arch: introduce initjmp() and Kconfig symbol HAVE_INITJMP
Add the HAVE_INIJMP symbol to be set by architectures that support
initjmp(), 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.
Add the initjmp() prototype to <include/setjmp.h> since it is common to
all architectures.
Add an entry to the API documentation: doc/api/setjmp.rst.
Signed-off-by: Jerome Forissier <jerome.forissier@linaro.org>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
diff --git a/doc/api/index.rst b/doc/api/index.rst
index a108718..0dc9ad4 100644
--- a/doc/api/index.rst
+++ b/doc/api/index.rst
@@ -25,6 +25,7 @@
rng
sandbox
serial
+ setjmp
sysreset
timer
unicode
diff --git a/doc/api/setjmp.rst b/doc/api/setjmp.rst
new file mode 100644
index 0000000..7718047
--- /dev/null
+++ b/doc/api/setjmp.rst
@@ -0,0 +1,10 @@
+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+Long jump API
+=============
+
+.. kernel-doc:: include/setjmp.h
+ :doc: Overview
+
+.. kernel-doc:: include/setjmp.h
+ :internal: