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