Staging
v0.7.0
v0.7.0
https://github.com/torvalds/linux
Tip revision: 45a3e24f65e90a047bef86f927ebdc4c710edaa1 authored by Linus Torvalds on 18 June 2023, 21:06:27 UTC
Linux 6.4-rc7
Linux 6.4-rc7
Tip revision: 45a3e24
riscv.c
// 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/unaligned.h>
#include "efistub.h"
typedef void __noreturn (*jump_kernel_func)(unsigned long, unsigned long);
static unsigned long hartid;
static int get_boot_hartid_from_fdt(void)
{
const void *fdt;
int chosen_node, len;
const void *prop;
fdt = get_efi_config_table(DEVICE_TREE_GUID);
if (!fdt)
return -EINVAL;
chosen_node = fdt_path_offset(fdt, "/chosen");
if (chosen_node < 0)
return -EINVAL;
prop = fdt_getprop((void *)fdt, chosen_node, "boot-hartid", &len);
if (!prop)
return -EINVAL;
if (len == sizeof(u32))
hartid = (unsigned long) fdt32_to_cpu(*(fdt32_t *)prop);
else if (len == sizeof(u64))
hartid = (unsigned long) fdt64_to_cpu(__get_unaligned_t(fdt64_t, prop));
else
return -EINVAL;
return 0;
}
static efi_status_t get_boot_hartid_from_efi(void)
{
efi_guid_t boot_protocol_guid = RISCV_EFI_BOOT_PROTOCOL_GUID;
struct riscv_efi_boot_protocol *boot_protocol;
efi_status_t status;
status = efi_bs_call(locate_protocol, &boot_protocol_guid, NULL,
(void **)&boot_protocol);
if (status != EFI_SUCCESS)
return status;
return efi_call_proto(boot_protocol, get_boot_hartid, &hartid);
}
efi_status_t check_platform_features(void)
{
efi_status_t status;
int ret;
status = get_boot_hartid_from_efi();
if (status != EFI_SUCCESS) {
ret = get_boot_hartid_from_fdt();
if (ret) {
efi_err("Failed to get boot hartid!\n");
return EFI_UNSUPPORTED;
}
}
return EFI_SUCCESS;
}
unsigned long __weak stext_offset(void)
{
/*
* This fallback definition is used by the EFI zboot stub, which loads
* the entire image so it can branch via the image header at offset #0.
*/
return 0;
}
void __noreturn efi_enter_kernel(unsigned long entrypoint, unsigned long fdt,
unsigned long fdt_size)
{
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);
}