Check the memory operand of INS/OUTS before emulating the instruction.
The #VC exception can get raised from user-space, but the memory operand
can be manipulated to access kernel memory before the emulation actually
begins and after the exception handler has run.
[ bp: Massage commit message. ]
Fixes: 597cfe48212a ("x86/boot/compressed/64: Setup a GHCB-based VC Exception handler")
Reported-by: Tom Dohrmann <erbse.13@gmx.de>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: <stable@kernel.org>
Check the IO permission bitmap (if present) before emulating IOIO #VC
exceptions for user-space. These permissions are checked by hardware
already before the #VC is raised, but due to the VC-handler decoding
race it needs to be checked again in software.
Fixes: 25189d08e516 ("x86/sev-es: Add support for handling IOIO exceptions")
Reported-by: Tom Dohrmann <erbse.13@gmx.de>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Tom Dohrmann <erbse.13@gmx.de>
Cc: <stable@kernel.org>
The decompressor has a hard limit on the number of page tables it can
allocate. This limit is defined at compile-time and will cause boot
failure if it is reached.
The kernel is very strict and calculates the limit precisely for the
worst-case scenario based on the current configuration. However, it is
easy to forget to adjust the limit when a new use-case arises. The
worst-case scenario is rarely encountered during sanity checks.
In the case of enabling 5-level paging, a use-case was overlooked. The
limit needs to be increased by one to accommodate the additional level.
This oversight went unnoticed until Aaron attempted to run the kernel
via kexec with 5-level paging and unaccepted memory enabled.
Update wost-case calculations to include 5-level paging.
To address this issue, let's allocate some extra space for page tables.
128K should be sufficient for any use-case. The logic can be simplified
by using a single value for all kernel configurations.
[ Also add a warning, should this memory run low - by Dave Hansen. ]
Fixes: 34bbb0009f3b ("x86/boot/compressed: Enable 5-level paging during decompression stage")
Reported-by: Aaron Lu <aaron.lu@intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20230915070221.10266-1-kirill.shutemov@linux.intel.com
The following commit deserves special mention:
22dc02f81cddd Revert "sched/fair: Move unused stub functions to header"
This is in x86/cleanups, because the revert is a re-application of a
number of cleanups that got removed inadvertedly.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'x86-cleanups-2023-08-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull misc x86 cleanups from Ingo Molnar:
"The following commit deserves special mention:
22dc02f81cddd Revert "sched/fair: Move unused stub functions to header"
This is in x86/cleanups, because the revert is a re-application of a
number of cleanups that got removed inadvertedly"
[ This also effectively undoes the amd_check_microcode() microcode
declaration change I had done in my microcode loader merge in commit
42a7f6e3ffe0 ("Merge tag 'x86_microcode_for_v6.6_rc1' [...]").
I picked the declaration change by Arnd from this branch instead,
which put it in <asm/processor.h> instead of <asm/microcode.h> like I
had done in my merge resolution - Linus ]
* tag 'x86-cleanups-2023-08-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/platform/uv: Refactor code using deprecated strncpy() interface to use strscpy()
x86/hpet: Refactor code using deprecated strncpy() interface to use strscpy()
x86/platform/uv: Refactor code using deprecated strcpy()/strncpy() interfaces to use strscpy()
x86/qspinlock-paravirt: Fix missing-prototype warning
x86/paravirt: Silence unused native_pv_lock_init() function warning
x86/alternative: Add a __alt_reloc_selftest() prototype
x86/purgatory: Include header for warn() declaration
x86/asm: Avoid unneeded __div64_32 function definition
Revert "sched/fair: Move unused stub functions to header"
x86/apic: Hide unused safe_smp_processor_id() on 32-bit UP
x86/cpu: Fix amd_check_microcode() declaration
range whose SEV encryption status needs to change, is not page aligned
so that callers which round up the number of pages to be decrypted,
would mark a trailing page as decrypted and thus cause corruption
during live migration.
- Return an error from the #VC handler on AMD SEV-* guests when the debug
registers swapping is enabled as a DR7 access should not happen then
- that register is guest/host switched.
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Merge tag 'x86_sev_for_v6.6_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 SEV updates from Borislav Petkov:
- Handle the case where the beginning virtual address of the address
range whose SEV encryption status needs to change, is not page
aligned so that callers which round up the number of pages to be
decrypted, would mark a trailing page as decrypted and thus cause
corruption during live migration.
- Return an error from the #VC handler on AMD SEV-* guests when the
debug registers swapping is enabled as a DR7 access should not happen
then - that register is guest/host switched.
* tag 'x86_sev_for_v6.6_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/sev: Make enc_dec_hypercall() accept a size instead of npages
x86/sev: Do not handle #VC for DR7 read/write
With MSR_AMD64_SEV_DEBUG_SWAP enabled, the guest is not expected to
receive a #VC for reads or writes of DR7.
Update the SNP_FEATURES_PRESENT mask with MSR_AMD64_SNP_DEBUG_SWAP so
an SNP guest doesn't gracefully terminate during SNP feature negotiation
if MSR_AMD64_SEV_DEBUG_SWAP is enabled.
Since a guest is not expected to receive a #VC on DR7 accesses when
MSR_AMD64_SEV_DEBUG_SWAP is enabled, return an error from the #VC
handler in this situation.
Signed-off-by: Alexey Kardashevskiy <aik@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Carlos Bilbao <carlos.bilbao@amd.com>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Pankaj Gupta <pankaj.gupta@amd.com>
Link: https://lore.kernel.org/r/20230816022122.981998-1-aik@amd.com
The bare metal decompressor code was never really intended to run in a
hosted environment such as the EFI boot services, and does a few things
that are becoming problematic in the context of EFI boot now that the
logo requirements are getting tighter: EFI executables will no longer be
allowed to consist of a single executable section that is mapped with
read, write and execute permissions if they are intended for use in a
context where Secure Boot is enabled (and where Microsoft's set of
certificates is used, i.e., every x86 PC built to run Windows).
To avoid stepping on reserved memory before having inspected the E820
tables, and to ensure the correct placement when running a kernel build
that is non-relocatable, the bare metal decompressor moves its own
executable image to the end of the allocation that was reserved for it,
in order to perform the decompression in place. This means the region in
question requires both write and execute permissions, which either need
to be given upfront (which EFI will no longer permit), or need to be
applied on demand using the existing page fault handling framework.
However, the physical placement of the kernel is usually randomized
anyway, and even if it isn't, a dedicated decompression output buffer
can be allocated anywhere in memory using EFI APIs when still running in
the boot services, given that EFI support already implies a relocatable
kernel. This means that decompression in place is never necessary, nor
is moving the compressed image from one end to the other.
Since EFI already maps all of memory 1:1, it is also unnecessary to
create new page tables or handle page faults when decompressing the
kernel. That means there is also no need to replace the special
exception handlers for SEV. Generally, there is little need to do
any of the things that the decompressor does beyond
- initialize SEV encryption, if needed,
- perform the 4/5 level paging switch, if needed,
- decompress the kernel
- relocate the kernel
So do all of this from the EFI stub code, and avoid the bare metal
decompressor altogether.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230807162720.545787-24-ardb@kernel.org
Before refactoring the EFI stub boot flow to avoid the legacy bare metal
decompressor, duplicate the SNP feature check in the EFI stub before
handing over to the kernel proper.
The SNP feature check can be performed while running under the EFI boot
services, which means it can force the boot to fail gracefully and
return an error to the bootloader if the loaded kernel does not
implement support for all the features that the hypervisor enabled.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230807162720.545787-23-ardb@kernel.org
Factor out the decompressor sequence that invokes the decompressor,
parses the ELF and applies the relocations so that it can be called
directly from the EFI stub.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230807162720.545787-21-ardb@kernel.org
It is no longer necessary to be cautious when referring to global
variables in the position independent decompressor code, now that it is
built using PIE codegen and makes an assertion in the linker script that
no GOT entries exist (which would require adjustment for the actual
runtime load address of the decompressor binary).
This means global variables can be referenced directly from C code,
instead of having to pass their runtime addresses into C routines from
asm code, which needs to happen at each call site. Do so for the code
that will be called directly from the EFI stub after a subsequent patch,
and avoid the need to duplicate this logic a third time.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230807162720.545787-20-ardb@kernel.org
Now that the trampoline setup code and the actual invocation of it are
all done from the C routine, the trampoline cleanup can be merged into
it as well, instead of returning to asm just to call another C function.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Link: https://lore.kernel.org/r/20230807162720.545787-16-ardb@kernel.org
The only remaining use of the trampoline address by the trampoline
itself is deriving the page table address from it, and this involves
adding an offset of 0x0. So simplify this, and pass the new CR3 value
directly.
This makes the fact that the page table happens to be at the start of
the trampoline allocation an implementation detail of the caller.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230807162720.545787-15-ardb@kernel.org
Since the current and desired number of paging levels are known when the
trampoline is being prepared, avoid calling the trampoline at all if it
is clear that calling it is not going to result in a change to the
number of paging levels.
Given that the CPU is already running in long mode, the PAE and LA57
settings are necessarily consistent with the currently active page
tables, and other fields in CR4 will be initialized by the startup code
in the kernel proper. So limit the manipulation of CR4 to toggling the
LA57 bit, which is the only thing that really needs doing at this point
in the boot. This also means that there is no need to pass the value of
l5_required to toggle_la57(), as it will not be called unless CR4.LA57
needs to toggle.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Link: https://lore.kernel.org/r/20230807162720.545787-14-ardb@kernel.org
Instead of returning to the asm calling code to invoke the trampoline,
call it straight from the C code that sets it up. That way, the struct
return type is no longer needed for returning two values, and the call
can be made conditional more cleanly in a subsequent patch.
This means that all callee save 64-bit registers need to be preserved
and restored, as their contents may not survive the legacy mode switch.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Link: https://lore.kernel.org/r/20230807162720.545787-13-ardb@kernel.org
The 32-bit trampoline no longer uses the stack for anything except
performing a far return back to long mode, and preserving the caller's
stack pointer value. Currently, the trampoline stack is placed in the
same page that carries the trampoline code, which means this page must
be mapped writable and executable, and the stack is therefore executable
as well.
Replace the far return with a far jump, so that the return address can
be pre-calculated and patched into the code before it is called. This
removes the need for a 32-bit addressable stack entirely, and in a later
patch, this will be taken advantage of by removing writable permissions
from (and adding executable permissions to) the trampoline code page
when booting via the EFI stub.
Note that the value of RSP still needs to be preserved explicitly across
the switch into 32-bit mode, as the register may get truncated to 32
bits.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Link: https://lore.kernel.org/r/20230807162720.545787-12-ardb@kernel.org
Update the trampoline code so its arguments are passed via RDI and RSI,
which matches the ordinary SysV calling convention for x86_64. This will
allow this code to be called directly from C.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Link: https://lore.kernel.org/r/20230807162720.545787-11-ardb@kernel.org
Move the long return to switch to 32-bit mode into the trampoline code
so it can be called as an ordinary function. This will allow it to be
called directly from C code in a subsequent patch.
While at it, reorganize the code somewhat to keep the prologue and
epilogue of the function together, making the code a bit easier to
follow. Also, given that the trampoline is now entered in 64-bit mode, a
simple RIP-relative reference can be used to take the address of the
exit point.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Link: https://lore.kernel.org/r/20230807162720.545787-10-ardb@kernel.org
There is no need to defer the assignment of the paging related global
variables 'pgdir_shift' and 'ptrs_per_p4d' until after the trampoline is
cleaned up, so assign them as soon as it is clear that 5-level paging
will be enabled.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230807162720.545787-9-ardb@kernel.org
Instead of pushing and popping %RSI several times to preserve the struct
boot_params pointer across the execution of the startup code, move it
into a callee save register before the first call into C, and copy it
back when needed.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230807162720.545787-8-ardb@kernel.org
The so-called EFI handover protocol is value-add from the distros that
permits a loader to simply copy a PE kernel image into memory and call
an alternative entrypoint that is described by an embedded boot_params
structure.
Most implementations of this protocol do not bother to check the PE
header for minimum alignment, section placement, etc, and therefore also
don't clear the image's BSS, or even allocate enough memory for it.
Allocating more memory on the fly is rather difficult, but at least
clear the BSS region explicitly when entering in this manner, so that
the EFI stub code does not get confused by global variables that were
not zero-initialized correctly.
When booting in mixed mode, this BSS clearing must occur before any
global state is created, so clear it in the 32-bit asm entry point.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230807162720.545787-7-ardb@kernel.org
The native 32-bit or 64-bit EFI handover protocol entrypoint offset
relative to the respective startup_32/64 address is described in
boot_params as handover_offset, so that the special Linux/x86 aware EFI
loader can find it there.
When mixed mode is enabled, this single field has to describe this
offset for both the 32-bit and 64-bit entrypoints, so their respective
relative offsets have to be identical. Given that startup_32 and
startup_64 are 0x200 bytes apart, and the EFI handover entrypoint
resides at a fixed offset, the 32-bit and 64-bit versions of those
entrypoints must be exactly 0x200 bytes apart as well.
Currently, hard-coded fixed offsets are used to ensure this, but it is
sufficient to emit the 64-bit entrypoint 0x200 bytes after the 32-bit
one, wherever it happens to reside. This allows this code (which is now
EFI mixed mode specific) to be moved into efi_mixed.S and out of the
startup code in head_64.S.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230807162720.545787-6-ardb@kernel.org
Now that the EFI entry code in assembler is only used by the optional
and deprecated EFI handover protocol, and given that the EFI stub C code
no longer returns to it, most of it can simply be dropped.
While at it, clarify the symbol naming, by merging efi_main() and
efi_stub_entry(), making the latter the shared entry point for all
different boot modes that enter via the EFI stub.
The efi32_stub_entry() and efi64_stub_entry() names are referenced
explicitly by the tooling that populates the setup header, so these must
be retained, but can be emitted as aliases of efi_stub_entry() where
appropriate.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230807162720.545787-5-ardb@kernel.org
The 4-to-5 level mode switch trampoline disables long mode and paging in
order to be able to flick the LA57 bit. According to section 3.4.1.1 of
the x86 architecture manual [0], 64-bit GPRs might not retain the upper
32 bits of their contents across such a mode switch.
Given that RBP, RBX and RSI are live at this point, preserve them on the
stack, along with the return address that might be above 4G as well.
[0] Intel® 64 and IA-32 Architectures Software Developer’s Manual, Volume 1: Basic Architecture
"Because the upper 32 bits of 64-bit general-purpose registers are
undefined in 32-bit modes, the upper 32 bits of any general-purpose
register are not preserved when switching from 64-bit mode to a 32-bit
mode (to protected mode or compatibility mode). Software must not
depend on these bits to maintain a value after a 64-bit to 32-bit
mode switch."
Fixes: 194a9749c73d650c ("x86/boot/compressed/64: Handle 5-level paging boot if kernel is above 4G")
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230807162720.545787-2-ardb@kernel.org
Tao Liu reported a boot hang on an Intel Atom machine due to an unmapped
EFI config table. The reason being that the CC blob which contains the
CPUID page for AMD SNP guests is parsed for before even checking
whether the machine runs on AMD hardware.
Usually that's not a problem on !AMD hw - it simply won't find the CC
blob's GUID and return. However, if any parts of the config table
pointers array is not mapped, the kernel will #PF very early in the
decompressor stage without any opportunity to recover.
Therefore, do a superficial CPUID check before poking for the CC blob.
This will fix the current issue on real hardware. It would also work as
a guest on a non-lying hypervisor.
For the lying hypervisor, the check is done again, *after* parsing the
CC blob as the real CPUID page will be present then.
Clear the #VC handler in case SEV-{ES,SNP} hasn't been detected, as
a precaution.
Fixes: c01fce9cef84 ("x86/compressed: Add SEV-SNP feature detection/setup")
Reported-by: Tao Liu <ltao@redhat.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
Tested-by: Tao Liu <ltao@redhat.com>
Cc: <stable@kernel.org>
Link: https://lore.kernel.org/r/20230601072043.24439-1-ltao@redhat.com
The purgatory code uses parts of the decompressor and provides its own
warn() function, but has to include the corresponding header file to
avoid a -Wmissing-prototypes warning.
It turns out that this function prototype actually differs from the
declaration, so change it to get a constant pointer in the declaration
and the other definition as well.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230803082619.1369127-5-arnd@kernel.org
a fatal shutdown during TDX private<=>shared conversion
- Annotate sites where VM "exit reasons" are reused as hypercall
numbers.
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Merge tag 'x86_tdx_for_6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 tdx updates from Dave Hansen:
- Fix a race window where load_unaligned_zeropad() could cause a fatal
shutdown during TDX private<=>shared conversion
The race has never been observed in practice but might allow
load_unaligned_zeropad() to catch a TDX page in the middle of its
conversion process which would lead to a fatal and unrecoverable
guest shutdown.
- Annotate sites where VM "exit reasons" are reused as hypercall
numbers.
* tag 'x86_tdx_for_6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mm: Fix enc_status_change_finish_noop()
x86/tdx: Fix race between set_memory_encrypted() and load_unaligned_zeropad()
x86/mm: Allow guest.enc_status_change_prepare() to fail
x86/tdx: Wrap exit reason with hcall_func()
and assert __x86_return_thunk's alignment so that future changes to
the symbol macros do not accidentally break them.
- Remove CONFIG_X86_FEATURE_NAMES Kconfig option as its existence is
pointless
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Merge tag 'x86_cpu_for_v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 cpu updates from Borislav Petkov:
- Compute the purposeful misalignment of zen_untrain_ret automatically
and assert __x86_return_thunk's alignment so that future changes to
the symbol macros do not accidentally break them.
- Remove CONFIG_X86_FEATURE_NAMES Kconfig option as its existence is
pointless
* tag 'x86_cpu_for_v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/retbleed: Add __x86_return_thunk alignment checks
x86/cpu: Remove X86_FEATURE_NAMES
x86/Kconfig: Make X86_FEATURE_NAMES non-configurable in prompt
The gist of it all is that Intel TDX and AMD SEV-SNP confidential
computing guests define the notion of accepting memory before using it
and thus preventing a whole set of attacks against such guests like
memory replay and the like.
There are a couple of strategies of how memory should be accepted
- the current implementation does an on-demand way of accepting.
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Merge tag 'x86_cc_for_v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 confidential computing update from Borislav Petkov:
- Add support for unaccepted memory as specified in the UEFI spec v2.9.
The gist of it all is that Intel TDX and AMD SEV-SNP confidential
computing guests define the notion of accepting memory before using
it and thus preventing a whole set of attacks against such guests
like memory replay and the like.
There are a couple of strategies of how memory should be accepted -
the current implementation does an on-demand way of accepting.
* tag 'x86_cc_for_v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
virt: sevguest: Add CONFIG_CRYPTO dependency
x86/efi: Safely enable unaccepted memory in UEFI
x86/sev: Add SNP-specific unaccepted memory support
x86/sev: Use large PSC requests if applicable
x86/sev: Allow for use of the early boot GHCB for PSC requests
x86/sev: Put PSC struct on the stack in prep for unaccepted memory support
x86/sev: Fix calculation of end address based on number of pages
x86/tdx: Add unaccepted memory support
x86/tdx: Refactor try_accept_one()
x86/tdx: Make _tdx_hypercall() and __tdx_module_call() available in boot stub
efi/unaccepted: Avoid load_unaligned_zeropad() stepping into unaccepted memory
efi: Add unaccepted memory support
x86/boot/compressed: Handle unaccepted memory
efi/libstub: Implement support for unaccepted memory
efi/x86: Get full memory map in allocate_e820()
mm: Add support for unaccepted memory
The Linux build process on x86 roughly consists of compiling all input
files, statically linking them into a vmlinux ELF file, and then taking
and turning this file into an actual bzImage bootable file.
vmlinux has in this process two main purposes:
1) It is an intermediate build target on the way to produce the final
bootable image.
2) It is a file that is expected to be used by debuggers and standard
ELF tooling to work with the built kernel.
For the second purpose, a vmlinux file is typically collected by various
package build recipes, such as distribution spec files, including the
kernel's own tar-pkg target.
When building a kernel supporting KASLR with CONFIG_X86_NEED_RELOCS,
vmlinux contains also relocation information produced by using the
--emit-relocs linker option. This is utilized by subsequent build steps
to create vmlinux.relocs and produce a relocatable image. However, the
information is not needed by debuggers and other standard ELF tooling.
The issue is then that the collected vmlinux file and hence distribution
packages end up unnecessarily large because of this extra data. The
following is a size comparison of vmlinux v6.0 with and without the
relocation information:
| Configuration | With relocs | Stripped relocs |
| x86_64_defconfig | 70 MB | 43 MB |
| +CONFIG_DEBUG_INFO | 818 MB | 367 MB |
Optimize a resulting vmlinux by adding a postlink step that splits the
relocation information into vmlinux.relocs and then strips it from the
vmlinux binary.
Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/r/20220927084632.14531-1-petr.pavlu@suse.com
Add SNP-specific hooks to the unaccepted memory support in the boot
path (__accept_memory()) and the core kernel (accept_memory()) in order
to support booting SNP guests when unaccepted memory is present. Without
this support, SNP guests will fail to boot and/or panic() when unaccepted
memory is present in the EFI memory map.
The process of accepting memory under SNP involves invoking the hypervisor
to perform a page state change for the page to private memory and then
issuing a PVALIDATE instruction to accept the page.
Since the boot path and the core kernel paths perform similar operations,
move the pvalidate_pages() and vmgexit_psc() functions into sev-shared.c
to avoid code duplication.
Create the new header file arch/x86/boot/compressed/sev.h because adding
the function declaration to any of the existing SEV related header files
pulls in too many other header files, causing the build to fail.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/a52fa69f460fd1876d70074b20ad68210dfc31dd.1686063086.git.thomas.lendacky@amd.com
Hookup TDX-specific code to accept memory.
Accepting the memory is done with ACCEPT_PAGE module call on every page
in the range. MAP_GPA hypercall is not required as the unaccepted memory
is considered private already.
Extract the part of tdx_enc_status_changed() that does memory acceptance
in a new helper. Move the helper tdx-shared.c. It is going to be used by
both main kernel and decompressor.
[ bp: Fix the INTEL_TDX_GUEST=y, KVM_GUEST=n build. ]
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230606142637.5171-10-kirill.shutemov@linux.intel.com
The firmware will pre-accept the memory used to run the stub. But, the
stub is responsible for accepting the memory into which it decompresses
the main kernel. Accept memory just before decompression starts.
The stub is also responsible for choosing a physical address in which to
place the decompressed kernel image. The KASLR mechanism will randomize
this physical address. Since the accepted memory region is relatively
small, KASLR would be quite ineffective if it only used the pre-accepted
area (EFI_CONVENTIONAL_MEMORY). Ensure that KASLR randomizes among the
entire physical address space by also including EFI_UNACCEPTED_MEMORY.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Liam Merwick <liam.merwick@oracle.com>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20230606142637.5171-5-kirill.shutemov@linux.intel.com
UEFI Specification version 2.9 introduces the concept of memory
acceptance: Some Virtual Machine platforms, such as Intel TDX or AMD
SEV-SNP, requiring memory to be accepted before it can be used by the
guest. Accepting happens via a protocol specific for the Virtual
Machine platform.
Accepting memory is costly and it makes VMM allocate memory for the
accepted guest physical address range. It's better to postpone memory
acceptance until memory is needed. It lowers boot time and reduces
memory overhead.
The kernel needs to know what memory has been accepted. Firmware
communicates this information via memory map: a new memory type --
EFI_UNACCEPTED_MEMORY -- indicates such memory.
Range-based tracking works fine for firmware, but it gets bulky for
the kernel: e820 (or whatever the arch uses) has to be modified on every
page acceptance. It leads to table fragmentation and there's a limited
number of entries in the e820 table.
Another option is to mark such memory as usable in e820 and track if the
range has been accepted in a bitmap. One bit in the bitmap represents a
naturally aligned power-2-sized region of address space -- unit.
For x86, unit size is 2MiB: 4k of the bitmap is enough to track 64GiB or
physical address space.
In the worst-case scenario -- a huge hole in the middle of the
address space -- It needs 256MiB to handle 4PiB of the address
space.
Any unaccepted memory that is not aligned to unit_size gets accepted
upfront.
The bitmap is allocated and constructed in the EFI stub and passed down
to the kernel via EFI configuration table. allocate_e820() allocates the
bitmap if unaccepted memory is present, according to the size of
unaccepted region.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20230606142637.5171-4-kirill.shutemov@linux.intel.com
TDX reuses VMEXIT "reasons" in its guest->host hypercall ABI. This is
confusing because there might not be a VMEXIT involved at *all*.
These instances are supposed to document situation and reduce confusion
by wrapping VMEXIT reasons with hcall_func().
The decompression code does not follow this convention.
Unify the TDX decompression code with the other TDX use of VMEXIT reasons.
No functional changes.
Signed-off-by: Nikolay Borisov <nik.borisov@suse.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Link: https://lore.kernel.org/all/20230505120332.1429957-1-nik.borisov%40suse.com
While discussing to change the visibility of X86_FEATURE_NAMES (see Link)
in order to remove CONFIG_EMBEDDED, Boris suggested to simply make the
X86_FEATURE_NAMES functionality unconditional.
As the need for really tiny kernel images has gone away and kernel images
with !X86_FEATURE_NAMES are hardly tested, remove this config and the whole
ifdeffery in the source code.
Suggested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/all/20230509084007.24373-1-lukas.bulwahn@gmail.com/
Link: https://lore.kernel.org/r/20230510065713.10996-3-lukas.bulwahn@gmail.com
assembly macro argument rather than a runtime register.
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Merge tag 'x86_tdx_for_6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 tdx update from Dave Hansen:
"The original tdx hypercall assembly code took two flags in %RSI to
tweak its behavior at runtime. PeterZ recently axed one flag in commit
e80a48bade61 ("x86/tdx: Remove TDX_HCALL_ISSUE_STI").
Kill the other flag too and tweak the 'output' mode with an assembly
macro instead. This results in elimination of one push/pop pair and
overall easier to read assembly.
- Do conditional __tdx_hypercall() 'output' processing via an
assembly macro argument rather than a runtime register"
* tag 'x86_tdx_for_6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/tdx: Drop flags from __tdx_hypercall()
Replace multiple __pa()/__va() definitions with a single one in misc.h.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/all/20230330114956.20342-2-kirill.shutemov%40linux.intel.com
Move the x86 documentation under Documentation/arch/ as a way of cleaning
up the top-level directory and making the structure of our docs more
closely match the structure of the source directories it describes.
All in-kernel references to the old paths have been updated.
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: linux-arch@vger.kernel.org
Cc: x86@kernel.org
Cc: Borislav Petkov <bp@alien8.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/lkml/20230315211523.108836-1-corbet@lwn.net/
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
After TDX_HCALL_ISSUE_STI got dropped, the only flag left is
TDX_HCALL_HAS_OUTPUT. The flag indicates if the caller wants to see
tdx_hypercall_args updated based on the hypercall output.
Drop the flags and provide __tdx_hypercall_ret() that matches
TDX_HCALL_HAS_OUTPUT semantics.
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20230321003511.9469-1-kirill.shutemov%40linux.intel.com
- Change V=1 option to print both short log and full command log.
- Allow V=1 and V=2 to be combined as V=12.
- Make W=1 detect wrong .gitignore files.
- Tree-wide cleanups for unused command line arguments passed to Clang.
- Stop using -Qunused-arguments with Clang.
- Make scripts/setlocalversion handle only correct release tags instead
of any arbitrary annotated tag.
- Create Debian and RPM source packages without cleaning the source tree.
- Various cleanups for packaging.
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Merge tag 'kbuild-v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:
- Change V=1 option to print both short log and full command log
- Allow V=1 and V=2 to be combined as V=12
- Make W=1 detect wrong .gitignore files
- Tree-wide cleanups for unused command line arguments passed to Clang
- Stop using -Qunused-arguments with Clang
- Make scripts/setlocalversion handle only correct release tags instead
of any arbitrary annotated tag
- Create Debian and RPM source packages without cleaning the source
tree
- Various cleanups for packaging
* tag 'kbuild-v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (74 commits)
kbuild: rpm-pkg: remove unneeded KERNELRELEASE from modules/headers_install
docs: kbuild: remove description of KBUILD_LDS_MODULE
.gitattributes: use 'dts' diff driver for *.dtso files
kbuild: deb-pkg: improve the usability of source package
kbuild: deb-pkg: fix binary-arch and clean in debian/rules
kbuild: tar-pkg: use tar rules in scripts/Makefile.package
kbuild: make perf-tar*-src-pkg work without relying on git
kbuild: deb-pkg: switch over to source format 3.0 (quilt)
kbuild: deb-pkg: make .orig tarball a hard link if possible
kbuild: deb-pkg: hide KDEB_SOURCENAME from Makefile
kbuild: srcrpm-pkg: create source package without cleaning
kbuild: rpm-pkg: build binary packages from source rpm
kbuild: deb-pkg: create source package without cleaning
kbuild: add a tool to list files ignored by git
Documentation/llvm: add Chimera Linux, Google and Meta datacenters
setlocalversion: use only the correct release tag for git-describe
setlocalversion: clean up the construction of version output
.gitignore: ignore *.cover and *.mbx
kbuild: remove --include-dir MAKEFLAG from top Makefile
kbuild: fix trivial typo in comment
...
- Robustify/fix calling startup_{32,64}() from the decompressor code,
and removing x86 quirk from scripts/head-object-list.txt as
a result.
- Do not register processors that cannot be onlined for x2APIC
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'x86-boot-2023-02-20' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 boot updates from Ingo Molnar:
- Robustify/fix calling startup_{32,64}() from the decompressor code,
and removing x86 quirk from scripts/head-object-list.txt as a result.
- Do not register processors that cannot be onlined for x2APIC
* tag 'x86-boot-2023-02-20' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/acpi/boot: Do not register processors that cannot be onlined for x2APIC
scripts/head-object-list: Remove x86 from the list
x86/boot: Robustify calling startup_{32,64}() from the decompressor code
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Merge tag 'v6.2-rc6' into sched/core, to pick up fixes
Pick up fixes before merging another batch of cpuidle updates.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
as-option tests new options using KBUILD_CFLAGS, which causes problems
when using as-option to update KBUILD_AFLAGS because many compiler
options are not valid assembler options.
This will be fixed in a follow up patch. Before doing so, move the
assembler test for -Wa,-mrelax-relocations=no from using as-option to
cc-option.
Link: https://lore.kernel.org/llvm/CAK7LNATcHt7GcXZ=jMszyH=+M_LC9Qr6yeAGRCBbE6xriLxtUQ@mail.gmail.com/
Suggested-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Linux Kernel Functional Testing <lkft@linaro.org>
Tested-by: Anders Roxell <anders.roxell@linaro.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
The hypervisor can enable various new features (SEV_FEATURES[1:63]) and start a
SNP guest. Some of these features need guest side implementation. If any of
these features are enabled without it, the behavior of the SNP guest will be
undefined. It may fail booting in a non-obvious way making it difficult to
debug.
Instead of allowing the guest to continue and have it fail randomly later,
detect this early and fail gracefully.
The SEV_STATUS MSR indicates features which the hypervisor has enabled. While
booting, SNP guests should ascertain that all the enabled features have guest
side implementation. In case a feature is not implemented in the guest, the
guest terminates booting with GHCB protocol Non-Automatic Exit(NAE) termination
request event, see "SEV-ES Guest-Hypervisor Communication Block Standardization"
document (currently at https://developer.amd.com/wp-content/resources/56421.pdf),
section "Termination Request".
Populate SW_EXITINFO2 with mask of unsupported features that the hypervisor can
easily report to the user.
More details in the AMD64 APM Vol 2, Section "SEV_STATUS MSR".
[ bp:
- Massage.
- Move snp_check_features() call to C code.
Note: the CC:stable@ aspect here is to be able to protect older, stable
kernels when running on newer hypervisors. Or not "running" but fail
reliably and in a well-defined manner instead of randomly. ]
Fixes: cbd3d4f7c4e5 ("x86/sev: Check SEV-SNP features support")
Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Cc: <stable@kernel.org>
Link: https://lore.kernel.org/r/20230118061943.534309-1-nikunj@amd.com
objtool found a few cases where this code called out into instrumented
code:
vmlinux.o: warning: objtool: __halt+0x2c: call to hcall_func.constprop.0() leaves .noinstr.text section
vmlinux.o: warning: objtool: __halt+0x3f: call to __tdx_hypercall() leaves .noinstr.text section
vmlinux.o: warning: objtool: __tdx_hypercall+0x66: call to __tdx_hypercall_failed() leaves .noinstr.text section
Fix it by:
- moving TDX tdcall assembly methods into .noinstr.text (they are already noistr-clean)
- marking __tdx_hypercall_failed() as 'noinstr'
- annotating hcall_func() as __always_inline
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Tony Lindgren <tony@atomide.com>
Tested-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20230112195541.111485720@infradead.org
With 'GNU assembler (GNU Binutils for Debian) 2.39.90.20221231' the
build now reports:
arch/x86/realmode/rm/../../boot/bioscall.S: Assembler messages:
arch/x86/realmode/rm/../../boot/bioscall.S:35: Warning: found `movsd'; assuming `movsl' was meant
arch/x86/realmode/rm/../../boot/bioscall.S:70: Warning: found `movsd'; assuming `movsl' was meant
arch/x86/boot/bioscall.S: Assembler messages:
arch/x86/boot/bioscall.S:35: Warning: found `movsd'; assuming `movsl' was meant
arch/x86/boot/bioscall.S:70: Warning: found `movsd'; assuming `movsl' was meant
Which is due to:
PR gas/29525
Note that with the dropped CMPSD and MOVSD Intel Syntax string insn
templates taking operands, mixed IsString/non-IsString template groups
(with memory operands) cannot occur anymore. With that
maybe_adjust_templates() becomes unnecessary (and is hence being
removed).
More details: https://sourceware.org/bugzilla/show_bug.cgi?id=29525
Borislav Petkov further explains:
" the particular problem here is is that the 'd' suffix is
"conflicting" in the sense that you can have SSE mnemonics like movsD %xmm...
and the same thing also for string ops (which is the case here) so apparently
the agreement in binutils land is to use the always accepted suffixes 'l' or 'q'
and phase out 'd' slowly... "
Fixes: 7a734e7dd93b ("x86, setup: "glove box" BIOS calls -- infrastructure")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/Y71I3Ex2pvIxMpsP@hirez.programming.kicks-ass.net
After commit ce697ccee1a8 ("kbuild: remove head-y syntax"), I
started digging whether x86 is ready for removing this old cruft.
Removing its objects from the list makes the kernel unbootable.
This applies only to bzImage, vmlinux still works correctly.
The reason is that with no strict object order determined by the
linker arguments, not the linker script, startup_64 can be placed
not right at the beginning of the kernel.
Here's vmlinux.map's beginning before removing:
ffffffff81000000 vmlinux.o:(.head.text)
ffffffff81000000 startup_64
ffffffff81000070 secondary_startup_64
ffffffff81000075 secondary_startup_64_no_verify
ffffffff81000160 verify_cpu
and after:
ffffffff81000000 vmlinux.o:(.head.text)
ffffffff81000000 pvh_start_xen
ffffffff81000080 startup_64
ffffffff810000f0 secondary_startup_64
ffffffff810000f5 secondary_startup_64_no_verify
Not a problem itself, but the self-extractor code has the address of
that function hardcoded the beginning, not looking onto the ELF
header, which always contains the address of startup_{32,64}().
So, instead of doing an "act of blind faith", just take the address
from the ELF header and extract a relative offset to the entry
point. The decompressor function already returns a pointer to the
beginning of the kernel to the Asm code, which then jumps to it,
so add that offset to the return value.
This doesn't change anything for now, but allows to resign from the
"head object list" for x86 and makes sure valid Kbuild or any other
improvements won't break anything here in general.
Signed-off-by: Alexander Lobakin <alexandr.lobakin@intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Jiri Slaby <jirislaby@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20230109170403.4117105-2-alexandr.lobakin@intel.com
been long in the making. It is a lighterweight software-only fix for
Skylake-based cores where enabling IBRS is a big hammer and causes a
significant performance impact.
What it basically does is, it aligns all kernel functions to 16 bytes
boundary and adds a 16-byte padding before the function, objtool
collects all functions' locations and when the mitigation gets applied,
it patches a call accounting thunk which is used to track the call depth
of the stack at any time.
When that call depth reaches a magical, microarchitecture-specific value
for the Return Stack Buffer, the code stuffs that RSB and avoids its
underflow which could otherwise lead to the Intel variant of Retbleed.
This software-only solution brings a lot of the lost performance back,
as benchmarks suggest:
https://lore.kernel.org/all/20220915111039.092790446@infradead.org/
That page above also contains a lot more detailed explanation of the
whole mechanism
- Implement a new control flow integrity scheme called FineIBT which is
based on the software kCFI implementation and uses hardware IBT support
where present to annotate and track indirect branches using a hash to
validate them
- Other misc fixes and cleanups
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Merge tag 'x86_core_for_v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 core updates from Borislav Petkov:
- Add the call depth tracking mitigation for Retbleed which has been
long in the making. It is a lighterweight software-only fix for
Skylake-based cores where enabling IBRS is a big hammer and causes a
significant performance impact.
What it basically does is, it aligns all kernel functions to 16 bytes
boundary and adds a 16-byte padding before the function, objtool
collects all functions' locations and when the mitigation gets
applied, it patches a call accounting thunk which is used to track
the call depth of the stack at any time.
When that call depth reaches a magical, microarchitecture-specific
value for the Return Stack Buffer, the code stuffs that RSB and
avoids its underflow which could otherwise lead to the Intel variant
of Retbleed.
This software-only solution brings a lot of the lost performance
back, as benchmarks suggest:
https://lore.kernel.org/all/20220915111039.092790446@infradead.org/
That page above also contains a lot more detailed explanation of the
whole mechanism
- Implement a new control flow integrity scheme called FineIBT which is
based on the software kCFI implementation and uses hardware IBT
support where present to annotate and track indirect branches using a
hash to validate them
- Other misc fixes and cleanups
* tag 'x86_core_for_v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (80 commits)
x86/paravirt: Use common macro for creating simple asm paravirt functions
x86/paravirt: Remove clobber bitmask from .parainstructions
x86/debug: Include percpu.h in debugreg.h to get DECLARE_PER_CPU() et al
x86/cpufeatures: Move X86_FEATURE_CALL_DEPTH from bit 18 to bit 19 of word 11, to leave space for WIP X86_FEATURE_SGX_EDECCSSA bit
x86/Kconfig: Enable kernel IBT by default
x86,pm: Force out-of-line memcpy()
objtool: Fix weak hole vs prefix symbol
objtool: Optimize elf_dirty_reloc_sym()
x86/cfi: Add boot time hash randomization
x86/cfi: Boot time selection of CFI scheme
x86/ibt: Implement FineIBT
objtool: Add --cfi to generate the .cfi_sites section
x86: Add prefix symbols for function padding
objtool: Add option to generate prefix symbols
objtool: Avoid O(bloody terrible) behaviour -- an ode to libelf
objtool: Slice up elf_create_section_symbol()
kallsyms: Revert "Take callthunks into account"
x86: Unconfuse CONFIG_ and X86_FEATURE_ namespaces
x86/retpoline: Fix crash printing warning
x86/paravirt: Fix a !PARAVIRT build warning
...
- Convert flexible array members, fix -Wstringop-overflow warnings,
and fix KCFI function type mismatches that went ignored by
maintainers (Gustavo A. R. Silva, Nathan Chancellor, Kees Cook).
- Remove the remaining side-effect users of ksize() by converting
dma-buf, btrfs, and coredump to using kmalloc_size_roundup(),
add more __alloc_size attributes, and introduce full testing
of all allocator functions. Finally remove the ksize() side-effect
so that each allocation-aware checker can finally behave without
exceptions.
- Introduce oops_limit (default 10,000) and warn_limit (default off)
to provide greater granularity of control for panic_on_oops and
panic_on_warn (Jann Horn, Kees Cook).
- Introduce overflows_type() and castable_to_type() helpers for
cleaner overflow checking.
- Improve code generation for strscpy() and update str*() kern-doc.
- Convert strscpy and sigphash tests to KUnit, and expand memcpy
tests.
- Always use a non-NULL argument for prepare_kernel_cred().
- Disable structleak plugin in FORTIFY KUnit test (Anders Roxell).
- Adjust orphan linker section checking to respect CONFIG_WERROR
(Xin Li).
- Make sure siginfo is cleared for forced SIGKILL (haifeng.xu).
- Fix um vs FORTIFY warnings for always-NULL arguments.
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Merge tag 'hardening-v6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull kernel hardening updates from Kees Cook:
- Convert flexible array members, fix -Wstringop-overflow warnings, and
fix KCFI function type mismatches that went ignored by maintainers
(Gustavo A. R. Silva, Nathan Chancellor, Kees Cook)
- Remove the remaining side-effect users of ksize() by converting
dma-buf, btrfs, and coredump to using kmalloc_size_roundup(), add
more __alloc_size attributes, and introduce full testing of all
allocator functions. Finally remove the ksize() side-effect so that
each allocation-aware checker can finally behave without exceptions
- Introduce oops_limit (default 10,000) and warn_limit (default off) to
provide greater granularity of control for panic_on_oops and
panic_on_warn (Jann Horn, Kees Cook)
- Introduce overflows_type() and castable_to_type() helpers for cleaner
overflow checking
- Improve code generation for strscpy() and update str*() kern-doc
- Convert strscpy and sigphash tests to KUnit, and expand memcpy tests
- Always use a non-NULL argument for prepare_kernel_cred()
- Disable structleak plugin in FORTIFY KUnit test (Anders Roxell)
- Adjust orphan linker section checking to respect CONFIG_WERROR (Xin
Li)
- Make sure siginfo is cleared for forced SIGKILL (haifeng.xu)
- Fix um vs FORTIFY warnings for always-NULL arguments
* tag 'hardening-v6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (31 commits)
ksmbd: replace one-element arrays with flexible-array members
hpet: Replace one-element array with flexible-array member
um: virt-pci: Avoid GCC non-NULL warning
signal: Initialize the info in ksignal
lib: fortify_kunit: build without structleak plugin
panic: Expose "warn_count" to sysfs
panic: Introduce warn_limit
panic: Consolidate open-coded panic_on_warn checks
exit: Allow oops_limit to be disabled
exit: Expose "oops_count" to sysfs
exit: Put an upper limit on how often we can oops
panic: Separate sysctl logic from CONFIG_SMP
mm/pgtable: Fix multiple -Wstringop-overflow warnings
mm: Make ksize() a reporting-only function
kunit/fortify: Validate __alloc_size attribute results
drm/sti: Fix return type of sti_{dvo,hda,hdmi}_connector_mode_valid()
drm/fsl-dcu: Fix return type of fsl_dcu_drm_connector_mode_valid()
driver core: Add __alloc_size hint to devm allocators
overflow: Introduce overflows_type() and castable_to_type()
coredump: Proactively round up to kmalloc bucket size
...
