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2020-09-14x86/boot/compressed: Disable relocation relaxationArvind Sankar
The x86-64 psABI [0] specifies special relocation types (R_X86_64_[REX_]GOTPCRELX) for indirection through the Global Offset Table, semantically equivalent to R_X86_64_GOTPCREL, which the linker can take advantage of for optimization (relaxation) at link time. This is supported by LLD and binutils versions 2.26 onwards. The compressed kernel is position-independent code, however, when using LLD or binutils versions before 2.27, it must be linked without the -pie option. In this case, the linker may optimize certain instructions into a non-position-independent form, by converting foo@GOTPCREL(%rip) to $foo. This potential issue has been present with LLD and binutils-2.26 for a long time, but it has never manifested itself before now: - LLD and binutils-2.26 only relax movq foo@GOTPCREL(%rip), %reg to leaq foo(%rip), %reg which is still position-independent, rather than mov $foo, %reg which is permitted by the psABI when -pie is not enabled. - GCC happens to only generate GOTPCREL relocations on mov instructions. - CLang does generate GOTPCREL relocations on non-mov instructions, but when building the compressed kernel, it uses its integrated assembler (due to the redefinition of KBUILD_CFLAGS dropping -no-integrated-as), which has so far defaulted to not generating the GOTPCRELX relocations. Nick Desaulniers reports [1,2]: "A recent change [3] to a default value of configuration variable (ENABLE_X86_RELAX_RELOCATIONS OFF -> ON) in LLVM now causes Clang's integrated assembler to emit R_X86_64_GOTPCRELX/R_X86_64_REX_GOTPCRELX relocations. LLD will relax instructions with these relocations based on whether the image is being linked as position independent or not. When not, then LLD will relax these instructions to use absolute addressing mode (R_RELAX_GOT_PC_NOPIC). This causes kernels built with Clang and linked with LLD to fail to boot." Patch series [4] is a solution to allow the compressed kernel to be linked with -pie unconditionally, but even if merged is unlikely to be backported. As a simple solution that can be applied to stable as well, prevent the assembler from generating the relaxed relocation types using the -mrelax-relocations=no option. For ease of backporting, do this unconditionally. [0] https://gitlab.com/x86-psABIs/x86-64-ABI/-/blob/master/x86-64-ABI/linker-optimization.tex#L65 [1] https://lore.kernel.org/lkml/20200807194100.3570838-1-ndesaulniers@google.com/ [2] https://github.com/ClangBuiltLinux/linux/issues/1121 [3] https://reviews.llvm.org/rGc41a18cf61790fc898dcda1055c3efbf442c14c0 [4] https://lore.kernel.org/lkml/20200731202738.2577854-1-nivedita@alum.mit.edu/ Reported-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Signed-off-by: Ingo Molnar <mingo@kernel.org> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Acked-by: Ard Biesheuvel <ardb@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20200812004308.1448603-1-nivedita@alum.mit.edu
2020-08-23treewide: Use fallthrough pseudo-keywordGustavo A. R. Silva
Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary fall-through markings when it is the case. [1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
2020-08-19x86/boot/compressed: Use builtin mem functions for decompressorArvind Sankar
Since commits c041b5ad8640 ("x86, boot: Create a separate string.h file to provide standard string functions") fb4cac573ef6 ("x86, boot: Move memcmp() into string.h and string.c") the decompressor stub has been using the compiler's builtin memcpy, memset and memcmp functions, _except_ where it would likely have the largest impact, in the decompression code itself. Remove the #undef's of memcpy and memset in misc.c so that the decompressor code also uses the compiler builtins. The rationale given in the comment doesn't really apply: just because some functions use the out-of-line version is no reason to not use the builtin version in the rest. Replace the comment with an explanation of why memzero and memmove are being #define'd. Drop the suggestion to #undef in boot/string.h as well: the out-of-line versions are not really optimized versions, they're generic code that's good enough for the preboot environment. The compiler will likely generate better code for constant-size memcpy/memset/memcmp if it is allowed to. Most decompressors' performance is unchanged, with the exception of LZ4 and 64-bit ZSTD. Before After ARCH LZ4 73ms 10ms 32 LZ4 120ms 10ms 64 ZSTD 90ms 74ms 64 Measurements on QEMU on 2.2GHz Broadwell Xeon, using defconfig kernels. Decompressor code size has small differences, with the largest being that 64-bit ZSTD decreases just over 2k. The largest code size increase was on 64-bit XZ, of about 400 bytes. Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Suggested-by: Nick Terrell <nickrterrell@gmail.com> Tested-by: Nick Terrell <nickrterrell@gmail.com> Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-09Merge tag 'kbuild-v5.9' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: - run the checker (e.g. sparse) after the compiler - remove unneeded cc-option tests for old compiler flags - fix tar-pkg to install dtbs - introduce ccflags-remove-y and asflags-remove-y syntax - allow to trace functions in sub-directories of lib/ - introduce hostprogs-always-y and userprogs-always-y syntax - various Makefile cleanups * tag 'kbuild-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: kbuild: stop filtering out $(GCC_PLUGINS_CFLAGS) from cc-option base kbuild: include scripts/Makefile.* only when relevant CONFIG is enabled kbuild: introduce hostprogs-always-y and userprogs-always-y kbuild: sort hostprogs before passing it to ifneq kbuild: move host .so build rules to scripts/gcc-plugins/Makefile kbuild: Replace HTTP links with HTTPS ones kbuild: trace functions in subdirectories of lib/ kbuild: introduce ccflags-remove-y and asflags-remove-y kbuild: do not export LDFLAGS_vmlinux kbuild: always create directories of targets powerpc/boot: add DTB to 'targets' kbuild: buildtar: add dtbs support kbuild: remove cc-option test of -ffreestanding kbuild: remove cc-option test of -fno-stack-protector Revert "kbuild: Create directory for target DTB" kbuild: run the checker after the compiler
2020-07-31x86: Add support for ZSTD compressed kernelNick Terrell
- Add support for zstd compressed kernel - Define __DISABLE_EXPORTS in Makefile - Remove __DISABLE_EXPORTS definition from kaslr.c - Bump the heap size for zstd. - Update the documentation. Integrates the ZSTD decompression code to the x86 pre-boot code. Zstandard requires slightly more memory during the kernel decompression on x86 (192 KB vs 64 KB), and the memory usage is independent of the window size. __DISABLE_EXPORTS is now defined in the Makefile, which covers both the existing use in kaslr.c, and the use needed by the zstd decompressor in misc.c. This patch has been boot tested with both a zstd and gzip compressed kernel on i386 and x86_64 using buildroot and QEMU. Additionally, this has been tested in production on x86_64 devices. We saw a 2 second boot time reduction by switching kernel compression from xz to zstd. Signed-off-by: Nick Terrell <terrelln@fb.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20200730190841.2071656-7-nickrterrell@gmail.com
2020-07-31x86: Bump ZO_z_extra_bytes margin for zstdNick Terrell
Bump the ZO_z_extra_bytes margin for zstd. Zstd needs 3 bytes per 128 KB, and has a 22 byte fixed overhead. Zstd needs to maintain 128 KB of space at all times, since that is the maximum block size. See the comments regarding in-place decompression added in lib/decompress_unzstd.c for details. The existing code is written so that all the compression algorithms use the same ZO_z_extra_bytes. It is taken to be the maximum of the growth rate plus the maximum fixed overhead. The comments just above this diff state that: Signed-off-by: Nick Terrell <terrelln@fb.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20200730190841.2071656-6-nickrterrell@gmail.com
2020-07-19Merge tag 'x86-urgent-2020-07-19' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into master Pull x86 fixes from Thomas Gleixner: "A pile of fixes for x86: - Fix the I/O bitmap invalidation on XEN PV, which was overlooked in the recent ioperm/iopl rework. This caused the TSS and XEN's I/O bitmap to get out of sync. - Use the proper vectors for HYPERV. - Make disabling of stack protector for the entry code work with GCC builds which enable stack protector by default. Removing the option is not sufficient, it needs an explicit -fno-stack-protector to shut it off. - Mark check_user_regs() noinstr as it is called from noinstr code. The missing annotation causes it to be placed in the text section which makes it instrumentable. - Add the missing interrupt disable in exc_alignment_check() - Fixup a XEN_PV build dependency in the 32bit entry code - A few fixes to make the Clang integrated assembler happy - Move EFI stub build to the right place for out of tree builds - Make prepare_exit_to_usermode() static. It's not longer called from ASM code" * tag 'x86-urgent-2020-07-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/boot: Don't add the EFI stub to targets x86/entry: Actually disable stack protector x86/ioperm: Fix io bitmap invalidation on Xen PV x86: math-emu: Fix up 'cmp' insn for clang ias x86/entry: Fix vectors to IDTENTRY_SYSVEC for CONFIG_HYPERV x86/entry: Add compatibility with IAS x86/entry/common: Make prepare_exit_to_usermode() static x86/entry: Mark check_user_regs() noinstr x86/traps: Disable interrupts in exc_aligment_check() x86/entry/32: Fix XEN_PV build dependency
2020-07-19x86/boot: Don't add the EFI stub to targetsArvind Sankar
vmlinux-objs-y is added to targets, which currently means that the EFI stub gets added to the targets as well. It shouldn't be added since it is built elsewhere. This confuses Makefile.build which interprets the EFI stub as a target $(obj)/$(objtree)/drivers/firmware/efi/libstub/lib.a and will create drivers/firmware/efi/libstub/ underneath arch/x86/boot/compressed, to hold this supposed target, if building out-of-tree. [0] Fix this by pulling the stub out of vmlinux-objs-y into efi-obj-y. [0] See scripts/Makefile.build near the end: # Create directories for object files if they do not exist Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Ard Biesheuvel <ardb@kernel.org> Link: https://lkml.kernel.org/r/20200715032631.1562882-1-nivedita@alum.mit.edu
2020-07-07kbuild: remove cc-option test of -ffreestandingMasahiro Yamada
Some Makefiles already pass -ffreestanding unconditionally. For example, arch/arm64/lib/Makefile, arch/x86/purgatory/Makefile. No problem report so far about hard-coding this option. So, we can assume all supported compilers know -ffreestanding. I confirmed GCC 4.8 and Clang manuals document this option. Get rid of cc-option from -ffreestanding. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Ard Biesheuvel <ardb@kernel.org>
2020-07-07kbuild: remove cc-option test of -fno-stack-protectorMasahiro Yamada
Some Makefiles already pass -fno-stack-protector unconditionally. For example, arch/arm64/kernel/vdso/Makefile, arch/x86/xen/Makefile. No problem report so far about hard-coding this option. So, we can assume all supported compilers know -fno-stack-protector. GCC 4.8 and Clang support this option (https://godbolt.org/z/_HDGzN) Get rid of cc-option from -fno-stack-protector. Remove CONFIG_CC_HAS_STACKPROTECTOR_NONE, which is always 'y'. Note: arch/mips/vdso/Makefile adds -fno-stack-protector twice, first unconditionally, and second conditionally. I removed the second one. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Ard Biesheuvel <ardb@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2020-06-17efi/x86: Setup stack correctly for efi_pe_entryArvind Sankar
Commit 17054f492dfd ("efi/x86: Implement mixed mode boot without the handover protocol") introduced a new entry point for the EFI stub to be booted in mixed mode on 32-bit firmware. When entered via efi32_pe_entry, control is first transferred to startup_32 to setup for the switch to long mode, and then the EFI stub proper is entered via efi_pe_entry. efi_pe_entry is an MS ABI function, and the ABI requires 32 bytes of shadow stack space to be allocated by the caller, as well as the stack being aligned to 8 mod 16 on entry. Allocate 40 bytes on the stack before switching to 64-bit mode when calling efi_pe_entry to account for this. For robustness, explicitly align boot_stack_end to 16 bytes. It is currently implicitly aligned since .bss is cacheline-size aligned, head_64.o is the first object file with a .bss section, and the heap and boot sizes are aligned. Fixes: 17054f492dfd ("efi/x86: Implement mixed mode boot without the handover protocol") Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Link: https://lore.kernel.org/r/20200617131957.2507632-1-nivedita@alum.mit.edu Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-06-11Rebase locking/kcsan to locking/urgentThomas Gleixner
Merge the state of the locking kcsan branch before the read/write_once() and the atomics modifications got merged. Squash the fallout of the rebase on top of the read/write once and atomic fallback work into the merge. The history of the original branch is preserved in tag locking-kcsan-2020-06-02. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2020-06-09mm: reorder includes after introduction of linux/pgtable.hMike Rapoport
The replacement of <asm/pgrable.h> with <linux/pgtable.h> made the include of the latter in the middle of asm includes. Fix this up with the aid of the below script and manual adjustments here and there. import sys import re if len(sys.argv) is not 3: print "USAGE: %s <file> <header>" % (sys.argv[0]) sys.exit(1) hdr_to_move="#include <linux/%s>" % sys.argv[2] moved = False in_hdrs = False with open(sys.argv[1], "r") as f: lines = f.readlines() for _line in lines: line = _line.rstrip(' ') if line == hdr_to_move: continue if line.startswith("#include <linux/"): in_hdrs = True elif not moved and in_hdrs: moved = True print hdr_to_move print line Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Cain <bcain@codeaurora.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chris Zankel <chris@zankel.net> Cc: "David S. Miller" <davem@davemloft.net> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Greentime Hu <green.hu@gmail.com> Cc: Greg Ungerer <gerg@linux-m68k.org> Cc: Guan Xuetao <gxt@pku.edu.cn> Cc: Guo Ren <guoren@kernel.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Helge Deller <deller@gmx.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Ley Foon Tan <ley.foon.tan@intel.com> Cc: Mark Salter <msalter@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Matt Turner <mattst88@gmail.com> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Simek <monstr@monstr.eu> Cc: Nick Hu <nickhu@andestech.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Richard Weinberger <richard@nod.at> Cc: Rich Felker <dalias@libc.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Stafford Horne <shorne@gmail.com> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Vincent Chen <deanbo422@gmail.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Will Deacon <will@kernel.org> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Link: http://lkml.kernel.org/r/20200514170327.31389-4-rppt@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09mm: introduce include/linux/pgtable.hMike Rapoport
The include/linux/pgtable.h is going to be the home of generic page table manipulation functions. Start with moving asm-generic/pgtable.h to include/linux/pgtable.h and make the latter include asm/pgtable.h. Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Cain <bcain@codeaurora.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chris Zankel <chris@zankel.net> Cc: "David S. Miller" <davem@davemloft.net> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Greentime Hu <green.hu@gmail.com> Cc: Greg Ungerer <gerg@linux-m68k.org> Cc: Guan Xuetao <gxt@pku.edu.cn> Cc: Guo Ren <guoren@kernel.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Helge Deller <deller@gmx.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Ley Foon Tan <ley.foon.tan@intel.com> Cc: Mark Salter <msalter@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Matt Turner <mattst88@gmail.com> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Simek <monstr@monstr.eu> Cc: Nick Hu <nickhu@andestech.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Richard Weinberger <richard@nod.at> Cc: Rich Felker <dalias@libc.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Stafford Horne <shorne@gmail.com> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Vincent Chen <deanbo422@gmail.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Will Deacon <will@kernel.org> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Link: http://lkml.kernel.org/r/20200514170327.31389-3-rppt@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-01Merge tag 'x86-build-2020-06-01' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 build updates from Ingo Molnar: "Misc dependency fixes, plus a documentation update about memory protection keys support" * tag 'x86-build-2020-06-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/Kconfig: Update config and kernel doc for MPK feature on AMD x86/boot: Discard .discard.unreachable for arch/x86/boot/compressed/vmlinux x86/boot/build: Add phony targets in arch/x86/boot/Makefile to PHONY x86/boot/build: Make 'make bzlilo' not depend on vmlinux or $(obj)/bzImage x86/boot/build: Add cpustr.h to targets and remove clean-files
2020-06-01Merge tag 'x86-boot-2020-06-01' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 boot updates from Ingo Molnar: "Misc updates: - Add the initrdmem= boot option to specify an initrd embedded in RAM (flash most likely) - Sanitize the CS value earlier during boot, which also fixes SEV-ES - Various fixes and smaller cleanups" * tag 'x86-boot-2020-06-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/boot: Correct relocation destination on old linkers x86/boot/compressed/64: Switch to __KERNEL_CS after GDT is loaded x86/boot: Fix -Wint-to-pointer-cast build warning x86/boot: Add kstrtoul() from lib/ x86/tboot: Mark tboot static x86/setup: Add an initrdmem= option to specify initrd physical address
2020-05-25Merge tag 'efi-changes-for-v5.8' of ↵Ingo Molnar
git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi into efi/core More EFI changes for v5.8: - Rename pr_efi/pr_efi_err to efi_info/efi_err, and use them consistently - Simplify and unify initrd loading - Parse the builtin command line on x86 (if provided) - Implement printk() support, including support for wide character strings - Some fixes for issues introduced by the first batch of v5.8 changes - Fix a missing prototypes warning - Simplify GDT handling in early mixed mode thunking code - Some other minor fixes and cleanups Conflicts: drivers/firmware/efi/libstub/efistub.h Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-05-25Merge tag 'v5.7-rc7' into efi/core, to refresh the branch and pick up fixesIngo Molnar
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-05-24efi/x86: Drop the special GDT for the EFI thunkArvind Sankar
Instead of using efi_gdt64 to switch back to 64-bit mode and then switching to the real boot-time GDT, just switch to the boot-time GDT directly. The two GDT's are identical other than efi_gdt64 not including the 32-bit code segment. Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Link: https://lore.kernel.org/r/20200523221513.1642948-1-nivedita@alum.mit.edu Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-05-22x86/boot: Discard .discard.unreachable for arch/x86/boot/compressed/vmlinuxFangrui Song
With commit ce5e3f909fc0 ("efi/printf: Add 64-bit and 8-bit integer support") arch/x86/boot/compressed/vmlinux may have an undesired .discard.unreachable section coming from drivers/firmware/efi/libstub/vsprintf.stub.o. That section gets generated from unreachable() annotations when CONFIG_STACK_VALIDATION is enabled. .discard.unreachable contains an R_X86_64_PC32 relocation which will be warned about by LLD: a non-SHF_ALLOC section (.discard.unreachable) is not part of the memory image, thus conceptually the distance between a non-SHF_ALLOC and a SHF_ALLOC is not a constant which can be resolved at link time: % ld.lld -m elf_x86_64 -T arch/x86/boot/compressed/vmlinux.lds ... -o arch/x86/boot/compressed/vmlinux ld.lld: warning: vsprintf.c:(.discard.unreachable+0x0): has non-ABS relocation R_X86_64_PC32 against symbol '' Reuse the DISCARDS macro which includes .discard.* to drop .discard.unreachable. [ bp: Massage and complete the commit message. ] Reported-by: kbuild test robot <lkp@intel.com> Signed-off-by: Fangrui Song <maskray@google.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Kees Cook <keescook@chromium.org> Tested-by: Arvind Sankar <nivedita@alum.mit.edu> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Link: https://lkml.kernel.org/r/20200520182010.242489-1-maskray@google.com
2020-05-19x86/boot: Correct relocation destination on old linkersArvind Sankar
For the 32-bit kernel, as described in 6d92bc9d483a ("x86/build: Build compressed x86 kernels as PIE"), pre-2.26 binutils generates R_386_32 relocations in PIE mode. Since the startup code does not perform relocation, any reloc entry with R_386_32 will remain as 0 in the executing code. Commit 974f221c84b0 ("x86/boot: Move compressed kernel to the end of the decompression buffer") added a new symbol _end but did not mark it hidden, which doesn't give the correct offset on older linkers. This causes the compressed kernel to be copied beyond the end of the decompression buffer, rather than flush against it. This region of memory may be reserved or already allocated for other purposes by the bootloader. Mark _end as hidden to fix. This changes the relocation from R_386_32 to R_386_RELATIVE even on the pre-2.26 binutils. For 64-bit, this is not strictly necessary, as the 64-bit kernel is only built as PIE if the linker supports -z noreloc-overflow, which implies binutils-2.27+, but for consistency, mark _end as hidden here too. The below illustrates the before/after impact of the patch using binutils-2.25 and gcc-4.6.4 (locally compiled from source) and QEMU. Disassembly before patch: 48: 8b 86 60 02 00 00 mov 0x260(%esi),%eax 4e: 2d 00 00 00 00 sub $0x0,%eax 4f: R_386_32 _end Disassembly after patch: 48: 8b 86 60 02 00 00 mov 0x260(%esi),%eax 4e: 2d 00 f0 76 00 sub $0x76f000,%eax 4f: R_386_RELATIVE *ABS* Dump from extract_kernel before patch: early console in extract_kernel input_data: 0x0207c098 <--- this is at output + init_size input_len: 0x0074fef1 output: 0x01000000 output_len: 0x00fa63d0 kernel_total_size: 0x0107c000 needed_size: 0x0107c000 Dump from extract_kernel after patch: early console in extract_kernel input_data: 0x0190d098 <--- this is at output + init_size - _end input_len: 0x0074fef1 output: 0x01000000 output_len: 0x00fa63d0 kernel_total_size: 0x0107c000 needed_size: 0x0107c000 Fixes: 974f221c84b0 ("x86/boot: Move compressed kernel to the end of the decompression buffer") Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20200207214926.3564079-1-nivedita@alum.mit.edu
2020-05-14x86/boot: Mark global variables as staticArvind Sankar
Mike Lothian reports that after commit 964124a97b97 ("efi/x86: Remove extra headroom for setup block") gcc 10.1.0 fails with HOSTCC arch/x86/boot/tools/build /usr/lib/gcc/x86_64-pc-linux-gnu/10.1.0/../../../../x86_64-pc-linux-gnu/bin/ld: error: linker defined: multiple definition of '_end' /usr/lib/gcc/x86_64-pc-linux-gnu/10.1.0/../../../../x86_64-pc-linux-gnu/bin/ld: /tmp/ccEkW0jM.o: previous definition here collect2: error: ld returned 1 exit status make[1]: *** [scripts/Makefile.host:103: arch/x86/boot/tools/build] Error 1 make: *** [arch/x86/Makefile:303: bzImage] Error 2 The issue is with the _end variable that was added, to hold the end of the compressed kernel from zoffsets.h (ZO__end). The name clashes with the linker-defined _end symbol that indicates the end of the build program itself. Even when there is no compile-time error, this causes build to use memory past the end of its .bss section. To solve this, mark _end as static, and for symmetry, mark the rest of the variables that keep track of symbols from the compressed kernel as static as well. Fixes: 964124a97b97 ("efi/x86: Remove extra headroom for setup block") Reported-by: Mike Lothian <mike@fireburn.co.uk> Tested-by: Mike Lothian <mike@fireburn.co.uk> Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Link: https://lore.kernel.org/r/20200511225849.1311869-1-nivedita@alum.mit.edu Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-05-04x86/boot/compressed/64: Switch to __KERNEL_CS after GDT is loadedJoerg Roedel
When the pre-decompression code loads its first GDT in startup_64(), it is still running on the CS value of the previous GDT. In the case of SEV-ES, this is the EFI GDT but it can be anything depending on what has loaded the kernel (boot loader, container runtime, etc.) To make exception handling work (especially IRET) the CPU needs to switch to a CS value in the current GDT, so jump to __KERNEL_CS after the first GDT is loaded. This is prudent also as a general sanitization of CS to a known good value. [ bp: Massage commit message. ] Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20200428151725.31091-13-joro@8bytes.org
2020-05-04x86/boot: Fix -Wint-to-pointer-cast build warningVamshi K Sthambamkadi
Fix this warning when building 32-bit with CONFIG_RANDOMIZE_BASE=y CONFIG_MEMORY_HOTREMOVE=y arch/x86/boot/compressed/acpi.c:316:9: warning: \ cast to pointer from integer of different size [-Wint-to-pointer-cast] Have get_cmdline_acpi_rsdp() return unsigned long which is the proper type to convert to a pointer of the respective width. [ bp: Rewrite commit message, touch ups. ] Signed-off-by: Vamshi K Sthambamkadi <vamshi.k.sthambamkadi@gmail.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/1587645588-7130-3-git-send-email-vamshi.k.sthambamkadi@gmail.com
2020-05-04x86/boot: Add kstrtoul() from lib/Vamshi K Sthambamkadi
Add kstrtoul() to ../boot/ to be used by facilities there too. [ bp: Massage, make _kstrtoul() static. Prepend function names with "boot_". This is a temporary workaround for build errors like: ld: arch/x86/boot/compressed/acpi.o: in function `count_immovable_mem_regions': acpi.c:(.text+0x463): undefined reference to `_kstrtoul' make[2]: *** [arch/x86/boot/compressed/Makefile:117: arch/x86/boot/compressed/vmlinux] Error 1 due to the namespace clash between x86/boot/ and kernel proper. Future reorg will get rid of the linux/linux/ namespace as much as possible so that x86/boot/ can be independent from kernel proper. ] Signed-off-by: Vamshi K Sthambamkadi <vamshi.k.sthambamkadi@gmail.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/1587645588-7130-2-git-send-email-vamshi.k.sthambamkadi@gmail.com
2020-04-24efi/x86: Remove __efistub_global and add relocation checkArvind Sankar
Instead of using __efistub_global to force variables into the .data section, leave them in the .bss but pull the EFI stub's .bss section into .data in the linker script for the compressed kernel. Add relocation checking for x86 as well to catch non-PC-relative relocations that require runtime processing, since the EFI stub does not do any runtime relocation processing. This will catch, for example, data relocations created by static initializers of pointers. Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Link: https://lore.kernel.org/r/20200416151227.3360778-3-nivedita@alum.mit.edu Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-04-21x86/boot/build: Add phony targets in arch/x86/boot/Makefile to PHONYMasahiro Yamada
These targets are correctly added to PHONY in arch/x86/Makefile, but not in arch/x86/boot/Makefile. Thus, with a file 'install' in the top directory, 'make install' does nothing: $ touch install $ make install make[1]: 'install' is up to date. Add them to the PHONY targets in the boot Makefile too. [ bp: Massage. ] Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20200215063852.8298-2-masahiroy@kernel.org
2020-04-21x86/boot/build: Make 'make bzlilo' not depend on vmlinux or $(obj)/bzImageMasahiro Yamada
bzlilo is an installation target because it copies files to $(INSTALL_PATH)/, then runs 'lilo'. However, arch/x86/Makefile and arch/x86/boot/Makefile have it depend on vmlinux and $(obj)/bzImage, respectively. 'make bzlilo' may update some build artifacts in the source tree. As commit 19514fc665ff ("arm, kbuild: make "make install" not depend on vmlinux") explained, this should not happen. Make 'bzlilo' not depend on any build artifact. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20200215063852.8298-1-masahiroy@kernel.org
2020-04-21x86/boot/build: Add cpustr.h to targets and remove clean-filesMasahiro Yamada
Files in $(targets) are always cleaned up. Move the 'targets' assignment out of the ifdef and remove 'clean-files'. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20200215063241.7437-1-masahiroy@kernel.org
2020-04-13Merge tag 'v5.7-rc1' into locking/kcsan, to resolve conflicts and refreshIngo Molnar
Resolve these conflicts: arch/x86/Kconfig arch/x86/kernel/Makefile Do a minor "evil merge" to move the KCSAN entry up a bit by a few lines in the Kconfig to reduce the probability of future conflicts. Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-04-03Merge tag 'spdx-5.7-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/spdx Pull SPDX updates from Greg KH: "Here are three SPDX patches for 5.7-rc1. One fixes up the SPDX tag for a single driver, while the other two go through the tree and add SPDX tags for all of the .gitignore files as needed. Nothing too complex, but you will get a merge conflict with your current tree, that should be trivial to handle (one file modified by two things, one file deleted.) All three of these have been in linux-next for a while, with no reported issues other than the merge conflict" * tag 'spdx-5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/spdx: ASoC: MT6660: make spdxcheck.py happy .gitignore: add SPDX License Identifier .gitignore: remove too obvious comments
2020-04-01Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial Pull trivial tree updates from Jiri Kosina: "My attempt to revitalize trivial queue I've been neglecting for years (what a disaster that was for this world, right? :) ) with patches collected from backlog that were still relevant and not applied elsewhere in the meantime" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: err.h: remove deprecated PTR_RET for good blk-mq: Fix typo in comment x86/boot: Fix comment spelling sh: mach-highlander: Fix comment spelling s390/dasd: Fix comment spelling mfd: wm8994: Fix comment spelling docs: Add reference in binfmt-misc.rst genirq: fix kerneldoc comment for irq_desc drm/amdgpu: fix two documentation mismatch issues HID: fix Kconfig word ordering list/hashtable: minor documentation corrections.
2020-03-31Merge branch 'x86-boot-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 boot updates from Ingo Molnar: "Misc cleanups and small enhancements all around the map" * 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/boot/compressed: Fix debug_puthex() parameter type x86/setup: Fix static memory detection x86/vmlinux: Drop unneeded linker script discard of .eh_frame x86/*/Makefile: Use -fno-asynchronous-unwind-tables to suppress .eh_frame sections x86/boot/compressed: Remove .eh_frame section from bzImage x86/boot/compressed/64: Remove .bss/.pgtable from bzImage x86/boot/compressed/64: Use 32-bit (zero-extended) MOV for z_output_len x86/boot/compressed/64: Use LEA to initialize boot stack pointer
2020-03-28x86/boot/compressed: Fix debug_puthex() parameter typeJoerg Roedel
In the CONFIG_X86_VERBOSE_BOOTUP=Y case, the debug_puthex() macro just turns into __puthex(), which takes 'unsigned long' as parameter. But in the CONFIG_X86_VERBOSE_BOOTUP=N case, it is a function which takes 'unsigned char *', causing compile warnings when the function is used. Fix the parameter type to get rid of the warnings. Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20200319091407.1481-11-joro@8bytes.org
2020-03-25.gitignore: add SPDX License IdentifierMasahiro Yamada
Add SPDX License Identifier to all .gitignore files. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-21Merge branch 'x86/kdump' into locking/kcsan, to resolve conflictsIngo Molnar
Conflicts: arch/x86/purgatory/Makefile Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-03-17x86/boot: Fix comment spellingGeert Uytterhoeven
Fix misspelling of "disconnect". Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2020-03-08efi/x86: Don't relocate the kernel unless necessaryArvind Sankar
Add alignment slack to the PE image size, so that we can realign the decompression buffer within the space allocated for the image. Only relocate the kernel if it has been loaded at an unsuitable address: - Below LOAD_PHYSICAL_ADDR, or - Above 64T for 64-bit and 512MiB for 32-bit For 32-bit, the upper limit is conservative, but the exact limit can be difficult to calculate. Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20200303221205.4048668-6-nivedita@alum.mit.edu Link: https://lore.kernel.org/r/20200308080859.21568-20-ardb@kernel.org
2020-03-08efi/x86: Remove extra headroom for setup blockArvind Sankar
The following commit: 223e3ee56f77 ("efi/x86: add headroom to decompressor BSS to account for setup block") added headroom to the PE image to account for the setup block, which wasn't used for the decompression buffer. Now that the decompression buffer is located at the start of the image, and includes the setup block, this is no longer required. Add a check to make sure that the head section of the compressed kernel won't overwrite itself while relocating. This is only for future-proofing as with current limits on the setup and the actual size of the head section, this can never happen. Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20200303221205.4048668-5-nivedita@alum.mit.edu Link: https://lore.kernel.org/r/20200308080859.21568-19-ardb@kernel.org
2020-03-08efi/x86: Add kernel preferred address to PE headerArvind Sankar
Store the kernel's link address as ImageBase in the PE header. Note that the PE specification requires the ImageBase to be 64k aligned. The preferred address should almost always satisfy that, except for 32-bit kernel if the configuration has been customized. Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20200303221205.4048668-4-nivedita@alum.mit.edu Link: https://lore.kernel.org/r/20200308080859.21568-18-ardb@kernel.org
2020-03-08efi/x86: Decompress at start of PE image load addressArvind Sankar
When booted via PE loader, define image_offset to hold the offset of startup_32() from the start of the PE image, and use it as the start of the decompression buffer. [ mingo: Fixed the grammar in the comments. ] Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20200303221205.4048668-3-nivedita@alum.mit.edu Link: https://lore.kernel.org/r/20200308080859.21568-17-ardb@kernel.org
2020-03-08x86/boot/compressed/32: Save the output address instead of recalculating itArvind Sankar
In preparation for being able to decompress into a buffer starting at a different address than startup_32, save the calculated output address instead of recalculating it later. We now keep track of three addresses: %edx: startup_32 as we were loaded by bootloader %ebx: new location of compressed kernel %ebp: start of decompression buffer Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20200303221205.4048668-2-nivedita@alum.mit.edu Link: https://lore.kernel.org/r/20200308080859.21568-16-ardb@kernel.org
2020-03-08x86/boot: Use unsigned comparison for addressesArvind Sankar
The load address is compared with LOAD_PHYSICAL_ADDR using a signed comparison currently (using jge instruction). When loading a 64-bit kernel using the new efi32_pe_entry() point added by: 97aa276579b2 ("efi/x86: Add true mixed mode entry point into .compat section") using Qemu with -m 3072, the firmware actually loads us above 2Gb, resulting in a very early crash. Use the JAE instruction to perform a unsigned comparison instead, as physical addresses should be considered unsigned. Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20200301230436.2246909-6-nivedita@alum.mit.edu Link: https://lore.kernel.org/r/20200308080859.21568-14-ardb@kernel.org
2020-03-08efi/x86: Avoid using code32_startArvind Sankar
code32_start is meant for 16-bit real-mode bootloaders to inform the kernel where the 32-bit protected mode code starts. Nothing in the protected mode kernel except the EFI stub uses it. efi_main() currently returns boot_params, with code32_start set inside it to tell efi_stub_entry() where startup_32 is located. Since it was invoked by efi_stub_entry() in the first place, boot_params is already known. Return the address of startup_32 instead. This will allow a 64-bit kernel to live above 4Gb, for example, and it's cleaner as well. Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20200301230436.2246909-5-nivedita@alum.mit.edu Link: https://lore.kernel.org/r/20200308080859.21568-13-ardb@kernel.org
2020-03-08efi/x86: Make efi32_pe_entry() more readableArvind Sankar
Set up a proper frame pointer in efi32_pe_entry() so that it's easier to calculate offsets for arguments. Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20200301230436.2246909-4-nivedita@alum.mit.edu Link: https://lore.kernel.org/r/20200308080859.21568-12-ardb@kernel.org
2020-03-08efi/x86: Respect 32-bit ABI in efi32_pe_entry()Arvind Sankar
verify_cpu() clobbers BX and DI. In case we have to return error, we need to preserve them to respect the 32-bit calling convention. Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20200301230436.2246909-3-nivedita@alum.mit.edu Link: https://lore.kernel.org/r/20200308080859.21568-11-ardb@kernel.org
2020-03-08efi/x86: Annotate the LOADED_IMAGE_PROTOCOL_GUID with SYM_DATAArvind Sankar
Use SYM_DATA*() macros to annotate this constant, and explicitly align it to 4-byte boundary. Use lower-case for hexadecimal data. Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20200301230436.2246909-2-nivedita@alum.mit.edu Link: https://lore.kernel.org/r/20200308080859.21568-10-ardb@kernel.org
2020-02-29x86/boot/compressed: Fix reloading of GDTR post-relocationArvind Sankar
The following commit: ef5a7b5eb13e ("efi/x86: Remove GDT setup from efi_main") introduced GDT setup into the 32-bit kernel's startup_32, and reloads the GDTR after relocating the kernel for paranoia's sake. A followup commit: 32d009137a56 ("x86/boot: Reload GDTR after copying to the end of the buffer") introduced a similar GDTR reload in the 64-bit kernel as well. The GDTR is adjusted by (init_size-_end), however this may not be the correct offset to apply if the kernel was loaded at a misaligned address or below LOAD_PHYSICAL_ADDR, as in that case the decompression buffer has an additional offset from the original load address. This should never happen for a conformant bootloader, but we're being paranoid anyway, so just store the new GDT address in there instead of adding any offsets, which is simpler as well. Fixes: ef5a7b5eb13e ("efi/x86: Remove GDT setup from efi_main") Fixes: 32d009137a56 ("x86/boot: Reload GDTR after copying to the end of the buffer") Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: linux-efi@vger.kernel.org Cc: Thomas Gleixner <tglx@linutronix.de> Cc: x86@kernel.org Link: https://lore.kernel.org/r/20200226230031.3011645-2-nivedita@alum.mit.edu
2020-02-26Merge tag 'efi-next' of ↵Ingo Molnar
git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi into efi/core Pull EFI updates for v5.7 from Ard Biesheuvel: This time, the set of changes for the EFI subsystem is much larger than usual. The main reasons are: - Get things cleaned up before EFI support for RISC-V arrives, which will increase the size of the validation matrix, and therefore the threshold to making drastic changes, - After years of defunct maintainership, the GRUB project has finally started to consider changes from the distros regarding UEFI boot, some of which are highly specific to the way x86 does UEFI secure boot and measured boot, based on knowledge of both shim internals and the layout of bootparams and the x86 setup header. Having this maintenance burden on other architectures (which don't need shim in the first place) is hard to justify, so instead, we are introducing a generic Linux/UEFI boot protocol. Summary of changes: - Boot time GDT handling changes (Arvind) - Simplify handling of EFI properties table on arm64 - Generic EFI stub cleanups, to improve command line handling, file I/O, memory allocation, etc. - Introduce a generic initrd loading method based on calling back into the firmware, instead of relying on the x86 EFI handover protocol or device tree. - Introduce a mixed mode boot method that does not rely on the x86 EFI handover protocol either, and could potentially be adopted by other architectures (if another one ever surfaces where one execution mode is a superset of another) - Clean up the contents of struct efi, and move out everything that doesn't need to be stored there. - Incorporate support for UEFI spec v2.8A changes that permit firmware implementations to return EFI_UNSUPPORTED from UEFI runtime services at OS runtime, and expose a mask of which ones are supported or unsupported via a configuration table. - Various documentation updates and minor code cleanups (Heinrich) - Partial fix for the lack of by-VA cache maintenance in the decompressor on 32-bit ARM. Note that these patches were deliberately put at the beginning so they can be used as a stable branch that will be shared with a PR containing the complete fix, which I will send to the ARM tree. Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-02-25x86/vmlinux: Drop unneeded linker script discard of .eh_frameArvind Sankar
Now that .eh_frame sections for the files in setup.elf and realmode.elf are not generated anymore, the linker scripts don't need the special output section name /DISCARD/ any more. Remove the one in the main kernel linker script as well, since there are no .eh_frame sections already, and fix up a comment referencing .eh_frame. Update the comment in asm/dwarf2.h referring to .eh_frame so it continues to make sense, as well as being more specific. [ bp: Touch up commit message. ] Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Tested-by: Nathan Chancellor <natechancellor@gmail.com> Link: https://lkml.kernel.org/r/20200224232129.597160-3-nivedita@alum.mit.edu