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2020-12-24Merge tag 'efi_updates_for_v5.11' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull EFI updates from Borislav Petkov: "These got delayed due to a last minute ia64 build issue which got fixed in the meantime. EFI updates collected by Ard Biesheuvel: - Don't move BSS section around pointlessly in the x86 decompressor - Refactor helper for discovering the EFI secure boot mode - Wire up EFI secure boot to IMA for arm64 - Some fixes for the capsule loader - Expose the RT_PROP table via the EFI test module - Relax DT and kernel placement restrictions on ARM with a few followup fixes: - fix the build breakage on IA64 caused by recent capsule loader changes - suppress a type mismatch build warning in the expansion of EFI_PHYS_ALIGN on ARM" * tag 'efi_updates_for_v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: efi: arm: force use of unsigned type for EFI_PHYS_ALIGN efi: ia64: disable the capsule loader efi: stub: get rid of efi_get_max_fdt_addr() efi/efi_test: read RuntimeServicesSupported efi: arm: reduce minimum alignment of uncompressed kernel efi: capsule: clean scatter-gather entries from the D-cache efi: capsule: use atomic kmap for transient sglist mappings efi: x86/xen: switch to efi_get_secureboot_mode helper arm64/ima: add ima_arch support ima: generalize x86/EFI arch glue for other EFI architectures efi: generalize efi_get_secureboot efi/libstub: EFI_GENERIC_STUB_INITRD_CMDLINE_LOADER should not default to yes efi/x86: Only copy the compressed kernel image in efi_relocate_kernel() efi/libstub/x86: simplify efi_is_native()
2020-12-22kasan, x86, s390: update undef CONFIG_KASANAndrey Konovalov1-0/+1
With the intoduction of hardware tag-based KASAN some kernel checks of this kind: ifdef CONFIG_KASAN will be updated to: if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS) x86 and s390 use a trick to #undef CONFIG_KASAN for some of the code that isn't linked with KASAN runtime and shouldn't have any KASAN annotations. Also #undef CONFIG_KASAN_GENERIC with CONFIG_KASAN. Link: https://lkml.kernel.org/r/9d84bfaaf8fabe0fc89f913c9e420a30bd31a260.1606161801.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Reviewed-by: Marco Elver <elver@google.com> Acked-by: Vasily Gorbik <gor@linux.ibm.com> Reviewed-by: Alexander Potapenko <glider@google.com> Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Branislav Rankov <Branislav.Rankov@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Evgenii Stepanov <eugenis@google.com> Cc: Kevin Brodsky <kevin.brodsky@arm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-12-15Merge tag 'x86_build_for_v5.11' of ↵Linus Torvalds1-12/+0
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 build updates from Borislav Petkov: "Two x86 build fixes: - Fix the vmlinux size check on 64-bit along with adding useful clarifications on the topic (Arvind Sankar) - Remove -m16 workaround now that the GCC versions that need it are unsupported (Nick Desaulniers)" * tag 'x86_build_for_v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/build: Remove -m16 workaround for unsupported versions of GCC x86/build: Fix vmlinux size check on 64-bit
2020-12-15Merge tag 'x86_cleanups_for_v5.11' of ↵Linus Torvalds2-14/+4
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 cleanups from Borislav Petkov: "Another branch with a nicely negative diffstat, just the way I like 'em: - Remove all uses of TIF_IA32 and TIF_X32 and reclaim the two bits in the end (Gabriel Krisman Bertazi) - All kinds of minor cleanups all over the tree" * tag 'x86_cleanups_for_v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits) x86/ia32_signal: Propagate __user annotation properly x86/alternative: Update text_poke_bp() kernel-doc comment x86/PCI: Make a kernel-doc comment a normal one x86/asm: Drop unused RDPID macro x86/boot/compressed/64: Use TEST %reg,%reg instead of CMP $0,%reg x86/head64: Remove duplicate include x86/mm: Declare 'start' variable where it is used x86/head/64: Remove unused GET_CR2_INTO() macro x86/boot: Remove unused finalize_identity_maps() x86/uaccess: Document copy_from_user_nmi() x86/dumpstack: Make show_trace_log_lvl() static x86/mtrr: Fix a kernel-doc markup x86/setup: Remove unused MCA variables x86, libnvdimm/test: Remove COPY_MC_TEST x86: Reclaim TIF_IA32 and TIF_X32 x86/mm: Convert mmu context ia32_compat into a proper flags field x86/elf: Use e_machine to check for x32/ia32 in setup_additional_pages() elf: Expose ELF header on arch_setup_additional_pages() x86/elf: Use e_machine to select start_thread for x32 elf: Expose ELF header in compat_start_thread() ...
2020-12-06Merge tag 'x86-urgent-2020-12-06' of ↵Linus Torvalds1-3/+2
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 fixes from Thomas Gleixner: "A set of fixes for x86: - Make the AMD L3 QoS code and data priorization enable/disable mechanism work correctly. The control bit was only set/cleared on one of the CPUs in a L3 domain, but it has to be modified on all CPUs in the domain. The initial documentation was not clear about this, but the updated one from Oct 2020 spells it out. - Fix an off by one in the UV platform detection code which causes the UV hubs to be identified wrongly. The chip revisions start at 1 not at 0. - Fix a long standing bug in the evaluation of prefixes in the uprobes code which fails to handle repeated prefixes properly. The aggregate size of the prefixes can be larger than the bytes array but the code blindly iterated over the aggregate size beyond the array boundary. Add a macro to handle this case properly and use it at the affected places" * tag 'x86-urgent-2020-12-06' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/sev-es: Use new for_each_insn_prefix() macro to loop over prefixes bytes x86/insn-eval: Use new for_each_insn_prefix() macro to loop over prefixes bytes x86/uprobes: Do not use prefixes.nbytes when looping over prefixes.bytes x86/platform/uv: Fix UV4 hub revision adjustment x86/resctrl: Fix AMD L3 QOS CDP enable/disable
2020-12-06x86/sev-es: Use new for_each_insn_prefix() macro to loop over prefixes bytesMasami Hiramatsu1-3/+2
Since insn.prefixes.nbytes can be bigger than the size of insn.prefixes.bytes[] when a prefix is repeated, the proper check must be: insn.prefixes.bytes[i] != 0 and i < 4 instead of using insn.prefixes.nbytes. Use the new for_each_insn_prefix() macro which does it correctly. Debugged by Kees Cook <keescook@chromium.org>. [ bp: Massage commit message. ] Fixes: 25189d08e516 ("x86/sev-es: Add support for handling IOIO exceptions") Reported-by: syzbot+9b64b619f10f19d19a7c@syzkaller.appspotmail.com Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/160697106089.3146288.2052422845039649176.stgit@devnote2
2020-12-01x86/build: Remove -m16 workaround for unsupported versions of GCCNick Desaulniers1-12/+0
Revert the following two commits: de3accdaec88 ("x86, build: Build 16-bit code with -m16 where possible") a9cfccee6604 ("x86, build: Change code16gcc.h from a C header to an assembly header") Since 0bddd227f3dc ("Documentation: update for gcc 4.9 requirement") the minimum supported version of GCC is gcc-4.9. It's now safe to remove this code. Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Reviewed-by: David Woodhouse <dwmw@amazon.co.uk> Link: https://lkml.kernel.org/r/20201201011307.3676986-1-ndesaulniers@google.com
2020-12-01kbuild: Hoist '--orphan-handling' into KconfigNathan Chancellor1-1/+3
Currently, '--orphan-handling=warn' is spread out across four different architectures in their respective Makefiles, which makes it a little unruly to deal with in case it needs to be disabled for a specific linker version (in this case, ld.lld 10.0.1). To make it easier to control this, hoist this warning into Kconfig and the main Makefile so that disabling it is simpler, as the warning will only be enabled in a couple places (main Makefile and a couple of compressed boot folders that blow away LDFLAGS_vmlinx) and making it conditional is easier due to Kconfig syntax. One small additional benefit of this is saving a call to ld-option on incremental builds because we will have already evaluated it for CONFIG_LD_ORPHAN_WARN. To keep the list of supported architectures the same, introduce CONFIG_ARCH_WANT_LD_ORPHAN_WARN, which an architecture can select to gain this automatically after all of the sections are specified and size asserted. A special thanks to Kees Cook for the help text on this config. Link: https://github.com/ClangBuiltLinux/linux/issues/1187 Acked-by: Kees Cook <keescook@chromium.org> Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-11-21x86/boot/compressed/64: Use TEST %reg,%reg instead of CMP $0,%regUros Bizjak1-4/+4
Use TEST %reg,%reg which sets the zero flag in the same way as CMP $0,%reg, but the encoding uses one byte less. Signed-off-by: Uros Bizjak <ubizjak@gmail.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Andy Lutomirski <luto@kernel.org> Link: https://lkml.kernel.org/r/20201029160258.139216-1-ubizjak@gmail.com
2020-11-18x86/boot: Remove unused finalize_identity_maps()Arvind Sankar1-10/+0
Commit 8570978ea030 ("x86/boot/compressed/64: Don't pre-map memory in KASLR code") removed all the references to finalize_identity_maps(), but neglected to delete the actual function. Remove it. Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20201005151208.2212886-2-nivedita@alum.mit.edu
2020-11-05efi: generalize efi_get_securebootChester Lin1-1/+1
Generalize the efi_get_secureboot() function so not only efistub but also other subsystems can use it. Note that the MokSbState handling is not factored out: the variable is boot time only, and so it cannot be parameterized as easily. Also, the IMA code will switch to this version in a future patch, and it does not incorporate the MokSbState exception in the first place. Note that the new efi_get_secureboot_mode() helper treats any failures to read SetupMode as setup mode being disabled. Co-developed-by: Chester Lin <clin@suse.com> Signed-off-by: Chester Lin <clin@suse.com> Acked-by: Mimi Zohar <zohar@linux.ibm.com> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-10-29x86/boot/compressed/64: Check SEV encryption in 64-bit boot-pathJoerg Roedel3-0/+7
Check whether the hypervisor reported the correct C-bit when running as an SEV guest. Using a wrong C-bit position could be used to leak sensitive data from the guest to the hypervisor. The check function is in a separate file: arch/x86/kernel/sev_verify_cbit.S so that it can be re-used in the running kernel image. [ bp: Massage. ] Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com> Link: https://lkml.kernel.org/r/20201028164659.27002-4-joro@8bytes.org
2020-10-29x86/boot/compressed/64: Introduce sev_statusJoerg Roedel1-1/+15
Introduce sev_status and initialize it together with sme_me_mask to have an indicator which SEV features are enabled. Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com> Link: https://lkml.kernel.org/r/20201028164659.27002-2-joro@8bytes.org
2020-10-26treewide: Convert macro and uses of __section(foo) to __section("foo")Joe Perches3-9/+9
Use a more generic form for __section that requires quotes to avoid complications with clang and gcc differences. Remove the quote operator # from compiler_attributes.h __section macro. Convert all unquoted __section(foo) uses to quoted __section("foo"). Also convert __attribute__((section("foo"))) uses to __section("foo") even if the __attribute__ has multiple list entry forms. Conversion done using the script at: https://lore.kernel.org/lkml/75393e5ddc272dc7403de74d645e6c6e0f4e70eb.camel@perches.com/2-convert_section.pl Signed-off-by: Joe Perches <joe@perches.com> Reviewed-by: Nick Desaulniers <ndesaulniers@gooogle.com> Reviewed-by: Miguel Ojeda <ojeda@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-19x86/boot/64: Explicitly map boot_params and command lineArvind Sankar2-3/+23
Commits ca0e22d4f011 ("x86/boot/compressed/64: Always switch to own page table") 8570978ea030 ("x86/boot/compressed/64: Don't pre-map memory in KASLR code") set up a new page table in the decompressor stub, but without explicit mappings for boot_params and the kernel command line, relying on the #PF handler instead. This is fragile, as boot_params and the command line mappings are required for the main kernel. If EARLY_PRINTK and RANDOMIZE_BASE are disabled, a QEMU/OVMF boot never accesses the command line in the decompressor stub, and so it never gets mapped. The main kernel accesses it from the identity mapping if AMD_MEM_ENCRYPT is enabled, and will crash. Fix this by adding back the explicit mapping of boot_params and the command line. Note: the changes also removed the explicit mapping of the main kernel, with the result that .bss and .brk may not be in the identity mapping, but those don't get accessed by the main kernel before it switches to its own page tables. [ bp: Pass boot_params with a MOV %rsp... instead of PUSH/POP. Use block formatting for the comment. ] Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Joerg Roedel <jroedel@suse.de> Link: https://lkml.kernel.org/r/20201016200404.1615994-1-nivedita@alum.mit.edu
2020-10-19x86/boot/64: Initialize 5-level paging variables earlierArvind Sankar3-14/+16
Commit ca0e22d4f011 ("x86/boot/compressed/64: Always switch to own page table") started using a new set of pagetables even without KASLR. After that commit, initialize_identity_maps() is called before the 5-level paging variables are setup in choose_random_location(), which will not work if 5-level paging is actually enabled. Fix this by moving the initialization of __pgtable_l5_enabled, pgdir_shift and ptrs_per_p4d into cleanup_trampoline(), which is called immediately after the finalization of whether the kernel is executing with 4- or 5-level paging. This will be earlier than anything that might require those variables, and keeps the 4- vs 5-level paging code all in one place. Fixes: ca0e22d4f011 ("x86/boot/compressed/64: Always switch to own page table") Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Joerg Roedel <jroedel@suse.de> Tested-by: Joerg Roedel <jroedel@suse.de> Tested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Link: https://lkml.kernel.org/r/20201010191110.4060905-1-nivedita@alum.mit.edu
2020-10-14Merge tag 'x86_seves_for_v5.10' of ↵Linus Torvalds11-207/+781
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 SEV-ES support from Borislav Petkov: "SEV-ES enhances the current guest memory encryption support called SEV by also encrypting the guest register state, making the registers inaccessible to the hypervisor by en-/decrypting them on world switches. Thus, it adds additional protection to Linux guests against exfiltration, control flow and rollback attacks. With SEV-ES, the guest is in full control of what registers the hypervisor can access. This is provided by a guest-host exchange mechanism based on a new exception vector called VMM Communication Exception (#VC), a new instruction called VMGEXIT and a shared Guest-Host Communication Block which is a decrypted page shared between the guest and the hypervisor. Intercepts to the hypervisor become #VC exceptions in an SEV-ES guest so in order for that exception mechanism to work, the early x86 init code needed to be made able to handle exceptions, which, in itself, brings a bunch of very nice cleanups and improvements to the early boot code like an early page fault handler, allowing for on-demand building of the identity mapping. With that, !KASLR configurations do not use the EFI page table anymore but switch to a kernel-controlled one. The main part of this series adds the support for that new exchange mechanism. The goal has been to keep this as much as possibly separate from the core x86 code by concentrating the machinery in two SEV-ES-specific files: arch/x86/kernel/sev-es-shared.c arch/x86/kernel/sev-es.c Other interaction with core x86 code has been kept at minimum and behind static keys to minimize the performance impact on !SEV-ES setups. Work by Joerg Roedel and Thomas Lendacky and others" * tag 'x86_seves_for_v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (73 commits) x86/sev-es: Use GHCB accessor for setting the MMIO scratch buffer x86/sev-es: Check required CPU features for SEV-ES x86/efi: Add GHCB mappings when SEV-ES is active x86/sev-es: Handle NMI State x86/sev-es: Support CPU offline/online x86/head/64: Don't call verify_cpu() on starting APs x86/smpboot: Load TSS and getcpu GDT entry before loading IDT x86/realmode: Setup AP jump table x86/realmode: Add SEV-ES specific trampoline entry point x86/vmware: Add VMware-specific handling for VMMCALL under SEV-ES x86/kvm: Add KVM-specific VMMCALL handling under SEV-ES x86/paravirt: Allow hypervisor-specific VMMCALL handling under SEV-ES x86/sev-es: Handle #DB Events x86/sev-es: Handle #AC Events x86/sev-es: Handle VMMCALL Events x86/sev-es: Handle MWAIT/MWAITX Events x86/sev-es: Handle MONITOR/MONITORX Events x86/sev-es: Handle INVD Events x86/sev-es: Handle RDPMC Events x86/sev-es: Handle RDTSC(P) Events ...
2020-10-13Merge tag 'x86_asm_for_v5.10' of ↵Linus Torvalds1-9/+0
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 asm updates from Borislav Petkov: "Two asm wrapper fixes: - Use XORL instead of XORQ to avoid a REX prefix and save some bytes in the .fixup section, by Uros Bizjak. - Replace __force_order dummy variable with a memory clobber to fix LLVM requiring a definition for former and to prevent memory accesses from still being cached/reordered, by Arvind Sankar" * tag 'x86_asm_for_v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/asm: Replace __force_order with a memory clobber x86/uaccess: Use XORL %0,%0 in __get_user_asm()
2020-10-13Merge tag 'x86-build-2020-10-12' of ↵Linus Torvalds1-4/+0
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 build update from Ingo Molnar: "Remove a couple of ancient and distracting printouts from the x86 build, such as the CRC sum or limited size data - most of which can be gained via tools" * tag 'x86-build-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/build: Declutter the build output
2020-10-13Merge tag 'x86-kaslr-2020-10-12' of ↵Linus Torvalds2-135/+107
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 kaslr updates from Ingo Molnar: "This cleans up and simplifies the x86 KASLR code, and also fixes some corner case bugs" * tag 'x86-kaslr-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (22 commits) x86/kaslr: Replace strlen() with strnlen() x86/kaslr: Add a check that the random address is in range x86/kaslr: Make local variables 64-bit x86/kaslr: Replace 'unsigned long long' with 'u64' x86/kaslr: Make minimum/image_size 'unsigned long' x86/kaslr: Small cleanup of find_random_phys_addr() x86/kaslr: Drop unnecessary alignment in find_random_virt_addr() x86/kaslr: Drop redundant check in store_slot_info() x86/kaslr: Make the type of number of slots/slot areas consistent x86/kaslr: Drop test for command-line parameters before parsing x86/kaslr: Simplify process_gb_huge_pages() x86/kaslr: Short-circuit gb_huge_pages on x86-32 x86/kaslr: Fix off-by-one error in process_gb_huge_pages() x86/kaslr: Drop some redundant checks from __process_mem_region() x86/kaslr: Drop redundant variable in __process_mem_region() x86/kaslr: Eliminate 'start_orig' local variable from __process_mem_region() x86/kaslr: Drop redundant cur_entry from __process_mem_region() x86/kaslr: Fix off-by-one error in __process_mem_region() x86/kaslr: Initialize mem_limit to the real maximum address x86/kaslr: Fix process_efi_entries comment ...
2020-10-12Merge tag 'core-build-2020-10-12' of ↵Linus Torvalds6-204/+159
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull orphan section checking from Ingo Molnar: "Orphan link sections were a long-standing source of obscure bugs, because the heuristics that various linkers & compilers use to handle them (include these bits into the output image vs discarding them silently) are both highly idiosyncratic and also version dependent. Instead of this historically problematic mess, this tree by Kees Cook (et al) adds build time asserts and build time warnings if there's any orphan section in the kernel or if a section is not sized as expected. And because we relied on so many silent assumptions in this area, fix a metric ton of dependencies and some outright bugs related to this, before we can finally enable the checks on the x86, ARM and ARM64 platforms" * tag 'core-build-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (36 commits) x86/boot/compressed: Warn on orphan section placement x86/build: Warn on orphan section placement arm/boot: Warn on orphan section placement arm/build: Warn on orphan section placement arm64/build: Warn on orphan section placement x86/boot/compressed: Add missing debugging sections to output x86/boot/compressed: Remove, discard, or assert for unwanted sections x86/boot/compressed: Reorganize zero-size section asserts x86/build: Add asserts for unwanted sections x86/build: Enforce an empty .got.plt section x86/asm: Avoid generating unused kprobe sections arm/boot: Handle all sections explicitly arm/build: Assert for unwanted sections arm/build: Add missing sections arm/build: Explicitly keep .ARM.attributes sections arm/build: Refactor linker script headers arm64/build: Assert for unwanted sections arm64/build: Add missing DWARF sections arm64/build: Use common DISCARDS in linker script arm64/build: Remove .eh_frame* sections due to unwind tables ...
2020-10-01x86/asm: Replace __force_order with a memory clobberArvind Sankar1-9/+0
The CRn accessor functions use __force_order as a dummy operand to prevent the compiler from reordering CRn reads/writes with respect to each other. The fact that the asm is volatile should be enough to prevent this: volatile asm statements should be executed in program order. However GCC 4.9.x and 5.x have a bug that might result in reordering. This was fixed in 8.1, 7.3 and 6.5. Versions prior to these, including 5.x and 4.9.x, may reorder volatile asm statements with respect to each other. There are some issues with __force_order as implemented: - It is used only as an input operand for the write functions, and hence doesn't do anything additional to prevent reordering writes. - It allows memory accesses to be cached/reordered across write functions, but CRn writes affect the semantics of memory accesses, so this could be dangerous. - __force_order is not actually defined in the kernel proper, but the LLVM toolchain can in some cases require a definition: LLVM (as well as GCC 4.9) requires it for PIE code, which is why the compressed kernel has a definition, but also the clang integrated assembler may consider the address of __force_order to be significant, resulting in a reference that requires a definition. Fix this by: - Using a memory clobber for the write functions to additionally prevent caching/reordering memory accesses across CRn writes. - Using a dummy input operand with an arbitrary constant address for the read functions, instead of a global variable. This will prevent reads from being reordered across writes, while allowing memory loads to be cached/reordered across CRn reads, which should be safe. Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com> Tested-by: Nathan Chancellor <natechancellor@gmail.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82602 Link: https://lore.kernel.org/lkml/20200527135329.1172644-1-arnd@arndb.de/ Link: https://lkml.kernel.org/r/20200902232152.3709896-1-nivedita@alum.mit.edu
2020-09-14x86/boot/compressed: Disable relocation relaxationArvind Sankar1-0/+2
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
2020-09-10x86/sev-es: Check required CPU features for SEV-ESMartin Radev3-6/+6
Make sure the machine supports RDRAND, otherwise there is no trusted source of randomness in the system. To also check this in the pre-decompression stage, make has_cpuflag() not depend on CONFIG_RANDOMIZE_BASE anymore. Signed-off-by: Martin Radev <martin.b.radev@gmail.com> Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lkml.kernel.org/r/20200907131613.12703-73-joro@8bytes.org
2020-09-10x86/efi: Add GHCB mappings when SEV-ES is activeTom Lendacky1-0/+1
Calling down to EFI runtime services can result in the firmware performing VMGEXIT calls. The firmware is likely to use the GHCB of the OS (e.g., for setting EFI variables), so each GHCB in the system needs to be identity-mapped in the EFI page tables, as unencrypted, to avoid page faults. Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> [ jroedel@suse.de: Moved GHCB mapping loop to sev-es.c ] Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Ard Biesheuvel <ardb@kernel.org> Link: https://lkml.kernel.org/r/20200907131613.12703-72-joro@8bytes.org
2020-09-09x86/sev-es: Handle RDTSC(P) EventsTom Lendacky1-0/+4
Implement a handler for #VC exceptions caused by RDTSC and RDTSCP instructions. Also make it available in the pre-decompression stage because the KASLR code uses RDTSC/RDTSCP to gather entropy and some hypervisors intercept these instructions. Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> [ jroedel@suse.de: - Adapt to #VC handling infrastructure - Make it available early ] Co-developed-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20200907131613.12703-55-joro@8bytes.org
2020-09-07x86/sev-es: Add CPUID handling to #VC handlerTom Lendacky1-0/+4
Handle #VC exceptions caused by CPUID instructions. These happen in early boot code when the KASLR code checks for RDTSC. Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> [ jroedel@suse.de: Adapt to #VC handling framework ] Co-developed-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20200907131613.12703-28-joro@8bytes.org
2020-09-07x86/sev-es: Add support for handling IOIO exceptionsTom Lendacky1-0/+32
Add support for decoding and handling #VC exceptions for IOIO events. [ jroedel@suse.de: Adapted code to #VC handling framework ] Co-developed-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20200907131613.12703-26-joro@8bytes.org
2020-09-07x86/boot/compressed/64: Unmap GHCB page before booting the kernelJoerg Roedel3-2/+35
Force a page-fault on any further accesses to the GHCB page when they shouldn't happen anymore. This will catch any bugs where a #VC exception is raised even though none is expected anymore. Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20200907131613.12703-25-joro@8bytes.org
2020-09-07x86/boot/compressed/64: Setup a GHCB-based VC Exception handlerJoerg Roedel6-1/+136
Install an exception handler for #VC exception that uses a GHCB. Also add the infrastructure for handling different exit-codes by decoding the instruction that caused the exception and error handling. Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20200907131613.12703-24-joro@8bytes.org
2020-09-07x86/boot/compressed/64: Add set_page_en/decrypted() helpersJoerg Roedel2-0/+135
The functions are needed to map the GHCB for SEV-ES guests. The GHCB is used for communication with the hypervisor, so its content must not be encrypted. After the GHCB is not needed anymore it must be mapped encrypted again so that the running kernel image can safely re-use the memory. Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20200907131613.12703-23-joro@8bytes.org
2020-09-07x86/boot/compressed/64: Check return value of kernel_ident_mapping_init()Joerg Roedel1-2/+5
The function can fail to create an identity mapping, check for that and bail out if it happens. Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20200907131613.12703-22-joro@8bytes.org
2020-09-07x86/boot/compressed/64: Call set_sev_encryption_mask() earlierJoerg Roedel2-4/+8
Call set_sev_encryption_mask() while still on the stage 1 #VC-handler because the stage 2 handler needs the kernel's own page tables to be set up, to which calling set_sev_encryption_mask() is a prerequisite. Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20200907131613.12703-21-joro@8bytes.org
2020-09-07x86/boot/compressed/64: Add stage1 #VC handlerJoerg Roedel5-0/+55
Add the first handler for #VC exceptions. At stage 1 there is no GHCB yet because the kernel might still be running on the EFI page table. The stage 1 handler is limited to the MSR-based protocol to talk to the hypervisor and can only support CPUID exit-codes, but that is enough to get to stage 2. [ bp: Zap superfluous newlines after rd/wrmsr instruction mnemonics. ] Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20200907131613.12703-20-joro@8bytes.org
2020-09-07x86/boot/compressed/64: Change add_identity_map() to take start and endJoerg Roedel1-10/+5
Changing the function to take start and end as parameters instead of start and size simplifies the callers which don't need to calculate the size if they already have start and end. Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lkml.kernel.org/r/20200907131613.12703-19-joro@8bytes.org
2020-09-07x86/boot/compressed/64: Don't pre-map memory in KASLR codeJoerg Roedel3-37/+3
With the page-fault handler in place, he identity mapping can be built on-demand. So remove the code which manually creates the mappings and unexport/remove the functions used for it. Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lkml.kernel.org/r/20200907131613.12703-18-joro@8bytes.org
2020-09-07x86/boot/compressed/64: Always switch to own page tableJoerg Roedel3-25/+32
When booted through startup_64(), the kernel keeps running on the EFI page table until the KASLR code sets up its own page table. Without KASLR, the pre-decompression boot code never switches off the EFI page table. Change that by unconditionally switching to a kernel-controlled page table after relocation. This makes sure the kernel can make changes to the mapping when necessary, for example map pages unencrypted in SEV and SEV-ES guests. Also, remove the debug_putstr() calls in initialize_identity_maps() because the function now runs before console_init() is called. [ bp: Massage commit message. ] Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lkml.kernel.org/r/20200907131613.12703-17-joro@8bytes.org
2020-09-07x86/boot/compressed/64: Add page-fault handlerJoerg Roedel4-0/+49
Install a page-fault handler to add an identity mapping to addresses not yet mapped. Also do some checking whether the error code is sane. This makes non SEV-ES machines use the exception handling infrastructure in the pre-decompressions boot code too, making it less likely to break in the future. Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lkml.kernel.org/r/20200907131613.12703-16-joro@8bytes.org
2020-09-07x86/boot/compressed/64: Rename kaslr_64.c to ident_map_64.cJoerg Roedel4-10/+18
The file contains only code related to identity-mapped page tables. Rename the file and compile it always in. Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lkml.kernel.org/r/20200907131613.12703-15-joro@8bytes.org
2020-09-07x86/boot/compressed/64: Add IDT InfrastructureJoerg Roedel5-1/+144
Add code needed to setup an IDT in the early pre-decompression boot-code. The IDT is loaded first in startup_64, which is after EfiExitBootServices() has been called, and later reloaded when the kernel image has been relocated to the end of the decompression area. This allows to setup different IDT handlers before and after the relocation. Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20200907131613.12703-14-joro@8bytes.org
2020-09-07x86/boot/compressed/64: Disable red-zone usageJoerg Roedel1-1/+1
The x86-64 ABI defines a red-zone on the stack: The 128-byte area beyond the location pointed to by %rsp is considered to be reserved and shall not be modified by signal or interrupt handlers. Therefore, functions may use this area for temporary data that is not needed across function calls. In particular, leaf functions may use this area for their entire stack frame, rather than adjusting the stack pointer in the prologue and epilogue. This area is known as the red zone. This is not compatible with exception handling, because the IRET frame written by the hardware at the stack pointer and the functions to handle the exception will overwrite the temporary variables of the interrupted function, causing undefined behavior. So disable red-zones for the pre-decompression boot code. Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lkml.kernel.org/r/20200907131613.12703-13-joro@8bytes.org
2020-09-07Merge 'x86/kaslr' to pick up dependent bitsBorislav Petkov2-135/+107
Signed-off-by: Borislav Petkov <bp@suse.de>
2020-09-03x86/boot/compressed: Warn on orphan section placementKees Cook1-0/+1
We don't want to depend on the linker's orphan section placement heuristics as these can vary between linkers, and may change between versions. All sections need to be explicitly handled in the linker script. Now that all sections are explicitly handled, enable orphan section warnings. Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Link: https://lore.kernel.org/r/20200902025347.2504702-6-keescook@chromium.org
2020-09-01x86/boot/compressed: Add missing debugging sections to outputKees Cook1-0/+2
Include the missing DWARF and STABS sections in the compressed image, when they are present. Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20200821194310.3089815-29-keescook@chromium.org
2020-09-01x86/boot/compressed: Remove, discard, or assert for unwanted sectionsKees Cook2-2/+13
In preparation for warning on orphan sections, stop the linker from generating the .eh_frame* sections, discard unwanted non-zero-sized generated sections, and enforce other expected-to-be-zero-sized sections (since discarding them might hide problems with them suddenly gaining unexpected entries). Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20200821194310.3089815-28-keescook@chromium.org
2020-09-01x86/boot/compressed: Reorganize zero-size section assertsKees Cook1-18/+26
For readability, move the zero-sized sections to the end after DISCARDS. Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20200821194310.3089815-27-keescook@chromium.org
2020-09-01vmlinux.lds.h: Split ELF_DETAILS from STABS_DEBUGKees Cook1-0/+2
The .comment section doesn't belong in STABS_DEBUG. Split it out into a new macro named ELF_DETAILS. This will gain other non-debug sections that need to be accounted for when linking with --orphan-handling=warn. Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: linux-arch@vger.kernel.org Link: https://lore.kernel.org/r/20200821194310.3089815-5-keescook@chromium.org
2020-08-24treewide: Use fallthrough pseudo-keywordGustavo A. R. Silva2-3/+3
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>
2020-08-20x86/build: Declutter the build outputIngo Molnar1-4/+0
We have some really ancient debug printouts in the x86 boot image build code: Setup is 14108 bytes (padded to 14336 bytes). System is 8802 kB CRC 27e909d4 None of these ever helped debug any sort of breakage that I know of, and they clutter the build output. Remove them - if anyone needs the see the various interim stages of this to debug an obscure bug, they can add these printfs and more. We still keep this one: Kernel: arch/x86/boot/bzImage is ready (#19) As a sentimental leftover, plus the '#19' build count tag is mildly useful. Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: linux-kernel@vger.kernel.org Cc: x86@kernel.org
2020-08-19x86/boot/compressed: Use builtin mem functions for decompressorArvind Sankar2-9/+3
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>
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