On Wed, 2020-04-22 at 19:24 +0200, Ard Biesheuvel wrote: > From: Atish Patra <atish.patra@xxxxxxx> > > Add a RISC-V architecture specific stub code that actually copies the > actual kernel image to a valid address and jump to it after boot > services > are terminated. Enable UEFI related kernel configs as well for RISC- > V. > > Signed-off-by: Atish Patra <atish.patra@xxxxxxx> > Link: > https://lore.kernel.org/r/20200421033336.9663-4-atish.patra@xxxxxxx > [ardb: - move hartid fetch into check_platform_features() > - use image_size not reserve_size > - moved asm/efi.h addition into separate patch ] > Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx> > --- > arch/riscv/Kconfig | 20 ++++ > arch/riscv/Makefile | 1 + > arch/riscv/configs/defconfig | 1 + > drivers/firmware/efi/Kconfig | 4 +- > drivers/firmware/efi/libstub/Makefile | 10 ++ > drivers/firmware/efi/libstub/riscv-stub.c | 109 ++++++++++++++++++++ > 6 files changed, 143 insertions(+), 2 deletions(-) > > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig > index f05dd09acd48..54c78cafcd35 100644 > --- a/arch/riscv/Kconfig > +++ b/arch/riscv/Kconfig > @@ -379,10 +379,30 @@ config CMDLINE_FORCE > > endchoice > > +config EFI_STUB > + bool > + > +config EFI > + bool "UEFI runtime support" > + depends on OF > + select LIBFDT > + select UCS2_STRING > + select EFI_PARAMS_FROM_FDT > + select EFI_STUB > + select EFI_GENERIC_STUB As palmer suggested RISCV_ISA_C should be selected here to avoid unintentional errors. Otherwise, every looks good. > + default y > + help > + This option provides support for runtime services provided > + by UEFI firmware (such as non-volatile variables, realtime > + clock, and platform reset). A UEFI stub is also provided to > + allow the kernel to be booted as an EFI application. This > + is only useful on systems that have UEFI firmware. > + > endmenu > > menu "Power management options" > > source "kernel/power/Kconfig" > +source "drivers/firmware/Kconfig" > > endmenu > diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile > index fb6e37db836d..079435804d6d 100644 > --- a/arch/riscv/Makefile > +++ b/arch/riscv/Makefile > @@ -80,6 +80,7 @@ head-y := arch/riscv/kernel/head.o > core-y += arch/riscv/ > > libs-y += arch/riscv/lib/ > +core-$(CONFIG_EFI_STUB) += > $(objtree)/drivers/firmware/efi/libstub/lib.a > > PHONY += vdso_install > vdso_install: > diff --git a/arch/riscv/configs/defconfig > b/arch/riscv/configs/defconfig > index 4da4886246a4..ae69e12d306a 100644 > --- a/arch/riscv/configs/defconfig > +++ b/arch/riscv/configs/defconfig > @@ -129,3 +129,4 @@ CONFIG_DEBUG_BLOCK_EXT_DEVT=y > # CONFIG_RUNTIME_TESTING_MENU is not set > CONFIG_MEMTEST=y > # CONFIG_SYSFS_SYSCALL is not set > +CONFIG_EFI=y > diff --git a/drivers/firmware/efi/Kconfig > b/drivers/firmware/efi/Kconfig > index 4e788dd55b03..8bfc17381b29 100644 > --- a/drivers/firmware/efi/Kconfig > +++ b/drivers/firmware/efi/Kconfig > @@ -111,7 +111,7 @@ config EFI_GENERIC_STUB > > config EFI_ARMSTUB_DTB_LOADER > bool "Enable the DTB loader" > - depends on EFI_GENERIC_STUB > + depends on EFI_GENERIC_STUB && !RISCV > default y > help > Select this config option to add support for the dtb= command > @@ -126,7 +126,7 @@ config EFI_ARMSTUB_DTB_LOADER > > config EFI_GENERIC_STUB_INITRD_CMDLINE_LOADER > bool "Enable the command line initrd loader" > - depends on EFI_GENERIC_STUB > + depends on EFI_GENERIC_STUB && !RISCV > default y > help > Select this config option to add support for the initrd= > command > diff --git a/drivers/firmware/efi/libstub/Makefile > b/drivers/firmware/efi/libstub/Makefile > index 75cb2c3a1519..a4fd1b048e8c 100644 > --- a/drivers/firmware/efi/libstub/Makefile > +++ b/drivers/firmware/efi/libstub/Makefile > @@ -22,6 +22,8 @@ cflags-$(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 > > @@ -56,6 +58,7 @@ 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=$(TEXT_OFFSET) > > @@ -80,6 +83,13 @@ STUBCOPY_FLAGS-$(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..349646928e9b > --- /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) { > + pr_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 kernel_entry = entrypoint + (unsigned > long)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, > + unsigned long dram_base, > + 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 = round_up(dram_base, MIN_KIMG_ALIGN) + > MIN_KIMG_ALIGN; > + status = efi_relocate_kernel(image_addr, kernel_size, > *image_size, > + preferred_addr, MIN_KIMG_ALIGN, > dram_base); > + > + if (status != EFI_SUCCESS) { > + pr_efi_err("Failed to relocate kernel\n"); > + *image_size = 0; > + } > + return status; > +} -- Regards, Atish
