Currently when a compare-and-trap instruction is executed, qemu will always raise a SIGILL signal. On real hardware, a SIGFPE is raised.
Change the PGM_DATA case in cpu_loop to follow the behavior in linux kernel /arch/s390/kernel/traps.c. * Only raise SIGILL if DXC == 0 * If DXC matches a non-simulated IEEE exception, raise SIGFPE with correct si_code * Raise SIGFPE with si_code == 0 for everything else When applied on 20210705210434.45824-2-...@linux.ibm.com, this fixes crashes in the java jdk such as the linked bug. Buglink: https://bugs.launchpad.net/qemu/+bug/1920913 Resolves: https://gitlab.com/qemu-project/qemu/-/issues/319 Signed-off-by: Jonathan Albrecht <jonathan.albre...@linux.vnet.ibm.com> --- linux-user/s390x/cpu_loop.c | 54 +++++++++++++++++++++++-------------- 1 file changed, 34 insertions(+), 20 deletions(-) diff --git a/linux-user/s390x/cpu_loop.c b/linux-user/s390x/cpu_loop.c index 22f2e89c62..6a69a6dd26 100644 --- a/linux-user/s390x/cpu_loop.c +++ b/linux-user/s390x/cpu_loop.c @@ -25,6 +25,35 @@ /* s390x masks the fault address it reports in si_addr for SIGSEGV and SIGBUS */ #define S390X_FAIL_ADDR_MASK -4096LL +static int get_pgm_data_si_code(int dxc_code) +{ + switch (dxc_code) { + /* Non-simulated IEEE exceptions */ + case 0x80: + return TARGET_FPE_FLTINV; + case 0x40: + return TARGET_FPE_FLTDIV; + case 0x20: + case 0x28: + case 0x2c: + return TARGET_FPE_FLTOVF; + case 0x10: + case 0x18: + case 0x1c: + return TARGET_FPE_FLTUND; + case 0x08: + case 0x0c: + return TARGET_FPE_FLTRES; + } + /* + * Non-IEEE and simulated IEEE: + * Includes compare-and-trap, quantum exception, etc. + * Simulated IEEE are included here to match current + * s390x linux kernel. + */ + return 0; +} + void cpu_loop(CPUS390XState *env) { CPUState *cs = env_cpu(env); @@ -106,29 +135,14 @@ void cpu_loop(CPUS390XState *env) case PGM_DATA: n = (env->fpc >> 8) & 0xff; - if (n == 0xff) { - /* compare-and-trap */ + if (n == 0) { goto do_sigill_opn; - } else { - /* An IEEE exception, simulated or otherwise. */ - if (n & 0x80) { - n = TARGET_FPE_FLTINV; - } else if (n & 0x40) { - n = TARGET_FPE_FLTDIV; - } else if (n & 0x20) { - n = TARGET_FPE_FLTOVF; - } else if (n & 0x10) { - n = TARGET_FPE_FLTUND; - } else if (n & 0x08) { - n = TARGET_FPE_FLTRES; - } else { - /* ??? Quantum exception; BFP, DFP error. */ - goto do_sigill_opn; - } - sig = TARGET_SIGFPE; - goto do_signal_pc; } + sig = TARGET_SIGFPE; + n = get_pgm_data_si_code(n); + goto do_signal_pc; + default: fprintf(stderr, "Unhandled program exception: %#x\n", n); cpu_dump_state(cs, stderr, 0); -- 2.31.1
