On 05/11/2020 21:23, Peter Maydell wrote:
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 handlerReview 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 Peter! This has been broken for a very long time indeed. Once this is merged I should probably look at getting a test environment set up.
ATB, Mark.
