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b10089a14c
qemu/linux-user/xtensa/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"
static void xtensa_rfw(CPUXtensaState *env)
{
xtensa_restore_owb(env);
env->pc = env->sregs[EPC1];
}
static void xtensa_rfwu(CPUXtensaState *env)
{
env->sregs[WINDOW_START] |= (1 << env->sregs[WINDOW_BASE]);
xtensa_rfw(env);
}
static void xtensa_rfwo(CPUXtensaState *env)
{
env->sregs[WINDOW_START] &= ~(1 << env->sregs[WINDOW_BASE]);
xtensa_rfw(env);
}
static void xtensa_overflow4(CPUXtensaState *env)
{
put_user_ual(env->regs[0], env->regs[5] - 16);
put_user_ual(env->regs[1], env->regs[5] - 12);
put_user_ual(env->regs[2], env->regs[5] - 8);
put_user_ual(env->regs[3], env->regs[5] - 4);
xtensa_rfwo(env);
}
static void xtensa_underflow4(CPUXtensaState *env)
{
get_user_ual(env->regs[0], env->regs[5] - 16);
get_user_ual(env->regs[1], env->regs[5] - 12);
get_user_ual(env->regs[2], env->regs[5] - 8);
get_user_ual(env->regs[3], env->regs[5] - 4);
xtensa_rfwu(env);
}
static void xtensa_overflow8(CPUXtensaState *env)
{
put_user_ual(env->regs[0], env->regs[9] - 16);
get_user_ual(env->regs[0], env->regs[1] - 12);
put_user_ual(env->regs[1], env->regs[9] - 12);
put_user_ual(env->regs[2], env->regs[9] - 8);
put_user_ual(env->regs[3], env->regs[9] - 4);
put_user_ual(env->regs[4], env->regs[0] - 32);
put_user_ual(env->regs[5], env->regs[0] - 28);
put_user_ual(env->regs[6], env->regs[0] - 24);
put_user_ual(env->regs[7], env->regs[0] - 20);
xtensa_rfwo(env);
}
static void xtensa_underflow8(CPUXtensaState *env)
{
get_user_ual(env->regs[0], env->regs[9] - 16);
get_user_ual(env->regs[1], env->regs[9] - 12);
get_user_ual(env->regs[2], env->regs[9] - 8);
get_user_ual(env->regs[7], env->regs[1] - 12);
get_user_ual(env->regs[3], env->regs[9] - 4);
get_user_ual(env->regs[4], env->regs[7] - 32);
get_user_ual(env->regs[5], env->regs[7] - 28);
get_user_ual(env->regs[6], env->regs[7] - 24);
get_user_ual(env->regs[7], env->regs[7] - 20);
xtensa_rfwu(env);
}
static void xtensa_overflow12(CPUXtensaState *env)
{
put_user_ual(env->regs[0], env->regs[13] - 16);
get_user_ual(env->regs[0], env->regs[1] - 12);
put_user_ual(env->regs[1], env->regs[13] - 12);
put_user_ual(env->regs[2], env->regs[13] - 8);
put_user_ual(env->regs[3], env->regs[13] - 4);
put_user_ual(env->regs[4], env->regs[0] - 48);
put_user_ual(env->regs[5], env->regs[0] - 44);
put_user_ual(env->regs[6], env->regs[0] - 40);
put_user_ual(env->regs[7], env->regs[0] - 36);
put_user_ual(env->regs[8], env->regs[0] - 32);
put_user_ual(env->regs[9], env->regs[0] - 28);
put_user_ual(env->regs[10], env->regs[0] - 24);
put_user_ual(env->regs[11], env->regs[0] - 20);
xtensa_rfwo(env);
}
static void xtensa_underflow12(CPUXtensaState *env)
{
get_user_ual(env->regs[0], env->regs[13] - 16);
get_user_ual(env->regs[1], env->regs[13] - 12);
get_user_ual(env->regs[2], env->regs[13] - 8);
get_user_ual(env->regs[11], env->regs[1] - 12);
get_user_ual(env->regs[3], env->regs[13] - 4);
get_user_ual(env->regs[4], env->regs[11] - 48);
get_user_ual(env->regs[5], env->regs[11] - 44);
get_user_ual(env->regs[6], env->regs[11] - 40);
get_user_ual(env->regs[7], env->regs[11] - 36);
get_user_ual(env->regs[8], env->regs[11] - 32);
get_user_ual(env->regs[9], env->regs[11] - 28);
get_user_ual(env->regs[10], env->regs[11] - 24);
get_user_ual(env->regs[11], env->regs[11] - 20);
xtensa_rfwu(env);
}
void cpu_loop(CPUXtensaState *env)
{
CPUState *cs = CPU(xtensa_env_get_cpu(env));
target_siginfo_t info;
abi_ulong ret;
int trapnr;
while (1) {
cpu_exec_start(cs);
trapnr = cpu_exec(cs);
cpu_exec_end(cs);
process_queued_cpu_work(cs);
env->sregs[PS] &= ~PS_EXCM;
switch (trapnr) {
case EXCP_INTERRUPT:
break;
case EXC_WINDOW_OVERFLOW4:
xtensa_overflow4(env);
break;
case EXC_WINDOW_UNDERFLOW4:
xtensa_underflow4(env);
break;
case EXC_WINDOW_OVERFLOW8:
xtensa_overflow8(env);
break;
case EXC_WINDOW_UNDERFLOW8:
xtensa_underflow8(env);
break;
case EXC_WINDOW_OVERFLOW12:
xtensa_overflow12(env);
break;
case EXC_WINDOW_UNDERFLOW12:
xtensa_underflow12(env);
break;
case EXC_USER:
switch (env->sregs[EXCCAUSE]) {
case ILLEGAL_INSTRUCTION_CAUSE:
case PRIVILEGED_CAUSE:
info.si_signo = TARGET_SIGILL;
info.si_errno = 0;
info.si_code =
env->sregs[EXCCAUSE] == ILLEGAL_INSTRUCTION_CAUSE ?
TARGET_ILL_ILLOPC : TARGET_ILL_PRVOPC;
info._sifields._sigfault._addr = env->sregs[EPC1];
queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
break;
case SYSCALL_CAUSE:
env->pc += 3;
ret = do_syscall(env, env->regs[2],
env->regs[6], env->regs[3],
env->regs[4], env->regs[5],
env->regs[8], env->regs[9], 0, 0);
switch (ret) {
default:
env->regs[2] = ret;
break;
case -TARGET_ERESTARTSYS:
env->pc -= 3;
break;
case -TARGET_QEMU_ESIGRETURN:
break;
}
break;
case ALLOCA_CAUSE:
env->sregs[PS] = deposit32(env->sregs[PS],
PS_OWB_SHIFT,
PS_OWB_LEN,
env->sregs[WINDOW_BASE]);
switch (env->regs[0] & 0xc0000000) {
case 0x00000000:
case 0x40000000:
xtensa_rotate_window(env, -1);
xtensa_underflow4(env);
break;
case 0x80000000:
xtensa_rotate_window(env, -2);
xtensa_underflow8(env);
break;
case 0xc0000000:
xtensa_rotate_window(env, -3);
xtensa_underflow12(env);
break;
}
break;
case INTEGER_DIVIDE_BY_ZERO_CAUSE:
info.si_signo = TARGET_SIGFPE;
info.si_errno = 0;
info.si_code = TARGET_FPE_INTDIV;
info._sifields._sigfault._addr = env->sregs[EPC1];
queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
break;
case LOAD_PROHIBITED_CAUSE:
case STORE_PROHIBITED_CAUSE:
info.si_signo = TARGET_SIGSEGV;
info.si_errno = 0;
info.si_code = TARGET_SEGV_ACCERR;
info._sifields._sigfault._addr = env->sregs[EXCVADDR];
queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
break;
default:
fprintf(stderr, "exccause = %d\n", env->sregs[EXCCAUSE]);
g_assert_not_reached();
}
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 EXC_DEBUG:
default:
fprintf(stderr, "trapnr = %d\n", trapnr);
g_assert_not_reached();
}
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->areg[i];
}
env->sregs[WINDOW_START] = regs->windowstart;
env->pc = regs->pc;
}
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