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// SPDX-License-Identifier: GPL-2.0
#include <linux/efi.h>
#include <linux/pe.h>
#include <asm/efi.h>
#include <linux/unaligned.h>
#include "efistub.h"
static unsigned long alloc_preferred_address(unsigned long alloc_size)
{
#ifdef EFI_KIMG_PREFERRED_ADDRESS
efi_physical_addr_t efi_addr = EFI_KIMG_PREFERRED_ADDRESS;
if (efi_bs_call(allocate_pages, EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
alloc_size / EFI_PAGE_SIZE, &efi_addr) == EFI_SUCCESS)
return efi_addr;
#endif
return ULONG_MAX;
}
void __weak efi_cache_sync_image(unsigned long image_base,
unsigned long alloc_size)
{
// Provided by the arch to perform the cache maintenance necessary for
// executable code loaded into memory to be safe for execution.
}
struct screen_info *alloc_screen_info(void)
{
return __alloc_screen_info();
}
asmlinkage efi_status_t __efiapi
efi_zboot_entry(efi_handle_t handle, efi_system_table_t *systab)
{
char *cmdline_ptr __free(efi_pool) = NULL;
unsigned long image_base, alloc_size;
efi_loaded_image_t *image;
efi_status_t status;
WRITE_ONCE(efi_system_table, systab);
status = efi_bs_call(handle_protocol, handle,
&LOADED_IMAGE_PROTOCOL_GUID, (void **)&image);
if (status != EFI_SUCCESS) {
efi_err("Failed to locate parent's loaded image protocol\n");
return status;
}
status = efi_handle_cmdline(image, &cmdline_ptr);
if (status != EFI_SUCCESS)
return status;
efi_info("Decompressing Linux Kernel...\n");
status = efi_zboot_decompress_init(&alloc_size);
if (status != EFI_SUCCESS)
return status;
// If the architecture has a preferred address for the image,
// try that first.
image_base = alloc_preferred_address(alloc_size);
if (image_base == ULONG_MAX) {
unsigned long min_kimg_align = efi_get_kimg_min_align();
u32 seed = U32_MAX;
if (!IS_ENABLED(CONFIG_RANDOMIZE_BASE)) {
// Setting the random seed to 0x0 is the same as
// allocating as low as possible
seed = 0;
} else if (efi_nokaslr) {
efi_info("KASLR disabled on kernel command line\n");
} else {
status = efi_get_random_bytes(sizeof(seed), (u8 *)&seed);
if (status == EFI_NOT_FOUND) {
efi_info("EFI_RNG_PROTOCOL unavailable\n");
efi_nokaslr = true;
} else if (status != EFI_SUCCESS) {
efi_err("efi_get_random_bytes() failed (0x%lx)\n",
status);
efi_nokaslr = true;
}
}
status = efi_random_alloc(alloc_size, min_kimg_align, &image_base,
seed, EFI_LOADER_CODE, 0, EFI_ALLOC_LIMIT);
if (status != EFI_SUCCESS) {
efi_err("Failed to allocate memory\n");
return status;
}
}
// Decompress the payload into the newly allocated buffer
status = efi_zboot_decompress((void *)image_base, alloc_size) ?:
efi_stub_common(handle, image, image_base, cmdline_ptr);
efi_free(alloc_size, image_base);
return status;
}
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