diff options
Diffstat (limited to 'drivers/firmware/efi/libstub')
| -rw-r--r-- | drivers/firmware/efi/libstub/Makefile | 10 | ||||
| -rw-r--r-- | drivers/firmware/efi/libstub/riscv-stub.c | 109 |
2 files changed, 119 insertions, 0 deletions
diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile index 296b18fbd7a2..e9fc2ddabd5f 100644 --- a/drivers/firmware/efi/libstub/Makefile +++ b/drivers/firmware/efi/libstub/Makefile @@ -22,6 +22,8 @@ cflags-$(CONFIG_ARM64) := $(subst $(CC_FLAGS_FTRACE),,$(KBUILD_CFLAGS)) \ cflags-$(CONFIG_ARM) := $(subst $(CC_FLAGS_FTRACE),,$(KBUILD_CFLAGS)) \ -fno-builtin -fpic \ $(call cc-option,-mno-single-pic-base) +cflags-$(CONFIG_RISCV) := $(subst $(CC_FLAGS_FTRACE),,$(KBUILD_CFLAGS)) \ + -fpic cflags-$(CONFIG_EFI_GENERIC_STUB) += -I$(srctree)/scripts/dtc/libfdt @@ -63,6 +65,7 @@ lib-$(CONFIG_EFI_GENERIC_STUB) += efi-stub.o fdt.o string.o \ lib-$(CONFIG_ARM) += arm32-stub.o lib-$(CONFIG_ARM64) += arm64-stub.o lib-$(CONFIG_X86) += x86-stub.o +lib-$(CONFIG_RISCV) += riscv-stub.o CFLAGS_arm32-stub.o := -DTEXT_OFFSET=$(TEXT_OFFSET) CFLAGS_arm64-stub.o := -DTEXT_OFFSET=$(TEXT_OFFSET) @@ -106,6 +109,13 @@ STUBCOPY_FLAGS-$(CONFIG_ARM64) += --prefix-alloc-sections=.init \ --prefix-symbols=__efistub_ STUBCOPY_RELOC-$(CONFIG_ARM64) := R_AARCH64_ABS +# For RISC-V, we don't need anything special other than arm64. Keep all the +# symbols in .init section and make sure that no absolute symbols references +# doesn't exist. +STUBCOPY_FLAGS-$(CONFIG_RISCV) += --prefix-alloc-sections=.init \ + --prefix-symbols=__efistub_ +STUBCOPY_RELOC-$(CONFIG_RISCV) := R_RISCV_HI20 + $(obj)/%.stub.o: $(obj)/%.o FORCE $(call if_changed,stubcopy) diff --git a/drivers/firmware/efi/libstub/riscv-stub.c b/drivers/firmware/efi/libstub/riscv-stub.c new file mode 100644 index 000000000000..380e4e251399 --- /dev/null +++ b/drivers/firmware/efi/libstub/riscv-stub.c @@ -0,0 +1,109 @@ +// 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; +} |