[PATCH for-5.2 0/3] linux-user: fix various sparc64 guest bugs

[Peter Maydell]

This set of patches fixes bugs which were preventing the
Debian sparc64 /bin/bash from running:
 * the target_ucontext structure put the registers in the
   wrong place (missing alignment specifier, mostly)
 * the set_context and get_context traps weren't saving fp
   and i7, which meant that guest code that did a longjmp would
   crash shortly afterwards (SPARC64 uses these traps to
   implement setjmp/longjmp)
 * we were trying to stuff a 64-bit PC into a uint32_t in
   sigreturn, which caused a SEGV on return from a signal handler

Review very much desired in particular from anybody who understands
SPARC register windows and how we handle them in linux-user for
patch 2! The other patches are straightforward.

This patchset is sufficient that I can at least chroot into
a Debian sparc64 chroot and run basic commands like 'ls' from
the shell prompt (together with Giuseppe Musacchio's patch that
fixes the stack_t struct).

There are clearly a bunch of other bugs in sparc signal handling
(starting with the fact that rt_frame support is simply not
implemented, but there are also some XXX/FIXME comments about TSTATE
save/restore in set/get_context and about the FPU state in the signal
frame code). There's also a Coverity issue about accessing off the
end of the sregs[] array in the target_mc_fpu struct -- the error is
actually harmless (we're accessing into the space in the union for
dregs[16..31] which is what we want to be doing) but I'll probably
put together a patch to make Coverity happier.

thanks
-- PMM

Peter Maydell (3):
  linux-user/sparc: Fix errors in target_ucontext structures
  linux-user/sparc: Correct set/get_context handling of fp and i7
  linux-user/sparc: Don't zero high half of PC, NPC, PSR in sigreturn

 linux-user/sparc/signal.c | 62 ++++++++++++++++++++-------------------
 1 file changed, 32 insertions(+), 30 deletions(-)

-- 
2.20.1