| Message ID | 20200226011037.7179-5-atish.patra@wdc.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add UEFI support for RISC-V | expand |
On Wed, 26 Feb 2020 at 02:10, Atish Patra <atish.patra@wdc.com> wrote: > > Linux kernel Image can appear as an EFI application With appropriate > PE/COFF header fields in the beginning of the Image header. An EFI > application loader can directly load a Linux kernel Image and an EFI > stub residing in kernel can boot Linux kernel directly. > > Add the necessary PE/COFF header. > > Signed-off-by: Atish Patra <atish.patra@wdc.com> > --- > arch/riscv/include/asm/Kbuild | 1 - > arch/riscv/include/asm/sections.h | 13 ++++ > arch/riscv/kernel/Makefile | 4 ++ > arch/riscv/kernel/efi-header.S | 107 ++++++++++++++++++++++++++++++ > arch/riscv/kernel/head.S | 15 +++++ > arch/riscv/kernel/image-vars.h | 52 +++++++++++++++ > arch/riscv/kernel/vmlinux.lds.S | 27 ++++++-- > 7 files changed, 212 insertions(+), 7 deletions(-) > create mode 100644 arch/riscv/include/asm/sections.h > create mode 100644 arch/riscv/kernel/efi-header.S > create mode 100644 arch/riscv/kernel/image-vars.h > > diff --git a/arch/riscv/include/asm/Kbuild b/arch/riscv/include/asm/Kbuild > index 517394390106..ef797fe44934 100644 > --- a/arch/riscv/include/asm/Kbuild > +++ b/arch/riscv/include/asm/Kbuild > @@ -24,7 +24,6 @@ generic-y += local64.h > generic-y += mm-arch-hooks.h > generic-y += percpu.h > generic-y += preempt.h > -generic-y += sections.h > generic-y += serial.h > generic-y += shmparam.h > generic-y += topology.h > diff --git a/arch/riscv/include/asm/sections.h b/arch/riscv/include/asm/sections.h > new file mode 100644 > index 000000000000..3a9971b1210f > --- /dev/null > +++ b/arch/riscv/include/asm/sections.h > @@ -0,0 +1,13 @@ > +/* SPDX-License-Identifier: GPL-2.0-only */ > +/* > + * Copyright (C) 2020 Western Digital Corporation or its affiliates. > + */ > +#ifndef __ASM_SECTIONS_H > +#define __ASM_SECTIONS_H > + > +#include <asm-generic/sections.h> > + > +extern char _start[]; > +extern char _start_kernel[]; > + > +#endif /* __ASM_SECTIONS_H */ > diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile > index 9601ac907f70..471b1c73f77d 100644 > --- a/arch/riscv/kernel/Makefile > +++ b/arch/riscv/kernel/Makefile > @@ -29,6 +29,10 @@ obj-y += cacheinfo.o > obj-$(CONFIG_MMU) += vdso.o vdso/ > > obj-$(CONFIG_RISCV_M_MODE) += clint.o > +OBJCOPYFLAGS := --prefix-symbols=__efistub_ > +$(obj)/%.stub.o: $(obj)/%.o FORCE > + $(call if_changed,objcopy) > + > obj-$(CONFIG_FPU) += fpu.o > obj-$(CONFIG_SMP) += smpboot.o > obj-$(CONFIG_SMP) += smp.o > diff --git a/arch/riscv/kernel/efi-header.S b/arch/riscv/kernel/efi-header.S > new file mode 100644 > index 000000000000..af959e748d93 > --- /dev/null > +++ b/arch/riscv/kernel/efi-header.S > @@ -0,0 +1,107 @@ > +/* SPDX-License-Identifier: GPL-2.0-only */ > +/* > + * Copyright (C) 2019 Western Digital Corporation or its affiliates. > + * Adapted from arch/arm64/kernel/efi-header.S > + */ > + > +#include <linux/pe.h> > +#include <linux/sizes.h> > + > + .macro __EFI_PE_HEADER > + .long PE_MAGIC > +coff_header: > + .short IMAGE_FILE_MACHINE_RISCV64 // Machine > + .short section_count // NumberOfSections > + .long 0 // TimeDateStamp > + .long 0 // PointerToSymbolTable > + .long 0 // NumberOfSymbols > + .short section_table - optional_header // SizeOfOptionalHeader > + .short IMAGE_FILE_DEBUG_STRIPPED | \ > + IMAGE_FILE_EXECUTABLE_IMAGE | \ > + IMAGE_FILE_LINE_NUMS_STRIPPED // Characteristics > + > +optional_header: > + .short PE_OPT_MAGIC_PE32PLUS // PE32+ format > + .byte 0x02 // MajorLinkerVersion > + .byte 0x14 // MinorLinkerVersion > + .long __text_end - efi_header_end // SizeOfCode > + .long _end - __text_end // SizeOfInitializedData > + .long 0 // SizeOfUninitializedData > + .long __efistub_efi_entry - _start // AddressOfEntryPoint > + .long efi_header_end - _start // BaseOfCode > + > +extra_header_fields: > + .quad 0 // ImageBase > + .long SZ_4K // SectionAlignment > + .long PECOFF_FILE_ALIGNMENT // FileAlignment > + .short 0 // MajorOperatingSystemVersion > + .short 0 // MinorOperatingSystemVersion > + .short 0 // MajorImageVersion > + .short 0 // MinorImageVersion Put LINUX_EFISTUB_MAJOR_VERSION and LINUX_EFISTUB_MINOR_VERSION here > + .short 0 // MajorSubsystemVersion > + .short 0 // MinorSubsystemVersion > + .long 0 // Win32VersionValue > + > + .long _end - _start // SizeOfImage > + > + // Everything before the kernel image is considered part of the header > + .long efi_header_end - _start // SizeOfHeaders > + .long 0 // CheckSum > + .short IMAGE_SUBSYSTEM_EFI_APPLICATION // Subsystem > + .short 0 // DllCharacteristics > + .quad 0 // SizeOfStackReserve > + .quad 0 // SizeOfStackCommit > + .quad 0 // SizeOfHeapReserve > + .quad 0 // SizeOfHeapCommit > + .long 0 // LoaderFlags > + .long (section_table - .) / 8 // NumberOfRvaAndSizes > + > + .quad 0 // ExportTable > + .quad 0 // ImportTable > + .quad 0 // ResourceTable > + .quad 0 // ExceptionTable > + .quad 0 // CertificationTable > + .quad 0 // BaseRelocationTable > + > + // Section table > +section_table: > + .ascii ".text\0\0\0" > + .long __text_end - efi_header_end // VirtualSize > + .long efi_header_end - _start // VirtualAddress > + .long __text_end - efi_header_end // SizeOfRawData > + .long efi_header_end - _start // PointerToRawData > + > + .long 0 // PointerToRelocations > + .long 0 // PointerToLineNumbers > + .short 0 // NumberOfRelocations > + .short 0 // NumberOfLineNumbers > + .long IMAGE_SCN_CNT_CODE | \ > + IMAGE_SCN_MEM_READ | \ > + IMAGE_SCN_MEM_EXECUTE // Characteristics > + > + .ascii ".data\0\0\0" > + .long __data_virt_size // VirtualSize > + .long __text_end - _start // VirtualAddress > + .long __data_raw_size // SizeOfRawData > + .long __text_end - _start // PointerToRawData > + > + .long 0 // PointerToRelocations > + .long 0 // PointerToLineNumbers > + .short 0 // NumberOfRelocations > + .short 0 // NumberOfLineNumbers > + .long IMAGE_SCN_CNT_INITIALIZED_DATA | \ > + IMAGE_SCN_MEM_READ | \ > + IMAGE_SCN_MEM_WRITE // Characteristics > + > + .set section_count, (. - section_table) / 40 > + You dropped the debug header here, which is actually *very* useful if you want to single step through the stub from DEBUG edk2 firmware. > + /* > + * EFI will load .text onwards at the 4k section alignment > + * described in the PE/COFF header. To ensure that instruction > + * sequences using an adrp and a :lo12: immediate will function Surely, this is inaccurate for RISC-V? > + * correctly at this alignment, we must ensure that .text is > + * placed at a 4k boundary in the Image to begin with. > + */ > + .align 12 > +efi_header_end: > + .endm > diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S > index ac5b0e0a02f6..835dc76de285 100644 > --- a/arch/riscv/kernel/head.S > +++ b/arch/riscv/kernel/head.S > @@ -13,6 +13,7 @@ > #include <asm/csr.h> > #include <asm/hwcap.h> > #include <asm/image.h> > +#include "efi-header.S" > > __HEAD > ENTRY(_start) > @@ -22,10 +23,17 @@ ENTRY(_start) > * Do not modify it without modifying the structure and all bootloaders > * that expects this header format!! > */ > +#ifdef CONFIG_EFI > + /* > + * This instruction decodes to "MZ" ASCII required by UEFI. > + */ > + li s4,-13 What happens if you try to do plain boot on an EFI kernel? On ARM and x86, we took care to use a 'MZ' opcode that behaves as a pseudo-NOP, and jump to start_kernel right after, so if you boot the EFI kernel as a normal kernel, it still works. > +#else > /* jump to start kernel */ > j _start_kernel > /* reserved */ > .word 0 > +#endif > .balign 8 > #if __riscv_xlen == 64 > /* Image load offset(2MB) from start of RAM */ > @@ -43,7 +51,14 @@ ENTRY(_start) > .ascii RISCV_IMAGE_MAGIC > .balign 4 > .ascii RISCV_IMAGE_MAGIC2 > +#ifdef CONFIG_EFI > + .word pe_head_start - _start > +pe_head_start: > + > + __EFI_PE_HEADER > +#else > .word 0 > +#endif > > .align 2 > #ifdef CONFIG_MMU > diff --git a/arch/riscv/kernel/image-vars.h b/arch/riscv/kernel/image-vars.h > new file mode 100644 > index 000000000000..57abb85065e9 > --- /dev/null > +++ b/arch/riscv/kernel/image-vars.h > @@ -0,0 +1,52 @@ > +/* SPDX-License-Identifier: GPL-2.0-only */ > +/* > + * Linker script variables to be set after section resolution, as > + * ld.lld does not like variables assigned before SECTIONS is processed. > + * Based on arch/arm64/kerne/image-vars.h > + */ > +#ifndef __RISCV_KERNEL_IMAGE_VARS_H > +#define __RISCV_KERNEL_IMAGE_VARS_H > + > +#ifndef LINKER_SCRIPT > +#error This file should only be included in vmlinux.lds.S > +#endif > + > +#ifdef CONFIG_EFI > + > +__efistub_stext_offset = _start_kernel - _start; > + > +/* > + * The EFI stub has its own symbol namespace prefixed by __efistub_, to > + * isolate it from the kernel proper. The following symbols are legally > + * accessed by the stub, so provide some aliases to make them accessible. > + * Only include data symbols here, or text symbols of functions that are > + * guaranteed to be safe when executed at another offset than they were > + * linked at. The routines below are all implemented in assembler in a > + * position independent manner > + */ > +__efistub_memcmp = memcmp; > +__efistub_memchr = memchr; > +__efistub_memcpy = memcpy; > +__efistub_memmove = memmove; > +__efistub_memset = memset; > +__efistub_strlen = strlen; > +__efistub_strnlen = strnlen; > +__efistub_strcmp = strcmp; > +__efistub_strncmp = strncmp; > +__efistub_strrchr = strrchr; > + > +#ifdef CONFIG_KASAN > +__efistub___memcpy = memcpy; > +__efistub___memmove = memmove; > +__efistub___memset = memset; > +#endif > + > +__efistub__start = _start; > +__efistub__start_kernel = _start_kernel; > +__efistub__end = _end; > +__efistub__edata = _edata; > +__efistub_screen_info = screen_info; > + > +#endif > + > +#endif /* __RISCV_KERNEL_IMAGE_VARS_H */ > diff --git a/arch/riscv/kernel/vmlinux.lds.S b/arch/riscv/kernel/vmlinux.lds.S > index b32640300d07..933b9e9a4b39 100644 > --- a/arch/riscv/kernel/vmlinux.lds.S > +++ b/arch/riscv/kernel/vmlinux.lds.S > @@ -9,6 +9,7 @@ > #include <asm/page.h> > #include <asm/cache.h> > #include <asm/thread_info.h> > +#include "image-vars.h" > > #include <linux/sizes.h> > OUTPUT_ARCH(riscv) > @@ -16,6 +17,14 @@ ENTRY(_start) > > jiffies = jiffies_64; > > +PECOFF_FILE_ALIGNMENT = 0x200; > +#ifdef CONFIG_EFI > +#define PECOFF_EDATA_PADDING \ > + .pecoff_edata_padding : { BYTE(0); . = ALIGN(PECOFF_FILE_ALIGNMENT); } > +#else > +#define PECOFF_EDATA_PADDING > +#endif > + > SECTIONS > { > /* Beginning of code and text segment */ > @@ -26,12 +35,15 @@ SECTIONS > > __init_begin = .; > INIT_TEXT_SECTION(PAGE_SIZE) > + > + /* Start of data section */ > INIT_DATA_SECTION(16) > /* we have to discard exit text and such at runtime, not link time */ > .exit.text : > { > EXIT_TEXT > } > + > .exit.data : > { > EXIT_DATA > @@ -54,7 +66,8 @@ SECTIONS > _etext = .; > } > > - /* Start of data section */ > + __text_end = .; > + > _sdata = .; > RO_DATA(L1_CACHE_BYTES) > .srodata : { > @@ -65,19 +78,21 @@ SECTIONS > .sdata : { > __global_pointer$ = . + 0x800; > *(.sdata*) > - /* End of data section */ > - _edata = .; > *(.sbss*) > } > - > - BSS_SECTION(PAGE_SIZE, PAGE_SIZE, 0) > - > + PECOFF_EDATA_PADDING > + __data_raw_size = ABSOLUTE(. - __text_end); > + /* End of data section */ > + _edata = .; > EXCEPTION_TABLE(0x10) > > .rel.dyn : { > *(.rel.dyn*) > } > > + BSS_SECTION(PAGE_SIZE, PAGE_SIZE, 0) > + __data_virt_size = ABSOLUTE(. - __text_end); > + > _end = .; > > STABS_DEBUG > -- > 2.24.0 >
On Wed, 2020-02-26 at 08:14 +0100, Ard Biesheuvel wrote: > On Wed, 26 Feb 2020 at 02:10, Atish Patra <atish.patra@wdc.com> > wrote: > > Linux kernel Image can appear as an EFI application With > > appropriate > > PE/COFF header fields in the beginning of the Image header. An EFI > > application loader can directly load a Linux kernel Image and an > > EFI > > stub residing in kernel can boot Linux kernel directly. > > > > Add the necessary PE/COFF header. > > > > Signed-off-by: Atish Patra <atish.patra@wdc.com> > > --- > > arch/riscv/include/asm/Kbuild | 1 - > > arch/riscv/include/asm/sections.h | 13 ++++ > > arch/riscv/kernel/Makefile | 4 ++ > > arch/riscv/kernel/efi-header.S | 107 > > ++++++++++++++++++++++++++++++ > > arch/riscv/kernel/head.S | 15 +++++ > > arch/riscv/kernel/image-vars.h | 52 +++++++++++++++ > > arch/riscv/kernel/vmlinux.lds.S | 27 ++++++-- > > 7 files changed, 212 insertions(+), 7 deletions(-) > > create mode 100644 arch/riscv/include/asm/sections.h > > create mode 100644 arch/riscv/kernel/efi-header.S > > create mode 100644 arch/riscv/kernel/image-vars.h > > > > diff --git a/arch/riscv/include/asm/Kbuild > > b/arch/riscv/include/asm/Kbuild > > index 517394390106..ef797fe44934 100644 > > --- a/arch/riscv/include/asm/Kbuild > > +++ b/arch/riscv/include/asm/Kbuild > > @@ -24,7 +24,6 @@ generic-y += local64.h > > generic-y += mm-arch-hooks.h > > generic-y += percpu.h > > generic-y += preempt.h > > -generic-y += sections.h > > generic-y += serial.h > > generic-y += shmparam.h > > generic-y += topology.h > > diff --git a/arch/riscv/include/asm/sections.h > > b/arch/riscv/include/asm/sections.h > > new file mode 100644 > > index 000000000000..3a9971b1210f > > --- /dev/null > > +++ b/arch/riscv/include/asm/sections.h > > @@ -0,0 +1,13 @@ > > +/* SPDX-License-Identifier: GPL-2.0-only */ > > +/* > > + * Copyright (C) 2020 Western Digital Corporation or its > > affiliates. > > + */ > > +#ifndef __ASM_SECTIONS_H > > +#define __ASM_SECTIONS_H > > + > > +#include <asm-generic/sections.h> > > + > > +extern char _start[]; > > +extern char _start_kernel[]; > > + > > +#endif /* __ASM_SECTIONS_H */ > > diff --git a/arch/riscv/kernel/Makefile > > b/arch/riscv/kernel/Makefile > > index 9601ac907f70..471b1c73f77d 100644 > > --- a/arch/riscv/kernel/Makefile > > +++ b/arch/riscv/kernel/Makefile > > @@ -29,6 +29,10 @@ obj-y += cacheinfo.o > > obj-$(CONFIG_MMU) += vdso.o vdso/ > > > > obj-$(CONFIG_RISCV_M_MODE) += clint.o > > +OBJCOPYFLAGS := --prefix-symbols=__efistub_ > > +$(obj)/%.stub.o: $(obj)/%.o FORCE > > + $(call if_changed,objcopy) > > + > > obj-$(CONFIG_FPU) += fpu.o > > obj-$(CONFIG_SMP) += smpboot.o > > obj-$(CONFIG_SMP) += smp.o > > diff --git a/arch/riscv/kernel/efi-header.S > > b/arch/riscv/kernel/efi-header.S > > new file mode 100644 > > index 000000000000..af959e748d93 > > --- /dev/null > > +++ b/arch/riscv/kernel/efi-header.S > > @@ -0,0 +1,107 @@ > > +/* SPDX-License-Identifier: GPL-2.0-only */ > > +/* > > + * Copyright (C) 2019 Western Digital Corporation or its > > affiliates. > > + * Adapted from arch/arm64/kernel/efi-header.S > > + */ > > + > > +#include <linux/pe.h> > > +#include <linux/sizes.h> > > + > > + .macro __EFI_PE_HEADER > > + .long PE_MAGIC > > +coff_header: > > + .short IMAGE_FILE_MACHINE_RISCV64 // Machine > > + .short section_count // > > NumberOfSections > > + .long 0 // > > TimeDateStamp > > + .long 0 // > > PointerToSymbolTable > > + .long 0 // > > NumberOfSymbols > > + .short section_table - optional_header // > > SizeOfOptionalHeader > > + .short IMAGE_FILE_DEBUG_STRIPPED | \ > > + IMAGE_FILE_EXECUTABLE_IMAGE | \ > > + IMAGE_FILE_LINE_NUMS_STRIPPED // > > Characteristics > > + > > +optional_header: > > + .short PE_OPT_MAGIC_PE32PLUS // PE32+ > > format > > + .byte 0x02 // > > MajorLinkerVersion > > + .byte 0x14 // > > MinorLinkerVersion > > + .long __text_end - efi_header_end // > > SizeOfCode > > + .long _end - __text_end // > > SizeOfInitializedData > > + .long 0 // > > SizeOfUninitializedData > > + .long __efistub_efi_entry - _start // > > AddressOfEntryPoint > > + .long efi_header_end - _start // > > BaseOfCode > > + > > +extra_header_fields: > > + .quad 0 // > > ImageBase > > + .long SZ_4K // > > SectionAlignment > > + .long PECOFF_FILE_ALIGNMENT // > > FileAlignment > > + .short 0 // > > MajorOperatingSystemVersion > > + .short 0 // > > MinorOperatingSystemVersion > > + .short 0 // > > MajorImageVersion > > + .short 0 // > > MinorImageVersion > > Put LINUX_EFISTUB_MAJOR_VERSION and LINUX_EFISTUB_MINOR_VERSION here > Sure. > > + .short 0 // > > MajorSubsystemVersion > > + .short 0 // > > MinorSubsystemVersion > > + .long 0 // > > Win32VersionValue > > + > > + .long _end - _start // > > SizeOfImage > > + > > + // Everything before the kernel image is considered part of > > the header > > + .long efi_header_end - _start // > > SizeOfHeaders > > + .long 0 // CheckSum > > + .short IMAGE_SUBSYSTEM_EFI_APPLICATION // > > Subsystem > > + .short 0 // > > DllCharacteristics > > + .quad 0 // > > SizeOfStackReserve > > + .quad 0 // > > SizeOfStackCommit > > + .quad 0 // > > SizeOfHeapReserve > > + .quad 0 // > > SizeOfHeapCommit > > + .long 0 // > > LoaderFlags > > + .long (section_table - .) / 8 // > > NumberOfRvaAndSizes > > + > > + .quad 0 // > > ExportTable > > + .quad 0 // > > ImportTable > > + .quad 0 // > > ResourceTable > > + .quad 0 // > > ExceptionTable > > + .quad 0 // > > CertificationTable > > + .quad 0 // > > BaseRelocationTable > > + > > + // Section table > > +section_table: > > + .ascii ".text\0\0\0" > > + .long __text_end - efi_header_end // > > VirtualSize > > + .long efi_header_end - _start // > > VirtualAddress > > + .long __text_end - efi_header_end // > > SizeOfRawData > > + .long efi_header_end - _start // > > PointerToRawData > > + > > + .long 0 // > > PointerToRelocations > > + .long 0 // > > PointerToLineNumbers > > + .short 0 // > > NumberOfRelocations > > + .short 0 // > > NumberOfLineNumbers > > + .long IMAGE_SCN_CNT_CODE | \ > > + IMAGE_SCN_MEM_READ | \ > > + IMAGE_SCN_MEM_EXECUTE // > > Characteristics > > + > > + .ascii ".data\0\0\0" > > + .long __data_virt_size // > > VirtualSize > > + .long __text_end - _start // > > VirtualAddress > > + .long __data_raw_size // > > SizeOfRawData > > + .long __text_end - _start // > > PointerToRawData > > + > > + .long 0 // > > PointerToRelocations > > + .long 0 // > > PointerToLineNumbers > > + .short 0 // > > NumberOfRelocations > > + .short 0 // > > NumberOfLineNumbers > > + .long IMAGE_SCN_CNT_INITIALIZED_DATA | \ > > + IMAGE_SCN_MEM_READ | \ > > + IMAGE_SCN_MEM_WRITE // > > Characteristics > > + > > + .set section_count, (. - section_table) / 40 > > + > > You dropped the debug header here, which is actually *very* useful if > you want to single step through the stub from DEBUG edk2 firmware. > Ahh I see. I was not sure how to use the debug feature :). Can we do the same in U-boot ? How about adding it back later once I can verify it with EDK2 ? > > + /* > > + * EFI will load .text onwards at the 4k section alignment > > + * described in the PE/COFF header. To ensure that > > instruction > > + * sequences using an adrp and a :lo12: immediate will > > function > > Surely, this is inaccurate for RISC-V? Sorry. I should have removed the comment. We keep the the _start and .head.text section aligned to a PAGE_SIZE anyways using the linker script. > > > + * correctly at this alignment, we must ensure that .text > > is > > + * placed at a 4k boundary in the Image to begin with. > > + */ > > + .align 12 > > +efi_header_end: > > + .endm > > diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S > > index ac5b0e0a02f6..835dc76de285 100644 > > --- a/arch/riscv/kernel/head.S > > +++ b/arch/riscv/kernel/head.S > > @@ -13,6 +13,7 @@ > > #include <asm/csr.h> > > #include <asm/hwcap.h> > > #include <asm/image.h> > > +#include "efi-header.S" > > > > __HEAD > > ENTRY(_start) > > @@ -22,10 +23,17 @@ ENTRY(_start) > > * Do not modify it without modifying the structure and all > > bootloaders > > * that expects this header format!! > > */ > > +#ifdef CONFIG_EFI > > + /* > > + * This instruction decodes to "MZ" ASCII required by UEFI. > > + */ > > + li s4,-13 > > What happens if you try to do plain boot on an EFI kernel? On ARM and > x86, we took care to use a 'MZ' opcode that behaves as a pseudo-NOP, > and jump to start_kernel right after, so if you boot the EFI kernel > as > a normal kernel, it still works. > There should have been a "j _start_kernel" after the "MZ" ascii. I just tested EFI kernel can now boot as a normal kernel as well with that change. Thanks for pointing that out. > > +#else > > /* jump to start kernel */ > > j _start_kernel > > /* reserved */ > > .word 0 > > +#endif > > .balign 8 > > #if __riscv_xlen == 64 > > /* Image load offset(2MB) from start of RAM */ > > @@ -43,7 +51,14 @@ ENTRY(_start) > > .ascii RISCV_IMAGE_MAGIC > > .balign 4 > > .ascii RISCV_IMAGE_MAGIC2 > > +#ifdef CONFIG_EFI > > + .word pe_head_start - _start > > +pe_head_start: > > + > > + __EFI_PE_HEADER > > +#else > > .word 0 > > +#endif > > > > .align 2 > > #ifdef CONFIG_MMU > > diff --git a/arch/riscv/kernel/image-vars.h > > b/arch/riscv/kernel/image-vars.h > > new file mode 100644 > > index 000000000000..57abb85065e9 > > --- /dev/null > > +++ b/arch/riscv/kernel/image-vars.h > > @@ -0,0 +1,52 @@ > > +/* SPDX-License-Identifier: GPL-2.0-only */ > > +/* > > + * Linker script variables to be set after section resolution, as > > + * ld.lld does not like variables assigned before SECTIONS is > > processed. > > + * Based on arch/arm64/kerne/image-vars.h > > + */ > > +#ifndef __RISCV_KERNEL_IMAGE_VARS_H > > +#define __RISCV_KERNEL_IMAGE_VARS_H > > + > > +#ifndef LINKER_SCRIPT > > +#error This file should only be included in vmlinux.lds.S > > +#endif > > + > > +#ifdef CONFIG_EFI > > + > > +__efistub_stext_offset = _start_kernel - _start; > > + > > +/* > > + * The EFI stub has its own symbol namespace prefixed by > > __efistub_, to > > + * isolate it from the kernel proper. The following symbols are > > legally > > + * accessed by the stub, so provide some aliases to make them > > accessible. > > + * Only include data symbols here, or text symbols of functions > > that are > > + * guaranteed to be safe when executed at another offset than they > > were > > + * linked at. The routines below are all implemented in assembler > > in a > > + * position independent manner > > + */ > > +__efistub_memcmp = memcmp; > > +__efistub_memchr = memchr; > > +__efistub_memcpy = memcpy; > > +__efistub_memmove = memmove; > > +__efistub_memset = memset; > > +__efistub_strlen = strlen; > > +__efistub_strnlen = strnlen; > > +__efistub_strcmp = strcmp; > > +__efistub_strncmp = strncmp; > > +__efistub_strrchr = strrchr; > > + > > +#ifdef CONFIG_KASAN > > +__efistub___memcpy = memcpy; > > +__efistub___memmove = memmove; > > +__efistub___memset = memset; > > +#endif > > + > > +__efistub__start = _start; > > +__efistub__start_kernel = _start_kernel; > > +__efistub__end = _end; > > +__efistub__edata = _edata; > > +__efistub_screen_info = screen_info; > > + > > +#endif > > + > > +#endif /* __RISCV_KERNEL_IMAGE_VARS_H */ > > diff --git a/arch/riscv/kernel/vmlinux.lds.S > > b/arch/riscv/kernel/vmlinux.lds.S > > index b32640300d07..933b9e9a4b39 100644 > > --- a/arch/riscv/kernel/vmlinux.lds.S > > +++ b/arch/riscv/kernel/vmlinux.lds.S > > @@ -9,6 +9,7 @@ > > #include <asm/page.h> > > #include <asm/cache.h> > > #include <asm/thread_info.h> > > +#include "image-vars.h" > > > > #include <linux/sizes.h> > > OUTPUT_ARCH(riscv) > > @@ -16,6 +17,14 @@ ENTRY(_start) > > > > jiffies = jiffies_64; > > > > +PECOFF_FILE_ALIGNMENT = 0x200; > > +#ifdef CONFIG_EFI > > +#define PECOFF_EDATA_PADDING \ > > + .pecoff_edata_padding : { BYTE(0); . = > > ALIGN(PECOFF_FILE_ALIGNMENT); } > > +#else > > +#define PECOFF_EDATA_PADDING > > +#endif > > + > > SECTIONS > > { > > /* Beginning of code and text segment */ > > @@ -26,12 +35,15 @@ SECTIONS > > > > __init_begin = .; > > INIT_TEXT_SECTION(PAGE_SIZE) > > + > > + /* Start of data section */ > > INIT_DATA_SECTION(16) > > /* we have to discard exit text and such at runtime, not > > link time */ > > .exit.text : > > { > > EXIT_TEXT > > } > > + > > .exit.data : > > { > > EXIT_DATA > > @@ -54,7 +66,8 @@ SECTIONS > > _etext = .; > > } > > > > - /* Start of data section */ > > + __text_end = .; > > + > > _sdata = .; > > RO_DATA(L1_CACHE_BYTES) > > .srodata : { > > @@ -65,19 +78,21 @@ SECTIONS > > .sdata : { > > __global_pointer$ = . + 0x800; > > *(.sdata*) > > - /* End of data section */ > > - _edata = .; > > *(.sbss*) > > } > > - > > - BSS_SECTION(PAGE_SIZE, PAGE_SIZE, 0) > > - > > + PECOFF_EDATA_PADDING > > + __data_raw_size = ABSOLUTE(. - __text_end); > > + /* End of data section */ > > + _edata = .; > > EXCEPTION_TABLE(0x10) > > > > .rel.dyn : { > > *(.rel.dyn*) > > } > > > > + BSS_SECTION(PAGE_SIZE, PAGE_SIZE, 0) > > + __data_virt_size = ABSOLUTE(. - __text_end); > > + > > _end = .; > > > > STABS_DEBUG > > -- > > 2.24.0 > >
On Thu, 27 Feb 2020 at 02:29, Atish Patra <Atish.Patra@wdc.com> wrote: > > On Wed, 2020-02-26 at 08:14 +0100, Ard Biesheuvel wrote: > > On Wed, 26 Feb 2020 at 02:10, Atish Patra <atish.patra@wdc.com> > > wrote: > > > Linux kernel Image can appear as an EFI application With > > > appropriate > > > PE/COFF header fields in the beginning of the Image header. An EFI > > > application loader can directly load a Linux kernel Image and an > > > EFI > > > stub residing in kernel can boot Linux kernel directly. > > > > > > Add the necessary PE/COFF header. > > > > > > Signed-off-by: Atish Patra <atish.patra@wdc.com> > > > --- > > > arch/riscv/include/asm/Kbuild | 1 - > > > arch/riscv/include/asm/sections.h | 13 ++++ > > > arch/riscv/kernel/Makefile | 4 ++ > > > arch/riscv/kernel/efi-header.S | 107 > > > ++++++++++++++++++++++++++++++ > > > arch/riscv/kernel/head.S | 15 +++++ > > > arch/riscv/kernel/image-vars.h | 52 +++++++++++++++ > > > arch/riscv/kernel/vmlinux.lds.S | 27 ++++++-- > > > 7 files changed, 212 insertions(+), 7 deletions(-) > > > create mode 100644 arch/riscv/include/asm/sections.h > > > create mode 100644 arch/riscv/kernel/efi-header.S > > > create mode 100644 arch/riscv/kernel/image-vars.h > > > > > > diff --git a/arch/riscv/include/asm/Kbuild > > > b/arch/riscv/include/asm/Kbuild > > > index 517394390106..ef797fe44934 100644 > > > --- a/arch/riscv/include/asm/Kbuild > > > +++ b/arch/riscv/include/asm/Kbuild > > > @@ -24,7 +24,6 @@ generic-y += local64.h > > > generic-y += mm-arch-hooks.h > > > generic-y += percpu.h > > > generic-y += preempt.h > > > -generic-y += sections.h > > > generic-y += serial.h > > > generic-y += shmparam.h > > > generic-y += topology.h > > > diff --git a/arch/riscv/include/asm/sections.h > > > b/arch/riscv/include/asm/sections.h > > > new file mode 100644 > > > index 000000000000..3a9971b1210f > > > --- /dev/null > > > +++ b/arch/riscv/include/asm/sections.h > > > @@ -0,0 +1,13 @@ > > > +/* SPDX-License-Identifier: GPL-2.0-only */ > > > +/* > > > + * Copyright (C) 2020 Western Digital Corporation or its > > > affiliates. > > > + */ > > > +#ifndef __ASM_SECTIONS_H > > > +#define __ASM_SECTIONS_H > > > + > > > +#include <asm-generic/sections.h> > > > + > > > +extern char _start[]; > > > +extern char _start_kernel[]; > > > + > > > +#endif /* __ASM_SECTIONS_H */ > > > diff --git a/arch/riscv/kernel/Makefile > > > b/arch/riscv/kernel/Makefile > > > index 9601ac907f70..471b1c73f77d 100644 > > > --- a/arch/riscv/kernel/Makefile > > > +++ b/arch/riscv/kernel/Makefile > > > @@ -29,6 +29,10 @@ obj-y += cacheinfo.o > > > obj-$(CONFIG_MMU) += vdso.o vdso/ > > > > > > obj-$(CONFIG_RISCV_M_MODE) += clint.o > > > +OBJCOPYFLAGS := --prefix-symbols=__efistub_ > > > +$(obj)/%.stub.o: $(obj)/%.o FORCE > > > + $(call if_changed,objcopy) > > > + > > > obj-$(CONFIG_FPU) += fpu.o > > > obj-$(CONFIG_SMP) += smpboot.o > > > obj-$(CONFIG_SMP) += smp.o > > > diff --git a/arch/riscv/kernel/efi-header.S > > > b/arch/riscv/kernel/efi-header.S > > > new file mode 100644 > > > index 000000000000..af959e748d93 > > > --- /dev/null > > > +++ b/arch/riscv/kernel/efi-header.S > > > @@ -0,0 +1,107 @@ > > > +/* SPDX-License-Identifier: GPL-2.0-only */ > > > +/* > > > + * Copyright (C) 2019 Western Digital Corporation or its > > > affiliates. > > > + * Adapted from arch/arm64/kernel/efi-header.S > > > + */ > > > + > > > +#include <linux/pe.h> > > > +#include <linux/sizes.h> > > > + > > > + .macro __EFI_PE_HEADER > > > + .long PE_MAGIC > > > +coff_header: > > > + .short IMAGE_FILE_MACHINE_RISCV64 // Machine > > > + .short section_count // > > > NumberOfSections > > > + .long 0 // > > > TimeDateStamp > > > + .long 0 // > > > PointerToSymbolTable > > > + .long 0 // > > > NumberOfSymbols > > > + .short section_table - optional_header // > > > SizeOfOptionalHeader > > > + .short IMAGE_FILE_DEBUG_STRIPPED | \ > > > + IMAGE_FILE_EXECUTABLE_IMAGE | \ > > > + IMAGE_FILE_LINE_NUMS_STRIPPED // > > > Characteristics > > > + > > > +optional_header: > > > + .short PE_OPT_MAGIC_PE32PLUS // PE32+ > > > format > > > + .byte 0x02 // > > > MajorLinkerVersion > > > + .byte 0x14 // > > > MinorLinkerVersion > > > + .long __text_end - efi_header_end // > > > SizeOfCode > > > + .long _end - __text_end // > > > SizeOfInitializedData > > > + .long 0 // > > > SizeOfUninitializedData > > > + .long __efistub_efi_entry - _start // > > > AddressOfEntryPoint > > > + .long efi_header_end - _start // > > > BaseOfCode > > > + > > > +extra_header_fields: > > > + .quad 0 // > > > ImageBase > > > + .long SZ_4K // > > > SectionAlignment > > > + .long PECOFF_FILE_ALIGNMENT // > > > FileAlignment > > > + .short 0 // > > > MajorOperatingSystemVersion > > > + .short 0 // > > > MinorOperatingSystemVersion > > > + .short 0 // > > > MajorImageVersion > > > + .short 0 // > > > MinorImageVersion > > > > Put LINUX_EFISTUB_MAJOR_VERSION and LINUX_EFISTUB_MINOR_VERSION here > > > > Sure. > > > > + .short 0 // > > > MajorSubsystemVersion > > > + .short 0 // > > > MinorSubsystemVersion > > > + .long 0 // > > > Win32VersionValue > > > + > > > + .long _end - _start // > > > SizeOfImage > > > + > > > + // Everything before the kernel image is considered part of > > > the header > > > + .long efi_header_end - _start // > > > SizeOfHeaders > > > + .long 0 // CheckSum > > > + .short IMAGE_SUBSYSTEM_EFI_APPLICATION // > > > Subsystem > > > + .short 0 // > > > DllCharacteristics > > > + .quad 0 // > > > SizeOfStackReserve > > > + .quad 0 // > > > SizeOfStackCommit > > > + .quad 0 // > > > SizeOfHeapReserve > > > + .quad 0 // > > > SizeOfHeapCommit > > > + .long 0 // > > > LoaderFlags > > > + .long (section_table - .) / 8 // > > > NumberOfRvaAndSizes > > > + > > > + .quad 0 // > > > ExportTable > > > + .quad 0 // > > > ImportTable > > > + .quad 0 // > > > ResourceTable > > > + .quad 0 // > > > ExceptionTable > > > + .quad 0 // > > > CertificationTable > > > + .quad 0 // > > > BaseRelocationTable > > > + > > > + // Section table > > > +section_table: > > > + .ascii ".text\0\0\0" > > > + .long __text_end - efi_header_end // > > > VirtualSize > > > + .long efi_header_end - _start // > > > VirtualAddress > > > + .long __text_end - efi_header_end // > > > SizeOfRawData > > > + .long efi_header_end - _start // > > > PointerToRawData > > > + > > > + .long 0 // > > > PointerToRelocations > > > + .long 0 // > > > PointerToLineNumbers > > > + .short 0 // > > > NumberOfRelocations > > > + .short 0 // > > > NumberOfLineNumbers > > > + .long IMAGE_SCN_CNT_CODE | \ > > > + IMAGE_SCN_MEM_READ | \ > > > + IMAGE_SCN_MEM_EXECUTE // > > > Characteristics > > > + > > > + .ascii ".data\0\0\0" > > > + .long __data_virt_size // > > > VirtualSize > > > + .long __text_end - _start // > > > VirtualAddress > > > + .long __data_raw_size // > > > SizeOfRawData > > > + .long __text_end - _start // > > > PointerToRawData > > > + > > > + .long 0 // > > > PointerToRelocations > > > + .long 0 // > > > PointerToLineNumbers > > > + .short 0 // > > > NumberOfRelocations > > > + .short 0 // > > > NumberOfLineNumbers > > > + .long IMAGE_SCN_CNT_INITIALIZED_DATA | \ > > > + IMAGE_SCN_MEM_READ | \ > > > + IMAGE_SCN_MEM_WRITE // > > > Characteristics > > > + > > > + .set section_count, (. - section_table) / 40 > > > + > > > > You dropped the debug header here, which is actually *very* useful if > > you want to single step through the stub from DEBUG edk2 firmware. > > > > Ahh I see. I was not sure how to use the debug feature :). Can we do > the same in U-boot ? > You could, but I doubt it has been implemented yet. Adding the debug header will cause the firmware to record the image path and its load address in a special debug table, which the firmware can use to expose the load address and path of the image as it is loaded (i.e. before moving itself into place) When I run this under a DEBUG build of EDK2, it prints a line like add-symbol-file /home/ardbie01/linux-build-arm64/vmlinux 0x74E0B000 which I can paste into the GDB command window, set a breakpoint on efi_entry(), and single step through the stub. > How about adding it back later once I can verify it with EDK2 ? > Sure, that is fine > > > + /* > > > + * EFI will load .text onwards at the 4k section alignment > > > + * described in the PE/COFF header. To ensure that > > > instruction > > > + * sequences using an adrp and a :lo12: immediate will > > > function > > > > Surely, this is inaccurate for RISC-V? > > Sorry. I should have removed the comment. We keep the the _start and > .head.text section aligned to a PAGE_SIZE anyways using the linker > script. ok > > > > > + * correctly at this alignment, we must ensure that .text > > > is > > > + * placed at a 4k boundary in the Image to begin with. > > > + */ > > > + .align 12 > > > +efi_header_end: > > > + .endm > > > diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S > > > index ac5b0e0a02f6..835dc76de285 100644 > > > --- a/arch/riscv/kernel/head.S > > > +++ b/arch/riscv/kernel/head.S > > > @@ -13,6 +13,7 @@ > > > #include <asm/csr.h> > > > #include <asm/hwcap.h> > > > #include <asm/image.h> > > > +#include "efi-header.S" > > > > > > __HEAD > > > ENTRY(_start) > > > @@ -22,10 +23,17 @@ ENTRY(_start) > > > * Do not modify it without modifying the structure and all > > > bootloaders > > > * that expects this header format!! > > > */ > > > +#ifdef CONFIG_EFI > > > + /* > > > + * This instruction decodes to "MZ" ASCII required by UEFI. > > > + */ > > > + li s4,-13 > > > > What happens if you try to do plain boot on an EFI kernel? On ARM and > > x86, we took care to use a 'MZ' opcode that behaves as a pseudo-NOP, > > and jump to start_kernel right after, so if you boot the EFI kernel > > as > > a normal kernel, it still works. > > > > There should have been a "j _start_kernel" after the "MZ" ascii. I just > tested EFI kernel can now boot as a normal kernel as well with that > change. Thanks for pointing that out. > Sure > > > +#else > > > /* jump to start kernel */ > > > j _start_kernel > > > /* reserved */ > > > .word 0 > > > +#endif > > > .balign 8 > > > #if __riscv_xlen == 64 > > > /* Image load offset(2MB) from start of RAM */ > > > @@ -43,7 +51,14 @@ ENTRY(_start) > > > .ascii RISCV_IMAGE_MAGIC > > > .balign 4 > > > .ascii RISCV_IMAGE_MAGIC2 > > > +#ifdef CONFIG_EFI > > > + .word pe_head_start - _start > > > +pe_head_start: > > > + > > > + __EFI_PE_HEADER > > > +#else > > > .word 0 > > > +#endif > > > > > > .align 2 > > > #ifdef CONFIG_MMU > > > diff --git a/arch/riscv/kernel/image-vars.h > > > b/arch/riscv/kernel/image-vars.h > > > new file mode 100644 > > > index 000000000000..57abb85065e9 > > > --- /dev/null > > > +++ b/arch/riscv/kernel/image-vars.h > > > @@ -0,0 +1,52 @@ > > > +/* SPDX-License-Identifier: GPL-2.0-only */ > > > +/* > > > + * Linker script variables to be set after section resolution, as > > > + * ld.lld does not like variables assigned before SECTIONS is > > > processed. > > > + * Based on arch/arm64/kerne/image-vars.h > > > + */ > > > +#ifndef __RISCV_KERNEL_IMAGE_VARS_H > > > +#define __RISCV_KERNEL_IMAGE_VARS_H > > > + > > > +#ifndef LINKER_SCRIPT > > > +#error This file should only be included in vmlinux.lds.S > > > +#endif > > > + > > > +#ifdef CONFIG_EFI > > > + > > > +__efistub_stext_offset = _start_kernel - _start; > > > + > > > +/* > > > + * The EFI stub has its own symbol namespace prefixed by > > > __efistub_, to > > > + * isolate it from the kernel proper. The following symbols are > > > legally > > > + * accessed by the stub, so provide some aliases to make them > > > accessible. > > > + * Only include data symbols here, or text symbols of functions > > > that are > > > + * guaranteed to be safe when executed at another offset than they > > > were > > > + * linked at. The routines below are all implemented in assembler > > > in a > > > + * position independent manner > > > + */ > > > +__efistub_memcmp = memcmp; > > > +__efistub_memchr = memchr; > > > +__efistub_memcpy = memcpy; > > > +__efistub_memmove = memmove; > > > +__efistub_memset = memset; > > > +__efistub_strlen = strlen; > > > +__efistub_strnlen = strnlen; > > > +__efistub_strcmp = strcmp; > > > +__efistub_strncmp = strncmp; > > > +__efistub_strrchr = strrchr; > > > + > > > +#ifdef CONFIG_KASAN > > > +__efistub___memcpy = memcpy; > > > +__efistub___memmove = memmove; > > > +__efistub___memset = memset; > > > +#endif > > > + > > > +__efistub__start = _start; > > > +__efistub__start_kernel = _start_kernel; > > > +__efistub__end = _end; > > > +__efistub__edata = _edata; > > > +__efistub_screen_info = screen_info; > > > + > > > +#endif > > > + > > > +#endif /* __RISCV_KERNEL_IMAGE_VARS_H */ > > > diff --git a/arch/riscv/kernel/vmlinux.lds.S > > > b/arch/riscv/kernel/vmlinux.lds.S > > > index b32640300d07..933b9e9a4b39 100644 > > > --- a/arch/riscv/kernel/vmlinux.lds.S > > > +++ b/arch/riscv/kernel/vmlinux.lds.S > > > @@ -9,6 +9,7 @@ > > > #include <asm/page.h> > > > #include <asm/cache.h> > > > #include <asm/thread_info.h> > > > +#include "image-vars.h" > > > > > > #include <linux/sizes.h> > > > OUTPUT_ARCH(riscv) > > > @@ -16,6 +17,14 @@ ENTRY(_start) > > > > > > jiffies = jiffies_64; > > > > > > +PECOFF_FILE_ALIGNMENT = 0x200; > > > +#ifdef CONFIG_EFI > > > +#define PECOFF_EDATA_PADDING \ > > > + .pecoff_edata_padding : { BYTE(0); . = > > > ALIGN(PECOFF_FILE_ALIGNMENT); } > > > +#else > > > +#define PECOFF_EDATA_PADDING > > > +#endif > > > + > > > SECTIONS > > > { > > > /* Beginning of code and text segment */ > > > @@ -26,12 +35,15 @@ SECTIONS > > > > > > __init_begin = .; > > > INIT_TEXT_SECTION(PAGE_SIZE) > > > + > > > + /* Start of data section */ > > > INIT_DATA_SECTION(16) > > > /* we have to discard exit text and such at runtime, not > > > link time */ > > > .exit.text : > > > { > > > EXIT_TEXT > > > } > > > + > > > .exit.data : > > > { > > > EXIT_DATA > > > @@ -54,7 +66,8 @@ SECTIONS > > > _etext = .; > > > } > > > > > > - /* Start of data section */ > > > + __text_end = .; > > > + > > > _sdata = .; > > > RO_DATA(L1_CACHE_BYTES) > > > .srodata : { > > > @@ -65,19 +78,21 @@ SECTIONS > > > .sdata : { > > > __global_pointer$ = . + 0x800; > > > *(.sdata*) > > > - /* End of data section */ > > > - _edata = .; > > > *(.sbss*) > > > } > > > - > > > - BSS_SECTION(PAGE_SIZE, PAGE_SIZE, 0) > > > - > > > + PECOFF_EDATA_PADDING > > > + __data_raw_size = ABSOLUTE(. - __text_end); > > > + /* End of data section */ > > > + _edata = .; > > > EXCEPTION_TABLE(0x10) > > > > > > .rel.dyn : { > > > *(.rel.dyn*) > > > } > > > > > > + BSS_SECTION(PAGE_SIZE, PAGE_SIZE, 0) > > > + __data_virt_size = ABSOLUTE(. - __text_end); > > > + > > > _end = .; > > > > > > STABS_DEBUG > > > -- > > > 2.24.0 > > > > > -- > Regards, > Atish
diff --git a/arch/riscv/include/asm/Kbuild b/arch/riscv/include/asm/Kbuild index 517394390106..ef797fe44934 100644 --- a/arch/riscv/include/asm/Kbuild +++ b/arch/riscv/include/asm/Kbuild @@ -24,7 +24,6 @@ generic-y += local64.h generic-y += mm-arch-hooks.h generic-y += percpu.h generic-y += preempt.h -generic-y += sections.h generic-y += serial.h generic-y += shmparam.h generic-y += topology.h diff --git a/arch/riscv/include/asm/sections.h b/arch/riscv/include/asm/sections.h new file mode 100644 index 000000000000..3a9971b1210f --- /dev/null +++ b/arch/riscv/include/asm/sections.h @@ -0,0 +1,13 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (C) 2020 Western Digital Corporation or its affiliates. + */ +#ifndef __ASM_SECTIONS_H +#define __ASM_SECTIONS_H + +#include <asm-generic/sections.h> + +extern char _start[]; +extern char _start_kernel[]; + +#endif /* __ASM_SECTIONS_H */ diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile index 9601ac907f70..471b1c73f77d 100644 --- a/arch/riscv/kernel/Makefile +++ b/arch/riscv/kernel/Makefile @@ -29,6 +29,10 @@ obj-y += cacheinfo.o obj-$(CONFIG_MMU) += vdso.o vdso/ obj-$(CONFIG_RISCV_M_MODE) += clint.o +OBJCOPYFLAGS := --prefix-symbols=__efistub_ +$(obj)/%.stub.o: $(obj)/%.o FORCE + $(call if_changed,objcopy) + obj-$(CONFIG_FPU) += fpu.o obj-$(CONFIG_SMP) += smpboot.o obj-$(CONFIG_SMP) += smp.o diff --git a/arch/riscv/kernel/efi-header.S b/arch/riscv/kernel/efi-header.S new file mode 100644 index 000000000000..af959e748d93 --- /dev/null +++ b/arch/riscv/kernel/efi-header.S @@ -0,0 +1,107 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (C) 2019 Western Digital Corporation or its affiliates. + * Adapted from arch/arm64/kernel/efi-header.S + */ + +#include <linux/pe.h> +#include <linux/sizes.h> + + .macro __EFI_PE_HEADER + .long PE_MAGIC +coff_header: + .short IMAGE_FILE_MACHINE_RISCV64 // Machine + .short section_count // NumberOfSections + .long 0 // TimeDateStamp + .long 0 // PointerToSymbolTable + .long 0 // NumberOfSymbols + .short section_table - optional_header // SizeOfOptionalHeader + .short IMAGE_FILE_DEBUG_STRIPPED | \ + IMAGE_FILE_EXECUTABLE_IMAGE | \ + IMAGE_FILE_LINE_NUMS_STRIPPED // Characteristics + +optional_header: + .short PE_OPT_MAGIC_PE32PLUS // PE32+ format + .byte 0x02 // MajorLinkerVersion + .byte 0x14 // MinorLinkerVersion + .long __text_end - efi_header_end // SizeOfCode + .long _end - __text_end // SizeOfInitializedData + .long 0 // SizeOfUninitializedData + .long __efistub_efi_entry - _start // AddressOfEntryPoint + .long efi_header_end - _start // BaseOfCode + +extra_header_fields: + .quad 0 // ImageBase + .long SZ_4K // SectionAlignment + .long PECOFF_FILE_ALIGNMENT // FileAlignment + .short 0 // MajorOperatingSystemVersion + .short 0 // MinorOperatingSystemVersion + .short 0 // MajorImageVersion + .short 0 // MinorImageVersion + .short 0 // MajorSubsystemVersion + .short 0 // MinorSubsystemVersion + .long 0 // Win32VersionValue + + .long _end - _start // SizeOfImage + + // Everything before the kernel image is considered part of the header + .long efi_header_end - _start // SizeOfHeaders + .long 0 // CheckSum + .short IMAGE_SUBSYSTEM_EFI_APPLICATION // Subsystem + .short 0 // DllCharacteristics + .quad 0 // SizeOfStackReserve + .quad 0 // SizeOfStackCommit + .quad 0 // SizeOfHeapReserve + .quad 0 // SizeOfHeapCommit + .long 0 // LoaderFlags + .long (section_table - .) / 8 // NumberOfRvaAndSizes + + .quad 0 // ExportTable + .quad 0 // ImportTable + .quad 0 // ResourceTable + .quad 0 // ExceptionTable + .quad 0 // CertificationTable + .quad 0 // BaseRelocationTable + + // Section table +section_table: + .ascii ".text\0\0\0" + .long __text_end - efi_header_end // VirtualSize + .long efi_header_end - _start // VirtualAddress + .long __text_end - efi_header_end // SizeOfRawData + .long efi_header_end - _start // PointerToRawData + + .long 0 // PointerToRelocations + .long 0 // PointerToLineNumbers + .short 0 // NumberOfRelocations + .short 0 // NumberOfLineNumbers + .long IMAGE_SCN_CNT_CODE | \ + IMAGE_SCN_MEM_READ | \ + IMAGE_SCN_MEM_EXECUTE // Characteristics + + .ascii ".data\0\0\0" + .long __data_virt_size // VirtualSize + .long __text_end - _start // VirtualAddress + .long __data_raw_size // SizeOfRawData + .long __text_end - _start // PointerToRawData + + .long 0 // PointerToRelocations + .long 0 // PointerToLineNumbers + .short 0 // NumberOfRelocations + .short 0 // NumberOfLineNumbers + .long IMAGE_SCN_CNT_INITIALIZED_DATA | \ + IMAGE_SCN_MEM_READ | \ + IMAGE_SCN_MEM_WRITE // Characteristics + + .set section_count, (. - section_table) / 40 + + /* + * EFI will load .text onwards at the 4k section alignment + * described in the PE/COFF header. To ensure that instruction + * sequences using an adrp and a :lo12: immediate will function + * correctly at this alignment, we must ensure that .text is + * placed at a 4k boundary in the Image to begin with. + */ + .align 12 +efi_header_end: + .endm diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S index ac5b0e0a02f6..835dc76de285 100644 --- a/arch/riscv/kernel/head.S +++ b/arch/riscv/kernel/head.S @@ -13,6 +13,7 @@ #include <asm/csr.h> #include <asm/hwcap.h> #include <asm/image.h> +#include "efi-header.S" __HEAD ENTRY(_start) @@ -22,10 +23,17 @@ ENTRY(_start) * Do not modify it without modifying the structure and all bootloaders * that expects this header format!! */ +#ifdef CONFIG_EFI + /* + * This instruction decodes to "MZ" ASCII required by UEFI. + */ + li s4,-13 +#else /* jump to start kernel */ j _start_kernel /* reserved */ .word 0 +#endif .balign 8 #if __riscv_xlen == 64 /* Image load offset(2MB) from start of RAM */ @@ -43,7 +51,14 @@ ENTRY(_start) .ascii RISCV_IMAGE_MAGIC .balign 4 .ascii RISCV_IMAGE_MAGIC2 +#ifdef CONFIG_EFI + .word pe_head_start - _start +pe_head_start: + + __EFI_PE_HEADER +#else .word 0 +#endif .align 2 #ifdef CONFIG_MMU diff --git a/arch/riscv/kernel/image-vars.h b/arch/riscv/kernel/image-vars.h new file mode 100644 index 000000000000..57abb85065e9 --- /dev/null +++ b/arch/riscv/kernel/image-vars.h @@ -0,0 +1,52 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Linker script variables to be set after section resolution, as + * ld.lld does not like variables assigned before SECTIONS is processed. + * Based on arch/arm64/kerne/image-vars.h + */ +#ifndef __RISCV_KERNEL_IMAGE_VARS_H +#define __RISCV_KERNEL_IMAGE_VARS_H + +#ifndef LINKER_SCRIPT +#error This file should only be included in vmlinux.lds.S +#endif + +#ifdef CONFIG_EFI + +__efistub_stext_offset = _start_kernel - _start; + +/* + * The EFI stub has its own symbol namespace prefixed by __efistub_, to + * isolate it from the kernel proper. The following symbols are legally + * accessed by the stub, so provide some aliases to make them accessible. + * Only include data symbols here, or text symbols of functions that are + * guaranteed to be safe when executed at another offset than they were + * linked at. The routines below are all implemented in assembler in a + * position independent manner + */ +__efistub_memcmp = memcmp; +__efistub_memchr = memchr; +__efistub_memcpy = memcpy; +__efistub_memmove = memmove; +__efistub_memset = memset; +__efistub_strlen = strlen; +__efistub_strnlen = strnlen; +__efistub_strcmp = strcmp; +__efistub_strncmp = strncmp; +__efistub_strrchr = strrchr; + +#ifdef CONFIG_KASAN +__efistub___memcpy = memcpy; +__efistub___memmove = memmove; +__efistub___memset = memset; +#endif + +__efistub__start = _start; +__efistub__start_kernel = _start_kernel; +__efistub__end = _end; +__efistub__edata = _edata; +__efistub_screen_info = screen_info; + +#endif + +#endif /* __RISCV_KERNEL_IMAGE_VARS_H */ diff --git a/arch/riscv/kernel/vmlinux.lds.S b/arch/riscv/kernel/vmlinux.lds.S index b32640300d07..933b9e9a4b39 100644 --- a/arch/riscv/kernel/vmlinux.lds.S +++ b/arch/riscv/kernel/vmlinux.lds.S @@ -9,6 +9,7 @@ #include <asm/page.h> #include <asm/cache.h> #include <asm/thread_info.h> +#include "image-vars.h" #include <linux/sizes.h> OUTPUT_ARCH(riscv) @@ -16,6 +17,14 @@ ENTRY(_start) jiffies = jiffies_64; +PECOFF_FILE_ALIGNMENT = 0x200; +#ifdef CONFIG_EFI +#define PECOFF_EDATA_PADDING \ + .pecoff_edata_padding : { BYTE(0); . = ALIGN(PECOFF_FILE_ALIGNMENT); } +#else +#define PECOFF_EDATA_PADDING +#endif + SECTIONS { /* Beginning of code and text segment */ @@ -26,12 +35,15 @@ SECTIONS __init_begin = .; INIT_TEXT_SECTION(PAGE_SIZE) + + /* Start of data section */ INIT_DATA_SECTION(16) /* we have to discard exit text and such at runtime, not link time */ .exit.text : { EXIT_TEXT } + .exit.data : { EXIT_DATA @@ -54,7 +66,8 @@ SECTIONS _etext = .; } - /* Start of data section */ + __text_end = .; + _sdata = .; RO_DATA(L1_CACHE_BYTES) .srodata : { @@ -65,19 +78,21 @@ SECTIONS .sdata : { __global_pointer$ = . + 0x800; *(.sdata*) - /* End of data section */ - _edata = .; *(.sbss*) } - - BSS_SECTION(PAGE_SIZE, PAGE_SIZE, 0) - + PECOFF_EDATA_PADDING + __data_raw_size = ABSOLUTE(. - __text_end); + /* End of data section */ + _edata = .; EXCEPTION_TABLE(0x10) .rel.dyn : { *(.rel.dyn*) } + BSS_SECTION(PAGE_SIZE, PAGE_SIZE, 0) + __data_virt_size = ABSOLUTE(. - __text_end); + _end = .; STABS_DEBUG
Linux kernel Image can appear as an EFI application With appropriate PE/COFF header fields in the beginning of the Image header. An EFI application loader can directly load a Linux kernel Image and an EFI stub residing in kernel can boot Linux kernel directly. Add the necessary PE/COFF header. Signed-off-by: Atish Patra <atish.patra@wdc.com> --- arch/riscv/include/asm/Kbuild | 1 - arch/riscv/include/asm/sections.h | 13 ++++ arch/riscv/kernel/Makefile | 4 ++ arch/riscv/kernel/efi-header.S | 107 ++++++++++++++++++++++++++++++ arch/riscv/kernel/head.S | 15 +++++ arch/riscv/kernel/image-vars.h | 52 +++++++++++++++ arch/riscv/kernel/vmlinux.lds.S | 27 ++++++-- 7 files changed, 212 insertions(+), 7 deletions(-) create mode 100644 arch/riscv/include/asm/sections.h create mode 100644 arch/riscv/kernel/efi-header.S create mode 100644 arch/riscv/kernel/image-vars.h