Commit graph

203,631 commits

Author SHA1 Message Date
Masahiro Yamada
3ae919c317 alpha: remove __init annotation from exported page_is_ram()
commit 6ccbd7fd47 upstream.

EXPORT_SYMBOL and __init is a bad combination because the .init.text
section is freed up after the initialization.

Commit c5a130325f ("ACPI/APEI: Add parameter check before error
injection") exported page_is_ram(), hence the __init annotation should
be removed.

This fixes the modpost warning in ARCH=alpha builds:

  WARNING: modpost: vmlinux: page_is_ram: EXPORT_SYMBOL used for init symbol. Remove __init or EXPORT_SYMBOL.

Fixes: c5a130325f ("ACPI/APEI: Add parameter check before error injection")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-16 18:27:31 +02:00
Arnd Bergmann
19e7feda89 x86: Move gds_ucode_mitigated() declaration to header
commit eb3515dc99 upstream.

The declaration got placed in the .c file of the caller, but that
causes a warning for the definition:

arch/x86/kernel/cpu/bugs.c:682:6: error: no previous prototype for 'gds_ucode_mitigated' [-Werror=missing-prototypes]

Move it to a header where both sides can observe it instead.

Fixes: 81ac7e5d74 ("KVM: Add GDS_NO support to KVM")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Tested-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Cc: stable@kernel.org
Link: https://lore.kernel.org/all/20230809130530.1913368-2-arnd%40kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-16 18:27:25 +02:00
Borislav Petkov (AMD)
179430c2aa x86/sev: Do not try to parse for the CC blob on non-AMD hardware
commit bee6cf1a80 upstream.

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: c01fce9cef ("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
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-16 18:27:25 +02:00
Kirill A. Shutemov
9ad49178c0 x86/mm: Fix VDSO and VVAR placement on 5-level paging machines
commit 1b8b1aa90c upstream.

Yingcong has noticed that on the 5-level paging machine, VDSO and VVAR
VMAs are placed above the 47-bit border:

8000001a9000-8000001ad000 r--p 00000000 00:00 0                          [vvar]
8000001ad000-8000001af000 r-xp 00000000 00:00 0                          [vdso]

This might confuse users who are not aware of 5-level paging and expect
all userspace addresses to be under the 47-bit border.

So far problem has only been triggered with ASLR disabled, although it
may also occur with ASLR enabled if the layout is randomized in a just
right way.

The problem happens due to custom placement for the VMAs in the VDSO
code: vdso_addr() tries to place them above the stack and checks the
result against TASK_SIZE_MAX, which is wrong. TASK_SIZE_MAX is set to
the 56-bit border on 5-level paging machines. Use DEFAULT_MAP_WINDOW
instead.

Fixes: b569bab78d ("x86/mm: Prepare to expose larger address space to userspace")
Reported-by: Yingcong Wu <yingcong.wu@intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/20230803151609.22141-1-kirill.shutemov%40linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-16 18:27:25 +02:00
Cristian Ciocaltea
25085250a1 x86/cpu/amd: Enable Zenbleed fix for AMD Custom APU 0405
commit 6dbef74aeb upstream.

Commit

  522b1d6921 ("x86/cpu/amd: Add a Zenbleed fix")

provided a fix for the Zen2 VZEROUPPER data corruption bug affecting
a range of CPU models, but the AMD Custom APU 0405 found on SteamDeck
was not listed, although it is clearly affected by the vulnerability.

Add this CPU variant to the Zenbleed erratum list, in order to
unconditionally enable the fallback fix until a proper microcode update
is available.

Fixes: 522b1d6921 ("x86/cpu/amd: Add a Zenbleed fix")
Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20230811203705.1699914-1-cristian.ciocaltea@collabora.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-16 18:27:25 +02:00
Nick Desaulniers
d93eeac34e x86/srso: Fix build breakage with the LLVM linker
commit cbe8ded48b upstream.

The assertion added to verify the difference in bits set of the
addresses of srso_untrain_ret_alias() and srso_safe_ret_alias() would fail
to link in LLVM's ld.lld linker with the following error:

  ld.lld: error: ./arch/x86/kernel/vmlinux.lds:210: at least one side of
  the expression must be absolute
  ld.lld: error: ./arch/x86/kernel/vmlinux.lds:211: at least one side of
  the expression must be absolute

Use ABSOLUTE to evaluate the expression referring to at least one of the
symbols so that LLD can evaluate the linker script.

Also, add linker version info to the comment about XOR being unsupported
in either ld.bfd or ld.lld until somewhat recently.

Fixes: fb3bd914b3 ("x86/srso: Add a Speculative RAS Overflow mitigation")
Closes: https://lore.kernel.org/llvm/CA+G9fYsdUeNu-gwbs0+T6XHi4hYYk=Y9725-wFhZ7gJMspLDRA@mail.gmail.com/
Reported-by: Nathan Chancellor <nathan@kernel.org>
Reported-by: Daniel Kolesa <daniel@octaforge.org>
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Suggested-by: Sven Volkinsfeld <thyrc@gmx.net>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://github.com/ClangBuiltLinux/linux/issues/1907
Link: https://lore.kernel.org/r/20230809-gds-v1-1-eaac90b0cbcc@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-16 18:27:25 +02:00
Torsten Duwe
3fdaa7fbc8 riscv/kexec: handle R_RISCV_CALL_PLT relocation type
commit d0b4f95a51 upstream.

R_RISCV_CALL has been deprecated and replaced by R_RISCV_CALL_PLT. See Enum
18-19 in Table 3. Relocation types here:

https://github.com/riscv-non-isa/riscv-elf-psabi-doc/blob/master/riscv-elf.adoc

It was deprecated in ("Deprecated R_RISCV_CALL, prefer R_RISCV_CALL_PLT"):

a0dced8501

Recent tools (at least GNU binutils-2.40) already use R_RISCV_CALL_PLT.
Kernels built with such binutils fail kexec_load_file(2) with:

 kexec_image: Unknown rela relocation: 19
 kexec_image: Error loading purgatory ret=-8

The binary code at the call site remains the same, so tell
arch_kexec_apply_relocations_add() to handle _PLT alike.

Fixes: 838b3e2848 ("RISC-V: Load purgatory in kexec_file")
Signed-off-by: Torsten Duwe <duwe@suse.de>
Signed-off-by: Petr Tesarik <petr.tesarik.ext@huawei.com>
Cc: Li Zhengyu <lizhengyu3@huawei.com>
Cc: stable@vger.kernel.org
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/all/b046b164af8efd33bbdb7d4003273bdf9196a5b0.1690365011.git.petr.tesarik.ext@huawei.com/
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-16 18:27:21 +02:00
Andrea Parri
b374684018 riscv,mmio: Fix readX()-to-delay() ordering
commit 4eb2eb1b4c upstream.

Section 2.1 of the Platform Specification [1] states:

  Unless otherwise specified by a given I/O device, I/O devices are on
  ordering channel 0 (i.e., they are point-to-point strongly ordered).

which is not sufficient to guarantee that a readX() by a hart completes
before a subsequent delay() on the same hart (cf. memory-barriers.txt,
"Kernel I/O barrier effects").

Set the I(nput) bit in __io_ar() to restore the ordering, align inline
comments.

[1] https://github.com/riscv/riscv-platform-specs

Signed-off-by: Andrea Parri <parri.andrea@gmail.com>
Link: https://lore.kernel.org/r/20230803042738.5937-1-parri.andrea@gmail.com
Fixes: fab957c11e ("RISC-V: Atomic and Locking Code")
Cc: stable@vger.kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-16 18:27:21 +02:00
Torsten Duwe
98a34f50c1 riscv/kexec: load initrd high in available memory
commit 49af7a2cd5 upstream.

When initrd is loaded low, the secondary kernel fails like this:

 INITRD: 0xdc581000+0x00eef000 overlaps in-use memory region

This initrd load address corresponds to the _end symbol, but the
reservation is aligned on PMD_SIZE, as explained by a comment in
setup_bootmem().

It is technically possible to align the initrd load address accordingly,
leaving a hole between the end of kernel and the initrd, but it is much
simpler to allocate the initrd top-down.

Fixes: 838b3e2848 ("RISC-V: Load purgatory in kexec_file")
Signed-off-by: Torsten Duwe <duwe@suse.de>
Signed-off-by: Petr Tesarik <petr.tesarik.ext@huawei.com>
Cc: stable@vger.kernel.org
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/all/67c8eb9eea25717c2c8208d9bfbfaa39e6e2a1c6.1690365011.git.petr.tesarik.ext@huawei.com/
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-16 18:27:21 +02:00
Paolo Bonzini
5bdf1c1f34 KVM: SEV: only access GHCB fields once
commit 7588dbcebc upstream.

A KVM guest using SEV-ES or SEV-SNP with multiple vCPUs can trigger
a double fetch race condition vulnerability and invoke the VMGEXIT
handler recursively.

sev_handle_vmgexit() maps the GHCB page using kvm_vcpu_map() and then
fetches the exit code using ghcb_get_sw_exit_code().  Soon after,
sev_es_validate_vmgexit() fetches the exit code again. Since the GHCB
page is shared with the guest, the guest is able to quickly swap the
values with another vCPU and hence bypass the validation. One vmexit code
that can be rejected by sev_es_validate_vmgexit() is SVM_EXIT_VMGEXIT;
if sev_handle_vmgexit() observes it in the second fetch, the call
to svm_invoke_exit_handler() will invoke sev_handle_vmgexit() again
recursively.

To avoid the race, always fetch the GHCB data from the places where
sev_es_sync_from_ghcb stores it.

Exploiting recursions on linux kernel has been proven feasible
in the past, but the impact is mitigated by stack guard pages
(CONFIG_VMAP_STACK).  Still, if an attacker manages to call the handler
multiple times, they can theoretically trigger a stack overflow and
cause a denial-of-service, or potentially guest-to-host escape in kernel
configurations without stack guard pages.

Note that winning the race reliably in every iteration is very tricky
due to the very tight window of the fetches; depending on the compiler
settings, they are often consecutive because of optimization and inlining.

Tested by booting an SEV-ES RHEL9 guest.

Fixes: CVE-2023-4155
Fixes: 291bd20d5d ("KVM: SVM: Add initial support for a VMGEXIT VMEXIT")
Cc: stable@vger.kernel.org
Reported-by: Andy Nguyen <theflow@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-16 18:27:20 +02:00
Paolo Bonzini
ec18273e41 KVM: SEV: snapshot the GHCB before accessing it
commit 4e15a0ddc3 upstream.

Validation of the GHCB is susceptible to time-of-check/time-of-use vulnerabilities.
To avoid them, we would like to always snapshot the fields that are read in
sev_es_validate_vmgexit(), and not use the GHCB anymore after it returns.

This means:

- invoking sev_es_sync_from_ghcb() before any GHCB access, including before
  sev_es_validate_vmgexit()

- snapshotting all fields including the valid bitmap and the sw_scratch field,
  which are currently not caching anywhere.

The valid bitmap is the first thing to be copied out of the GHCB; then,
further accesses will use the copy in svm->sev_es.

Fixes: 291bd20d5d ("KVM: SVM: Add initial support for a VMGEXIT VMEXIT")
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-16 18:27:20 +02:00
Greg Kroah-Hartman
ed2f8701fb Revert "loongarch/cpu: Switch to arch_cpu_finalize_init()"
This reverts commit 08e86d42e2 which is
commit 9841c42316 upstream.

As Gunter reports:
	Building loongarch:defconfig ... failed
	--------------
	Error log:
	<stdin>:569:2: warning: #warning syscall fstat not implemented [-Wcpp]
	arch/loongarch/kernel/setup.c: In function 'arch_cpu_finalize_init':
	arch/loongarch/kernel/setup.c:86:9: error: implicit declaration of function 'alternative_instructions'

	Actually introduced in v6.1.44 with commit 08e86d42e2 ("loongarch/cpu:
	Switch to arch_cpu_finalize_init()"). Alternative instruction support
	was only introduced for loongarch in v6.2 with commit 19e5eb15b0
	("LoongArch: Add alternative runtime patching mechanism").

So revert it from 6.1.y.

Reported-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/fcd7b764-9047-22ba-a040-41b6ff99959c@roeck-us.net
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-16 18:27:20 +02:00
Borislav Petkov (AMD)
f2615bb47b x86/CPU/AMD: Do not leak quotient data after a division by 0
commit 77245f1c3c upstream.

Under certain circumstances, an integer division by 0 which faults, can
leave stale quotient data from a previous division operation on Zen1
microarchitectures.

Do a dummy division 0/1 before returning from the #DE exception handler
in order to avoid any leaks of potentially sensitive data.

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: <stable@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-11 12:08:27 +02:00
Mark Brown
99255a2b68 arm64/ptrace: Don't enable SVE when setting streaming SVE
commit 045aecdfcb upstream.

Systems which implement SME without also implementing SVE are
architecturally valid but were not initially supported by the kernel,
unfortunately we missed one issue in the ptrace code.

The SVE register setting code is shared between SVE and streaming mode
SVE. When we set full SVE register state we currently enable TIF_SVE
unconditionally, in the case where streaming SVE is being configured on a
system that supports vanilla SVE this is not an issue since we always
initialise enough state for both vector lengths but on a system which only
support SME it will result in us attempting to restore the SVE vector
length after having set streaming SVE registers.

Fix this by making the enabling of SVE conditional on setting SVE vector
state. If we set streaming SVE state and SVE was not already enabled this
will result in a SVE access trap on next use of normal SVE, this will cause
us to flush our register state but this is fine since the only way to
trigger a SVE access trap would be to exit streaming mode which will cause
the in register state to be flushed anyway.

Fixes: e12310a0d3 ("arm64/sme: Implement ptrace support for streaming mode SVE registers")
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20230803-arm64-fix-ptrace-ssve-no-sve-v1-1-49df214bfb3e@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
[Fix up backport -- broonie]
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-11 12:08:26 +02:00
Aneesh Kumar K.V
a492b8281c powerpc/mm/altmap: Fix altmap boundary check
[ Upstream commit 6722b25712 ]

altmap->free includes the entire free space from which altmap blocks
can be allocated. So when checking whether the kernel is doing altmap
block free, compute the boundary correctly, otherwise memory hotunplug
can fail.

Fixes: 9ef34630a4 ("powerpc/mm: Fallback to RAM if the altmap is unusable")
Signed-off-by: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230724181320.471386-1-aneesh.kumar@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-08-11 12:08:25 +02:00
Mark Brown
61f96da37d arm64/fpsimd: Sync FPSIMD state with SVE for SME only systems
commit 507ea5dd92 upstream.

Currently we guard FPSIMD/SVE state conversions with a check for the system
supporting SVE but SME only systems may need to sync streaming mode SVE
state so add a check for SME support too.  These functions are only used
by the ptrace code.

Fixes: e12310a0d3 ("arm64/sme: Implement ptrace support for streaming mode SVE registers")
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20230803-arm64-fix-ptrace-ssve-no-sve-v1-2-49df214bfb3e@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-11 12:08:22 +02:00
Mark Brown
654c1dd350 arm64/fpsimd: Clear SME state in the target task when setting the VL
commit c9bb40b7f7 upstream.

When setting SME vector lengths we clear TIF_SME to reenable SME traps,
doing a reallocation of the backing storage on next use. We do this using
clear_thread_flag() which operates on the current thread, meaning that when
setting the vector length via ptrace we may both not force traps for the
target task and force a spurious flush of any SME state that the tracing
task may have.

Clear the flag in the target task.

Fixes: e12310a0d3 ("arm64/sme: Implement ptrace support for streaming mode SVE registers")
Reported-by: David Spickett <David.Spickett@arm.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20230803-arm64-fix-ptrace-tif-sme-v1-1-88312fd6fbfd@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-11 12:08:21 +02:00
Mark Brown
bae353469a arm64/fpsimd: Sync and zero pad FPSIMD state for streaming SVE
commit 69af56ae56 upstream.

We have a function sve_sync_from_fpsimd_zeropad() which is used by the
ptrace code to update the SVE state when the user writes to the the
FPSIMD register set.  Currently this checks that the task has SVE
enabled but this will miss updates for tasks which have streaming SVE
enabled if SVE has not been enabled for the thread, also do the
conversion if the task has streaming SVE enabled.

Fixes: e12310a0d3 ("arm64/sme: Implement ptrace support for streaming mode SVE registers")
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20230803-arm64-fix-ptrace-ssve-no-sve-v1-3-49df214bfb3e@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-11 12:08:21 +02:00
Naveen N Rao
b8ea2a4691 powerpc/ftrace: Create a dummy stackframe to fix stack unwind
commit 41a506ef71 upstream.

With ppc64 -mprofile-kernel and ppc32 -pg, profiling instructions to
call into ftrace are emitted right at function entry. The instruction
sequence used is minimal to reduce overhead. Crucially, a stackframe is
not created for the function being traced. This breaks stack unwinding
since the function being traced does not have a stackframe for itself.
As such, it never shows up in the backtrace:

/sys/kernel/debug/tracing # echo 1 > /proc/sys/kernel/stack_tracer_enabled
/sys/kernel/debug/tracing # cat stack_trace
        Depth    Size   Location    (17 entries)
        -----    ----   --------
  0)     4144      32   ftrace_call+0x4/0x44
  1)     4112     432   get_page_from_freelist+0x26c/0x1ad0
  2)     3680     496   __alloc_pages+0x290/0x1280
  3)     3184     336   __folio_alloc+0x34/0x90
  4)     2848     176   vma_alloc_folio+0xd8/0x540
  5)     2672     272   __handle_mm_fault+0x700/0x1cc0
  6)     2400     208   handle_mm_fault+0xf0/0x3f0
  7)     2192      80   ___do_page_fault+0x3e4/0xbe0
  8)     2112     160   do_page_fault+0x30/0xc0
  9)     1952     256   data_access_common_virt+0x210/0x220
 10)     1696     400   0xc00000000f16b100
 11)     1296     384   load_elf_binary+0x804/0x1b80
 12)      912     208   bprm_execve+0x2d8/0x7e0
 13)      704      64   do_execveat_common+0x1d0/0x2f0
 14)      640     160   sys_execve+0x54/0x70
 15)      480      64   system_call_exception+0x138/0x350
 16)      416     416   system_call_common+0x160/0x2c4

Fix this by having ftrace create a dummy stackframe for the function
being traced. With this, backtraces now capture the function being
traced:

/sys/kernel/debug/tracing # cat stack_trace
        Depth    Size   Location    (17 entries)
        -----    ----   --------
  0)     3888      32   _raw_spin_trylock+0x8/0x70
  1)     3856     576   get_page_from_freelist+0x26c/0x1ad0
  2)     3280      64   __alloc_pages+0x290/0x1280
  3)     3216     336   __folio_alloc+0x34/0x90
  4)     2880     176   vma_alloc_folio+0xd8/0x540
  5)     2704     416   __handle_mm_fault+0x700/0x1cc0
  6)     2288      96   handle_mm_fault+0xf0/0x3f0
  7)     2192      48   ___do_page_fault+0x3e4/0xbe0
  8)     2144     192   do_page_fault+0x30/0xc0
  9)     1952     608   data_access_common_virt+0x210/0x220
 10)     1344      16   0xc0000000334bbb50
 11)     1328     416   load_elf_binary+0x804/0x1b80
 12)      912      64   bprm_execve+0x2d8/0x7e0
 13)      848     176   do_execveat_common+0x1d0/0x2f0
 14)      672     192   sys_execve+0x54/0x70
 15)      480      64   system_call_exception+0x138/0x350
 16)      416     416   system_call_common+0x160/0x2c4

This results in two additional stores in the ftrace entry code, but
produces reliable backtraces.

Fixes: 153086644f ("powerpc/ftrace: Add support for -mprofile-kernel ftrace ABI")
Cc: stable@vger.kernel.org
Signed-off-by: Naveen N Rao <naveen@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230621051349.759567-1-naveen@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-11 12:08:21 +02:00
Michael Kelley
98cccbd0a1 x86/hyperv: Disable IBT when hypercall page lacks ENDBR instruction
commit d5ace2a776 upstream.

On hardware that supports Indirect Branch Tracking (IBT), Hyper-V VMs
with ConfigVersion 9.3 or later support IBT in the guest. However,
current versions of Hyper-V have a bug in that there's not an ENDBR64
instruction at the beginning of the hypercall page. Since hypercalls are
made with an indirect call to the hypercall page, all hypercall attempts
fail with an exception and Linux panics.

A Hyper-V fix is in progress to add ENDBR64. But guard against the Linux
panic by clearing X86_FEATURE_IBT if the hypercall page doesn't start
with ENDBR. The VM will boot and run without IBT.

If future Linux 32-bit kernels were to support IBT, additional hypercall
page hackery would be needed to make IBT work for such kernels in a
Hyper-V VM.

Cc: stable@vger.kernel.org
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/1690001476-98594-1-git-send-email-mikelley@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-11 12:08:21 +02:00
Dinh Nguyen
367fdf369d arm64: dts: stratix10: fix incorrect I2C property for SCL signal
commit db66795f61 upstream.

The correct dts property for the SCL falling time is
"i2c-scl-falling-time-ns".

Fixes: c8da1d15b8 ("arm64: dts: stratix10: i2c clock running out of spec")
Cc: stable@vger.kernel.org
Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-11 12:08:20 +02:00
Heiko Carstens
a759972d25 KVM: s390: fix sthyi error handling
[ Upstream commit 0c02cc576e ]

Commit 9fb6c9b3fe ("s390/sthyi: add cache to store hypervisor info")
added cache handling for store hypervisor info. This also changed the
possible return code for sthyi_fill().

Instead of only returning a condition code like the sthyi instruction would
do, it can now also return a negative error value (-ENOMEM). handle_styhi()
was not changed accordingly. In case of an error, the negative error value
would incorrectly injected into the guest PSW.

Add proper error handling to prevent this, and update the comment which
describes the possible return values of sthyi_fill().

Fixes: 9fb6c9b3fe ("s390/sthyi: add cache to store hypervisor info")
Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Link: https://lore.kernel.org/r/20230727182939.2050744-1-hca@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-08-11 12:08:11 +02:00
ndesaulniers@google.com
f168188174 word-at-a-time: use the same return type for has_zero regardless of endianness
[ Upstream commit 79e8328e5a ]

Compiling big-endian targets with Clang produces the diagnostic:

  fs/namei.c:2173:13: warning: use of bitwise '|' with boolean operands [-Wbitwise-instead-of-logical]
	} while (!(has_zero(a, &adata, &constants) | has_zero(b, &bdata, &constants)));
	          ~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
                                               ||
  fs/namei.c:2173:13: note: cast one or both operands to int to silence this warning

It appears that when has_zero was introduced, two definitions were
produced with different signatures (in particular different return
types).

Looking at the usage in hash_name() in fs/namei.c, I suspect that
has_zero() is meant to be invoked twice per while loop iteration; using
logical-or would not update `bdata` when `a` did not have zeros.  So I
think it's preferred to always return an unsigned long rather than a
bool than update the while loop in hash_name() to use a logical-or
rather than bitwise-or.

[ Also changed powerpc version to do the same  - Linus ]

Link: https://github.com/ClangBuiltLinux/linux/issues/1832
Link: https://lore.kernel.org/lkml/20230801-bitwise-v1-1-799bec468dc4@google.com/
Fixes: 36126f8f2e ("word-at-a-time: make the interfaces truly generic")
Debugged-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-08-11 12:08:11 +02:00
Benjamin Gaignard
7b0582dddd arm64: dts: freescale: Fix VPU G2 clock
[ Upstream commit b27bfc5103 ]

Set VPU G2 clock to 300MHz like described in documentation.
This fixes pixels error occurring with large resolution ( >= 2560x1600)
HEVC test stream when using the postprocessor to produce NV12.

Fixes: 4ac7e4a812 ("arm64: dts: imx8mq: Enable both G1 and G2 VPU's with vpu-blk-ctrl")
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-08-11 12:08:10 +02:00
Hugo Villeneuve
5841d3d0c3 arm64: dts: imx8mn-var-som: add missing pull-up for onboard PHY reset pinmux
[ Upstream commit 253be5b53c ]

For SOMs with an onboard PHY, the RESET_N pull-up resistor is
currently deactivated in the pinmux configuration. When the pinmux
code selects the GPIO function for this pin, with a default direction
of input, this prevents the RESET_N pin from being taken to the proper
3.3V level (deasserted), and this results in the PHY being not
detected since it is held in reset.

Taken from RESET_N pin description in ADIN13000 datasheet:
    This pin requires a 1K pull-up resistor to AVDD_3P3.

Activate the pull-up resistor to fix the issue.

Fixes: ade0176dd8 ("arm64: dts: imx8mn-var-som: Add Variscite VAR-SOM-MX8MN System on Module")
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-08-11 12:08:10 +02:00
Yashwanth Varakala
a24f67b71a arm64: dts: phycore-imx8mm: Correction in gpio-line-names
[ Upstream commit 1ef0aa137a ]

Remove unused nINT_ETHPHY entry from gpio-line-names in gpio1 nodes of
phyCORE-i.MX8MM and phyBOARD-Polis-i.MX8MM devicetrees.

Fixes: ae6847f26a ("arm64: dts: freescale: Add phyBOARD-Polis-i.MX8MM support")
Signed-off-by: Yashwanth Varakala <y.varakala@phytec.de>
Signed-off-by: Cem Tenruh <c.tenruh@phytec.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-08-11 12:08:10 +02:00
Yashwanth Varakala
753a927c58 arm64: dts: phycore-imx8mm: Label typo-fix of VPU
[ Upstream commit cddeefc166 ]

Corrected the label of the VPU regulator node (buck 3)
from reg_vdd_gpu to reg_vdd_vpu.

Fixes: ae6847f26a ("arm64: dts: freescale: Add phyBOARD-Polis-i.MX8MM support")
Signed-off-by: Yashwanth Varakala <y.varakala@phytec.de>
Signed-off-by: Cem Tenruh <c.tenruh@phytec.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-08-11 12:08:10 +02:00
Tim Harvey
608ac7ea5f arm64: dts: imx8mm-venice-gw7904: disable disp_blk_ctrl
[ Upstream commit f7a0b57524 ]

The GW7904 does not connect the VDD_MIPI power rails thus MIPI is
disabled. However we must also disable disp_blk_ctrl as it uses the
pgc_mipi power domain and without it being disabled imx8m-blk-ctrl will
fail to probe:
imx8m-blk-ctrl 32e28000.blk-ctrl: error -ETIMEDOUT: failed to attach
power domain "mipi-dsi"
imx8m-blk-ctrl: probe of 32e28000.blk-ctrl failed with error -110

Fixes: b999bdaf05 ("arm64: dts: imx: Add i.mx8mm Gateworks gw7904 dts support")
Signed-off-by: Tim Harvey <tharvey@gateworks.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-08-11 12:08:10 +02:00
Tim Harvey
d060bbb2fe arm64: dts: imx8mm-venice-gw7903: disable disp_blk_ctrl
[ Upstream commit 3e7d3c5e13 ]

The GW7903 does not connect the VDD_MIPI power rails thus MIPI is
disabled. However we must also disable disp_blk_ctrl as it uses the
pgc_mipi power domain and without it being disabled imx8m-blk-ctrl will
fail to probe:
imx8m-blk-ctrl 32e28000.blk-ctrl: error -ETIMEDOUT: failed to attach power domain "mipi-dsi"
imx8m-blk-ctrl: probe of 32e28000.blk-ctrl failed with error -110

Fixes: a72ba91e5b ("arm64: dts: imx: Add i.mx8mm Gateworks gw7903 dts support")
Signed-off-by: Tim Harvey <tharvey@gateworks.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-08-11 12:08:10 +02:00
Greg Kroah-Hartman
dd5f2ef16e x86: fix backwards merge of GDS/SRSO bit
Stable-tree-only change.

Due to the way the GDS and SRSO patches flowed into the stable tree, it
was a 50% chance that the merge of the which value GDS and SRSO should
be.  Of course, I lost that bet, and chose the opposite of what Linus
chose in commit 64094e7e31 ("Merge tag 'gds-for-linus-2023-08-01' of
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip")

Fix this up by switching the values to match what is now in Linus's tree
as that is the correct value to mirror.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:51 +02:00
Borislav Petkov (AMD)
4f25355540 x86/srso: Tie SBPB bit setting to microcode patch detection
commit 5a15d83488 upstream.

The SBPB bit in MSR_IA32_PRED_CMD is supported only after a microcode
patch has been applied so set X86_FEATURE_SBPB only then. Otherwise,
guests would attempt to set that bit and #GP on the MSR write.

While at it, make SMT detection more robust as some guests - depending
on how and what CPUID leafs their report - lead to cpu_smt_control
getting set to CPU_SMT_NOT_SUPPORTED but SRSO_NO should be set for any
guest incarnation where one simply cannot do SMT, for whatever reason.

Fixes: fb3bd914b3 ("x86/srso: Add a Speculative RAS Overflow mitigation")
Reported-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reported-by: Salvatore Bonaccorso <carnil@debian.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:51 +02:00
Borislav Petkov (AMD)
77cf32d0db x86/srso: Add a forgotten NOENDBR annotation
Upstream commit: 3bbbe97ad8

Fix:

  vmlinux.o: warning: objtool: .export_symbol+0x29e40: data relocation to !ENDBR: srso_untrain_ret_alias+0x0

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:51 +02:00
Josh Poimboeuf
c7f2cd0455 x86/srso: Fix return thunks in generated code
Upstream commit: 238ec850b9

Set X86_FEATURE_RETHUNK when enabling the SRSO mitigation so that
generated code (e.g., ftrace, static call, eBPF) generates "jmp
__x86_return_thunk" instead of RET.

  [ bp: Add a comment. ]

Fixes: fb3bd914b3 ("x86/srso: Add a Speculative RAS Overflow mitigation")
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:51 +02:00
Borislav Petkov (AMD)
c9ae63d773 x86/srso: Add IBPB on VMEXIT
Upstream commit: d893832d0e

Add the option to flush IBPB only on VMEXIT in order to protect from
malicious guests but one otherwise trusts the software that runs on the
hypervisor.

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:50 +02:00
Borislav Petkov (AMD)
79c8091888 x86/srso: Add IBPB
Upstream commit: 233d6f68b9

Add the option to mitigate using IBPB on a kernel entry. Pull in the
Retbleed alternative so that the IBPB call from there can be used. Also,
if Retbleed mitigation is done using IBPB, the same mitigation can and
must be used here.

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:50 +02:00
Borislav Petkov (AMD)
98f62883e7 x86/srso: Add SRSO_NO support
Upstream commit: 1b5277c0ea

Add support for the CPUID flag which denotes that the CPU is not
affected by SRSO.

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:50 +02:00
Borislav Petkov (AMD)
9139f4b6dd x86/srso: Add IBPB_BRTYPE support
Upstream commit: 79113e4060

Add support for the synthetic CPUID flag which "if this bit is 1,
it indicates that MSR 49h (PRED_CMD) bit 0 (IBPB) flushes all branch
type predictions from the CPU branch predictor."

This flag is there so that this capability in guests can be detected
easily (otherwise one would have to track microcode revisions which is
impossible for guests).

It is also needed only for Zen3 and -4. The other two (Zen1 and -2)
always flush branch type predictions by default.

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:50 +02:00
Borislav Petkov (AMD)
ac41e90d8d x86/srso: Add a Speculative RAS Overflow mitigation
Upstream commit: fb3bd914b3

Add a mitigation for the speculative return address stack overflow
vulnerability found on AMD processors.

The mitigation works by ensuring all RET instructions speculate to
a controlled location, similar to how speculation is controlled in the
retpoline sequence.  To accomplish this, the __x86_return_thunk forces
the CPU to mispredict every function return using a 'safe return'
sequence.

To ensure the safety of this mitigation, the kernel must ensure that the
safe return sequence is itself free from attacker interference.  In Zen3
and Zen4, this is accomplished by creating a BTB alias between the
untraining function srso_untrain_ret_alias() and the safe return
function srso_safe_ret_alias() which results in evicting a potentially
poisoned BTB entry and using that safe one for all function returns.

In older Zen1 and Zen2, this is accomplished using a reinterpretation
technique similar to Retbleed one: srso_untrain_ret() and
srso_safe_ret().

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:50 +02:00
Kim Phillips
dec3b91f2c x86/cpu, kvm: Add support for CPUID_80000021_EAX
commit 8415a74852 upstream.

Add support for CPUID leaf 80000021, EAX. The majority of the features will be
used in the kernel and thus a separate leaf is appropriate.

Include KVM's reverse_cpuid entry because features are used by VM guests, too.

  [ bp: Massage commit message. ]

Signed-off-by: Kim Phillips <kim.phillips@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20230124163319.2277355-2-kim.phillips@amd.com
[bwh: Backported to 6.1: adjust context]
Signed-off-by: Ben Hutchings <benh@debian.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:50 +02:00
Borislav Petkov (AMD)
dfede4cb8e x86/bugs: Increase the x86 bugs vector size to two u32s
Upstream commit: 0e52740ffd

There was never a doubt in my mind that they would not fit into a single
u32 eventually.

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:50 +02:00
Peter Zijlstra
9ae15aaff3 x86/mm: Use mm_alloc() in poking_init()
commit 3f4c8211d9 upstream.

Instead of duplicating init_mm, allocate a fresh mm. The advantage is
that mm_alloc() has much simpler dependencies. Additionally it makes
more conceptual sense, init_mm has no (and must not have) user state
to duplicate.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20221025201057.816175235@infradead.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:49 +02:00
Juergen Gross
d972c8c08f x86/mm: fix poking_init() for Xen PV guests
commit 26ce6ec364 upstream.

Commit 3f4c8211d9 ("x86/mm: Use mm_alloc() in poking_init()") broke
the kernel for running as Xen PV guest.

It seems as if the new address space is never activated before being
used, resulting in Xen rejecting to accept the new CR3 value (the PGD
isn't pinned).

Fix that by adding the now missing call of paravirt_arch_dup_mmap() to
poking_init(). That call was previously done by dup_mm()->dup_mmap() and
it is a NOP for all cases but for Xen PV, where it is just doing the
pinning of the PGD.

Fixes: 3f4c8211d9 ("x86/mm: Use mm_alloc() in poking_init()")
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20230109150922.10578-1-jgross@suse.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:49 +02:00
Juergen Gross
7f3982de36 x86/xen: Fix secondary processors' FPU initialization
commit fe3e0a13e5 upstream.

Moving the call of fpu__init_cpu() from cpu_init() to start_secondary()
broke Xen PV guests, as those don't call start_secondary() for APs.

Call fpu__init_cpu() in Xen's cpu_bringup(), which is the Xen PV
replacement of start_secondary().

Fixes: b81fac906a ("x86/fpu: Move FPU initialization into arch_cpu_finalize_init()")
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230703130032.22916-1-jgross@suse.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:49 +02:00
Thomas Gleixner
baa7b7501e x86/mem_encrypt: Unbreak the AMD_MEM_ENCRYPT=n build
commit 0a9567ac5e upstream.

Moving mem_encrypt_init() broke the AMD_MEM_ENCRYPT=n because the
declaration of that function was under #ifdef CONFIG_AMD_MEM_ENCRYPT and
the obvious placement for the inline stub was the #else path.

This is a leftover of commit 20f07a044a ("x86/sev: Move common memory
encryption code to mem_encrypt.c") which made mem_encrypt_init() depend on
X86_MEM_ENCRYPT without moving the prototype. That did not fail back then
because there was no stub inline as the core init code had a weak function.

Move both the declaration and the stub out of the CONFIG_AMD_MEM_ENCRYPT
section and guard it with CONFIG_X86_MEM_ENCRYPT.

Fixes: 439e17576e ("init, x86: Move mem_encrypt_init() into arch_cpu_finalize_init()")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Closes: https://lore.kernel.org/oe-kbuild-all/202306170247.eQtCJPE8-lkp@intel.com/
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:49 +02:00
Daniel Sneddon
b6fd07c41b KVM: Add GDS_NO support to KVM
commit 81ac7e5d74 upstream

Gather Data Sampling (GDS) is a transient execution attack using
gather instructions from the AVX2 and AVX512 extensions. This attack
allows malicious code to infer data that was previously stored in
vector registers. Systems that are not vulnerable to GDS will set the
GDS_NO bit of the IA32_ARCH_CAPABILITIES MSR. This is useful for VM
guests that may think they are on vulnerable systems that are, in
fact, not affected. Guests that are running on affected hosts where
the mitigation is enabled are protected as if they were running
on an unaffected system.

On all hosts that are not affected or that are mitigated, set the
GDS_NO bit.

Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:48 +02:00
Daniel Sneddon
c04579e954 x86/speculation: Add Kconfig option for GDS
commit 53cf5797f1 upstream

Gather Data Sampling (GDS) is mitigated in microcode. However, on
systems that haven't received the updated microcode, disabling AVX
can act as a mitigation. Add a Kconfig option that uses the microcode
mitigation if available and disables AVX otherwise. Setting this
option has no effect on systems not affected by GDS. This is the
equivalent of setting gather_data_sampling=force.

Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:48 +02:00
Daniel Sneddon
92fc27c79b x86/speculation: Add force option to GDS mitigation
commit 553a5c03e9 upstream

The Gather Data Sampling (GDS) vulnerability allows malicious software
to infer stale data previously stored in vector registers. This may
include sensitive data such as cryptographic keys. GDS is mitigated in
microcode, and systems with up-to-date microcode are protected by
default. However, any affected system that is running with older
microcode will still be vulnerable to GDS attacks.

Since the gather instructions used by the attacker are part of the
AVX2 and AVX512 extensions, disabling these extensions prevents gather
instructions from being executed, thereby mitigating the system from
GDS. Disabling AVX2 is sufficient, but we don't have the granularity
to do this. The XCR0[2] disables AVX, with no option to just disable
AVX2.

Add a kernel parameter gather_data_sampling=force that will enable the
microcode mitigation if available, otherwise it will disable AVX on
affected systems.

This option will be ignored if cmdline mitigations=off.

This is a *big* hammer.  It is known to break buggy userspace that
uses incomplete, buggy AVX enumeration.  Unfortunately, such userspace
does exist in the wild:

	https://www.mail-archive.com/bug-coreutils@gnu.org/msg33046.html

[ dhansen: add some more ominous warnings about disabling AVX ]

Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:48 +02:00
Daniel Sneddon
c66ebe070d x86/speculation: Add Gather Data Sampling mitigation
commit 8974eb5882 upstream

Gather Data Sampling (GDS) is a hardware vulnerability which allows
unprivileged speculative access to data which was previously stored in
vector registers.

Intel processors that support AVX2 and AVX512 have gather instructions
that fetch non-contiguous data elements from memory. On vulnerable
hardware, when a gather instruction is transiently executed and
encounters a fault, stale data from architectural or internal vector
registers may get transiently stored to the destination vector
register allowing an attacker to infer the stale data using typical
side channel techniques like cache timing attacks.

This mitigation is different from many earlier ones for two reasons.
First, it is enabled by default and a bit must be set to *DISABLE* it.
This is the opposite of normal mitigation polarity. This means GDS can
be mitigated simply by updating microcode and leaving the new control
bit alone.

Second, GDS has a "lock" bit. This lock bit is there because the
mitigation affects the hardware security features KeyLocker and SGX.
It needs to be enabled and *STAY* enabled for these features to be
mitigated against GDS.

The mitigation is enabled in the microcode by default. Disable it by
setting gather_data_sampling=off or by disabling all mitigations with
mitigations=off. The mitigation status can be checked by reading:

    /sys/devices/system/cpu/vulnerabilities/gather_data_sampling

Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:48 +02:00
Thomas Gleixner
f25ad76d92 x86/fpu: Move FPU initialization into arch_cpu_finalize_init()
commit b81fac906a upstream

Initializing the FPU during the early boot process is a pointless
exercise. Early boot is convoluted and fragile enough.

Nothing requires that the FPU is set up early. It has to be initialized
before fork_init() because the task_struct size depends on the FPU register
buffer size.

Move the initialization to arch_cpu_finalize_init() which is the perfect
place to do so.

No functional change.

This allows to remove quite some of the custom early command line parsing,
but that's subject to the next installment.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230613224545.902376621@linutronix.de
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:48 +02:00
Thomas Gleixner
e26932942b x86/fpu: Mark init functions __init
commit 1703db2b90 upstream

No point in keeping them around.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230613224545.841685728@linutronix.de
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:48 +02:00