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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2020 Western Digital Corporation or its affiliates.
*/
#include <linux/efi.h>
#include <linux/libfdt.h>
#include <asm/efi.h>
#include <asm/sections.h>
#include "efistub.h"
/*
* RISC-V requires the kernel image to placed 2 MB aligned base for 64 bit and
* 4MB for 32 bit.
*/
#ifdef CONFIG_64BIT
#define MIN_KIMG_ALIGN SZ_2M
#else
#define MIN_KIMG_ALIGN SZ_4M
#endif
typedef void __noreturn (*jump_kernel_func)(unsigned int, unsigned long);
static u32 hartid;
static u32 get_boot_hartid_from_fdt(void)
{
const void *fdt;
int chosen_node, len;
const fdt32_t *prop;
fdt = get_efi_config_table(DEVICE_TREE_GUID);
if (!fdt)
return U32_MAX;
chosen_node = fdt_path_offset(fdt, "/chosen");
if (chosen_node < 0)
return U32_MAX;
prop = fdt_getprop((void *)fdt, chosen_node, "boot-hartid", &len);
if (!prop || len != sizeof(u32))
return U32_MAX;
return fdt32_to_cpu(*prop);
}
efi_status_t check_platform_features(void)
{
hartid = get_boot_hartid_from_fdt();
if (hartid == U32_MAX) {
efi_err("/chosen/boot-hartid missing or invalid!\n");
return EFI_UNSUPPORTED;
}
return EFI_SUCCESS;
}
void __noreturn efi_enter_kernel(unsigned long entrypoint, unsigned long fdt,
unsigned long fdt_size)
{
unsigned long stext_offset = _start_kernel - _start;
unsigned long kernel_entry = entrypoint + stext_offset;
jump_kernel_func jump_kernel = (jump_kernel_func)kernel_entry;
/*
* Jump to real kernel here with following constraints.
* 1. MMU should be disabled.
* 2. a0 should contain hartid
* 3. a1 should DT address
*/
csr_write(CSR_SATP, 0);
jump_kernel(hartid, fdt);
}
efi_status_t handle_kernel_image(unsigned long *image_addr,
unsigned long *image_size,
unsigned long *reserve_addr,
unsigned long *reserve_size,
efi_loaded_image_t *image)
{
unsigned long kernel_size = 0;
unsigned long preferred_addr;
efi_status_t status;
kernel_size = _edata - _start;
*image_addr = (unsigned long)_start;
*image_size = kernel_size + (_end - _edata);
/*
* RISC-V kernel maps PAGE_OFFSET virtual address to the same physical
* address where kernel is booted. That's why kernel should boot from
* as low as possible to avoid wastage of memory. Currently, dram_base
* is occupied by the firmware. So the preferred address for kernel to
* boot is next aligned address. If preferred address is not available,
* relocate_kernel will fall back to efi_low_alloc_above to allocate
* lowest possible memory region as long as the address and size meets
* the alignment constraints.
*/
preferred_addr = MIN_KIMG_ALIGN;
status = efi_relocate_kernel(image_addr, kernel_size, *image_size,
preferred_addr, MIN_KIMG_ALIGN, 0x0);
if (status != EFI_SUCCESS) {
efi_err("Failed to relocate kernel\n");
*image_size = 0;
}
return status;
}
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