On Tue, Jul 12, 2016 at 9:39 AM, Peter Maydell <peter.mayd...@linaro.org> wrote:
> On 2 July 2016 at 02:07, Alistair Francis <alistair.fran...@xilinx.com> wrote:
>> Add a generic loader to QEMU which can be used to load images or set
>> memory values.
>>
>> Signed-off-by: Alistair Francis <alistair.fran...@xilinx.com>
>> ---
>> V8:
>> - Code corrections
>> - Rebase
>> V7:
>> - Rebase
>> V6:
>> - Add error checking
>> V5:
>> - Rebase
>> V4:
>> - Allow the loader to work with every architecture
>> - Move the file to hw/core
>> - Increase the maximum number of CPUs
>> - Make the CPU operations conditional
>> - Convert the cpu option to cpu-num
>> - Require the user to specify endianess
>> V3:
>> - Pass the ram_size to load_image_targphys()
>> V2:
>> - Add maintainers entry
>> - Perform bounds checking
>> - Register and unregister the reset in the realise/unrealise
>> Changes since RFC:
>> - Add BE support
>>
>> MAINTAINERS | 6 ++
>> hw/core/Makefile.objs | 2 +
>> hw/core/generic-loader.c | 177
>> +++++++++++++++++++++++++++++++++++++++
>> include/hw/core/generic-loader.h | 45 ++++++++++
>> 4 files changed, 230 insertions(+)
>> create mode 100644 hw/core/generic-loader.c
>> create mode 100644 include/hw/core/generic-loader.h
>>
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index 2ab6e3b..0077e22 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -992,6 +992,12 @@ M: Dmitry Fleytman <dmi...@daynix.com>
>> S: Maintained
>> F: hw/net/e1000e*
>>
>> +Generic Loader
>> +M: Alistair Francis <alistair.fran...@xilinx.com>
>> +S: Maintained
>> +F: hw/core/generic-loader.c
>> +F: include/hw/core/generic-loader.h
>> +
>> Subsystems
>> ----------
>> Audio
>> diff --git a/hw/core/Makefile.objs b/hw/core/Makefile.objs
>> index 82a9ef8..ab238fa 100644
>> --- a/hw/core/Makefile.objs
>> +++ b/hw/core/Makefile.objs
>> @@ -16,3 +16,5 @@ common-obj-$(CONFIG_SOFTMMU) += null-machine.o
>> common-obj-$(CONFIG_SOFTMMU) += loader.o
>> common-obj-$(CONFIG_SOFTMMU) += qdev-properties-system.o
>> common-obj-$(CONFIG_PLATFORM_BUS) += platform-bus.o
>> +
>> +obj-$(CONFIG_SOFTMMU) += generic-loader.o
>> diff --git a/hw/core/generic-loader.c b/hw/core/generic-loader.c
>> new file mode 100644
>> index 0000000..c9b0572
>> --- /dev/null
>> +++ b/hw/core/generic-loader.c
>> @@ -0,0 +1,177 @@
>> +/*
>> + * Generic Loader
>> + *
>> + * Copyright (C) 2014 Li Guang
>> + * Copyright (C) 2016 Xilinx Inc.
>> + * Written by Li Guang <lig.f...@cn.fujitsu.com>
>> + *
>> + * 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.
>> + */
>> +
>> +#include "qemu/osdep.h"
>> +#include "qom/cpu.h"
>> +#include "hw/sysbus.h"
>> +#include "sysemu/dma.h"
>> +#include "hw/loader.h"
>> +#include "qapi/error.h"
>> +#include "hw/core/generic-loader.h"
>> +
>> +#define CPU_NONE 0xFFFF
>
> This should be updated now we've widened the type from 16 bits.
Fixed
>
>> +
>> +static void generic_loader_reset(void *opaque)
>> +{
>> + GenericLoaderState *s = GENERIC_LOADER(opaque);
>> +
>> + if (s->cpu) {
>> + CPUClass *cc = CPU_GET_CLASS(s->cpu);
>> + cpu_reset(s->cpu);
>> + if (cc) {
>> + cc->set_pc(s->cpu, s->addr);
>
> If something else sets the PC later on this gets lost, which is
> ugly and fragile. It's kinda-sorta OK that we bodge this for things
> like the hw/arm/boot.c code because all the pieces are inside QEMU,
> but when you start adding in command line devices I'm a bit
> nervous. Maybe we should actually figure out our reset order
> woes properly ?
This is up to the user to specify the commands in the order they want
them applied. What other method should we be using?
>
>> + }
>> + }
>> +
>> + if (s->data_len) {
>> + assert(s->data_len < sizeof(s->data));
>> + dma_memory_write((s->cpu ? s->cpu : first_cpu)->as, s->addr,
>> &s->data,
>> + s->data_len);
>
> We rule out specifying cpu_num below, so when is s->cpu non-NULL?
I have removed this.
>
>> + }
>> +}
>> +
>> +static void generic_loader_realize(DeviceState *dev, Error **errp)
>> +{
>> + GenericLoaderState *s = GENERIC_LOADER(dev);
>> + hwaddr entry;
>> + int big_endian;
>> + int size = 0;
>> +
>> + /* Perform some error checking on the user's options */
>> + if (s->data || s->data_len || s->data_be) {
>> + /* User is loading memory values */
>> + if (s->file) {
>> + error_setg(errp, "Specifying a file is not supported when
>> loading "
>> + "memory values");
>> + return;
>> + } else if (s->force_raw) {
>> + error_setg(errp, "Specifying force raw is not supported when "
>
> "force-raw", ie state the option name. Similarly in these other errors.
Fixed
>
>> + "loading memory values");
>> + return;
>> + } else if (!s->data || !s->data_len) {
>> + error_setg(errp, "Both data and data length must be specified");
>> + return;
>> + } else if (s->cpu_num) {
>> + error_setg(errp, "Setting data and a cpu number is not
>> supported");
>> + return;
>> + }
>> + } else if (s->file || s->force_raw) {
>> + /* User is loading an image */
>> + if (s->data || s->data_len || s->data_be) {
>> + error_setg(errp, "Data can not be specified when loading an "
>> + "image");
>> + return;
>> + }
>> + } else if (s->data_len) {
>> + if (s->data_len > 8) {
>> + error_setg(errp, "data-len cannot be greate then 8 bytes");
>
> "greater"
Fixed
>
>> + return;
>> + } else if (s->data_len > sizeof(s->data)) {
>> + error_setg(errp, "data-len cannot be more then the data size");
>> + return;
>> + }
>> + }
>> +
>> + qemu_register_reset(generic_loader_reset, dev);
>
> What's wrong with a device reset function set via dc->reset ?
This allows setting values from the HMP command line interface once
the machine is running. The dc->reset isn't applied in that case.
>
>> +
>> + if (s->cpu_num != CPU_NONE) {
>> + s->cpu = qemu_get_cpu(s->cpu_num);
>> + if (!s->cpu) {
>> + error_setg(errp, "Specified boot CPU#%d is nonexistent",
>> + s->cpu_num);
>> + return;
>> + }
>> + }
>> +
>> +#ifdef TARGET_WORDS_BIGENDIAN
>> + big_endian = 1;
>> +#else
>> + big_endian = 0;
>> +#endif
>> +
>> + if (s->file) {
>> + if (!s->force_raw) {
>> + size = load_elf_as(s->file, NULL, NULL, &entry, NULL, NULL,
>> + big_endian, 0, 0, 0,
>> + (s->cpu ? s->cpu : first_cpu)->as);
>> +
>> + if (size < 0) {
>> + size = load_uimage(s->file, &entry, NULL, NULL, NULL, NULL);
>> + }
>> + }
>> +
>> + if (size < 0 || s->force_raw) {
>> + /* Default to the maximum size being the machine's ram size */
>> + size = load_image_targphys(s->file, s->addr, ram_size);
>> + } else {
>> + s->addr = entry;
>> + }
>
> We only use the CPU's address space for ELF loads, not for uimage or raw.
> That's an annoying inconsistency. I think we need to use the CPU's
> address space for everything or nothing, preferably for everything.
Agreed, I just wanted to make sure that this approach was agreed upon before
I converted every other image loading.
>
> Changing that after this goes into the tree would be a command
> line compatibility break, so this inclines me to saying that this
> isn't baked enough for 2.7 and we should aim to put it into 2.8.
That's fair, but upsetting.
Thanks,
Alistair
>
> thanks
> -- PMM
>
