qemu-patch-raspberry4/linux-user/s390x/cpu_loop.c
Peter Maydell b10089a14c linux-user: Don't call gdb_handlesig() before queue_signal()
The CPU main-loop routines for linux-user generally
call gdb_handlesig() when they're about to queue a
SIGTRAP signal. This is wrong, because queue_signal()
will cause us to pend a signal, and process_pending_signals()
will then call gdb_handlesig() itself. So the effect is that
we notify gdb of the SIGTRAP, and then if gdb says "OK,
continue with signal X" we will incorrectly notify
gdb of the signal X as well. We don't do this double-notify
for anything else, only SIGTRAP.

Remove this unnecessary and incorrect code from all
the targets except for nios2 (whose main loop is
doing something different and broken, and will be handled
in a separate patch).

This bug only manifests if the user responds to the reported
SIGTRAP using "signal SIGFOO" rather than "continue"; since
the latter is the overwhelmingly common thing to do after a
breakpoint most people won't have hit this.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20181019174958.26616-2-peter.maydell@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
2018-11-12 15:48:00 +01:00

163 lines
5.2 KiB
C

/*
* qemu user cpu loop
*
* Copyright (c) 2003-2008 Fabrice Bellard
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include "qemu/osdep.h"
#include "qemu.h"
#include "cpu_loop-common.h"
/* s390x masks the fault address it reports in si_addr for SIGSEGV and SIGBUS */
#define S390X_FAIL_ADDR_MASK -4096LL
void cpu_loop(CPUS390XState *env)
{
CPUState *cs = CPU(s390_env_get_cpu(env));
int trapnr, n, sig;
target_siginfo_t info;
target_ulong addr;
abi_long ret;
while (1) {
cpu_exec_start(cs);
trapnr = cpu_exec(cs);
cpu_exec_end(cs);
process_queued_cpu_work(cs);
switch (trapnr) {
case EXCP_INTERRUPT:
/* Just indicate that signals should be handled asap. */
break;
case EXCP_SVC:
n = env->int_svc_code;
if (!n) {
/* syscalls > 255 */
n = env->regs[1];
}
env->psw.addr += env->int_svc_ilen;
ret = do_syscall(env, n, env->regs[2], env->regs[3],
env->regs[4], env->regs[5],
env->regs[6], env->regs[7], 0, 0);
if (ret == -TARGET_ERESTARTSYS) {
env->psw.addr -= env->int_svc_ilen;
} else if (ret != -TARGET_QEMU_ESIGRETURN) {
env->regs[2] = ret;
}
break;
case EXCP_DEBUG:
sig = TARGET_SIGTRAP;
n = TARGET_TRAP_BRKPT;
goto do_signal_pc;
case EXCP_PGM:
n = env->int_pgm_code;
switch (n) {
case PGM_OPERATION:
case PGM_PRIVILEGED:
sig = TARGET_SIGILL;
n = TARGET_ILL_ILLOPC;
goto do_signal_pc;
case PGM_PROTECTION:
case PGM_ADDRESSING:
sig = TARGET_SIGSEGV;
/* XXX: check env->error_code */
n = TARGET_SEGV_MAPERR;
addr = env->__excp_addr & S390X_FAIL_ADDR_MASK;
goto do_signal;
case PGM_EXECUTE:
case PGM_SPECIFICATION:
case PGM_SPECIAL_OP:
case PGM_OPERAND:
do_sigill_opn:
sig = TARGET_SIGILL;
n = TARGET_ILL_ILLOPN;
goto do_signal_pc;
case PGM_FIXPT_OVERFLOW:
sig = TARGET_SIGFPE;
n = TARGET_FPE_INTOVF;
goto do_signal_pc;
case PGM_FIXPT_DIVIDE:
sig = TARGET_SIGFPE;
n = TARGET_FPE_INTDIV;
goto do_signal_pc;
case PGM_DATA:
n = (env->fpc >> 8) & 0xff;
if (n == 0xff) {
/* compare-and-trap */
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;
}
default:
fprintf(stderr, "Unhandled program exception: %#x\n", n);
cpu_dump_state(cs, stderr, fprintf, 0);
exit(EXIT_FAILURE);
}
break;
do_signal_pc:
addr = env->psw.addr;
do_signal:
info.si_signo = sig;
info.si_errno = 0;
info.si_code = n;
info._sifields._sigfault._addr = addr;
queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
break;
case EXCP_ATOMIC:
cpu_exec_step_atomic(cs);
break;
default:
fprintf(stderr, "Unhandled trap: 0x%x\n", trapnr);
cpu_dump_state(cs, stderr, fprintf, 0);
exit(EXIT_FAILURE);
}
process_pending_signals (env);
}
}
void target_cpu_copy_regs(CPUArchState *env, struct target_pt_regs *regs)
{
int i;
for (i = 0; i < 16; i++) {
env->regs[i] = regs->gprs[i];
}
env->psw.mask = regs->psw.mask;
env->psw.addr = regs->psw.addr;
}