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hw: arm: boot: macho: support loading ramdisks

Ramdisks are loaded with -initrd. If you want to boot from a ramdisk, you also need to
add "rd=md0" to the boot args.
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zhuowei committed Jul 19, 2018
1 parent fa1625e commit 52895a031fa000b7d5721b8d96e29469a8bbb973
Showing with 45 additions and 0 deletions.
  1. +45 −0 hw/arm/boot.c
@@ -998,6 +998,30 @@ static void macho_highest_lowest(struct mach_header_64* mh, uint64_t *lowaddr, u
*lowaddr = low_addr_temp;
*highaddr = high_addr_temp;
}
#define xnu_kPropNameLength 32
struct xnu_DeviceTreeNodeProperty {
char name[xnu_kPropNameLength];
uint32_t length;
char value[];
};
static void macho_add_ramdisk_to_dtb(uint8_t* dtb_data, size_t dtb_size, uint64_t ramdisk_addr, uint64_t ramdisk_size) {
struct xnu_DeviceTreeNodeProperty* dtNode = NULL;
for (size_t i = 0; i < dtb_size; i++) {
if (strncmp((const char*)dtb_data + i, "MemoryMapReserved-0", xnu_kPropNameLength) == 0) {
dtNode = (struct xnu_DeviceTreeNodeProperty*)(dtb_data + i);
break;
}
}
if (!dtNode) {
fprintf(stderr, "Can't write device tree node for ramdisk!\n");
abort();
}
strncpy(dtNode->name, "RAMDisk", xnu_kPropNameLength);
uint64_t* valuePtr = (uint64_t*)&dtNode->value;
valuePtr[0] = ramdisk_addr;
valuePtr[1] = ramdisk_size;
}
#define VAtoPA(addr) (((addr) & 0x3fffffff) + mem_base + kernel_load_offset)
@@ -1043,13 +1067,34 @@ static uint64_t arm_load_macho(struct arm_boot_info *info, uint64_t *pentry, Add
ret = true;
uint64_t load_extra_offset = high_addr_temp;
uint64_t ramdisk_address = load_extra_offset;
gsize ramdisk_size = 0;
// load ramdisk if exists
if (info->initrd_filename) {
uint8_t* ramdisk_data = NULL;
if (g_file_get_contents(info->initrd_filename, (char**) &ramdisk_data, &ramdisk_size, NULL)) {
info->initrd_filename = NULL;
rom_add_blob_fixed_as("xnu_ramdisk", ramdisk_data, ramdisk_size, VAtoPA(ramdisk_address), as);
load_extra_offset = (load_extra_offset + ramdisk_size + 0xffffull) & ~0xffffull;
g_free(ramdisk_data);
} else {
fprintf(stderr, "ramdisk failed?!\n");
abort();
}
}
uint64_t dtb_address = load_extra_offset;
gsize dtb_size = 0;
// load device tree
if (info->dtb_filename) {
uint8_t* dtb_data = NULL;
if (g_file_get_contents(info->dtb_filename, (char**) &dtb_data, &dtb_size, NULL)) {
info->dtb_filename = NULL;
if (ramdisk_size != 0) {
macho_add_ramdisk_to_dtb(dtb_data, dtb_size, VAtoPA(ramdisk_address), ramdisk_size);
}
rom_add_blob_fixed_as("xnu_dtb", dtb_data, dtb_size, VAtoPA(dtb_address), as);
load_extra_offset = (load_extra_offset + dtb_size + 0xffffull) & ~0xffffull;
g_free(dtb_data);

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