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qemu/linux-user/alpha/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

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/*
* 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"
void cpu_loop(CPUAlphaState *env)
{
CPUState *cs = CPU(alpha_env_get_cpu(env));
int trapnr;
target_siginfo_t info;
abi_long sysret;
while (1) {
bool arch_interrupt = true;
cpu_exec_start(cs);
trapnr = cpu_exec(cs);
cpu_exec_end(cs);
process_queued_cpu_work(cs);
switch (trapnr) {
case EXCP_RESET:
fprintf(stderr, "Reset requested. Exit\n");
exit(EXIT_FAILURE);
break;
case EXCP_MCHK:
fprintf(stderr, "Machine check exception. Exit\n");
exit(EXIT_FAILURE);
break;
case EXCP_SMP_INTERRUPT:
case EXCP_CLK_INTERRUPT:
case EXCP_DEV_INTERRUPT:
fprintf(stderr, "External interrupt. Exit\n");
exit(EXIT_FAILURE);
break;
case EXCP_MMFAULT:
info.si_signo = TARGET_SIGSEGV;
info.si_errno = 0;
info.si_code = (page_get_flags(env->trap_arg0) & PAGE_VALID
? TARGET_SEGV_ACCERR : TARGET_SEGV_MAPERR);
info._sifields._sigfault._addr = env->trap_arg0;
queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
break;
case EXCP_UNALIGN:
info.si_signo = TARGET_SIGBUS;
info.si_errno = 0;
info.si_code = TARGET_BUS_ADRALN;
info._sifields._sigfault._addr = env->trap_arg0;
queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
break;
case EXCP_OPCDEC:
do_sigill:
info.si_signo = TARGET_SIGILL;
info.si_errno = 0;
info.si_code = TARGET_ILL_ILLOPC;
info._sifields._sigfault._addr = env->pc;
queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
break;
case EXCP_ARITH:
info.si_signo = TARGET_SIGFPE;
info.si_errno = 0;
info.si_code = TARGET_FPE_FLTINV;
info._sifields._sigfault._addr = env->pc;
queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
break;
case EXCP_FEN:
/* No-op. Linux simply re-enables the FPU. */
break;
case EXCP_CALL_PAL:
switch (env->error_code) {
case 0x80:
/* BPT */
info.si_signo = TARGET_SIGTRAP;
info.si_errno = 0;
info.si_code = TARGET_TRAP_BRKPT;
info._sifields._sigfault._addr = env->pc;
queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
break;
case 0x81:
/* BUGCHK */
info.si_signo = TARGET_SIGTRAP;
info.si_errno = 0;
info.si_code = 0;
info._sifields._sigfault._addr = env->pc;
queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
break;
case 0x83:
/* CALLSYS */
trapnr = env->ir[IR_V0];
sysret = do_syscall(env, trapnr,
env->ir[IR_A0], env->ir[IR_A1],
env->ir[IR_A2], env->ir[IR_A3],
env->ir[IR_A4], env->ir[IR_A5],
0, 0);
if (sysret == -TARGET_ERESTARTSYS) {
env->pc -= 4;
break;
}
if (sysret == -TARGET_QEMU_ESIGRETURN) {
break;
}
/* Syscall writes 0 to V0 to bypass error check, similar
to how this is handled internal to Linux kernel.
(Ab)use trapnr temporarily as boolean indicating error. */
trapnr = (env->ir[IR_V0] != 0 && sysret < 0);
env->ir[IR_V0] = (trapnr ? -sysret : sysret);
env->ir[IR_A3] = trapnr;
break;
case 0x86:
/* IMB */
/* ??? We can probably elide the code using page_unprotect
that is checking for self-modifying code. Instead we
could simply call tb_flush here. Until we work out the
changes required to turn off the extra write protection,
this can be a no-op. */
break;
case 0x9E:
/* RDUNIQUE */
/* Handled in the translator for usermode. */
abort();
case 0x9F:
/* WRUNIQUE */
/* Handled in the translator for usermode. */
abort();
case 0xAA:
/* GENTRAP */
info.si_signo = TARGET_SIGFPE;
switch (env->ir[IR_A0]) {
case TARGET_GEN_INTOVF:
info.si_code = TARGET_FPE_INTOVF;
break;
case TARGET_GEN_INTDIV:
info.si_code = TARGET_FPE_INTDIV;
break;
case TARGET_GEN_FLTOVF:
info.si_code = TARGET_FPE_FLTOVF;
break;
case TARGET_GEN_FLTUND:
info.si_code = TARGET_FPE_FLTUND;
break;
case TARGET_GEN_FLTINV:
info.si_code = TARGET_FPE_FLTINV;
break;
case TARGET_GEN_FLTINE:
info.si_code = TARGET_FPE_FLTRES;
break;
case TARGET_GEN_ROPRAND:
info.si_code = 0;
break;
default:
info.si_signo = TARGET_SIGTRAP;
info.si_code = 0;
break;
}
info.si_errno = 0;
info._sifields._sigfault._addr = env->pc;
queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
break;
default:
goto do_sigill;
}
break;
case EXCP_DEBUG:
info.si_signo = TARGET_SIGTRAP;
info.si_errno = 0;
info.si_code = TARGET_TRAP_BRKPT;
queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
break;
case EXCP_INTERRUPT:
/* Just indicate that signals should be handled asap. */
break;
case EXCP_ATOMIC:
cpu_exec_step_atomic(cs);
arch_interrupt = false;
break;
default:
fprintf(stderr, "Unhandled trap: 0x%x\n", trapnr);
cpu_dump_state(cs, stderr, fprintf, 0);
exit(EXIT_FAILURE);
}
process_pending_signals (env);
/* Most of the traps imply a transition through PALcode, which
implies an REI instruction has been executed. Which means
that RX and LOCK_ADDR should be cleared. But there are a
few exceptions for traps internal to QEMU. */
if (arch_interrupt) {
env->flags &= ~ENV_FLAG_RX_FLAG;
env->lock_addr = -1;
}
}
}
void target_cpu_copy_regs(CPUArchState *env, struct target_pt_regs *regs)
{
int i;
for(i = 0; i < 28; i++) {
env->ir[i] = ((abi_ulong *)regs)[i];
}
env->ir[IR_SP] = regs->usp;
env->pc = regs->pc;
}
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