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linux-user/s390x: signal with SIGFPE on compare-and-trap 

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-iii@linux.ibm.com, this fixes
crashes in the java jdk such as the linked bug.

Signed-off-by: Jonathan Albrecht <jonathan.albrecht@linux.vnet.ibm.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Buglink: https://bugs.launchpad.net/qemu/+bug/1920913
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/319
Message-Id: <20210709160459.4962-2-jonathan.albrecht@linux.vnet.ibm.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
This commit is contained in:
Jonathan Albrecht 2021-07-09 12:04:58 -04:00 committed by Thomas Huth
parent 54ba2161d8
commit ccb5f2708f
1 changed files with 34 additions and 20 deletions
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54
linux-user/s390x/cpu_loop.c
View File

@ -25,6 +25,35 @@
/* s390x masks the fault address it reports in si_addr for SIGSEGV and SIGBUS */ /* s390x masks the fault address it reports in si_addr for SIGSEGV and SIGBUS */
#define S390X_FAIL_ADDR_MASK -4096LL #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) void cpu_loop(CPUS390XState *env)
{ {
CPUState *cs = env_cpu(env); CPUState *cs = env_cpu(env);
@ -106,29 +135,14 @@ void cpu_loop(CPUS390XState *env)
case PGM_DATA: case PGM_DATA:
n = (env->fpc >> 8) & 0xff; n = (env->fpc >> 8) & 0xff;
if (n == 0xff) { if (n == 0) {
/* compare-and-trap */
goto do_sigill_opn; 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: default:
fprintf(stderr, "Unhandled program exception: %#x\n", n); fprintf(stderr, "Unhandled program exception: %#x\n", n);
cpu_dump_state(cs, stderr, 0); cpu_dump_state(cs, stderr, 0);