task 15: add task readme

2 files changed, 45 insertions, 1 deletions

diff --git a/readme.rst b/readme.rst
index 2058fba..ac6afd4 100644
--- a/readme.rst
+++ b/readme.rst
@@ -39,4 +39,6 @@ Here are the links to each task's readme:
 
 13. Optimizing Linked Lists: `task <https://git.bryanbrattlof.com/eudyptula-challenge/tree/tasks/13/readme>`__
 
-14. Process Task: `task <https://git.bryanbrattlof.com/eudyptula-challenge/tree/tasks/13/readme>`__
+14. Process Task: `task <https://git.bryanbrattlof.com/eudyptula-challenge/tree/tasks/14/readme>`__
+
+15. Create a syscall: `task <https://git.bryanbrattlof.com/eudyptula-challenge/tree/tasks/15/readme>`__
diff --git a/tasks/15/readme b/tasks/15/readme
new file mode 100644
index 0000000..aaa5a1e
--- /dev/null
+++ b/tasks/15/readme
@@ -0,0 +1,42 @@
+Task 15
+=======
+
+That process task turned out to not be all that complex, but digging
+through the core kernel was a tough task, nice work with that.
+
+Speaking of "core kernel" tasks, let's do another one.  It's one of the
+most common undergraduate tasks there is: create a new syscall!
+Yeah, loads of fun, but it's good to know the basics of how to do this,
+and, how to call it from userspace.
+
+For this task:
+
+  - Add a new syscall to the kernel called "sys_eudyptula", so this is
+    all going to be changes to the kernel tree itself, no stand-alone
+    module needed for this task (unless you want to do it that way
+    without hacking around the syscall table, if so, bonus points for
+    you...)
+
+  - The syscall number needs to be the next syscall number for the
+    architecture you test it on (some of you all are doing this on ARM
+    systems, showoffs, and syscall numbers are not the same across all
+    architectures).  Document the arch you are using and why you picked
+    this number in the module.
+
+  - The syscall should take two parameters: int high_id, int low_id.
+
+  - The syscall will take the two values, mush them together into one
+    64bit value (low_id being the lower 32bits of the id, high_id being
+    the upper 32bits of the id).
+
+  - If the id value matches your id (which of course you know as
+    "7c1caf2f50d1", then the syscall returns success.  Otherwise it
+    returns a return code signifying an invalid value was passed to it.
+
+  - Write a userspace C program that calls the syscall and properly
+    exercises it (valid and invalid calls need to be made).
+
+  - "Proof" of running the code needs to be provided.
+
+So you need to send in a .c userspace program, a kernel patch, and
+"proof" that it all works, as a response.
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