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
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
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
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
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
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
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
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
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
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
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
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
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
Since commits
c041b5ad86 ("x86, boot: Create a separate string.h file to provide standard string functions")
fb4cac573e ("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>
Add a linker script check that there are no run-time relocations, and
remove the old one that tries to check via looking for specially-named
sections in the object files.
Drop the tests for -fPIE compiler option and -pie linker option, as they
are available in all supported gcc and binutils versions (as well as
clang and lld).
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Fangrui Song <maskray@google.com>
Reviewed-by: Sedat Dilek <sedat.dilek@gmail.com>
Link: https://lore.kernel.org/r/20200731230820.1742553-8-keescook@chromium.org
The BFD linker generates run-time relocations for z_input_len and
z_output_len, even though they are absolute symbols.
This is fixed for binutils-2.35 [1]. Work around this for earlier
versions by defining two variables input_len and output_len in addition
to the symbols, and use them via position-independent references.
This eliminates the last two run-time relocations in the head code and
allows us to drop the -z noreloc-overflow flag to the linker.
Move the -pie and --no-dynamic-linker LDFLAGS to LDFLAGS_vmlinux instead
of KBUILD_LDFLAGS. There shouldn't be anything else getting linked, but
this is the more logical location for these flags, and modversions might
call the linker if an EXPORT_SYMBOL is left over accidentally in one of
the decompressors.
[1] https://sourceware.org/bugzilla/show_bug.cgi?id=25754
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Fangrui Song <maskray@google.com>
Link: https://lore.kernel.org/r/20200731230820.1742553-7-keescook@chromium.org
The assembly code in head_{32,64}.S, while meant to be
position-independent, generates run-time relocations because it uses
instructions such as:
leal gdt(%edx), %eax
which make the assembler and linker think that the code is using %edx as
an index into gdt, and hence gdt needs to be relocated to its run-time
address.
On 32-bit, with lld Dmitry Golovin reports that this results in a
link-time error with default options (i.e. unless -z notext is
explicitly passed):
LD arch/x86/boot/compressed/vmlinux
ld.lld: error: can't create dynamic relocation R_386_32 against local
symbol in readonly segment; recompile object files with -fPIC or pass
'-Wl,-z,notext' to allow text relocations in the output
With the BFD linker, this generates a warning during the build, if
--warn-shared-textrel is enabled, which at least Gentoo enables by
default:
LD arch/x86/boot/compressed/vmlinux
ld: arch/x86/boot/compressed/head_32.o: warning: relocation in read-only section `.head.text'
ld: warning: creating a DT_TEXTREL in object
On 64-bit, it is not possible to link the kernel as -pie with lld, and
it is only possible with a BFD linker that supports -z noreloc-overflow,
i.e. versions >2.26. This is because these instructions cannot really be
relocated: the displacement field is only 32-bits wide, and thus cannot
be relocated for a 64-bit load address. The -z noreloc-overflow option
simply overrides the linker error, and results in R_X86_64_RELATIVE
relocations that apply a 64-bit relocation to a 32-bit field anyway.
This happens to work because nothing will process these run-time
relocations.
Start fixing this by removing relocations from .head.text:
- On 32-bit, use a base register that holds the address of the GOT and
reference symbol addresses using @GOTOFF, i.e.
leal gdt@GOTOFF(%edx), %eax
- On 64-bit, most of the code can (and already does) use %rip-relative
addressing, however the .code32 bits can't, and the 64-bit code also
needs to reference symbol addresses as they will be after moving the
compressed kernel to the end of the decompression buffer.
For these cases, reference the symbols as an offset to startup_32 to
avoid creating relocations, i.e.:
leal (gdt-startup_32)(%bp), %eax
This only works in .head.text as the subtraction cannot be represented
as a PC-relative relocation unless startup_32 is in the same section
as the code. Move efi32_pe_entry into .head.text so that it can use
the same method to avoid relocations.
Reported-by: Dmitry Golovin <dima@golovin.in>
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Fangrui Song <maskray@google.com>
Link: https://lore.kernel.org/r/20200731230820.1742553-6-keescook@chromium.org
In a previous patch, we have eliminated GOT entries from the decompressor
binary and added an assertion that the .got section is empty. This means
that the GOT fixup routines that exist in both the 32-bit and 64-bit
startup routines have become dead code, and can be removed.
While at it, drop the KEEP() from the linker script, as it has no effect
on the contents of output sections that are created by the linker itself.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20200731230820.1742553-4-keescook@chromium.org
Eliminate all GOT entries in the decompressor binary, by forcing hidden
visibility for all symbol references, which informs the compiler that
such references will be resolved at link time without the need for
allocating GOT entries.
To ensure that no GOT entries will creep back in, add an assertion to
the decompressor linker script that will fire if the .got section has
a non-zero size.
[Arvind: move hidden.h to include/linux instead of making a copy]
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20200731230820.1742553-3-keescook@chromium.org
The .got.plt section contains the part of the GOT which is used by PLT
entries, and which gets updated lazily by the dynamic loader when
function calls are dispatched through those PLT entries.
On fully linked binaries such as the kernel proper or the decompressor,
this never happens, and so in practice, the .got.plt section consists
only of the first 3 magic entries that are meant to point at the _DYNAMIC
section and at the fixup routine in the loader. However, since we don't
use a dynamic loader, those entries are never populated or used.
This means that treating those entries like ordinary GOT entries, and
updating their values based on the actual placement of the executable in
memory is completely pointless, and we can just ignore the .got.plt
section entirely, provided that it has no additional entries beyond
the first 3 ones.
So add an assertion in the linker script to ensure that this assumption
holds, and move the contents out of the [_got, _egot) memory range that
is modified by the GOT fixup routines.
While at it, drop the KEEP(), since it has no effect on the contents
of output sections that are created by the linker itself.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20200731230820.1742553-2-keescook@chromium.org
- run the checker (e.g. sparse) after the compiler
- remove unneeded cc-option tests for old compiler flags
- fix tar-pkg to install dtbs
- introduce ccflags-remove-y and asflags-remove-y syntax
- allow to trace functions in sub-directories of lib/
- introduce hostprogs-always-y and userprogs-always-y syntax
- various Makefile cleanups
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Merge tag 'kbuild-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:
- run the checker (e.g. sparse) after the compiler
- remove unneeded cc-option tests for old compiler flags
- fix tar-pkg to install dtbs
- introduce ccflags-remove-y and asflags-remove-y syntax
- allow to trace functions in sub-directories of lib/
- introduce hostprogs-always-y and userprogs-always-y syntax
- various Makefile cleanups
* tag 'kbuild-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
kbuild: stop filtering out $(GCC_PLUGINS_CFLAGS) from cc-option base
kbuild: include scripts/Makefile.* only when relevant CONFIG is enabled
kbuild: introduce hostprogs-always-y and userprogs-always-y
kbuild: sort hostprogs before passing it to ifneq
kbuild: move host .so build rules to scripts/gcc-plugins/Makefile
kbuild: Replace HTTP links with HTTPS ones
kbuild: trace functions in subdirectories of lib/
kbuild: introduce ccflags-remove-y and asflags-remove-y
kbuild: do not export LDFLAGS_vmlinux
kbuild: always create directories of targets
powerpc/boot: add DTB to 'targets'
kbuild: buildtar: add dtbs support
kbuild: remove cc-option test of -ffreestanding
kbuild: remove cc-option test of -fno-stack-protector
Revert "kbuild: Create directory for target DTB"
kbuild: run the checker after the compiler
- Add support for zstd compressed kernel
- Define __DISABLE_EXPORTS in Makefile
- Remove __DISABLE_EXPORTS definition from kaslr.c
- Bump the heap size for zstd.
- Update the documentation.
Integrates the ZSTD decompression code to the x86 pre-boot code.
Zstandard requires slightly more memory during the kernel decompression
on x86 (192 KB vs 64 KB), and the memory usage is independent of the
window size.
__DISABLE_EXPORTS is now defined in the Makefile, which covers both
the existing use in kaslr.c, and the use needed by the zstd decompressor
in misc.c.
This patch has been boot tested with both a zstd and gzip compressed
kernel on i386 and x86_64 using buildroot and QEMU.
Additionally, this has been tested in production on x86_64 devices.
We saw a 2 second boot time reduction by switching kernel compression
from xz to zstd.
Signed-off-by: Nick Terrell <terrelln@fb.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20200730190841.2071656-7-nickrterrell@gmail.com
Change the type of local variables/fields that store mem_vector
addresses to u64 to make it less likely that 32-bit overflow will cause
issues on 32-bit.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200728225722.67457-21-nivedita@alum.mit.edu
Change type of minimum/image_size arguments in process_mem_region to
'unsigned long'. These actually can never be above 4G (even on x86_64),
and they're 'unsigned long' in every other function except this one.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200728225722.67457-19-nivedita@alum.mit.edu
Just a trivial rearrangement to do all the processing together, and only
have one call to slots_fetch_random() in the source.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200728225722.67457-18-nivedita@alum.mit.edu
Drop unnecessary alignment of image_size to CONFIG_PHYSICAL_ALIGN in
find_random_virt_addr, it cannot change the result: the largest valid
slot is the largest n that satisfies
minimum + n * CONFIG_PHYSICAL_ALIGN + image_size <= KERNEL_IMAGE_SIZE
(since minimum is already aligned) and so n is equal to
(KERNEL_IMAGE_SIZE - minimum - image_size) / CONFIG_PHYSICAL_ALIGN
even if image_size is not aligned to CONFIG_PHYSICAL_ALIGN.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200728225722.67457-17-nivedita@alum.mit.edu
Drop unnecessary check that number of slots is not zero in
store_slot_info, it's guaranteed to be at least 1 by the calculation.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200728225722.67457-16-nivedita@alum.mit.edu
The number of slots can be 'unsigned int', since on 64-bit, the maximum
amount of memory is 2^52, the minimum alignment is 2^21, so the slot
number cannot be greater than 2^31. But in case future processors have
more than 52 physical address bits, make it 'unsigned long'.
The slot areas are limited by MAX_SLOT_AREA, currently 100. It is
indexed by an int, but the number of areas is stored as 'unsigned long'.
Change both to 'unsigned int' for consistency.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200728225722.67457-15-nivedita@alum.mit.edu
This check doesn't save anything. In the case when none of the
parameters are present, each strstr will scan args twice (once to find
the length and then for searching), six scans in total. Just going ahead
and parsing the arguments only requires three scans: strlen, memcpy, and
parsing. This will be the first malloc, so free will actually free up
the memory, so the check doesn't save heap space either.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200728225722.67457-14-nivedita@alum.mit.edu
32-bit does not have GB pages, so don't bother checking for them. Using
the IS_ENABLED() macro allows the compiler to completely remove the
gb_huge_pages code.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200728225722.67457-12-nivedita@alum.mit.edu
Clip the start and end of the region to minimum and mem_limit prior to
the loop. region.start can only increase during the loop, so raising it
to minimum before the loop is enough.
A region that becomes empty due to this will get checked in
the first iteration of the loop.
Drop the check for overlap extending beyond the end of the region. This
will get checked in the next loop iteration anyway.
Rename end to region_end for symmetry with region.start.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200728225722.67457-10-nivedita@alum.mit.edu
region.size can be trimmed to store the portion of the region before the
overlap, instead of a separate mem_vector variable.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200728225722.67457-9-nivedita@alum.mit.edu
In case of an overlap, the beginning of the region should be used even
if it is exactly image_size, not just strictly larger.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200728225722.67457-6-nivedita@alum.mit.edu
On 64-bit, the kernel must be placed below MAXMEM (64TiB with 4-level
paging or 4PiB with 5-level paging). This is currently not enforced by
KASLR, which thus implicitly relies on physical memory being limited to
less than 64TiB.
On 32-bit, the limit is KERNEL_IMAGE_SIZE (512MiB). This is enforced by
special checks in __process_mem_region().
Initialize mem_limit to the maximum (depending on architecture), instead
of ULLONG_MAX, and make sure the command-line arguments can only
decrease it. This makes the enforcement explicit on 64-bit, and
eliminates the 32-bit specific checks to keep the kernel below 512M.
Check upfront to make sure the minimum address is below the limit before
doing any work.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20200727230801.3468620-5-nivedita@alum.mit.edu
Since commit:
0982adc746 ("x86/boot/KASLR: Work around firmware bugs by excluding EFI_BOOT_SERVICES_* and EFI_LOADER_* from KASLR's choice")
process_efi_entries() will return true if we have an EFI memmap, not just
if it contained EFI_MEMORY_MORE_RELIABLE regions.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20200727230801.3468620-4-nivedita@alum.mit.edu
Drop the warning on seeing "--" in handle_mem_options(). This will trigger
whenever one of the memory options is present in the command line
together with "--", but there's no problem if that is the case.
Replace goto with break.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20200727230801.3468620-3-nivedita@alum.mit.edu
Handle the possibility that the command line is NULL.
Replace open-coded strlen with a function call.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20200727230801.3468620-2-nivedita@alum.mit.edu
- Fix the I/O bitmap invalidation on XEN PV, which was overlooked in the
recent ioperm/iopl rework. This caused the TSS and XEN's I/O bitmap to
get out of sync.
- Use the proper vectors for HYPERV.
- Make disabling of stack protector for the entry code work with GCC
builds which enable stack protector by default. Removing the option is
not sufficient, it needs an explicit -fno-stack-protector to shut it
off.
- Mark check_user_regs() noinstr as it is called from noinstr code. The
missing annotation causes it to be placed in the text section which
makes it instrumentable.
- Add the missing interrupt disable in exc_alignment_check()
- Fixup a XEN_PV build dependency in the 32bit entry code
- A few fixes to make the Clang integrated assembler happy
- Move EFI stub build to the right place for out of tree builds
- Make prepare_exit_to_usermode() static. It's not longer called from ASM
code.
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Merge tag 'x86-urgent-2020-07-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into master
Pull x86 fixes from Thomas Gleixner:
"A pile of fixes for x86:
- Fix the I/O bitmap invalidation on XEN PV, which was overlooked in
the recent ioperm/iopl rework. This caused the TSS and XEN's I/O
bitmap to get out of sync.
- Use the proper vectors for HYPERV.
- Make disabling of stack protector for the entry code work with GCC
builds which enable stack protector by default. Removing the option
is not sufficient, it needs an explicit -fno-stack-protector to
shut it off.
- Mark check_user_regs() noinstr as it is called from noinstr code.
The missing annotation causes it to be placed in the text section
which makes it instrumentable.
- Add the missing interrupt disable in exc_alignment_check()
- Fixup a XEN_PV build dependency in the 32bit entry code
- A few fixes to make the Clang integrated assembler happy
- Move EFI stub build to the right place for out of tree builds
- Make prepare_exit_to_usermode() static. It's not longer called from
ASM code"
* tag 'x86-urgent-2020-07-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/boot: Don't add the EFI stub to targets
x86/entry: Actually disable stack protector
x86/ioperm: Fix io bitmap invalidation on Xen PV
x86: math-emu: Fix up 'cmp' insn for clang ias
x86/entry: Fix vectors to IDTENTRY_SYSVEC for CONFIG_HYPERV
x86/entry: Add compatibility with IAS
x86/entry/common: Make prepare_exit_to_usermode() static
x86/entry: Mark check_user_regs() noinstr
x86/traps: Disable interrupts in exc_aligment_check()
x86/entry/32: Fix XEN_PV build dependency
vmlinux-objs-y is added to targets, which currently means that the EFI
stub gets added to the targets as well. It shouldn't be added since it
is built elsewhere.
This confuses Makefile.build which interprets the EFI stub as a target
$(obj)/$(objtree)/drivers/firmware/efi/libstub/lib.a
and will create drivers/firmware/efi/libstub/ underneath
arch/x86/boot/compressed, to hold this supposed target, if building
out-of-tree. [0]
Fix this by pulling the stub out of vmlinux-objs-y into efi-obj-y.
[0] See scripts/Makefile.build near the end:
# Create directories for object files if they do not exist
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lkml.kernel.org/r/20200715032631.1562882-1-nivedita@alum.mit.edu
Some Makefiles already pass -ffreestanding unconditionally.
For example, arch/arm64/lib/Makefile, arch/x86/purgatory/Makefile.
No problem report so far about hard-coding this option. So, we can
assume all supported compilers know -ffreestanding.
I confirmed GCC 4.8 and Clang manuals document this option.
Get rid of cc-option from -ffreestanding.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Some Makefiles already pass -fno-stack-protector unconditionally.
For example, arch/arm64/kernel/vdso/Makefile, arch/x86/xen/Makefile.
No problem report so far about hard-coding this option. So, we can
assume all supported compilers know -fno-stack-protector.
GCC 4.8 and Clang support this option (https://godbolt.org/z/_HDGzN)
Get rid of cc-option from -fno-stack-protector.
Remove CONFIG_CC_HAS_STACKPROTECTOR_NONE, which is always 'y'.
Note:
arch/mips/vdso/Makefile adds -fno-stack-protector twice, first
unconditionally, and second conditionally. I removed the second one.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Commit
17054f492d ("efi/x86: Implement mixed mode boot without the handover protocol")
introduced a new entry point for the EFI stub to be booted in mixed mode
on 32-bit firmware.
When entered via efi32_pe_entry, control is first transferred to
startup_32 to setup for the switch to long mode, and then the EFI stub
proper is entered via efi_pe_entry. efi_pe_entry is an MS ABI function,
and the ABI requires 32 bytes of shadow stack space to be allocated by
the caller, as well as the stack being aligned to 8 mod 16 on entry.
Allocate 40 bytes on the stack before switching to 64-bit mode when
calling efi_pe_entry to account for this.
For robustness, explicitly align boot_stack_end to 16 bytes. It is
currently implicitly aligned since .bss is cacheline-size aligned,
head_64.o is the first object file with a .bss section, and the heap and
boot sizes are aligned.
Fixes: 17054f492d ("efi/x86: Implement mixed mode boot without the handover protocol")
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20200617131957.2507632-1-nivedita@alum.mit.edu
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Merge the state of the locking kcsan branch before the read/write_once()
and the atomics modifications got merged.
Squash the fallout of the rebase on top of the read/write once and atomic
fallback work into the merge. The history of the original branch is
preserved in tag locking-kcsan-2020-06-02.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The replacement of <asm/pgrable.h> with <linux/pgtable.h> made the include
of the latter in the middle of asm includes. Fix this up with the aid of
the below script and manual adjustments here and there.
import sys
import re
if len(sys.argv) is not 3:
print "USAGE: %s <file> <header>" % (sys.argv[0])
sys.exit(1)
hdr_to_move="#include <linux/%s>" % sys.argv[2]
moved = False
in_hdrs = False
with open(sys.argv[1], "r") as f:
lines = f.readlines()
for _line in lines:
line = _line.rstrip('
')
if line == hdr_to_move:
continue
if line.startswith("#include <linux/"):
in_hdrs = True
elif not moved and in_hdrs:
moved = True
print hdr_to_move
print line
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vincent Chen <deanbo422@gmail.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/20200514170327.31389-4-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The include/linux/pgtable.h is going to be the home of generic page table
manipulation functions.
Start with moving asm-generic/pgtable.h to include/linux/pgtable.h and
make the latter include asm/pgtable.h.
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vincent Chen <deanbo422@gmail.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/20200514170327.31389-3-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'x86-build-2020-06-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 build updates from Ingo Molnar:
"Misc dependency fixes, plus a documentation update about memory
protection keys support"
* tag 'x86-build-2020-06-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/Kconfig: Update config and kernel doc for MPK feature on AMD
x86/boot: Discard .discard.unreachable for arch/x86/boot/compressed/vmlinux
x86/boot/build: Add phony targets in arch/x86/boot/Makefile to PHONY
x86/boot/build: Make 'make bzlilo' not depend on vmlinux or $(obj)/bzImage
x86/boot/build: Add cpustr.h to targets and remove clean-files
- Add the initrdmem= boot option to specify an initrd embedded in RAM (flash most likely)
- Sanitize the CS value earlier during boot, which also fixes SEV-ES.
- Various fixes and smaller cleanups.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'x86-boot-2020-06-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 boot updates from Ingo Molnar:
"Misc updates:
- Add the initrdmem= boot option to specify an initrd embedded in RAM
(flash most likely)
- Sanitize the CS value earlier during boot, which also fixes SEV-ES
- Various fixes and smaller cleanups"
* tag 'x86-boot-2020-06-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/boot: Correct relocation destination on old linkers
x86/boot/compressed/64: Switch to __KERNEL_CS after GDT is loaded
x86/boot: Fix -Wint-to-pointer-cast build warning
x86/boot: Add kstrtoul() from lib/
x86/tboot: Mark tboot static
x86/setup: Add an initrdmem= option to specify initrd physical address
Instead of using efi_gdt64 to switch back to 64-bit mode and then
switching to the real boot-time GDT, just switch to the boot-time GDT
directly. The two GDT's are identical other than efi_gdt64 not including
the 32-bit code segment.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20200523221513.1642948-1-nivedita@alum.mit.edu
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
With commit
ce5e3f909f ("efi/printf: Add 64-bit and 8-bit integer support")
arch/x86/boot/compressed/vmlinux may have an undesired .discard.unreachable
section coming from drivers/firmware/efi/libstub/vsprintf.stub.o. That section
gets generated from unreachable() annotations when CONFIG_STACK_VALIDATION is
enabled.
.discard.unreachable contains an R_X86_64_PC32 relocation which will be
warned about by LLD: a non-SHF_ALLOC section (.discard.unreachable) is
not part of the memory image, thus conceptually the distance between a
non-SHF_ALLOC and a SHF_ALLOC is not a constant which can be resolved at
link time:
% ld.lld -m elf_x86_64 -T arch/x86/boot/compressed/vmlinux.lds ... -o arch/x86/boot/compressed/vmlinux
ld.lld: warning: vsprintf.c:(.discard.unreachable+0x0): has non-ABS relocation R_X86_64_PC32 against symbol ''
Reuse the DISCARDS macro which includes .discard.* to drop
.discard.unreachable.
[ bp: Massage and complete the commit message. ]
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Fangrui Song <maskray@google.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Arvind Sankar <nivedita@alum.mit.edu>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Link: https://lkml.kernel.org/r/20200520182010.242489-1-maskray@google.com
For the 32-bit kernel, as described in
6d92bc9d48 ("x86/build: Build compressed x86 kernels as PIE"),
pre-2.26 binutils generates R_386_32 relocations in PIE mode. Since the
startup code does not perform relocation, any reloc entry with R_386_32
will remain as 0 in the executing code.
Commit
974f221c84 ("x86/boot: Move compressed kernel to the end of the
decompression buffer")
added a new symbol _end but did not mark it hidden, which doesn't give
the correct offset on older linkers. This causes the compressed kernel
to be copied beyond the end of the decompression buffer, rather than
flush against it. This region of memory may be reserved or already
allocated for other purposes by the bootloader.
Mark _end as hidden to fix. This changes the relocation from R_386_32 to
R_386_RELATIVE even on the pre-2.26 binutils.
For 64-bit, this is not strictly necessary, as the 64-bit kernel is only
built as PIE if the linker supports -z noreloc-overflow, which implies
binutils-2.27+, but for consistency, mark _end as hidden here too.
The below illustrates the before/after impact of the patch using
binutils-2.25 and gcc-4.6.4 (locally compiled from source) and QEMU.
Disassembly before patch:
48: 8b 86 60 02 00 00 mov 0x260(%esi),%eax
4e: 2d 00 00 00 00 sub $0x0,%eax
4f: R_386_32 _end
Disassembly after patch:
48: 8b 86 60 02 00 00 mov 0x260(%esi),%eax
4e: 2d 00 f0 76 00 sub $0x76f000,%eax
4f: R_386_RELATIVE *ABS*
Dump from extract_kernel before patch:
early console in extract_kernel
input_data: 0x0207c098 <--- this is at output + init_size
input_len: 0x0074fef1
output: 0x01000000
output_len: 0x00fa63d0
kernel_total_size: 0x0107c000
needed_size: 0x0107c000
Dump from extract_kernel after patch:
early console in extract_kernel
input_data: 0x0190d098 <--- this is at output + init_size - _end
input_len: 0x0074fef1
output: 0x01000000
output_len: 0x00fa63d0
kernel_total_size: 0x0107c000
needed_size: 0x0107c000
Fixes: 974f221c84 ("x86/boot: Move compressed kernel to the end of the decompression buffer")
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200207214926.3564079-1-nivedita@alum.mit.edu
When the pre-decompression code loads its first GDT in startup_64(), it
is still running on the CS value of the previous GDT. In the case of
SEV-ES, this is the EFI GDT but it can be anything depending on what has
loaded the kernel (boot loader, container runtime, etc.)
To make exception handling work (especially IRET) the CPU needs to
switch to a CS value in the current GDT, so jump to __KERNEL_CS after
the first GDT is loaded. This is prudent also as a general sanitization
of CS to a known good value.
[ bp: Massage commit message. ]
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200428151725.31091-13-joro@8bytes.org
Fix this warning when building 32-bit with
CONFIG_RANDOMIZE_BASE=y
CONFIG_MEMORY_HOTREMOVE=y
arch/x86/boot/compressed/acpi.c:316:9: warning: \
cast to pointer from integer of different size [-Wint-to-pointer-cast]
Have get_cmdline_acpi_rsdp() return unsigned long which is the proper
type to convert to a pointer of the respective width.
[ bp: Rewrite commit message, touch ups. ]
Signed-off-by: Vamshi K Sthambamkadi <vamshi.k.sthambamkadi@gmail.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/1587645588-7130-3-git-send-email-vamshi.k.sthambamkadi@gmail.com
Instead of using __efistub_global to force variables into the .data
section, leave them in the .bss but pull the EFI stub's .bss section
into .data in the linker script for the compressed kernel.
Add relocation checking for x86 as well to catch non-PC-relative
relocations that require runtime processing, since the EFI stub does not
do any runtime relocation processing.
This will catch, for example, data relocations created by static
initializers of pointers.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20200416151227.3360778-3-nivedita@alum.mit.edu
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
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Merge tag 'v5.7-rc1' into locking/kcsan, to resolve conflicts and refresh
Resolve these conflicts:
arch/x86/Kconfig
arch/x86/kernel/Makefile
Do a minor "evil merge" to move the KCSAN entry up a bit by a few lines
in the Kconfig to reduce the probability of future conflicts.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Here are 3 SPDX patches for 5.7-rc1.
One fixes up the SPDX tag for a single driver, while the other two go
through the tree and add SPDX tags for all of the .gitignore files as
needed.
Nothing too complex, but you will get a merge conflict with your current
tree, that should be trivial to handle (one file modified by two things,
one file deleted.)
All 3 of these have been in linux-next for a while, with no reported
issues other than the merge conflict.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'spdx-5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/spdx
Pull SPDX updates from Greg KH:
"Here are three SPDX patches for 5.7-rc1.
One fixes up the SPDX tag for a single driver, while the other two go
through the tree and add SPDX tags for all of the .gitignore files as
needed.
Nothing too complex, but you will get a merge conflict with your
current tree, that should be trivial to handle (one file modified by
two things, one file deleted.)
All three of these have been in linux-next for a while, with no
reported issues other than the merge conflict"
* tag 'spdx-5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/spdx:
ASoC: MT6660: make spdxcheck.py happy
.gitignore: add SPDX License Identifier
.gitignore: remove too obvious comments
Pull x86 boot updates from Ingo Molnar:
"Misc cleanups and small enhancements all around the map"
* 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/boot/compressed: Fix debug_puthex() parameter type
x86/setup: Fix static memory detection
x86/vmlinux: Drop unneeded linker script discard of .eh_frame
x86/*/Makefile: Use -fno-asynchronous-unwind-tables to suppress .eh_frame sections
x86/boot/compressed: Remove .eh_frame section from bzImage
x86/boot/compressed/64: Remove .bss/.pgtable from bzImage
x86/boot/compressed/64: Use 32-bit (zero-extended) MOV for z_output_len
x86/boot/compressed/64: Use LEA to initialize boot stack pointer
In the CONFIG_X86_VERBOSE_BOOTUP=Y case, the debug_puthex() macro just
turns into __puthex(), which takes 'unsigned long' as parameter.
But in the CONFIG_X86_VERBOSE_BOOTUP=N case, it is a function which
takes 'unsigned char *', causing compile warnings when the function is
used. Fix the parameter type to get rid of the warnings.
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200319091407.1481-11-joro@8bytes.org
In preparation for being able to decompress into a buffer starting at a
different address than startup_32, save the calculated output address
instead of recalculating it later.
We now keep track of three addresses:
%edx: startup_32 as we were loaded by bootloader
%ebx: new location of compressed kernel
%ebp: start of decompression buffer
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200303221205.4048668-2-nivedita@alum.mit.edu
Link: https://lore.kernel.org/r/20200308080859.21568-16-ardb@kernel.org
The load address is compared with LOAD_PHYSICAL_ADDR using a signed
comparison currently (using jge instruction).
When loading a 64-bit kernel using the new efi32_pe_entry() point added by:
97aa276579 ("efi/x86: Add true mixed mode entry point into .compat section")
using Qemu with -m 3072, the firmware actually loads us above 2Gb,
resulting in a very early crash.
Use the JAE instruction to perform a unsigned comparison instead, as physical
addresses should be considered unsigned.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200301230436.2246909-6-nivedita@alum.mit.edu
Link: https://lore.kernel.org/r/20200308080859.21568-14-ardb@kernel.org
code32_start is meant for 16-bit real-mode bootloaders to inform the
kernel where the 32-bit protected mode code starts. Nothing in the
protected mode kernel except the EFI stub uses it.
efi_main() currently returns boot_params, with code32_start set inside it
to tell efi_stub_entry() where startup_32 is located. Since it was invoked
by efi_stub_entry() in the first place, boot_params is already known.
Return the address of startup_32 instead.
This will allow a 64-bit kernel to live above 4Gb, for example, and it's
cleaner as well.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200301230436.2246909-5-nivedita@alum.mit.edu
Link: https://lore.kernel.org/r/20200308080859.21568-13-ardb@kernel.org
The following commit:
ef5a7b5eb1 ("efi/x86: Remove GDT setup from efi_main")
introduced GDT setup into the 32-bit kernel's startup_32, and reloads
the GDTR after relocating the kernel for paranoia's sake.
A followup commit:
32d009137a ("x86/boot: Reload GDTR after copying to the end of the buffer")
introduced a similar GDTR reload in the 64-bit kernel as well.
The GDTR is adjusted by (init_size-_end), however this may not be the
correct offset to apply if the kernel was loaded at a misaligned address
or below LOAD_PHYSICAL_ADDR, as in that case the decompression buffer
has an additional offset from the original load address.
This should never happen for a conformant bootloader, but we're being
paranoid anyway, so just store the new GDT address in there instead of
adding any offsets, which is simpler as well.
Fixes: ef5a7b5eb1 ("efi/x86: Remove GDT setup from efi_main")
Fixes: 32d009137a ("x86/boot: Reload GDTR after copying to the end of the buffer")
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: linux-efi@vger.kernel.org
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86@kernel.org
Link: https://lore.kernel.org/r/20200226230031.3011645-2-nivedita@alum.mit.edu
This time, the set of changes for the EFI subsystem is much larger than
usual. The main reasons are:
- Get things cleaned up before EFI support for RISC-V arrives, which will
increase the size of the validation matrix, and therefore the threshold to
making drastic changes,
- After years of defunct maintainership, the GRUB project has finally started
to consider changes from the distros regarding UEFI boot, some of which are
highly specific to the way x86 does UEFI secure boot and measured boot,
based on knowledge of both shim internals and the layout of bootparams and
the x86 setup header. Having this maintenance burden on other architectures
(which don't need shim in the first place) is hard to justify, so instead,
we are introducing a generic Linux/UEFI boot protocol.
Summary of changes:
- Boot time GDT handling changes (Arvind)
- Simplify handling of EFI properties table on arm64
- Generic EFI stub cleanups, to improve command line handling, file I/O,
memory allocation, etc.
- Introduce a generic initrd loading method based on calling back into
the firmware, instead of relying on the x86 EFI handover protocol or
device tree.
- Introduce a mixed mode boot method that does not rely on the x86 EFI
handover protocol either, and could potentially be adopted by other
architectures (if another one ever surfaces where one execution mode
is a superset of another)
- Clean up the contents of struct efi, and move out everything that
doesn't need to be stored there.
- Incorporate support for UEFI spec v2.8A changes that permit firmware
implementations to return EFI_UNSUPPORTED from UEFI runtime services at
OS runtime, and expose a mask of which ones are supported or unsupported
via a configuration table.
- Various documentation updates and minor code cleanups (Heinrich)
- Partial fix for the lack of by-VA cache maintenance in the decompressor
on 32-bit ARM. Note that these patches were deliberately put at the
beginning so they can be used as a stable branch that will be shared with
a PR containing the complete fix, which I will send to the ARM tree.
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Merge tag 'efi-next' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi into efi/core
Pull EFI updates for v5.7 from Ard Biesheuvel:
This time, the set of changes for the EFI subsystem is much larger than
usual. The main reasons are:
- Get things cleaned up before EFI support for RISC-V arrives, which will
increase the size of the validation matrix, and therefore the threshold to
making drastic changes,
- After years of defunct maintainership, the GRUB project has finally started
to consider changes from the distros regarding UEFI boot, some of which are
highly specific to the way x86 does UEFI secure boot and measured boot,
based on knowledge of both shim internals and the layout of bootparams and
the x86 setup header. Having this maintenance burden on other architectures
(which don't need shim in the first place) is hard to justify, so instead,
we are introducing a generic Linux/UEFI boot protocol.
Summary of changes:
- Boot time GDT handling changes (Arvind)
- Simplify handling of EFI properties table on arm64
- Generic EFI stub cleanups, to improve command line handling, file I/O,
memory allocation, etc.
- Introduce a generic initrd loading method based on calling back into
the firmware, instead of relying on the x86 EFI handover protocol or
device tree.
- Introduce a mixed mode boot method that does not rely on the x86 EFI
handover protocol either, and could potentially be adopted by other
architectures (if another one ever surfaces where one execution mode
is a superset of another)
- Clean up the contents of struct efi, and move out everything that
doesn't need to be stored there.
- Incorporate support for UEFI spec v2.8A changes that permit firmware
implementations to return EFI_UNSUPPORTED from UEFI runtime services at
OS runtime, and expose a mask of which ones are supported or unsupported
via a configuration table.
- Various documentation updates and minor code cleanups (Heinrich)
- Partial fix for the lack of by-VA cache maintenance in the decompressor
on 32-bit ARM. Note that these patches were deliberately put at the
beginning so they can be used as a stable branch that will be shared with
a PR containing the complete fix, which I will send to the ARM tree.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Now that .eh_frame sections for the files in setup.elf and realmode.elf
are not generated anymore, the linker scripts don't need the special
output section name /DISCARD/ any more.
Remove the one in the main kernel linker script as well, since there are
no .eh_frame sections already, and fix up a comment referencing .eh_frame.
Update the comment in asm/dwarf2.h referring to .eh_frame so it continues
to make sense, as well as being more specific.
[ bp: Touch up commit message. ]
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>
Link: https://lkml.kernel.org/r/20200224232129.597160-3-nivedita@alum.mit.edu
While discussing a patch to discard .eh_frame from the compressed
vmlinux using the linker script, Fangrui Song pointed out [1] that these
sections shouldn't exist in the first place because arch/x86/Makefile
uses -fno-asynchronous-unwind-tables.
It turns out this is because the Makefiles used to build the compressed
kernel redefine KBUILD_CFLAGS, dropping this flag.
Add the flag to the Makefile for the compressed kernel, as well as the
EFI stub Makefile to fix this.
Also add the flag to boot/Makefile and realmode/rm/Makefile so that the
kernel's boot code (boot/setup.elf) and realmode trampoline
(realmode/rm/realmode.elf) won't be compiled with .eh_frame sections,
since their linker scripts also just discard them.
[1] https://lore.kernel.org/lkml/20200222185806.ywnqhfqmy67akfsa@google.com/
Suggested-by: Fangrui Song <maskray@google.com>
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>
Link: https://lkml.kernel.org/r/20200224232129.597160-2-nivedita@alum.mit.edu
Discarding unnecessary sections with "*(*)" (see thread at Link: below)
works fine with the bfd linker but fails with lld:
$ make -j$(nproc) -s CC=clang LD=ld.lld O=out.x86_64 distclean defconfig bzImage
ld.lld: error: discarding .shstrtab section is not allowed
lld tries to also discard essential sections like .shstrtab, .symtab and
.strtab, which results in the link failing since .shstrtab is required
by the ELF specification: the e_shstrndx field in the ELF header is the
index of .shstrtab, and each section in the section table is required to
have an sh_name that points into the .shstrtab.
.symtab and .strtab are also necessary to generate the zoffset.h file
for the bzImage header.
Since the only sizeable section that can be discarded is .eh_frame,
restrict the discard to only .eh_frame to be safe.
[ bp: Flesh out commit message and replace offending commit with this one. ]
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Borislav Petkov <bp@suse.de>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>
Link: https://lkml.kernel.org/r/20200109150218.16544-2-nivedita@alum.mit.edu
Add support for booting 64-bit x86 kernels from 32-bit firmware running
on 64-bit capable CPUs without requiring the bootloader to implement
the EFI handover protocol or allocate the setup block, etc etc, all of
which can be done by the stub itself, using code that already exists.
Instead, create an ordinary EFI application entrypoint but implemented
in 32-bit code [so that it can be invoked by 32-bit firmware], and stash
the address of this 32-bit entrypoint in the .compat section where the
bootloader can find it.
Note that we use the setup block embedded in the binary to go through
startup_32(), but it gets reallocated and copied in efi_pe_entry(),
using the same code that runs when the x86 kernel is booted in EFI
mode from native firmware. This requires the loaded image protocol to
be installed on the kernel image's EFI handle, and point to the kernel
image itself and not to its loader. This, in turn, requires the
bootloader to use the LoadImage() boot service to load the 64-bit
image from 32-bit firmware, which is in fact supported by firmware
based on EDK2. (Only StartImage() will fail, and instead, the newly
added entrypoint needs to be invoked)
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Most of the EFI stub source files of all architectures reside under
drivers/firmware/efi/libstub, where they share a Makefile with special
CFLAGS and an include file with declarations that are only relevant
for stub code.
Currently, we carry a lot of stub specific stuff in linux/efi.h only
because eboot.c in arch/x86 needs them as well. So let's move eboot.c
into libstub/, and move the contents of eboot.h that we still care
about into efistub.h
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
When using the native PE entry point (as opposed to the EFI handover
protocol entry point that is used more widely), we set code32_start,
which is a 32-bit wide field, to the effective symbol address of
startup_32, which could overflow given that the EFI loader may have
located the running image anywhere in memory, and we haven't reached
the point yet where we relocate ourselves.
Since we relocate ourselves if code32_start != pref_address, this
isn't likely to lead to problems in practice, given how unlikely
it is that the truncated effective address of startup_32 happens
to equal pref_address. But it is better to defer the assignment
of code32_start to after the relocation, when it is guaranteed to
fit.
While at it, move the call to efi_relocate_kernel() to an earlier
stage so it is more likely that our preferred offset in memory has
not been occupied by other memory allocations done in the mean time.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
We have some code in the EFI stub entry point that takes the address
of the apm_bios_info struct in the newly allocated and zeroed out
boot_params structure, only to zero it out again. This is pointless
so remove it.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Rearrange the instructions a bit to use a 32-bit displacement once
instead of 2/3 times. This saves 8 bytes of machine code.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20200202171353.3736319-8-nivedita@alum.mit.edu
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
The limit value for the GDTR should be such that adding it to the base
address gives the address of the last byte of the GDT, i.e. it should be
one less than the size, not the size.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20200202171353.3736319-7-nivedita@alum.mit.edu
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
The 64-bit kernel will already load a GDT in startup_64, which is the
next function to execute after return from efi_main.
Add GDT setup code to the 32-bit kernel's startup_32 as well. Doing it
in the head code has the advantage that we can avoid potentially
corrupting the GDT during copy/decompression. This also removes
dependence on having a specific GDT layout setup by the bootloader.
Both startup_32 and startup_64 now clear interrupts on entry, so we can
remove that from efi_main as well.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20200202171353.3736319-6-nivedita@alum.mit.edu
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
startup_32 already clears these flags on entry, do it in startup_64 as
well for consistency.
The direction flag in particular is not specified to be cleared in the
boot protocol documentation, and we currently call into C code
(paging_prepare) without explicitly clearing it.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20200202171353.3736319-5-nivedita@alum.mit.edu
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
The GDT may get overwritten during the copy or during extract_kernel,
which will cause problems if any segment register is touched before the
GDTR is reloaded by the decompressed kernel. For safety update the GDTR
to point to the GDT within the copied kernel.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20200202171353.3736319-4-nivedita@alum.mit.edu
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
When booting in mixed mode, the firmware's GDT is still installed at
handover entry in efi32_stub_entry. We save the GDTR for later use in
__efi64_thunk but we are assuming that descriptor 2 (__KERNEL_CS) is a
valid 32-bit code segment descriptor and that descriptor 3
(__KERNEL_DS/__BOOT_DS) is a valid data segment descriptor.
This happens to be true for OVMF (it actually uses descriptor 1 for data
segments, but descriptor 3 is also setup as data), but we shouldn't
depend on this being the case.
Fix this by saving the code and data selectors in addition to the GDTR
in efi32_stub_entry, and restoring them in __efi64_thunk before calling
the firmware. The UEFI specification guarantees that selectors will be
flat, so using the DS selector for all the segment registers should be
enough.
We also need to install our own GDT before initializing segment
registers in startup_32, so move the GDT load up to the beginning of the
function.
[ardb: mention mixed mode in the commit log]
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20200202171353.3736319-3-nivedita@alum.mit.edu
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Commit
5b11f1cee5 ("x86, boot: straighten out ranges to copy/zero in
compressed/head*.S")
introduced a separate .pgtable section, splitting it out from the rest
of .bss. This section was added without the writeable flag, marking it
as read-only. This results in the linker putting the .rela.dyn section
(containing bogus dynamic relocations from head_64.o) after the .bss and
.pgtable sections.
When objcopy is used to convert compressed/vmlinux into a binary for
the bzImage:
$ objcopy -O binary -R .note -R .comment -S arch/x86/boot/compressed/vmlinux \
arch/x86/boot/vmlinux.bin
the .bss and .pgtable sections get materialized as ~176KiB of zero
bytes in the binary in order to place .rela.dyn at the correct location.
Fix this by marking .pgtable as writeable. This moves the .rela.dyn
section up in the ELF image layout so that .bss and .pgtable are the
last allocated sections and so don't appear in bzImage.
[ bp: Massage commit message. ]
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Kees Cook <keescook@chromium.org>
Link: https://lkml.kernel.org/r/20200109150218.16544-1-nivedita@alum.mit.edu
GCC 10 changed the default to -fno-common, which leads to
LD arch/x86/boot/compressed/vmlinux
ld: arch/x86/boot/compressed/pgtable_64.o:(.bss+0x0): multiple definition of `__force_order'; \
arch/x86/boot/compressed/kaslr_64.o:(.bss+0x0): first defined here
make[2]: *** [arch/x86/boot/compressed/Makefile:119: arch/x86/boot/compressed/vmlinux] Error 1
Since __force_order is already provided in pgtable_64.c, there is no
need to declare __force_order in kaslr_64.c.
Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200124181811.4780-1-hjl.tools@gmail.com
z_output_len is the size of the decompressed payload (i.e. vmlinux +
vmlinux.relocs) and is generated as an unsigned 32-bit quantity by
mkpiggy.c.
The current
movq $z_output_len, %r9
instruction generates a sign-extended move to %r9. Using
movl $z_output_len, %r9d
will instead zero-extend into %r9, which is appropriate for an unsigned
32-bit quantity. This is also what is already done for z_input_len, the
size of the compressed payload.
[ bp:
Also, z_output_len cannot be a 64-bit quantity because it participates
in:
init_size: .long INIT_SIZE # kernel initialization size
through INIT_SIZE which is a 32-bit quantity determined by the .long
directive (vs .quad for 64-bit). Furthermore, if it really must be a
64-bit quantity, then the insn must be MOVABS which can accommodate a
64-bit immediate and which the toolchain does not generate automatically.
]
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200211173333.1722739-1-nivedita@alum.mit.edu
- fix randconfig to generate a sane .config
- rename hostprogs-y / always to hostprogs / always-y, which are
more natual syntax.
- optimize scripts/kallsyms
- fix yes2modconfig and mod2yesconfig
- make multiple directory targets ('make foo/ bar/') work
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Merge tag 'kbuild-v5.6-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull more Kbuild updates from Masahiro Yamada:
- fix randconfig to generate a sane .config
- rename hostprogs-y / always to hostprogs / always-y, which are more
natual syntax.
- optimize scripts/kallsyms
- fix yes2modconfig and mod2yesconfig
- make multiple directory targets ('make foo/ bar/') work
* tag 'kbuild-v5.6-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
kbuild: make multiple directory targets work
kconfig: Invalidate all symbols after changing to y or m.
kallsyms: fix type of kallsyms_token_table[]
scripts/kallsyms: change table to store (strcut sym_entry *)
scripts/kallsyms: rename local variables in read_symbol()
kbuild: rename hostprogs-y/always to hostprogs/always-y
kbuild: fix the document to use extra-y for vmlinux.lds
kconfig: fix broken dependency in randconfig-generated .config
