execution as is the case with setjmp()), and with a custom stack.
Both things are needed to spin off a new thread. Then the usual
setjmp()/longjmp() pair is enough to save and restore a context, i.e.,
switch thread.

Signed-off-by: Jerome Forissier <jerome.forissier@linaro.org>
Acked-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/arch/Kconfig b/arch/Kconfig
index 14111ca14fb..7a3141e92b3 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -95,6 +95,7 @@ config ARC
 config ARM
 	bool "ARM architecture"
 	select HAVE_SETJMP
+	select HAVE_INITJMP
 	select ARCH_SUPPORTS_LTO
 	select CREATE_ARCH_SYMLINK
 	select HAVE_PRIVATE_LIBGCC if !ARM64