Adding extra information

Add external library depedencies and known bug notice.

Signed-off-by: Charalampos Mainas <Charalampos.Mainas@neclab.eu>
Reviewed-by: Felipe Huici <felipe.huici@neclab.eu>

diff --git a/README.md b/README.md
index 5ce667767376f49f58285c2a7e5bd838e350ef29..e3460cda4d88ea3b492b2631bfb796008f10e6c5 100644 (file)
--- a/README.md
+++ b/README.md
@@ -1,7 +1,23 @@
 gcc for Unikraft
 =============================
 
-This is the port of gcc for Unikraft as external library.
+This is a port of gcc for Unikraft as an external library.
+
+For the time being we only port libbacktrace and libffi libraries as
+they are needed for the libgo port. You will need newlib for both
+libraries to build. In addition, 
+
+For libffi you will need the pthread\_embedded external library too.
+
+For libbacktrace you will need the following external libraries:
++ compiler-rt 
++ libunwind
++ libcxx
++ libcxxabi
+
+Note that because of a documented bug in libunwind `unw_getcontext`
+leads to a page fault, and in turn `backtrace_full`will also lead to
+one as it uses `_Unwind_Backtrace` which calls `unw_getcontext`.
 
 Please refer to the `README.md` as well as the documentation in the `doc/`
-subdirectory of the main unikraft repository.
+subdirectory of the main unikraft repository for further information.