Breno Leitao <lei...@debian.org> writes: > On 12/20/18 10:51 AM, Michael Ellerman wrote: >> Breno Leitao <lei...@debian.org> writes: >> >>> A new self test that forces MSR[TS] to be set without calling any TM >>> instruction. This test also tries to cause a page fault at a signal >>> handler, exactly between MSR[TS] set and tm_recheckpoint(), forcing >>> thread->texasr to be rewritten with TEXASR[FS] = 0, which will cause a BUG >>> when tm_recheckpoint() is called. >>> >>> This test is not deterministic since it is hard to guarantee that the page >>> access will cause a page fault. Tests have shown that the bug could be >>> exposed with few interactions in a buggy kernel. This test is configured to >>> loop 5000x, having a good chance to hit the kernel issue in just one run. >>> This self test takes less than two seconds to run. >>> >>> This test uses set/getcontext because the kernel will recheckpoint >>> zeroed structures, causing the test to segfault, which is undesired because >>> the test needs to rerun, so, there is a signal handler for SIGSEGV which >>> will restart the test. >> And reference the ucontext->mcontext MSR using UCONTEXT_MSR() macro. >> Hi Breno, >> >> Thanks for the test, some of these TM tests are getting pretty advanced! :) >> >> Unfortunately it doesn't build in a few configurations. >> >> On Ubuntu 18.10 built with powerpc-linux-gnu-gcc I get: >> >> tm-signal-force-msr.c: In function 'trap_signal_handler': >> tm-signal-force-msr.c:42:19: error: 'union uc_regs_ptr' has no member >> named 'gp_regs'; did you mean 'uc_regs'? >> ucp->uc_mcontext.gp_regs[PT_MSR] |= MSR_TS_S; >> ^~~~~~~ >> uc_regs >> tm-signal-force-msr.c:17:29: error: left shift count >= width of type >> [-Werror=shift-count-overflow] >> #define __MASK(X) (1UL<<(X)) >> ^~ >> tm-signal-force-msr.c:20:25: note: in expansion of macro '__MASK' >> #define MSR_TS_S __MASK(MSR_TS_S_LG) /* Transaction Suspended */ >> ^~~~~~ >> tm-signal-force-msr.c:42:38: note: in expansion of macro 'MSR_TS_S' >> ucp->uc_mcontext.gp_regs[PT_MSR] |= MSR_TS_S; >> ^~~~~~~~ >> > > That is because I missed the -m64 compilation flag on Makefile. I understand > that this test only make sense when compiled in 64 bits. Do you agree?
I think the test could work as a 32-bit binary on a 64-bit kernel, but I don't mind if you force it to build 64-bit. cheers
