On Wed, 22 Apr 2020 at 20:48, Atish Patra <Atish.Patra@xxxxxxx> wrote: > > 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. > Ah, I must have misunderstood. I thought using c.li instead of li was sufficient here. In any case, once Palmer confirms that he is ok with the approach I suggested, he can fix that up when applying the patches. Thanks, Ard. > > + 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
