generic-loader: Add a generic loader

Add a generic loader to QEMU which can be used to load images or set
memory values.

Internally inside QEMU this is a device. It is a strange device that
provides no hardware interface but allows QEMU to monkey patch memory
specified when it is created. To be able to do this it has a reset
callback that does the memory operations.

This device allows the user to monkey patch memory. To be able to do
this it needs a backend to manage the datas, the same as other
memory-related devices. In this case as the backend is so trivial we
have merged it with the frontend instead of creating and maintaining a
seperate backend.

Signed-off-by: Alistair Francis <alistair.francis@xilinx.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Acked-by: Markus Armbruster <armbru@redhat.com>
Message-id: 10f2a9dce5e5e11b6c6d959415b0ad6ee22bcba5.1475195078.git.alistair.francis@xilinx.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

MAINTAINERS

@@ -1029,6 +1029,12 @@ M: Dmitry Fleytman <dmitry@daynix.com>
 S: Maintained
 F: hw/net/e1000e*
 
+Generic Loader
+M: Alistair Francis <alistair.francis@xilinx.com>
+S: Maintained
+F: hw/core/generic-loader.c
+F: include/hw/core/generic-loader.h
+
 Subsystems
 ----------
 Audio

hw/core/Makefile.objs

@@ -18,3 +18,5 @@ common-obj-$(CONFIG_SOFTMMU) += qdev-properties-system.o
 common-obj-$(CONFIG_SOFTMMU) += register.o
 common-obj-$(CONFIG_SOFTMMU) += or-irq.o
 common-obj-$(CONFIG_PLATFORM_BUS) += platform-bus.o
+
+obj-$(CONFIG_SOFTMMU) += generic-loader.o

hw/core/generic-loader.c

@@ -0,0 +1,211 @@
+/*
+ * Generic Loader
+ *
+ * Copyright (C) 2014 Li Guang
+ * Copyright (C) 2016 Xilinx Inc.
+ * Written by Li Guang <lig.fnst@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.
+ *
+ */
+
+/*
+ * Internally inside QEMU this is a device. It is a strange device that
+ * provides no hardware interface but allows QEMU to monkey patch memory
+ * specified when it is created. To be able to do this it has a reset
+ * callback that does the memory operations.
+
+ * This device allows the user to monkey patch memory. To be able to do
+ * this it needs a backend to manage the datas, the same as other
+ * memory-related devices. In this case as the backend is so trivial we
+ * have merged it with the frontend instead of creating and maintaining a
+ * seperate backend.
+ */
+
+#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 0xFFFFFFFF
+
+static void generic_loader_reset(void *opaque)
+{
+    GenericLoaderState *s = GENERIC_LOADER(opaque);
+
+    if (s->set_pc) {
+        CPUClass *cc = CPU_GET_CLASS(s->cpu);
+        cpu_reset(s->cpu);
+        if (cc) {
+            cc->set_pc(s->cpu, s->addr);
+        }
+    }
+
+    if (s->data_len) {
+        assert(s->data_len < sizeof(s->data));
+        dma_memory_write(s->cpu->as, s->addr, &s->data, s->data_len);
+    }
+}
+
+static void generic_loader_realize(DeviceState *dev, Error **errp)
+{
+    GenericLoaderState *s = GENERIC_LOADER(dev);
+    hwaddr entry;
+    int big_endian;
+    int size = 0;
+
+    s->set_pc = false;
+
+    /* 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 "
+                       "loading memory values");
+            return;
+        } else if (!s->data_len) {
+            /* We cant' check for !data here as a value of 0 is still valid. */
+            error_setg(errp, "Both data and data-len must be specified");
+            return;
+        } else if (s->data_len > 8) {
+            error_setg(errp, "data-len cannot be greater then 8 bytes");
+            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;
+        }
+        s->set_pc = true;
+    } else if (s->addr) {
+        /* User is setting the PC */
+        if (s->data || s->data_len || s->data_be) {
+            error_setg(errp, "data can not be specified when setting a "
+                       "program counter");
+            return;
+        } else if (!s->cpu_num) {
+            error_setg(errp, "cpu_num must be specified when setting a "
+                       "program counter");
+            return;
+        }
+        s->set_pc = true;
+    } else {
+        /* Did the user specify anything? */
+        error_setg(errp, "please include valid arguments");
+        return;
+    }
+
+    qemu_register_reset(generic_loader_reset, dev);
+
+    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;
+        }
+    } else {
+        s->cpu = first_cpu;
+    }
+
+#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->as);
+
+            if (size < 0) {
+                size = load_uimage_as(s->file, &entry, NULL, NULL, NULL, NULL,
+                                      s->cpu->as);
+            }
+        }
+
+        if (size < 0 || s->force_raw) {
+            /* Default to the maximum size being the machine's ram size */
+            size = load_image_targphys_as(s->file, s->addr, ram_size,
+                                          s->cpu->as);
+        } else {
+            s->addr = entry;
+        }
+
+        if (size < 0) {
+            error_setg(errp, "Cannot load specified image %s", s->file);
+            return;
+        }
+    }
+
+    /* Convert the data endiannes */
+    if (s->data_be) {
+        s->data = cpu_to_be64(s->data);
+    } else {
+        s->data = cpu_to_le64(s->data);
+    }
+}
+
+static void generic_loader_unrealize(DeviceState *dev, Error **errp)
+{
+    qemu_unregister_reset(generic_loader_reset, dev);
+}
+
+static Property generic_loader_props[] = {
+    DEFINE_PROP_UINT64("addr", GenericLoaderState, addr, 0),
+    DEFINE_PROP_UINT64("data", GenericLoaderState, data, 0),
+    DEFINE_PROP_UINT8("data-len", GenericLoaderState, data_len, 0),
+    DEFINE_PROP_BOOL("data-be", GenericLoaderState, data_be, false),
+    DEFINE_PROP_UINT32("cpu-num", GenericLoaderState, cpu_num, CPU_NONE),
+    DEFINE_PROP_BOOL("force-raw", GenericLoaderState, force_raw, false),
+    DEFINE_PROP_STRING("file", GenericLoaderState, file),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static void generic_loader_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    /* The reset function is not registered here and is instead registered in
+     * the realize function to allow this device to be added via the device_add
+     * command in the QEMU monitor.
+     * TODO: Improve the device_add functionality to allow resets to be
+     * connected
+     */
+    dc->realize = generic_loader_realize;
+    dc->unrealize = generic_loader_unrealize;
+    dc->props = generic_loader_props;
+    dc->desc = "Generic Loader";
+}
+
+static TypeInfo generic_loader_info = {
+    .name = TYPE_GENERIC_LOADER,
+    .parent = TYPE_DEVICE,
+    .instance_size = sizeof(GenericLoaderState),
+    .class_init = generic_loader_class_init,
+};
+
+static void generic_loader_register_type(void)
+{
+    type_register_static(&generic_loader_info);
+}
+
+type_init(generic_loader_register_type)

include/hw/core/generic-loader.h

@@ -0,0 +1,46 @@
+/*
+ * Generic Loader
+ *
+ * Copyright (C) 2014 Li Guang
+ * Written by Li Guang <lig.fnst@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.
+ */
+
+#ifndef GENERIC_LOADER_H
+#define GENERIC_LOADER_H
+
+#include "elf.h"
+
+typedef struct GenericLoaderState {
+    /* <private> */
+    DeviceState parent_obj;
+
+    /* <public> */
+    CPUState *cpu;
+
+    uint64_t addr;
+    uint64_t data;
+    uint8_t data_len;
+    uint32_t cpu_num;
+
+    char *file;
+
+    bool force_raw;
+    bool data_be;
+    bool set_pc;
+} GenericLoaderState;
+
+#define TYPE_GENERIC_LOADER "loader"
+#define GENERIC_LOADER(obj) OBJECT_CHECK(GenericLoaderState, (obj), \
+                                         TYPE_GENERIC_LOADER)
+
+#endif