Commit Graph

1053 Commits

Author SHA1 Message Date
Linus Torvalds 1b98ed0e83 Modernize the genimage.sh script, add a 'hdimage' target and EFI support.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'x86-boot-2021-06-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 boot update from Ingo Molnar:
 "Modernize the genimage.sh script, add a 'hdimage' target and EFI
  support"

* tag 'x86-boot-2021-06-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/boot: Modernize genimage script; hdimage+EFI support
2021-06-28 13:05:09 -07:00
Nick Desaulniers a554e740b6 x86/boot/compressed: Enable -Wundef
A discussion around -Wundef showed that there were still a few boolean
Kconfigs where #if was used rather than #ifdef to guard different code.
Kconfig doesn't define boolean configs, which can result in -Wundef
warnings.

arch/x86/boot/compressed/Makefile resets the CFLAGS used for this
directory, and doesn't re-enable -Wundef as the top level Makefile does.
If re-added, with RANDOMIZE_BASE and X86_NEED_RELOCS disabled, the
following warnings are visible.

  arch/x86/boot/compressed/misc.h:82:5: warning: 'CONFIG_RANDOMIZE_BASE'
  is not defined, evaluates to 0 [-Wundef]
      ^
  arch/x86/boot/compressed/misc.c:175:5: warning: 'CONFIG_X86_NEED_RELOCS'
  is not defined, evaluates to 0 [-Wundef]
      ^

Simply fix these and re-enable this warning for this directory.

Suggested-by: Nathan Chancellor <nathan@kernel.org>
Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20210422190450.3903999-1-ndesaulniers@google.com
2021-05-12 21:39:56 +02:00
H. Peter Anvin (Intel) f279b49f13 x86/boot: Modernize genimage script; hdimage+EFI support
The image generation scripts in arch/x86/boot are pretty out of date,
except for the isoimage target. Update and clean up the
genimage.sh script, and make it support an arbitrary number of
initramfs files in the image.

Add a "hdimage" target, which can be booted by either BIOS or
EFI (if the kernel is compiled with the EFI stub.) For EFI to be able
to pass the command line to the kernel, we need the EFI shell, but the
firmware builtin EFI shell, if it even exists, is pretty much always
the last resort boot option, so search for OVMF or EDK2 and explicitly
include a copy of the EFI shell.

To make this all work, use bash features in the script.  Furthermore,
this version of the script makes use of some mtools features,
especially mpartition, that might not exist in very old version of
mtools, but given all the other dependencies on this script this
doesn't seem such a big deal.

Finally, put a volume label ("LINUX_BOOT") on all generated images.

Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210510082840.628372-1-hpa@zytor.com
2021-05-10 12:27:50 +02:00
Brijesh Singh e759959fe3 x86/sev-es: Rename sev-es.{ch} to sev.{ch}
SEV-SNP builds upon the SEV-ES functionality while adding new hardware
protection. Version 2 of the GHCB specification adds new NAE events that
are SEV-SNP specific. Rename the sev-es.{ch} to sev.{ch} so that all
SEV* functionality can be consolidated in one place.

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Joerg Roedel <jroedel@suse.de>
Link: https://lkml.kernel.org/r/20210427111636.1207-2-brijesh.singh@amd.com
2021-05-10 07:40:27 +02:00
Linus Torvalds c6536676c7 - turn the stack canary into a normal __percpu variable on 32-bit which
gets rid of the LAZY_GS stuff and a lot of code.
 
 - Add an insn_decode() API which all users of the instruction decoder
 should preferrably use. Its goal is to keep the details of the
 instruction decoder away from its users and simplify and streamline how
 one decodes insns in the kernel. Convert its users to it.
 
 - kprobes improvements and fixes
 
 - Set the maximum DIE per package variable on Hygon
 
 - Rip out the dynamic NOP selection and simplify all the machinery around
 selecting NOPs. Use the simplified NOPs in objtool now too.
 
 - Add Xeon Sapphire Rapids to list of CPUs that support PPIN
 
 - Simplify the retpolines by folding the entire thing into an
 alternative now that objtool can handle alternatives with stack
 ops. Then, have objtool rewrite the call to the retpoline with the
 alternative which then will get patched at boot time.
 
 - Document Intel uarch per models in intel-family.h
 
 - Make Sub-NUMA Clustering topology the default and Cluster-on-Die the
 exception on Intel.
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Merge tag 'x86_core_for_v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 updates from Borislav Petkov:

 - Turn the stack canary into a normal __percpu variable on 32-bit which
   gets rid of the LAZY_GS stuff and a lot of code.

 - Add an insn_decode() API which all users of the instruction decoder
   should preferrably use. Its goal is to keep the details of the
   instruction decoder away from its users and simplify and streamline
   how one decodes insns in the kernel. Convert its users to it.

 - kprobes improvements and fixes

 - Set the maximum DIE per package variable on Hygon

 - Rip out the dynamic NOP selection and simplify all the machinery
   around selecting NOPs. Use the simplified NOPs in objtool now too.

 - Add Xeon Sapphire Rapids to list of CPUs that support PPIN

 - Simplify the retpolines by folding the entire thing into an
   alternative now that objtool can handle alternatives with stack ops.
   Then, have objtool rewrite the call to the retpoline with the
   alternative which then will get patched at boot time.

 - Document Intel uarch per models in intel-family.h

 - Make Sub-NUMA Clustering topology the default and Cluster-on-Die the
   exception on Intel.

* tag 'x86_core_for_v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (53 commits)
  x86, sched: Treat Intel SNC topology as default, COD as exception
  x86/cpu: Comment Skylake server stepping too
  x86/cpu: Resort and comment Intel models
  objtool/x86: Rewrite retpoline thunk calls
  objtool: Skip magical retpoline .altinstr_replacement
  objtool: Cache instruction relocs
  objtool: Keep track of retpoline call sites
  objtool: Add elf_create_undef_symbol()
  objtool: Extract elf_symbol_add()
  objtool: Extract elf_strtab_concat()
  objtool: Create reloc sections implicitly
  objtool: Add elf_create_reloc() helper
  objtool: Rework the elf_rebuild_reloc_section() logic
  objtool: Fix static_call list generation
  objtool: Handle per arch retpoline naming
  objtool: Correctly handle retpoline thunk calls
  x86/retpoline: Simplify retpolines
  x86/alternatives: Optimize optimize_nops()
  x86: Add insn_decode_kernel()
  x86/kprobes: Move 'inline' to the beginning of the kprobe_is_ss() declaration
  ...
2021-04-27 17:45:09 -07:00
Linus Torvalds ca53fb2c7c A bunch of clang build fixes and a Kconfig highmem selection fix for
486SX.
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Merge tag 'x86_build_for_v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 build updates from Borislav Petkov:
 "A bunch of clang build fixes and a Kconfig highmem selection fix for
  486SX"

* tag 'x86_build_for_v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/build: Disable HIGHMEM64G selection for M486SX
  efi/libstub: Add $(CLANG_FLAGS) to x86 flags
  x86/boot: Add $(CLANG_FLAGS) to compressed KBUILD_CFLAGS
  x86/build: Propagate $(CLANG_FLAGS) to $(REALMODE_FLAGS)
2021-04-26 09:32:35 -07:00
Linus Torvalds ea5bc7b977 Trivial cleanups and fixes all over the place.
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Merge tag 'x86_cleanups_for_v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull misc x86 cleanups from Borislav Petkov:
 "Trivial cleanups and fixes all over the place"

* tag 'x86_cleanups_for_v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  MAINTAINERS: Remove me from IDE/ATAPI section
  x86/pat: Do not compile stubbed functions when X86_PAT is off
  x86/asm: Ensure asm/proto.h can be included stand-alone
  x86/platform/intel/quark: Fix incorrect kernel-doc comment syntax in files
  x86/msr: Make locally used functions static
  x86/cacheinfo: Remove unneeded dead-store initialization
  x86/process/64: Move cpu_current_top_of_stack out of TSS
  tools/turbostat: Unmark non-kernel-doc comment
  x86/syscalls: Fix -Wmissing-prototypes warnings from COND_SYSCALL()
  x86/fpu/math-emu: Fix function cast warning
  x86/msr: Fix wr/rdmsr_safe_regs_on_cpu() prototypes
  x86: Fix various typos in comments, take #2
  x86: Remove unusual Unicode characters from comments
  x86/kaslr: Return boolean values from a function returning bool
  x86: Fix various typos in comments
  x86/setup: Remove unused RESERVE_BRK_ARRAY()
  stacktrace: Move documentation for arch_stack_walk_reliable() to header
  x86: Remove duplicate TSC DEADLINE MSR definitions
2021-04-26 09:25:47 -07:00
Linus Torvalds 90e66ce9e8 Consolidation and cleanup of the early memory reservations, along with a
couple of gcc11 warning fixes.
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Merge tag 'x86_boot_for_v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 boot updates from Borislav Petkov:
 "Consolidation and cleanup of the early memory reservations, along with
  a couple of gcc11 warning fixes"

* tag 'x86_boot_for_v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/setup: Move trim_snb_memory() later in setup_arch() to fix boot hangs
  x86/setup: Merge several reservations of start of memory
  x86/setup: Consolidate early memory reservations
  x86/boot/compressed: Avoid gcc-11 -Wstringop-overread warning
  x86/boot/tboot: Avoid Wstringop-overread-warning
2021-04-26 09:24:06 -07:00
Nathan Chancellor d5cbd80e30 x86/boot: Add $(CLANG_FLAGS) to compressed KBUILD_CFLAGS
When cross compiling x86 on an ARM machine with clang, there are several
errors along the lines of:

  arch/x86/include/asm/string_64.h:27:10: error: invalid output constraint '=&c' in asm

This happens because the compressed boot Makefile reassigns KBUILD_CFLAGS
and drops the clang flags that set the target architecture ('--target=')
and the path to the GNU cross tools ('--prefix='), meaning that the host
architecture is targeted.

These flags are available as $(CLANG_FLAGS) from the main Makefile so
add them to the compressed boot folder's KBUILD_CFLAGS so that cross
compiling works as expected.

Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lkml.kernel.org/r/20210326000435.4785-3-nathan@kernel.org
2021-03-26 11:32:55 +01:00
Arnd Bergmann e14cfb3bdd x86/boot/compressed: Avoid gcc-11 -Wstringop-overread warning
GCC gets confused by the comparison of a pointer to an integer literal,
with the assumption that this is an offset from a NULL pointer and that
dereferencing it is invalid:

  In file included from arch/x86/boot/compressed/misc.c:18:
  In function ‘parse_elf’,
      inlined from ‘extract_kernel’ at arch/x86/boot/compressed/misc.c:442:2:
  arch/x86/boot/compressed/../string.h:15:23: error: ‘__builtin_memcpy’ reading 64 bytes from a region of size 0 [-Werror=stringop-overread]
     15 | #define memcpy(d,s,l) __builtin_memcpy(d,s,l)
        |                       ^~~~~~~~~~~~~~~~~~~~~~~
  arch/x86/boot/compressed/misc.c:283:9: note: in expansion of macro ‘memcpy’
    283 |         memcpy(&ehdr, output, sizeof(ehdr));
        |         ^~~~~~

I could not find any good workaround for this, but as this is only
a warning for a failure during early boot, removing the line entirely
works around the warning.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Martin Sebor <msebor@gmail.com>
Link: https://lore.kernel.org/r/20210322160253.4032422-2-arnd@kernel.org
2021-03-23 00:16:25 +01:00
Ingo Molnar 163b099146 x86: Fix various typos in comments, take #2
Fix another ~42 single-word typos in arch/x86/ code comments,
missed a few in the first pass, in particular in .S files.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-kernel@vger.kernel.org
2021-03-21 23:50:28 +01:00
Jiapeng Chong 21d6a7dcbf x86/kaslr: Return boolean values from a function returning bool
Fix the following coccicheck warnings:

  ./arch/x86/boot/compressed/kaslr.c:642:10-11: WARNING: return of 0/1 in
  function 'process_mem_region' with return type bool.

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/1615283963-67277-1-git-send-email-jiapeng.chong@linux.alibaba.com
2021-03-19 13:25:07 +01:00
Joerg Roedel f15a0a732a x86/sev-es: Replace open-coded hlt-loops with sev_es_terminate()
There are a few places left in the SEV-ES C code where hlt loops and/or
terminate requests are implemented. Replace them all with calls to
sev_es_terminate().

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210312123824.306-9-joro@8bytes.org
2021-03-18 23:04:12 +01:00
Joerg Roedel fef81c8626 x86/boot/compressed/64: Check SEV encryption in the 32-bit boot-path
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.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210312123824.306-8-joro@8bytes.org
2021-03-18 23:04:12 +01:00
Joerg Roedel e927e62d8e x86/boot/compressed/64: Add CPUID sanity check to 32-bit boot-path
The 32-bit #VC handler has no GHCB and can only handle CPUID exit codes.
It is needed by the early boot code to handle #VC exceptions raised in
verify_cpu() and to get the position of the C-bit.

But the CPUID information comes from the hypervisor which is untrusted
and might return results which trick the guest into the no-SEV boot path
with no C-bit set in the page-tables. All data written to memory would
then be unencrypted and could leak sensitive data to the hypervisor.

Add sanity checks to the 32-bit boot #VC handler to make sure the
hypervisor does not pretend that SEV is not enabled.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210312123824.306-7-joro@8bytes.org
2021-03-18 23:04:12 +01:00
Joerg Roedel 1ccdbf748d x86/boot/compressed/64: Add 32-bit boot #VC handler
Add a #VC exception handler which is used when the kernel still executes
in protected mode. This boot-path already uses CPUID, which will cause #VC
exceptions in an SEV-ES guest.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210312123824.306-6-joro@8bytes.org
2021-03-18 23:03:43 +01:00
Joerg Roedel 79419e13e8 x86/boot/compressed/64: Setup IDT in startup_32 boot path
This boot path needs exception handling when it is used with SEV-ES.
Setup an IDT and provide a helper function to write IDT entries for
use in 32-bit protected mode.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210312123824.306-5-joro@8bytes.org
2021-03-18 16:44:46 +01:00
Joerg Roedel 0c289ff81c x86/boot/compressed/64: Reload CS in startup_32
Exception handling in the startup_32 boot path requires the CS
selector to be correctly set up. Reload it from the current GDT.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210312123824.306-4-joro@8bytes.org
2021-03-18 16:44:43 +01:00
Joerg Roedel eab696d8e8 x86/sev: Do not require Hypervisor CPUID bit for SEV guests
A malicious hypervisor could disable the CPUID intercept for an SEV or
SEV-ES guest and trick it into the no-SEV boot path, where it could
potentially reveal secrets. This is not an issue for SEV-SNP guests,
as the CPUID intercept can't be disabled for those.

Remove the Hypervisor CPUID bit check from the SEV detection code to
protect against this kind of attack and add a Hypervisor bit equals zero
check to the SME detection path to prevent non-encrypted guests from
trying to enable SME.

This handles the following cases:

	1) SEV(-ES) guest where CPUID intercept is disabled. The guest
	   will still see leaf 0x8000001f and the SEV bit. It can
	   retrieve the C-bit and boot normally.

	2) Non-encrypted guests with intercepted CPUID will check
	   the SEV_STATUS MSR and find it 0 and will try to enable SME.
	   This will fail when the guest finds MSR_K8_SYSCFG to be zero,
	   as it is emulated by KVM. But we can't rely on that, as there
	   might be other hypervisors which return this MSR with bit
	   23 set. The Hypervisor bit check will prevent that the guest
	   tries to enable SME in this case.

	3) Non-encrypted guests on SEV capable hosts with CPUID intercept
	   disabled (by a malicious hypervisor) will try to boot into
	   the SME path. This will fail, but it is also not considered
	   a problem because non-encrypted guests have no protection
	   against the hypervisor anyway.

 [ bp: s/non-SEV/non-encrypted/g ]

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lkml.kernel.org/r/20210312123824.306-3-joro@8bytes.org
2021-03-18 16:44:40 +01:00
Joerg Roedel b099155e2d x86/boot/compressed/64: Cleanup exception handling before booting kernel
Disable the exception handling before booting the kernel to make sure
any exceptions that happen during early kernel boot are not directed to
the pre-decompression code.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210312123824.306-2-joro@8bytes.org
2021-03-18 16:44:36 +01:00
Borislav Petkov 514ef77607 x86/boot/compressed/sev-es: Convert to insn_decode()
Other than simplifying the code there should be no functional changes
resulting from this.

Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210304174237.31945-7-bp@alien8.de
2021-03-15 11:18:35 +01:00
Linus Torvalds 4a1106afee 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
 
 + 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
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Merge tag 'efi_updates_for_v5.11' of 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()
2020-12-24 12:40:07 -08:00
Andrey Konovalov 8a494023b8 kasan, x86, s390: update undef CONFIG_KASAN
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>
2020-12-22 12:55:08 -08:00
Linus Torvalds 84292fffc2 - 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)
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Merge tag 'x86_build_for_v5.11' of 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
2020-12-14 13:54:50 -08:00
Linus Torvalds 405f868f13 - 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.
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Merge tag 'x86_cleanups_for_v5.11' of 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()
  ...
2020-12-14 13:45:26 -08:00
Linus Torvalds 8100a58044 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.
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Merge tag 'x86-urgent-2020-12-06' of 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
2020-12-06 11:22:39 -08:00
Masami Hiramatsu 84da009f06 x86/sev-es: Use new for_each_insn_prefix() macro to loop over prefixes bytes
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: 25189d08e5 ("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
2020-12-06 10:03:08 +01:00
Nick Desaulniers 2838307b01 x86/build: Remove -m16 workaround for unsupported versions of GCC
Revert the following two commits:

  de3accdaec ("x86, build: Build 16-bit code with -m16 where possible")
  a9cfccee66 ("x86, build: Change code16gcc.h from a C header to an assembly header")

Since

  0bddd227f3 ("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
2020-12-01 17:17:18 +01:00
Nathan Chancellor 59612b24f7 kbuild: Hoist '--orphan-handling' into Kconfig
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>
2020-12-01 22:45:36 +09:00
Uros Bizjak ab09b58e4b x86/boot/compressed/64: Use TEST %reg,%reg instead of CMP $0,%reg
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
2020-11-21 10:26:25 +01:00
Arvind Sankar 0ac317e897 x86/boot: Remove unused finalize_identity_maps()
Commit

  8570978ea0 ("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
2020-11-18 16:04:23 +01:00
Chester Lin e1ac4b2406 efi: generalize efi_get_secureboot
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>
2020-11-04 23:05:40 +01:00
Joerg Roedel 86ce43f7dd x86/boot/compressed/64: Check SEV encryption in 64-bit boot-path
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
2020-10-29 18:06:52 +01:00
Joerg Roedel 3ad84246a4 x86/boot/compressed/64: Introduce sev_status
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
2020-10-29 10:54:36 +01:00
Joe Perches 33def8498f treewide: Convert macro and uses of __section(foo) to __section("foo")
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>
2020-10-25 14:51:49 -07:00
Arvind Sankar b17a45b6e5 x86/boot/64: Explicitly map boot_params and command line
Commits

  ca0e22d4f0 ("x86/boot/compressed/64: Always switch to own page table")
  8570978ea0 ("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
2020-10-19 19:39:50 +02:00
Arvind Sankar e5ceb9a024 x86/boot/64: Initialize 5-level paging variables earlier
Commit

  ca0e22d4f0 ("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: ca0e22d4f0 ("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
2020-10-19 12:47:21 +02:00
Linus Torvalds da9803dfd3 This feature 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.
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Merge tag 'x86_seves_for_v5.10' of 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
  ...
2020-10-14 10:21:34 -07:00
Linus Torvalds 029f56db6a * 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.
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Merge tag 'x86_asm_for_v5.10' of 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()
2020-10-13 13:36:07 -07:00
Linus Torvalds ad884ff329 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.
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'x86-build-2020-10-12' of 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
2020-10-12 15:14:11 -07:00
Linus Torvalds b85cac5745 This tree cleans up and simplifies the x86 KASLR code, and
also fixes some corner case bugs.
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'x86-kaslr-2020-10-12' of 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
  ...
2020-10-12 14:42:19 -07:00
Linus Torvalds 34eb62d868 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.
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'core-build-2020-10-12' of 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
  ...
2020-10-12 13:39:19 -07:00
Arvind Sankar aa5cacdc29 x86/asm: Replace __force_order with a memory clobber
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
2020-10-01 10:31:48 +02:00
Arvind Sankar 09e43968db x86/boot/compressed: Disable relocation relaxation
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
2020-09-14 11:14:45 +02:00
Martin Radev f5ed777586 x86/sev-es: Check required CPU features for SEV-ES
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
2020-09-10 21:49:25 +02:00
Tom Lendacky 39336f4ffb x86/efi: Add GHCB mappings when SEV-ES is active
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
2020-09-10 21:48:50 +02:00
Tom Lendacky 4711e7acaa x86/sev-es: Handle RDTSC(P) Events
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
2020-09-09 11:33:20 +02:00
Tom Lendacky a7de15d489 x86/sev-es: Add CPUID handling to #VC handler
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
2020-09-07 20:15:51 +02:00
Tom Lendacky 25189d08e5 x86/sev-es: Add support for handling IOIO exceptions
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
2020-09-07 19:45:26 +02:00
Joerg Roedel 69add17a7c x86/boot/compressed/64: Unmap GHCB page before booting the kernel
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
2020-09-07 19:45:26 +02:00