| Message ID | 20200421033336.9663-4-atish.patra@wdc.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add UEFI support for RISC-V | expand |
On Mon, 20 Apr 2020 20:33:36 PDT (-0700), Atish Patra wrote: > 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@wdc.com> > --- > arch/riscv/Kconfig | 20 ++++ > arch/riscv/Makefile | 1 + > arch/riscv/configs/defconfig | 1 + > arch/riscv/include/asm/efi.h | 44 +++++++++ > drivers/firmware/efi/Kconfig | 2 +- > drivers/firmware/efi/libstub/Makefile | 10 ++ > drivers/firmware/efi/libstub/riscv-stub.c | 106 ++++++++++++++++++++++ > 7 files changed, 183 insertions(+), 1 deletion(-) > create mode 100644 arch/riscv/include/asm/efi.h > create mode 100644 drivers/firmware/efi/libstub/riscv-stub.c > > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig > index f39e326a7a42..eb4f41c8f3ce 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 So I guess just "select RISCV_ISA_C" would be sufficient to make this work, but I still feel flike an explicit "c.li" is saner. > + 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/arch/riscv/include/asm/efi.h b/arch/riscv/include/asm/efi.h > new file mode 100644 > index 000000000000..62d7d5eafed8 > --- /dev/null > +++ b/arch/riscv/include/asm/efi.h > @@ -0,0 +1,44 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +/* > + * Copyright (C) 2020 Western Digital Corporation or its affiliates. > + * Based on arch/arm64/include/asm/efi.h > + */ > +#ifndef _ASM_EFI_H > +#define _ASM_EFI_H > + > +#include <asm/io.h> > +#include <asm/mmu_context.h> > +#include <asm/ptrace.h> > +#include <asm/tlbflush.h> > + > +#define VA_BITS_MIN 39 I don't see this actually being used, but if it's releant to some macro that I'm missing then EFI support should depend on rv64. > + > +/* on RISC-V, the FDT may be located anywhere in system RAM */ > +static inline unsigned long efi_get_max_fdt_addr(unsigned long dram_base) > +{ > + return ULONG_MAX; > +} > + > +/* Load initrd at enough distance from DRAM start */ > +static inline unsigned long efi_get_max_initrd_addr(unsigned long dram_base, > + unsigned long image_addr) > +{ > + return dram_base + SZ_256M; > +} > + > +#define efi_bs_call(func, ...) efi_system_table()->boottime->func(__VA_ARGS__) > +#define efi_rt_call(func, ...) efi_system_table()->runtime->func(__VA_ARGS__) > +#define efi_is_native() (true) > + > +#define efi_table_attr(inst, attr) (inst->attr) > + > +#define efi_call_proto(inst, func, ...) inst->func(inst, ##__VA_ARGS__) > + > +#define alloc_screen_info(x...) (&screen_info) > +extern char stext_offset[]; > + > +static inline void free_screen_info(struct screen_info *si) > +{ > +} > + > +#endif /* _ASM_EFI_H */ > diff --git a/drivers/firmware/efi/Kconfig b/drivers/firmware/efi/Kconfig > index 2a2b2b96a1dc..fcdc789d3f87 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 > diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile > index 0f57293d777e..eb365c55c0fe 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 > > @@ -57,6 +59,7 @@ 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=$(TEXT_OFFSET) > > @@ -100,6 +103,13 @@ STUBCOPY_FLAGS-$(CONFIG_X86) += --rename-section .bss=.bss.efistub,load,alloc > STUBCOPY_RELOC-$(CONFIG_X86_32) := R_386_32 > STUBCOPY_RELOC-$(CONFIG_X86_64) := R_X86_64_64 > > +# 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..bd1d6fed8754 > --- /dev/null > +++ b/drivers/firmware/efi/libstub/riscv-stub.c > @@ -0,0 +1,106 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Copyright (C) 2013, 2014 Linaro Ltd; <roy.franz@linaro.org> > + * Copyright (C) 2020 Western Digital Corporation or its affiliates. > + * > + * This file implements the EFI boot stub for the RISC-V kernel. > + * Adapted from ARM64 version at drivers/firmware/efi/libstub/arm64-stub.c. > + */ > + > +#include <linux/efi.h> > +#include <linux/libfdt.h> > +#include <linux/libfdt_env.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 __attribute__((noreturn)) void (*jump_kernel_func)(unsigned int, > + unsigned long); > +efi_status_t check_platform_features(void) > +{ > + return EFI_SUCCESS; > +} > + > +static u32 get_boot_hartid_from_fdt(unsigned long fdt) > +{ > + int chosen_node, len; > + const fdt32_t *prop; > + > + chosen_node = fdt_path_offset((void *)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); > +} > + > +/* > + * Jump to real kernel here with following constraints. > + * 1. MMU should be disabled. > + * 2. a0 should contain hartid > + * 3. a1 should DT address > + */ > +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; > + u32 hartid = get_boot_hartid_from_fdt(fdt); > + > + if (hartid == U32_MAX) > + /* We can not use panic or BUG at this point */ > + __asm__ __volatile__ ("ebreak"); > + /* Disable MMU */ > + 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) > +{ > + efi_status_t status; > + unsigned long kernel_size = 0; > + unsigned long preferred_addr; > + > + kernel_size = _edata - _start; > + *reserve_size = kernel_size + (_end - _edata); > + *image_addr = (unsigned long)_start; > + > + /* > + * 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, *reserve_size, > + preferred_addr, MIN_KIMG_ALIGN, dram_base); > + > + if (status != EFI_SUCCESS) { > + pr_efi_err("Failed to relocate kernel\n"); > + *reserve_size = 0; > + return status; > + } > + > + return EFI_SUCCESS; > +}
On Tue, 2020-04-21 at 13:08 -0700, Palmer Dabbelt wrote: > On Mon, 20 Apr 2020 20:33:36 PDT (-0700), Atish Patra wrote: > > 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@wdc.com> > > --- > > arch/riscv/Kconfig | 20 ++++ > > arch/riscv/Makefile | 1 + > > arch/riscv/configs/defconfig | 1 + > > arch/riscv/include/asm/efi.h | 44 +++++++++ > > drivers/firmware/efi/Kconfig | 2 +- > > drivers/firmware/efi/libstub/Makefile | 10 ++ > > drivers/firmware/efi/libstub/riscv-stub.c | 106 > > ++++++++++++++++++++++ > > 7 files changed, 183 insertions(+), 1 deletion(-) > > create mode 100644 arch/riscv/include/asm/efi.h > > create mode 100644 drivers/firmware/efi/libstub/riscv-stub.c > > > > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig > > index f39e326a7a42..eb4f41c8f3ce 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 > > So I guess just "select RISCV_ISA_C" would be sufficient to make this > work, but > I still feel flike an explicit "c.li" is saner. > will fix it. > > + 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/arch/riscv/include/asm/efi.h > > b/arch/riscv/include/asm/efi.h > > new file mode 100644 > > index 000000000000..62d7d5eafed8 > > --- /dev/null > > +++ b/arch/riscv/include/asm/efi.h > > @@ -0,0 +1,44 @@ > > +/* SPDX-License-Identifier: GPL-2.0 */ > > +/* > > + * Copyright (C) 2020 Western Digital Corporation or its > > affiliates. > > + * Based on arch/arm64/include/asm/efi.h > > + */ > > +#ifndef _ASM_EFI_H > > +#define _ASM_EFI_H > > + > > +#include <asm/io.h> > > +#include <asm/mmu_context.h> > > +#include <asm/ptrace.h> > > +#include <asm/tlbflush.h> > > + > > +#define VA_BITS_MIN 39 > > I don't see this actually being used, but if it's releant to some > macro that > I'm missing then EFI support should depend on rv64. > Yeah. This was a left over from the previous patch. Thanks for pointing out. I will remove it. > > + > > +/* on RISC-V, the FDT may be located anywhere in system RAM */ > > +static inline unsigned long efi_get_max_fdt_addr(unsigned long > > dram_base) > > +{ > > + return ULONG_MAX; > > +} > > + > > +/* Load initrd at enough distance from DRAM start */ > > +static inline unsigned long efi_get_max_initrd_addr(unsigned long > > dram_base, > > + unsigned long > > image_addr) > > +{ > > + return dram_base + SZ_256M; > > +} > > + > > +#define efi_bs_call(func, ...) efi_system_table()->boottime- > > >func(__VA_ARGS__) > > +#define efi_rt_call(func, ...) efi_system_table()->runtime- > > >func(__VA_ARGS__) > > +#define efi_is_native() (true) > > + > > +#define efi_table_attr(inst, attr) (inst->attr) > > + > > +#define efi_call_proto(inst, func, ...) inst->func(inst, > > ##__VA_ARGS__) > > + > > +#define alloc_screen_info(x...) (&screen_info) > > +extern char stext_offset[]; > > + > > +static inline void free_screen_info(struct screen_info *si) > > +{ > > +} > > + > > +#endif /* _ASM_EFI_H */ > > diff --git a/drivers/firmware/efi/Kconfig > > b/drivers/firmware/efi/Kconfig > > index 2a2b2b96a1dc..fcdc789d3f87 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 > > diff --git a/drivers/firmware/efi/libstub/Makefile > > b/drivers/firmware/efi/libstub/Makefile > > index 0f57293d777e..eb365c55c0fe 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 > > > > @@ -57,6 +59,7 @@ 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=$(TEXT_OFFSET) > > > > @@ -100,6 +103,13 @@ STUBCOPY_FLAGS-$(CONFIG_X86) += --rename- > > section .bss=.bss.efistub,load,alloc > > STUBCOPY_RELOC-$(CONFIG_X86_32) := R_386_32 > > STUBCOPY_RELOC-$(CONFIG_X86_64) := R_X86_64_64 > > > > +# 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..bd1d6fed8754 > > --- /dev/null > > +++ b/drivers/firmware/efi/libstub/riscv-stub.c > > @@ -0,0 +1,106 @@ > > +// SPDX-License-Identifier: GPL-2.0 > > +/* > > + * Copyright (C) 2013, 2014 Linaro Ltd; <roy.franz@linaro.org> > > + * Copyright (C) 2020 Western Digital Corporation or its > > affiliates. > > + * > > + * This file implements the EFI boot stub for the RISC-V kernel. > > + * Adapted from ARM64 version at > > drivers/firmware/efi/libstub/arm64-stub.c. > > + */ > > + > > +#include <linux/efi.h> > > +#include <linux/libfdt.h> > > +#include <linux/libfdt_env.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 __attribute__((noreturn)) void > > (*jump_kernel_func)(unsigned int, > > + unsigned > > long); > > +efi_status_t check_platform_features(void) > > +{ > > + return EFI_SUCCESS; > > +} > > + > > +static u32 get_boot_hartid_from_fdt(unsigned long fdt) > > +{ > > + int chosen_node, len; > > + const fdt32_t *prop; > > + > > + chosen_node = fdt_path_offset((void *)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); > > +} > > + > > +/* > > + * Jump to real kernel here with following constraints. > > + * 1. MMU should be disabled. > > + * 2. a0 should contain hartid > > + * 3. a1 should DT address > > + */ > > +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; > > + u32 hartid = get_boot_hartid_from_fdt(fdt); > > + > > + if (hartid == U32_MAX) > > + /* We can not use panic or BUG at this point */ > > + __asm__ __volatile__ ("ebreak"); > > + /* Disable MMU */ > > + 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) > > +{ > > + efi_status_t status; > > + unsigned long kernel_size = 0; > > + unsigned long preferred_addr; > > + > > + kernel_size = _edata - _start; > > + *reserve_size = kernel_size + (_end - _edata); > > + *image_addr = (unsigned long)_start; > > + > > + /* > > + * 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, > > *reserve_size, > > + preferred_addr, MIN_KIMG_ALIGN, > > dram_base); > > + > > + if (status != EFI_SUCCESS) { > > + pr_efi_err("Failed to relocate kernel\n"); > > + *reserve_size = 0; > > + return status; > > + } > > + > > + return EFI_SUCCESS; > > +}
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index f39e326a7a42..eb4f41c8f3ce 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 + 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/arch/riscv/include/asm/efi.h b/arch/riscv/include/asm/efi.h new file mode 100644 index 000000000000..62d7d5eafed8 --- /dev/null +++ b/arch/riscv/include/asm/efi.h @@ -0,0 +1,44 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2020 Western Digital Corporation or its affiliates. + * Based on arch/arm64/include/asm/efi.h + */ +#ifndef _ASM_EFI_H +#define _ASM_EFI_H + +#include <asm/io.h> +#include <asm/mmu_context.h> +#include <asm/ptrace.h> +#include <asm/tlbflush.h> + +#define VA_BITS_MIN 39 + +/* on RISC-V, the FDT may be located anywhere in system RAM */ +static inline unsigned long efi_get_max_fdt_addr(unsigned long dram_base) +{ + return ULONG_MAX; +} + +/* Load initrd at enough distance from DRAM start */ +static inline unsigned long efi_get_max_initrd_addr(unsigned long dram_base, + unsigned long image_addr) +{ + return dram_base + SZ_256M; +} + +#define efi_bs_call(func, ...) efi_system_table()->boottime->func(__VA_ARGS__) +#define efi_rt_call(func, ...) efi_system_table()->runtime->func(__VA_ARGS__) +#define efi_is_native() (true) + +#define efi_table_attr(inst, attr) (inst->attr) + +#define efi_call_proto(inst, func, ...) inst->func(inst, ##__VA_ARGS__) + +#define alloc_screen_info(x...) (&screen_info) +extern char stext_offset[]; + +static inline void free_screen_info(struct screen_info *si) +{ +} + +#endif /* _ASM_EFI_H */ diff --git a/drivers/firmware/efi/Kconfig b/drivers/firmware/efi/Kconfig index 2a2b2b96a1dc..fcdc789d3f87 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 diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile index 0f57293d777e..eb365c55c0fe 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 @@ -57,6 +59,7 @@ 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=$(TEXT_OFFSET) @@ -100,6 +103,13 @@ STUBCOPY_FLAGS-$(CONFIG_X86) += --rename-section .bss=.bss.efistub,load,alloc STUBCOPY_RELOC-$(CONFIG_X86_32) := R_386_32 STUBCOPY_RELOC-$(CONFIG_X86_64) := R_X86_64_64 +# 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..bd1d6fed8754 --- /dev/null +++ b/drivers/firmware/efi/libstub/riscv-stub.c @@ -0,0 +1,106 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2013, 2014 Linaro Ltd; <roy.franz@linaro.org> + * Copyright (C) 2020 Western Digital Corporation or its affiliates. + * + * This file implements the EFI boot stub for the RISC-V kernel. + * Adapted from ARM64 version at drivers/firmware/efi/libstub/arm64-stub.c. + */ + +#include <linux/efi.h> +#include <linux/libfdt.h> +#include <linux/libfdt_env.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 __attribute__((noreturn)) void (*jump_kernel_func)(unsigned int, + unsigned long); +efi_status_t check_platform_features(void) +{ + return EFI_SUCCESS; +} + +static u32 get_boot_hartid_from_fdt(unsigned long fdt) +{ + int chosen_node, len; + const fdt32_t *prop; + + chosen_node = fdt_path_offset((void *)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); +} + +/* + * Jump to real kernel here with following constraints. + * 1. MMU should be disabled. + * 2. a0 should contain hartid + * 3. a1 should DT address + */ +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; + u32 hartid = get_boot_hartid_from_fdt(fdt); + + if (hartid == U32_MAX) + /* We can not use panic or BUG at this point */ + __asm__ __volatile__ ("ebreak"); + /* Disable MMU */ + 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) +{ + efi_status_t status; + unsigned long kernel_size = 0; + unsigned long preferred_addr; + + kernel_size = _edata - _start; + *reserve_size = kernel_size + (_end - _edata); + *image_addr = (unsigned long)_start; + + /* + * 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, *reserve_size, + preferred_addr, MIN_KIMG_ALIGN, dram_base); + + if (status != EFI_SUCCESS) { + pr_efi_err("Failed to relocate kernel\n"); + *reserve_size = 0; + return status; + } + + return EFI_SUCCESS; +}
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@wdc.com> --- arch/riscv/Kconfig | 20 ++++ arch/riscv/Makefile | 1 + arch/riscv/configs/defconfig | 1 + arch/riscv/include/asm/efi.h | 44 +++++++++ drivers/firmware/efi/Kconfig | 2 +- drivers/firmware/efi/libstub/Makefile | 10 ++ drivers/firmware/efi/libstub/riscv-stub.c | 106 ++++++++++++++++++++++ 7 files changed, 183 insertions(+), 1 deletion(-) create mode 100644 arch/riscv/include/asm/efi.h create mode 100644 drivers/firmware/efi/libstub/riscv-stub.c