qemu-patch-raspberry4/hw/arm/armv7m.c
Peter Crosthwaite 7ef295ea5b loader: Add data swap option to load-elf
Some CPUs are of an opposite data-endianness to other components in the
system. Sometimes elfs have the data sections layed out with this CPU
data-endianness accounting for when loaded via the CPU, so byte swaps
(relative to other system components) will occur.

The leading example, is ARM's BE32 mode, which is is basically LE with
address manipulation on half-word and byte accesses to access the
hw/byte reversed address. This means that word data is invariant
across LE and BE32. This also means that instructions are still LE.
The expectation is that the elf will be loaded via the CPU in this
endianness scheme, which means the data in the elf is reversed at
compile time.

As QEMU loads via the system memory directly, rather than the CPU, we
need a mechanism to reverse elf data endianness to implement this
possibility.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Crosthwaite <crosthwaite.peter@gmail.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2016-03-04 11:30:21 +00:00

263 lines
6.6 KiB
C

/*
* ARMV7M System emulation.
*
* Copyright (c) 2006-2007 CodeSourcery.
* Written by Paul Brook
*
* This code is licensed under the GPL.
*/
#include "qemu/osdep.h"
#include "hw/sysbus.h"
#include "hw/arm/arm.h"
#include "hw/loader.h"
#include "elf.h"
#include "sysemu/qtest.h"
#include "qemu/error-report.h"
/* Bitbanded IO. Each word corresponds to a single bit. */
/* Get the byte address of the real memory for a bitband access. */
static inline uint32_t bitband_addr(void * opaque, uint32_t addr)
{
uint32_t res;
res = *(uint32_t *)opaque;
res |= (addr & 0x1ffffff) >> 5;
return res;
}
static uint32_t bitband_readb(void *opaque, hwaddr offset)
{
uint8_t v;
cpu_physical_memory_read(bitband_addr(opaque, offset), &v, 1);
return (v & (1 << ((offset >> 2) & 7))) != 0;
}
static void bitband_writeb(void *opaque, hwaddr offset,
uint32_t value)
{
uint32_t addr;
uint8_t mask;
uint8_t v;
addr = bitband_addr(opaque, offset);
mask = (1 << ((offset >> 2) & 7));
cpu_physical_memory_read(addr, &v, 1);
if (value & 1)
v |= mask;
else
v &= ~mask;
cpu_physical_memory_write(addr, &v, 1);
}
static uint32_t bitband_readw(void *opaque, hwaddr offset)
{
uint32_t addr;
uint16_t mask;
uint16_t v;
addr = bitband_addr(opaque, offset) & ~1;
mask = (1 << ((offset >> 2) & 15));
mask = tswap16(mask);
cpu_physical_memory_read(addr, &v, 2);
return (v & mask) != 0;
}
static void bitband_writew(void *opaque, hwaddr offset,
uint32_t value)
{
uint32_t addr;
uint16_t mask;
uint16_t v;
addr = bitband_addr(opaque, offset) & ~1;
mask = (1 << ((offset >> 2) & 15));
mask = tswap16(mask);
cpu_physical_memory_read(addr, &v, 2);
if (value & 1)
v |= mask;
else
v &= ~mask;
cpu_physical_memory_write(addr, &v, 2);
}
static uint32_t bitband_readl(void *opaque, hwaddr offset)
{
uint32_t addr;
uint32_t mask;
uint32_t v;
addr = bitband_addr(opaque, offset) & ~3;
mask = (1 << ((offset >> 2) & 31));
mask = tswap32(mask);
cpu_physical_memory_read(addr, &v, 4);
return (v & mask) != 0;
}
static void bitband_writel(void *opaque, hwaddr offset,
uint32_t value)
{
uint32_t addr;
uint32_t mask;
uint32_t v;
addr = bitband_addr(opaque, offset) & ~3;
mask = (1 << ((offset >> 2) & 31));
mask = tswap32(mask);
cpu_physical_memory_read(addr, &v, 4);
if (value & 1)
v |= mask;
else
v &= ~mask;
cpu_physical_memory_write(addr, &v, 4);
}
static const MemoryRegionOps bitband_ops = {
.old_mmio = {
.read = { bitband_readb, bitband_readw, bitband_readl, },
.write = { bitband_writeb, bitband_writew, bitband_writel, },
},
.endianness = DEVICE_NATIVE_ENDIAN,
};
#define TYPE_BITBAND "ARM,bitband-memory"
#define BITBAND(obj) OBJECT_CHECK(BitBandState, (obj), TYPE_BITBAND)
typedef struct {
/*< private >*/
SysBusDevice parent_obj;
/*< public >*/
MemoryRegion iomem;
uint32_t base;
} BitBandState;
static int bitband_init(SysBusDevice *dev)
{
BitBandState *s = BITBAND(dev);
memory_region_init_io(&s->iomem, OBJECT(s), &bitband_ops, &s->base,
"bitband", 0x02000000);
sysbus_init_mmio(dev, &s->iomem);
return 0;
}
static void armv7m_bitband_init(void)
{
DeviceState *dev;
dev = qdev_create(NULL, TYPE_BITBAND);
qdev_prop_set_uint32(dev, "base", 0x20000000);
qdev_init_nofail(dev);
sysbus_mmio_map(SYS_BUS_DEVICE(dev), 0, 0x22000000);
dev = qdev_create(NULL, TYPE_BITBAND);
qdev_prop_set_uint32(dev, "base", 0x40000000);
qdev_init_nofail(dev);
sysbus_mmio_map(SYS_BUS_DEVICE(dev), 0, 0x42000000);
}
/* Board init. */
static void armv7m_reset(void *opaque)
{
ARMCPU *cpu = opaque;
cpu_reset(CPU(cpu));
}
/* Init CPU and memory for a v7-M based board.
mem_size is in bytes.
Returns the NVIC array. */
DeviceState *armv7m_init(MemoryRegion *system_memory, int mem_size, int num_irq,
const char *kernel_filename, const char *cpu_model)
{
ARMCPU *cpu;
CPUARMState *env;
DeviceState *nvic;
int image_size;
uint64_t entry;
uint64_t lowaddr;
int big_endian;
MemoryRegion *hack = g_new(MemoryRegion, 1);
if (cpu_model == NULL) {
cpu_model = "cortex-m3";
}
cpu = cpu_arm_init(cpu_model);
if (cpu == NULL) {
fprintf(stderr, "Unable to find CPU definition\n");
exit(1);
}
env = &cpu->env;
armv7m_bitband_init();
nvic = qdev_create(NULL, "armv7m_nvic");
qdev_prop_set_uint32(nvic, "num-irq", num_irq);
env->nvic = nvic;
qdev_init_nofail(nvic);
sysbus_connect_irq(SYS_BUS_DEVICE(nvic), 0,
qdev_get_gpio_in(DEVICE(cpu), ARM_CPU_IRQ));
#ifdef TARGET_WORDS_BIGENDIAN
big_endian = 1;
#else
big_endian = 0;
#endif
if (!kernel_filename && !qtest_enabled()) {
fprintf(stderr, "Guest image must be specified (using -kernel)\n");
exit(1);
}
if (kernel_filename) {
image_size = load_elf(kernel_filename, NULL, NULL, &entry, &lowaddr,
NULL, big_endian, EM_ARM, 1, 0);
if (image_size < 0) {
image_size = load_image_targphys(kernel_filename, 0, mem_size);
lowaddr = 0;
}
if (image_size < 0) {
error_report("Could not load kernel '%s'", kernel_filename);
exit(1);
}
}
/* Hack to map an additional page of ram at the top of the address
space. This stops qemu complaining about executing code outside RAM
when returning from an exception. */
memory_region_init_ram(hack, NULL, "armv7m.hack", 0x1000, &error_fatal);
vmstate_register_ram_global(hack);
memory_region_add_subregion(system_memory, 0xfffff000, hack);
qemu_register_reset(armv7m_reset, cpu);
return nvic;
}
static Property bitband_properties[] = {
DEFINE_PROP_UINT32("base", BitBandState, base, 0),
DEFINE_PROP_END_OF_LIST(),
};
static void bitband_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);
k->init = bitband_init;
dc->props = bitband_properties;
}
static const TypeInfo bitband_info = {
.name = TYPE_BITBAND,
.parent = TYPE_SYS_BUS_DEVICE,
.instance_size = sizeof(BitBandState),
.class_init = bitband_class_init,
};
static void armv7m_register_types(void)
{
type_register_static(&bitband_info);
}
type_init(armv7m_register_types)