qemu/target/hppa/cpu.c
Helge Deller 4a4554c6c5 hppa: Add support for an emulated TOC/NMI button.
Almost all PA-RISC machines have either a button that is labeled with 'TOC' or
a BMC/GSP function to trigger a TOC.  TOC is a non-maskable interrupt that is
sent to the processor.  This can be used for diagnostic purposes like obtaining
a stack trace/register dump or to enter KDB/KGDB in Linux.

This patch adds support for such an emulated TOC button.

It wires up the qemu monitor "nmi" command to trigger a TOC.  For that it
provides the hppa_nmi function which is assigned to the nmi_monitor_handler
function pointer.  When called it raises the EXCP_TOC hardware interrupt in the
hppa_cpu_do_interrupt() function.  The interrupt function then calls the
architecturally defined TOC function in SeaBIOS-hppa firmware (at fixed address
0xf0000000).

According to the PA-RISC PDC specification, the SeaBIOS firmware then writes
the CPU registers into PIM (processor internal memmory) for later analysis.  In
order to write all registers it needs to know the contents of the CPU "shadow
registers" and the IASQ- and IAOQ-back values. The IAOQ/IASQ values are
provided by qemu in shadow registers when entering the SeaBIOS TOC function.
This patch adds a new aritificial opcode "getshadowregs" (0xfffdead2) which
restores the original values of the shadow registers. With this opcode SeaBIOS
can store those registers as well into PIM before calling an OS-provided TOC
handler.

To trigger a TOC, switch to the qemu monitor with Ctrl-A C, and type in the
command "nmi".  After the TOC started the OS-debugger, exit the qemu monitor
with Ctrl-A C.

Signed-off-by: Helge Deller <deller@gmx.de>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
2022-02-02 18:46:42 +01:00

197 lines
5.3 KiB
C

/*
* QEMU HPPA CPU
*
* Copyright (c) 2016 Richard Henderson <rth@twiddle.net>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see
* <http://www.gnu.org/licenses/lgpl-2.1.html>
*/
#include "qemu/osdep.h"
#include "qapi/error.h"
#include "qemu/qemu-print.h"
#include "cpu.h"
#include "qemu/module.h"
#include "exec/exec-all.h"
#include "fpu/softfloat.h"
static void hppa_cpu_set_pc(CPUState *cs, vaddr value)
{
HPPACPU *cpu = HPPA_CPU(cs);
cpu->env.iaoq_f = value;
cpu->env.iaoq_b = value + 4;
}
static void hppa_cpu_synchronize_from_tb(CPUState *cs,
const TranslationBlock *tb)
{
HPPACPU *cpu = HPPA_CPU(cs);
#ifdef CONFIG_USER_ONLY
cpu->env.iaoq_f = tb->pc;
cpu->env.iaoq_b = tb->cs_base;
#else
/* Recover the IAOQ values from the GVA + PRIV. */
uint32_t priv = (tb->flags >> TB_FLAG_PRIV_SHIFT) & 3;
target_ulong cs_base = tb->cs_base;
target_ulong iasq_f = cs_base & ~0xffffffffull;
int32_t diff = cs_base;
cpu->env.iasq_f = iasq_f;
cpu->env.iaoq_f = (tb->pc & ~iasq_f) + priv;
if (diff) {
cpu->env.iaoq_b = cpu->env.iaoq_f + diff;
}
#endif
cpu->env.psw_n = (tb->flags & PSW_N) != 0;
}
static bool hppa_cpu_has_work(CPUState *cs)
{
return cs->interrupt_request & (CPU_INTERRUPT_HARD | CPU_INTERRUPT_NMI);
}
static void hppa_cpu_disas_set_info(CPUState *cs, disassemble_info *info)
{
info->mach = bfd_mach_hppa20;
info->print_insn = print_insn_hppa;
}
#ifndef CONFIG_USER_ONLY
static void QEMU_NORETURN
hppa_cpu_do_unaligned_access(CPUState *cs, vaddr addr,
MMUAccessType access_type, int mmu_idx,
uintptr_t retaddr)
{
HPPACPU *cpu = HPPA_CPU(cs);
CPUHPPAState *env = &cpu->env;
cs->exception_index = EXCP_UNALIGN;
if (env->psw & PSW_Q) {
/* ??? Needs tweaking for hppa64. */
env->cr[CR_IOR] = addr;
env->cr[CR_ISR] = addr >> 32;
}
cpu_loop_exit_restore(cs, retaddr);
}
#endif /* CONFIG_USER_ONLY */
static void hppa_cpu_realizefn(DeviceState *dev, Error **errp)
{
CPUState *cs = CPU(dev);
HPPACPUClass *acc = HPPA_CPU_GET_CLASS(dev);
Error *local_err = NULL;
cpu_exec_realizefn(cs, &local_err);
if (local_err != NULL) {
error_propagate(errp, local_err);
return;
}
qemu_init_vcpu(cs);
acc->parent_realize(dev, errp);
#ifndef CONFIG_USER_ONLY
{
HPPACPU *cpu = HPPA_CPU(cs);
cpu->alarm_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL,
hppa_cpu_alarm_timer, cpu);
}
#endif
}
static void hppa_cpu_initfn(Object *obj)
{
CPUState *cs = CPU(obj);
HPPACPU *cpu = HPPA_CPU(obj);
CPUHPPAState *env = &cpu->env;
cpu_set_cpustate_pointers(cpu);
cs->exception_index = -1;
cpu_hppa_loaded_fr0(env);
cpu_hppa_put_psw(env, PSW_W);
}
static ObjectClass *hppa_cpu_class_by_name(const char *cpu_model)
{
return object_class_by_name(TYPE_HPPA_CPU);
}
#ifndef CONFIG_USER_ONLY
#include "hw/core/sysemu-cpu-ops.h"
static const struct SysemuCPUOps hppa_sysemu_ops = {
.get_phys_page_debug = hppa_cpu_get_phys_page_debug,
};
#endif
#include "hw/core/tcg-cpu-ops.h"
static const struct TCGCPUOps hppa_tcg_ops = {
.initialize = hppa_translate_init,
.synchronize_from_tb = hppa_cpu_synchronize_from_tb,
#ifndef CONFIG_USER_ONLY
.tlb_fill = hppa_cpu_tlb_fill,
.cpu_exec_interrupt = hppa_cpu_exec_interrupt,
.do_interrupt = hppa_cpu_do_interrupt,
.do_unaligned_access = hppa_cpu_do_unaligned_access,
#endif /* !CONFIG_USER_ONLY */
};
static void hppa_cpu_class_init(ObjectClass *oc, void *data)
{
DeviceClass *dc = DEVICE_CLASS(oc);
CPUClass *cc = CPU_CLASS(oc);
HPPACPUClass *acc = HPPA_CPU_CLASS(oc);
device_class_set_parent_realize(dc, hppa_cpu_realizefn,
&acc->parent_realize);
cc->class_by_name = hppa_cpu_class_by_name;
cc->has_work = hppa_cpu_has_work;
cc->dump_state = hppa_cpu_dump_state;
cc->set_pc = hppa_cpu_set_pc;
cc->gdb_read_register = hppa_cpu_gdb_read_register;
cc->gdb_write_register = hppa_cpu_gdb_write_register;
#ifndef CONFIG_USER_ONLY
dc->vmsd = &vmstate_hppa_cpu;
cc->sysemu_ops = &hppa_sysemu_ops;
#endif
cc->disas_set_info = hppa_cpu_disas_set_info;
cc->gdb_num_core_regs = 128;
cc->tcg_ops = &hppa_tcg_ops;
}
static const TypeInfo hppa_cpu_type_info = {
.name = TYPE_HPPA_CPU,
.parent = TYPE_CPU,
.instance_size = sizeof(HPPACPU),
.instance_init = hppa_cpu_initfn,
.abstract = false,
.class_size = sizeof(HPPACPUClass),
.class_init = hppa_cpu_class_init,
};
static void hppa_cpu_register_types(void)
{
type_register_static(&hppa_cpu_type_info);
}
type_init(hppa_cpu_register_types)