CVS log for src/tests/lib/libc/sys/t_swapcontext.c

Up to [cvs.NetBSD.org] / src / tests / lib / libc / sys

Request diff between arbitrary revisions

Keyword substitution: kv
Default branch: MAIN

Mark as expected-fail on VAX (PR port-vax/58290).

fix RCSIDs.

sync with head.

for a reference, the tree before this commit was tagged
as yamt-pagecache-tag8.

this commit was splitted into small chunks to avoid
a limitation of cvs.  ("Protocol error: too many arguments")

resync from head

Whitespace

Resync to 2012-11-19 00:00:00 UTC

sync with head

file t_swapcontext.c was added on branch yamt-pagecache on 2012-10-30 19:00:02 +0000

Simplify

setcontext() used to be incompatible with -lpthread since it affected
the TLS pointer, therefore wrecking the pthread environement.

Some ports had _UC_TLSBASE flag or equivalent (_UC_UNIQUE on alpha)
that controlled whether setcontext() would change the TLS pointer.
This change let libpthread override setcontext() with its own version
that unsets _UC_TLSBASE, enabling safe usage of setcontext() with
-lpthread.

We also have the following required changes here:
- rename alpha's _UC_UNIQUE into _UC_TLSBASE
- add _UC_TLSBASE definition in header file for all ports
  (powerpc, sh3, sparc and sparc64 lack the implementation for now)
- introduce a libc stub that can be overriden for setcontext()
- modify MD libcs swapcontext() implementations so that they use the
  setcontext() libc stub instead of doing a plain system call.

While we are there:
- document various MD _UC_* flags in header file
- add libc and libpthread tests for swapcontext() behavior
  (hopefully helpful to spot MD problems introduced with this change)

Future work:
- Deciding whether kernel support or _UC_TLSBASE should be added for
  powerpc, sh3, sparc and sparc64 is left to portmasters
  sparc64

Approved by core@