Once we update the early kernel mapping code to only map the kernel once
with the right permissions, we can no longer perform code patching via
this mapping.
So move this code to an earlier stage of the boot, right after applying
the relocations.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20240214122845.2033971-54-ardb+git@google.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
We will want to parse the ID register overrides even earlier, so that we
can take them into account before creating the kernel mapping. So
migrate the code and make it work in the context of the early C runtime.
We will move the invocation to an earlier stage in a subsequent patch.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20240214122845.2033971-49-ardb+git@google.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Now that we have a mini C runtime before the kernel mapping is up, we
can move the non-trivial relocation processing code out of head.S and
reimplement it in C.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20240214122845.2033971-48-ardb+git@google.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Full LTO takes the '-mbranch-protection=none' passed to the compiler
when generating the dynamic shadow call stack patching code as a hint to
stop emitting PAC instructions altogether. (Thin LTO appears unaffected
by this)
Work around this by disabling LTO for the compilation unit, which
appears to convince the linker that it should still use PAC in the rest
of the kernel..
Fixes: 3b619e22c4 ("arm64: implement dynamic shadow call stack for Clang")
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Tested-by: Sami Tolvanen <samitolvanen@google.com>
Link: https://lore.kernel.org/r/20240123133052.1417449-6-ardb+git@google.com
Signed-off-by: Will Deacon <will@kernel.org>
This reverts commit 8c5a19cb17 ("arm64: scs: Work around full LTO
issue with dynamic SCS"), which did not quite fix the issue as intended.
Apparently, -fno-unwind-tables is ignored for the final full LTO link
when it is set on any of the objects, resulting in an early boot crash
due to the SCS patching code patching itself, and attempting to pop the
return address from the shadow stack while the associated push was still
a PACIASP instruction when it executed.
Reported-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Tested-by: Sami Tolvanen <samitolvanen@google.com>
Link: https://lore.kernel.org/r/20240123133052.1417449-5-ardb+git@google.com
Signed-off-by: Will Deacon <will@kernel.org>
Full LTO takes the '-mbranch-protection=none' passed to the compiler
when generating the dynamic shadow call stack patching code as a hint to
stop emitting PAC instructions altogether. (Thin LTO appears unaffected
by this)
Work around this by stripping unwind tables from the object in question,
which should be sufficient to prevent the patching code from attempting
to patch itself.
Fixes: 3b619e22c4 ("arm64: implement dynamic shadow call stack for Clang")
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20240110132619.258809-2-ardb+git@google.com
Signed-off-by: Will Deacon <will@kernel.org>
top-level directories.
- Douglas Anderson has added a new "buddy" mode to the hardlockup
detector. It permits the detector to work on architectures which
cannot provide the required interrupts, by having CPUs periodically
perform checks on other CPUs.
- Zhen Lei has enhanced kexec's ability to support two crash regions.
- Petr Mladek has done a lot of cleanup on the hard lockup detector's
Kconfig entries.
- And the usual bunch of singleton patches in various places.
-----BEGIN PGP SIGNATURE-----
iHUEABYIAB0WIQTTMBEPP41GrTpTJgfdBJ7gKXxAjgUCZJelTAAKCRDdBJ7gKXxA
juDkAP0VXWynzkXoojdS/8e/hhi+htedmQ3v2dLZD+vBrctLhAEA7rcH58zAVoWa
2ejqO6wDrRGUC7JQcO9VEjT0nv73UwU=
=F293
-----END PGP SIGNATURE-----
Merge tag 'mm-nonmm-stable-2023-06-24-19-23' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull non-mm updates from Andrew Morton:
- Arnd Bergmann has fixed a bunch of -Wmissing-prototypes in top-level
directories
- Douglas Anderson has added a new "buddy" mode to the hardlockup
detector. It permits the detector to work on architectures which
cannot provide the required interrupts, by having CPUs periodically
perform checks on other CPUs
- Zhen Lei has enhanced kexec's ability to support two crash regions
- Petr Mladek has done a lot of cleanup on the hard lockup detector's
Kconfig entries
- And the usual bunch of singleton patches in various places
* tag 'mm-nonmm-stable-2023-06-24-19-23' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (72 commits)
kernel/time/posix-stubs.c: remove duplicated include
ocfs2: remove redundant assignment to variable bit_off
watchdog/hardlockup: fix typo in config HARDLOCKUP_DETECTOR_PREFER_BUDDY
powerpc: move arch_trigger_cpumask_backtrace from nmi.h to irq.h
devres: show which resource was invalid in __devm_ioremap_resource()
watchdog/hardlockup: define HARDLOCKUP_DETECTOR_ARCH
watchdog/sparc64: define HARDLOCKUP_DETECTOR_SPARC64
watchdog/hardlockup: make HAVE_NMI_WATCHDOG sparc64-specific
watchdog/hardlockup: declare arch_touch_nmi_watchdog() only in linux/nmi.h
watchdog/hardlockup: make the config checks more straightforward
watchdog/hardlockup: sort hardlockup detector related config values a logical way
watchdog/hardlockup: move SMP barriers from common code to buddy code
watchdog/buddy: simplify the dependency for HARDLOCKUP_DETECTOR_PREFER_BUDDY
watchdog/buddy: don't copy the cpumask in watchdog_next_cpu()
watchdog/buddy: cleanup how watchdog_buddy_check_hardlockup() is called
watchdog/hardlockup: remove softlockup comment in touch_nmi_watchdog()
watchdog/hardlockup: in watchdog_hardlockup_check() use cpumask_copy()
watchdog/hardlockup: don't use raw_cpu_ptr() in watchdog_hardlockup_kick()
watchdog/hardlockup: HAVE_NMI_WATCHDOG must implement watchdog_hardlockup_probe()
watchdog/hardlockup: keep kernel.nmi_watchdog sysctl as 0444 if probe fails
...
Set safe maximum CPU frequency to 5 GHz in case a particular platform
doesn't implement cpufreq driver. Although, architecture doesn't put any
restrictions on maximum frequency but 5 GHz seems to be safe maximum given
the available Arm CPUs in the market which are clocked much less than 5
GHz.
On the other hand, we can't make it much higher as it would lead to a
large hard-lockup detection timeout on parts which are running slower (eg.
1GHz on Developerbox) and doesn't possess a cpufreq driver.
Link: https://lkml.kernel.org/r/20230519101840.v5.17.Ia9d02578e89c3f44d3cb12eec8b0176603c8ab2f@changeid
Co-developed-by: Sumit Garg <sumit.garg@linaro.org>
Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Co-developed-by: Pingfan Liu <kernelfans@gmail.com>
Signed-off-by: Pingfan Liu <kernelfans@gmail.com>
Signed-off-by: Lecopzer Chen <lecopzer.chen@mediatek.com>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chen-Yu Tsai <wens@csie.org>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Colin Cross <ccross@android.com>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Guenter Roeck <groeck@chromium.org>
Cc: Ian Rogers <irogers@google.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masayoshi Mizuma <msys.mizuma@gmail.com>
Cc: Matthias Kaehlcke <mka@chromium.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com>
Cc: Ricardo Neri <ricardo.neri@intel.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Stephen Boyd <swboyd@chromium.org>
Cc: Tzung-Bi Shih <tzungbi@chromium.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Contemporary kernels and modules can be relatively large, especially
when common debug options are enabled. Using GCC 12.1.0, a v6.3-rc7
defconfig kernel is ~38M, and with PROVE_LOCKING + KASAN_INLINE enabled
this expands to ~117M. Shanker reports [1] that the NVIDIA GPU driver
alone can consume 110M of module space in some configurations.
Both KASLR and ARM64_ERRATUM_843419 select MODULE_PLTS, so anyone
wanting a kernel to have KASLR or run on Cortex-A53 will have
MODULE_PLTS selected. This is the case in defconfig and distribution
kernels (e.g. Debian, Android, etc).
Practically speaking, this means we're very likely to need MODULE_PLTS
and while it's almost guaranteed that MODULE_PLTS will be selected, it
is possible to disable support, and we have to maintain some awkward
special cases for such unusual configurations.
This patch removes the MODULE_PLTS config option, with the support code
always enabled if MODULES is selected. This results in a slight
simplification, and will allow for further improvement in subsequent
patches.
For any config which currently selects MODULE_PLTS, there will be no
functional change as a result of this patch.
[1] https://lore.kernel.org/linux-arm-kernel/159ceeab-09af-3174-5058-445bc8dcf85b@nvidia.com/
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Shanker Donthineni <sdonthineni@nvidia.com>
Cc: Will Deacon <will@kernel.org>
Tested-by: Shanker Donthineni <sdonthineni@nvidia.com>
Link: https://lore.kernel.org/r/20230530110328.2213762-6-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Having the ARM PMUv3 driver sitting in arch/arm64/kernel is getting
in the way of being able to use perf on ARMv8 cores running a 32bit
kernel, such as 32bit KVM guests.
This patch moves it into drivers/perf/arm_pmuv3.c, with an include
file in include/linux/perf/arm_pmuv3.h. The only thing left in
arch/arm64 is some mundane perf stuff.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Zaid Al-Bassam <zalbassam@google.com>
Tested-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20230317195027.3746949-2-zalbassam@google.com
Signed-off-by: Will Deacon <will@kernel.org>
- Refactor the zboot code so that it incorporates all the EFI stub
logic, rather than calling the decompressed kernel as a EFI app.
- Add support for initrd= command line option to x86 mixed mode.
- Allow initrd= to be used with arbitrary EFI accessible file systems
instead of just the one the kernel itself was loaded from.
- Move some x86-only handling and manipulation of the EFI memory map
into arch/x86, as it is not used anywhere else.
- More flexible handling of any random seeds provided by the boot
environment (i.e., systemd-boot) so that it becomes available much
earlier during the boot.
- Allow improved arch-agnostic EFI support in loaders, by setting a
uniform baseline of supported features, and adding a generic magic
number to the DOS/PE header. This should allow loaders such as GRUB or
systemd-boot to reduce the amount of arch-specific handling
substantially.
- (arm64) Run EFI runtime services from a dedicated stack, and use it to
recover from synchronous exceptions that might occur in the firmware
code.
- (arm64) Ensure that we don't allocate memory outside of the 48-bit
addressable physical range.
- Make EFI pstore record size configurable
- Add support for decoding CXL specific CPER records
-----BEGIN PGP SIGNATURE-----
iQGzBAABCgAdFiEE+9lifEBpyUIVN1cpw08iOZLZjyQFAmOTQ1cACgkQw08iOZLZ
jyQRkAv+LqaZFWeVwhAQHiw/N3RnRM0nZHea6++D2p1y/ZbCpwv3pdLl2YHQ1KmW
wDG9Nr4C1ITLtfy1YZKeYpwloQtq9S1GZDWnFpVv/hdo7L924eRAwIlxowWn1OnP
ruxv2PaYXyb0plh1YD1f6E1BqrfUOtajET55Kxs9ZsxmnMtDpIX3NiYy4LKMBIZC
+Eywt41M3uBX+wgmSujFBMVVJjhOX60WhUYXqy0RXwDKOyrz/oW5td+eotSCreB6
FVbjvwQvUdtzn4s1FayOMlTrkxxLw4vLhsaUGAdDOHd3rg3sZT9Xh1HqFFD6nss6
ZAzAYQ6BzdiV/5WSB9meJe+BeG1hjTNKjJI6JPO2lctzYJqlnJJzI6JzBuH9vzQ0
dffLB8NITeEW2rphIh+q+PAKFFNbXWkJtV4BMRpqmzZ/w7HwupZbUXAzbWE8/5km
qlFpr0kmq8GlVcbXNOFjmnQVrJ8jPYn+O3AwmEiVAXKZJOsMH0sjlXHKsonme9oV
Sk71c6Em
=JEXz
-----END PGP SIGNATURE-----
Merge tag 'efi-next-for-v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi
Pull EFI updates from Ard Biesheuvel:
"Another fairly sizable pull request, by EFI subsystem standards.
Most of the work was done by me, some of it in collaboration with the
distro and bootloader folks (GRUB, systemd-boot), where the main focus
has been on removing pointless per-arch differences in the way EFI
boots a Linux kernel.
- Refactor the zboot code so that it incorporates all the EFI stub
logic, rather than calling the decompressed kernel as a EFI app.
- Add support for initrd= command line option to x86 mixed mode.
- Allow initrd= to be used with arbitrary EFI accessible file systems
instead of just the one the kernel itself was loaded from.
- Move some x86-only handling and manipulation of the EFI memory map
into arch/x86, as it is not used anywhere else.
- More flexible handling of any random seeds provided by the boot
environment (i.e., systemd-boot) so that it becomes available much
earlier during the boot.
- Allow improved arch-agnostic EFI support in loaders, by setting a
uniform baseline of supported features, and adding a generic magic
number to the DOS/PE header. This should allow loaders such as GRUB
or systemd-boot to reduce the amount of arch-specific handling
substantially.
- (arm64) Run EFI runtime services from a dedicated stack, and use it
to recover from synchronous exceptions that might occur in the
firmware code.
- (arm64) Ensure that we don't allocate memory outside of the 48-bit
addressable physical range.
- Make EFI pstore record size configurable
- Add support for decoding CXL specific CPER records"
* tag 'efi-next-for-v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi: (43 commits)
arm64: efi: Recover from synchronous exceptions occurring in firmware
arm64: efi: Execute runtime services from a dedicated stack
arm64: efi: Limit allocations to 48-bit addressable physical region
efi: Put Linux specific magic number in the DOS header
efi: libstub: Always enable initrd command line loader and bump version
efi: stub: use random seed from EFI variable
efi: vars: prohibit reading random seed variables
efi: random: combine bootloader provided RNG seed with RNG protocol output
efi/cper, cxl: Decode CXL Error Log
efi/cper, cxl: Decode CXL Protocol Error Section
efi: libstub: fix efi_load_initrd_dev_path() kernel-doc comment
efi: x86: Move EFI runtime map sysfs code to arch/x86
efi: runtime-maps: Clarify purpose and enable by default for kexec
efi: pstore: Add module parameter for setting the record size
efi: xen: Set EFI_PARAVIRT for Xen dom0 boot on all architectures
efi: memmap: Move manipulation routines into x86 arch tree
efi: memmap: Move EFI fake memmap support into x86 arch tree
efi: libstub: Undeprecate the command line initrd loader
efi: libstub: Add mixed mode support to command line initrd loader
efi: libstub: Permit mixed mode return types other than efi_status_t
...
Implement dynamic shadow call stack support on Clang, by parsing the
unwind tables at init time to locate all occurrences of PACIASP/AUTIASP
instructions, and replacing them with the shadow call stack push and pop
instructions, respectively.
This is useful because the overhead of the shadow call stack is
difficult to justify on hardware that implements pointer authentication
(PAC), and given that the PAC instructions are executed as NOPs on
hardware that doesn't, we can just replace them without breaking
anything. As PACIASP/AUTIASP are guaranteed to be paired with respect to
manipulations of the return address, replacing them 1:1 with shadow call
stack pushes and pops is guaranteed to result in the desired behavior.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Tested-by: Sami Tolvanen <samitolvanen@google.com>
Link: https://lore.kernel.org/r/20221027155908.1940624-4-ardb@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
We will be sharing efi-entry.S with the zboot decompressor build, which
does not link against vmlinux directly. So move it into the libstub
source directory so we can include in the libstub static library.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
- Remove potentially incomplete targets when Kbuid is interrupted by
SIGINT etc. in case GNU Make may miss to do that when stderr is piped
to another program.
- Rewrite the single target build so it works more correctly.
- Fix rpm-pkg builds with V=1.
- List top-level subdirectories in ./Kbuild.
- Ignore auto-generated __kstrtab_* and __kstrtabns_* symbols in kallsyms.
- Avoid two different modules in lib/zstd/ having shared code, which
potentially causes building the common code as build-in and modular
back-and-forth.
- Unify two modpost invocations to optimize the build process.
- Remove head-y syntax in favor of linker scripts for placing particular
sections in the head of vmlinux.
- Bump the minimal GNU Make version to 3.82.
- Clean up misc Makefiles and scripts.
-----BEGIN PGP SIGNATURE-----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=DHiN
-----END PGP SIGNATURE-----
Merge tag 'kbuild-v6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:
- Remove potentially incomplete targets when Kbuid is interrupted by
SIGINT etc in case GNU Make may miss to do that when stderr is piped
to another program.
- Rewrite the single target build so it works more correctly.
- Fix rpm-pkg builds with V=1.
- List top-level subdirectories in ./Kbuild.
- Ignore auto-generated __kstrtab_* and __kstrtabns_* symbols in
kallsyms.
- Avoid two different modules in lib/zstd/ having shared code, which
potentially causes building the common code as build-in and modular
back-and-forth.
- Unify two modpost invocations to optimize the build process.
- Remove head-y syntax in favor of linker scripts for placing
particular sections in the head of vmlinux.
- Bump the minimal GNU Make version to 3.82.
- Clean up misc Makefiles and scripts.
* tag 'kbuild-v6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (41 commits)
docs: bump minimal GNU Make version to 3.82
ia64: simplify esi object addition in Makefile
Revert "kbuild: Check if linker supports the -X option"
kbuild: rebuild .vmlinux.export.o when its prerequisite is updated
kbuild: move modules.builtin(.modinfo) rules to Makefile.vmlinux_o
zstd: Fixing mixed module-builtin objects
kallsyms: ignore __kstrtab_* and __kstrtabns_* symbols
kallsyms: take the input file instead of reading stdin
kallsyms: drop duplicated ignore patterns from kallsyms.c
kbuild: reuse mksysmap output for kallsyms
mksysmap: update comment about __crc_*
kbuild: remove head-y syntax
kbuild: use obj-y instead extra-y for objects placed at the head
kbuild: hide error checker logs for V=1 builds
kbuild: re-run modpost when it is updated
kbuild: unify two modpost invocations
kbuild: move vmlinux.o rule to the top Makefile
kbuild: move .vmlinux.objs rule to Makefile.modpost
kbuild: list sub-directories in ./Kbuild
Makefile.compiler: replace cc-ifversion with compiler-specific macros
...
The objects placed at the head of vmlinux need special treatments:
- arch/$(SRCARCH)/Makefile adds them to head-y in order to place
them before other archives in the linker command line.
- arch/$(SRCARCH)/kernel/Makefile adds them to extra-y instead of
obj-y to avoid them going into built-in.a.
This commit gets rid of the latter.
Create vmlinux.a to collect all the objects that are unconditionally
linked to vmlinux. The objects listed in head-y are moved to the head
of vmlinux.a by using 'ar m'.
With this, arch/$(SRCARCH)/kernel/Makefile can consistently use obj-y
for builtin objects.
There is no *.o that is directly linked to vmlinux. Drop unneeded code
in scripts/clang-tools/gen_compile_commands.py.
$(AR) mPi needs 'T' to workaround the llvm-ar bug. The fix was suggested
by Nathan Chancellor [1].
[1]: https://lore.kernel.org/llvm/YyjjT5gQ2hGMH0ni@dev-arch.thelio-3990X/
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
The 32-bit ARM kernel implements fixups on behalf of user space when
using LDM/STM or LDRD/STRD instructions on addresses that are not 32-bit
aligned. This is not something that is supported by the architecture,
but was done anyway to increase compatibility with user space software,
which mostly targeted x86 at the time and did not care about aligned
accesses.
This feature is one of the remaining impediments to being able to switch
to 64-bit kernels on 64-bit capable hardware running 32-bit user space,
so let's implement it for the arm64 compat layer as well.
Note that the intent is to implement the exact same handling of
misaligned multi-word loads and stores as the 32-bit kernel does,
including what appears to be missing support for user space programs
that rely on SETEND to switch to a different byte order and back. Also,
like the 32-bit ARM version, we rely on the faulting address reported by
the CPU to infer the memory address, instead of decoding the instruction
fully to obtain this information.
This implementation is taken from the 32-bit ARM tree, with all pieces
removed that deal with instructions other than LDRD/STRD and LDM/STM, or
that deal with alignment exceptions taken in kernel mode.
Cc: debian-arm@lists.debian.org
Cc: Vagrant Cascadian <vagrant@debian.org>
Cc: Riku Voipio <riku.voipio@iki.fi>
Cc: Steve McIntyre <steve@einval.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20220701135322.3025321-1-ardb@kernel.org
[catalin.marinas@arm.com: change the option to 'default n']
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* for-next/boot: (34 commits)
arm64: fix KASAN_INLINE
arm64: Add an override for ID_AA64SMFR0_EL1.FA64
arm64: Add the arm64.nosve command line option
arm64: Add the arm64.nosme command line option
arm64: Expose a __check_override primitive for oddball features
arm64: Allow the idreg override to deal with variable field width
arm64: Factor out checking of a feature against the override into a macro
arm64: Allow sticky E2H when entering EL1
arm64: Save state of HCR_EL2.E2H before switch to EL1
arm64: Rename the VHE switch to "finalise_el2"
arm64: mm: fix booting with 52-bit address space
arm64: head: remove __PHYS_OFFSET
arm64: lds: use PROVIDE instead of conditional definitions
arm64: setup: drop early FDT pointer helpers
arm64: head: avoid relocating the kernel twice for KASLR
arm64: kaslr: defer initialization to initcall where permitted
arm64: head: record CPU boot mode after enabling the MMU
arm64: head: populate kernel page tables with MMU and caches on
arm64: head: factor out TTBR1 assignment into a macro
arm64: idreg-override: use early FDT mapping in ID map
...
Currently, when KASLR is in effect, we set up the kernel virtual address
space twice: the first time, the KASLR seed is looked up in the device
tree, and the kernel virtual mapping is torn down and recreated again,
after which the relocations are applied a second time. The latter step
means that statically initialized global pointer variables will be reset
to their initial values, and to ensure that BSS variables are not set to
values based on the initial translation, they are cleared again as well.
All of this is needed because we need the command line (taken from the
DT) to tell us whether or not to randomize the virtual address space
before entering the kernel proper. However, this code has expanded
little by little and now creates global state unrelated to the virtual
randomization of the kernel before the mapping is torn down and set up
again, and the BSS cleared for a second time. This has created some
issues in the past, and it would be better to avoid this little dance if
possible.
So instead, let's use the temporary mapping of the device tree, and
execute the bare minimum of code to decide whether or not KASLR should
be enabled, and what the seed is. Only then, create the virtual kernel
mapping, clear BSS, etc and proceed as normal. This avoids the issues
around inconsistent global state due to BSS being cleared twice, and is
generally more maintainable, as it permits us to defer all the remaining
DT parsing and KASLR initialization to a later time.
This means the relocation fixup code runs only a single time as well,
allowing us to simplify the RELR handling code too, which is not
idempotent and was therefore required to keep track of the offset that
was applied the first time around.
Note that this means we have to clone a pair of FDT library objects, so
that we can control how they are built - we need the stack protector
and other instrumentation disabled so that the code can tolerate being
called this early. Note that only the kernel page tables and the
temporary stack are mapped read-write at this point, which ensures that
the early code does not modify any global state inadvertently.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20220624150651.1358849-21-ardb@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
Disable KASAN instrumentation of arch/arm64/kernel/stacktrace.c.
This speeds up Generic KASAN by 5-20%.
As a side-effect, KASAN is now unable to detect bugs in the stack trace
collection code. This is taken as an acceptable downside.
Also replace READ_ONCE_NOCHECK() with READ_ONCE() in stacktrace.c.
As the file is now not instrumented, there is no need to use the
NOCHECK version of READ_ONCE().
Suggested-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Link: https://lore.kernel.org/r/c4c944a2a905e949760fbeb29258185087171708.1653317461.git.andreyknvl@google.com
Signed-off-by: Will Deacon <will@kernel.org>
There is currently no dependency for vdso*-wrap.S on vdso*.so, which means that
you can get a build that uses a stale vdso*-wrap.o.
In commit a5b8ca97fb, the file that includes the vdso.so was moved and renamed
from arch/arm64/kernel/vdso/vdso.S to arch/arm64/kernel/vdso-wrap.S, when this
happened the Makefile was not updated to force the dependcy on vdso.so.
Fixes: a5b8ca97fb ("arm64: do not descend to vdso directories twice")
Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20220510102721.50811-1-joey.gouly@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
For each vma mapped with PROT_MTE (the VM_MTE flag set), generate a
PT_ARM_MEMTAG_MTE segment in the core file and dump the corresponding
tags. The in-file size for such segments is 128 bytes per page.
For pages in a VM_MTE vma which are not present in the user page tables
or don't have the PG_mte_tagged flag set (e.g. execute-only), just write
zeros in the core file.
An example of program headers for two vmas, one 2-page, the other 4-page
long:
Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align
...
LOAD 0x030000 0x0000ffff80034000 0x0000000000000000 0x000000 0x002000 RW 0x1000
LOAD 0x030000 0x0000ffff80036000 0x0000000000000000 0x004000 0x004000 RW 0x1000
...
LOPROC+0x1 0x05b000 0x0000ffff80034000 0x0000000000000000 0x000100 0x002000 0
LOPROC+0x1 0x05b100 0x0000ffff80036000 0x0000000000000000 0x000200 0x004000 0
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Luis Machado <luis.machado@linaro.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220131165456.2160675-5-catalin.marinas@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Documentation/kbuild/makefiles.rst suggests to use "archclean" for
cleaning arch/$(SRCARCH)/boot/, but it is not a hard requirement.
Since commit d92cc4d516 ("kbuild: require all architectures to have
arch/$(SRCARCH)/Kbuild"), we can use the "subdir- += boot" trick for
all architectures. This can take advantage of the parallel option (-j)
for "make clean".
I also cleaned up the comments in arch/$(SRCARCH)/Makefile. The "archdep"
target no longer exists.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
We suppress KCOV for entry.o rather than entry-common.o. As entry.o is
built from entry.S, this is pointless, and permits instrumentation of
entry-common.o, which is built from entry-common.c.
Fix the Makefile to suppress KCOV for entry-common.o, as we had intended
to begin with. I've verified with objdump that this is working as
expected.
Fixes: bf6fa2c0dd ("arm64: entry: don't instrument entry code with KCOV")
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20210715123049.9990-1-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
The low-level idle code in arch_cpu_idle() and its callees runs at a
time where where portions of the kernel environment aren't available.
For example, RCU may not be watching, and lockdep state may be
out-of-sync with the hardware. Due to this, it is not sound to
instrument this code.
We generally avoid instrumentation by marking the entry functions as
`noinstr`, but currently this doesn't inhibit KCOV instrumentation.
Prevent this by factoring these functions into a new idle.c so that we
can disable KCOV for the entire compilation unit, as is done for the
core idle code in kernel/sched/idle.c.
We'd like to keep instrumentation of the rest of process.c, and for the
existing code in cpuidle.c, so a new compilation unit is preferable. The
arch_cpu_idle_dead() function in process.c is a cpu hotplug function
that is safe to instrument, so it is left as-is in process.c.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20210607094624.34689-21-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
The code in entry-common.c runs at exception entry and return
boundaries, where portions of the kernel environment aren't available.
For example, RCU may not be watching, and lockdep state may be
out-of-sync with the hardware. Due to this, it is not sound to
instrument this code.
We generally avoid instrumentation by marking the entry functions as
`noinstr`, but currently this doesn't inhibit KCOV instrumentation.
Prevent this by disabling KCOV for the entire compilation unit.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20210607094624.34689-20-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Aarch64 instruction set encoding and decoding logic can prove useful
for some features/tools both part of the kernel and outside the kernel.
Isolate the function dealing only with encoding/decoding instructions,
with minimal dependency on kernel utilities in order to be able to reuse
that code.
Code was only moved, no code should have been added, removed nor
modifier.
Signed-off-by: Julien Thierry <jthierry@redhat.com>
Link: https://lore.kernel.org/r/20210303170536.1838032-5-jthierry@redhat.com
Signed-off-by: Will Deacon <will@kernel.org>
Files insn.[c|h] containt some functions used for instruction patching.
In order to reuse the instruction encoder/decoder, move the patching
utilities to their own file.
Signed-off-by: Julien Thierry <jthierry@redhat.com>
Link: https://lore.kernel.org/r/20210303170536.1838032-2-jthierry@redhat.com
[will: Include patching.h in insn.h to fix header mess; add __ASSEMBLY__ guards]
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
Allow for a randomized stack offset on a per-syscall basis, with roughly
5 bits of entropy. (And include AAPCS rationale AAPCS thanks to Mark
Rutland.)
In order to avoid unconditional stack canaries on syscall entry (due to
the use of alloca()), also disable stack protector to avoid triggering
needless checks and slowing down the entry path. As there is no general
way to control stack protector coverage with a function attribute[1],
this must be disabled at the compilation unit level. This isn't a problem
here, though, since stack protector was not triggered before: examining
the resulting syscall.o, there are no changes in canary coverage (none
before, none now).
[1] a working __attribute__((no_stack_protector)) has been added to GCC
and Clang but has not been released in any version yet:
https://gcc.gnu.org/git/gitweb.cgi?p=gcc.git;h=346b302d09c1e6db56d9fe69048acb32fbb97845https://reviews.llvm.org/rG4fbf84c1732fca596ad1d6e96015e19760eb8a9b
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20210401232347.2791257-6-keescook@chromium.org
vDSO build improvements.
* for-next/vdso:
arm64: Support running gen_vdso_offsets.sh with BSD userland.
arm64: do not descend to vdso directories twice
In order to be able to override CPU features at boot time,
let's add a command line parser that matches options of the
form "cpureg.feature=value", and store the corresponding
value into the override val/mask pair.
No features are currently defined, so no expected change in
functionality.
Signed-off-by: Marc Zyngier <maz@kernel.org>
Acked-by: David Brazdil <dbrazdil@google.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20210208095732.3267263-14-maz@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
arm64 descends into each vdso directory twice; first in vdso_prepare,
second during the ordinary build process.
PPC mimicked it and uncovered a problem [1]. In the first descend,
Kbuild directly visits the vdso directories, therefore it does not
inherit subdir-ccflags-y from upper directories.
This means the command line parameters may differ between the two.
If it happens, the offset values in the generated headers might be
different from real offsets of vdso.so in the kernel.
This potential danger should be avoided. The vdso directories are
built in the vdso_prepare stage, so the second descend is unneeded.
[1]: https://lore.kernel.org/linux-kbuild/CAK7LNARAkJ3_-4gX0VA2UkapbOftuzfSTVMBbgbw=HD8n7N+7w@mail.gmail.com/T/#ma10dcb961fda13f36d42d58fa6cb2da988b7e73a
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Link: https://lore.kernel.org/r/20201218024540.1102650-1-masahiroy@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
Use scs_alloc() to allocate also IRQ and SDEI shadow stacks instead of
using statically allocated stacks.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201130233442.2562064-3-samitolvanen@google.com
[will: Move CONFIG_SHADOW_CALL_STACK check into init_irq_scs()]
Signed-off-by: Will Deacon <will@kernel.org>
Add userspace support for the Memory Tagging Extension introduced by
Armv8.5.
(Catalin Marinas and others)
* for-next/mte: (30 commits)
arm64: mte: Fix typo in memory tagging ABI documentation
arm64: mte: Add Memory Tagging Extension documentation
arm64: mte: Kconfig entry
arm64: mte: Save tags when hibernating
arm64: mte: Enable swap of tagged pages
mm: Add arch hooks for saving/restoring tags
fs: Handle intra-page faults in copy_mount_options()
arm64: mte: ptrace: Add NT_ARM_TAGGED_ADDR_CTRL regset
arm64: mte: ptrace: Add PTRACE_{PEEK,POKE}MTETAGS support
arm64: mte: Allow {set,get}_tagged_addr_ctrl() on non-current tasks
arm64: mte: Restore the GCR_EL1 register after a suspend
arm64: mte: Allow user control of the generated random tags via prctl()
arm64: mte: Allow user control of the tag check mode via prctl()
mm: Allow arm64 mmap(PROT_MTE) on RAM-based files
arm64: mte: Validate the PROT_MTE request via arch_validate_flags()
mm: Introduce arch_validate_flags()
arm64: mte: Add PROT_MTE support to mmap() and mprotect()
mm: Introduce arch_calc_vm_flag_bits()
arm64: mte: Tags-aware aware memcmp_pages() implementation
arm64: Avoid unnecessary clear_user_page() indirection
...
Fix and subsequently rewrite Spectre mitigations, including the addition
of support for PR_SPEC_DISABLE_NOEXEC.
(Will Deacon and Marc Zyngier)
* for-next/ghostbusters: (22 commits)
arm64: Add support for PR_SPEC_DISABLE_NOEXEC prctl() option
arm64: Pull in task_stack_page() to Spectre-v4 mitigation code
KVM: arm64: Allow patching EL2 vectors even with KASLR is not enabled
arm64: Get rid of arm64_ssbd_state
KVM: arm64: Convert ARCH_WORKAROUND_2 to arm64_get_spectre_v4_state()
KVM: arm64: Get rid of kvm_arm_have_ssbd()
KVM: arm64: Simplify handling of ARCH_WORKAROUND_2
arm64: Rewrite Spectre-v4 mitigation code
arm64: Move SSBD prctl() handler alongside other spectre mitigation code
arm64: Rename ARM64_SSBD to ARM64_SPECTRE_V4
arm64: Treat SSBS as a non-strict system feature
arm64: Group start_thread() functions together
KVM: arm64: Set CSV2 for guests on hardware unaffected by Spectre-v2
arm64: Rewrite Spectre-v2 mitigation code
arm64: Introduce separate file for spectre mitigations and reporting
arm64: Rename ARM64_HARDEN_BRANCH_PREDICTOR to ARM64_SPECTRE_V2
KVM: arm64: Simplify install_bp_hardening_cb()
KVM: arm64: Replace CONFIG_KVM_INDIRECT_VECTORS with CONFIG_RANDOMIZE_BASE
arm64: Remove Spectre-related CONFIG_* options
arm64: Run ARCH_WORKAROUND_2 enabling code on all CPUs
...
As part of the spectre consolidation effort to shift all of the ghosts
into their own proton pack, move all of the horrible SSBD prctl() code
out of its own 'ssbd.c' file.
Signed-off-by: Will Deacon <will@kernel.org>
The spectre mitigation code is spread over a few different files, which
makes it both hard to follow, but also hard to remove it should we want
to do that in future.
Introduce a new file for housing the spectre mitigations, and populate
it with the spectre-v1 reporting code to start with.
Signed-off-by: Will Deacon <will@kernel.org>
The spectre mitigations are too configurable for their own good, leading
to confusing logic trying to figure out when we should mitigate and when
we shouldn't. Although the plethora of command-line options need to stick
around for backwards compatibility, the default-on CONFIG options that
depend on EXPERT can be dropped, as the mitigations only do anything if
the system is vulnerable, a mitigation is available and the command-line
hasn't disabled it.
Remove CONFIG_HARDEN_BRANCH_PREDICTOR and CONFIG_ARM64_SSBD in favour of
enabling this code unconditionally.
Signed-off-by: Will Deacon <will@kernel.org>
TEXT_OFFSET serves no purpose, and for this reason, it was redefined
as 0x0 in the v5.8 timeframe. Since this does not appear to have caused
any issues that require us to revisit that decision, let's get rid of the
macro entirely, along with any references to it.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20200825135440.11288-1-ardb@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
The Memory Tagging Extension has two modes of notifying a tag check
fault at EL0, configurable through the SCTLR_EL1.TCF0 field:
1. Synchronous raising of a Data Abort exception with DFSC 17.
2. Asynchronous setting of a cumulative bit in TFSRE0_EL1.
Add the exception handler for the synchronous exception and handling of
the asynchronous TFSRE0_EL1.TF0 bit setting via a new TIF flag in
do_notify_resume().
On a tag check failure in user-space, whether synchronous or
asynchronous, a SIGSEGV will be raised on the faulting thread.
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Co-developed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
In preparation for removing the signal trampoline from the compat vDSO,
allow the sigpage and the compat vDSO to co-exist.
For the moment the vDSO signal trampoline will still be used when built.
Subsequent patches will move to the sigpage consistently.
Acked-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
efi-entry.o is built on demand for efi-entry.stub.o, so you do not have
to repeat $(CONFIG_EFI) here. Adding it to 'targets' is enough.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
This patch converts the EL1 sync entry assembly logic to C code.
Doing this will allow us to make changes in a slightly more
readable way. A case in point is supporting kernel-first RAS.
do_sea() should be called on the CPU that took the fault.
Largely the assembly code is converted to C in a relatively
straightforward manner.
Since all sync sites share a common asm entry point, the ASM_BUG()
instances are no longer required for effective backtraces back to
assembly, and we don't need similar BUG() entries.
The ESR_ELx.EC codes for all (supported) debug exceptions are now
checked in the el1_sync_handler's switch statement, which renders the
check in el1_dbg redundant. This both simplifies the el1_dbg handler,
and makes the EL1 exception handling more robust to
currently-unallocated ESR_ELx.EC encodings.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
[split out of a bigger series, added nokprobes, moved prototypes]
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Cc: Julien Thierry <julien.thierry.kdev@gmail.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
When kuser helpers are enabled the kernel maps the relative code at
a fixed address (0xffff0000). Making configurable the option to disable
them means that the kernel can remove this mapping and any access to
this memory area results in a sigfault.
Add a KUSER_HELPERS config option that can be used to disable the
mapping when it is turned off.
This option can be turned off if and only if the applications are
designed specifically for the platform and they do not make use of the
kuser helpers code.
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
[will: Use IS_ENABLED() instead of #ifdef]
Signed-off-by: Will Deacon <will.deacon@arm.com>
To make it possible to disable kuser helpers in aarch32 we need to
divide the kuser and the sigreturn functionalities.
Split the current version of kuser32 in kuser32 (for kuser helpers)
and sigreturn32 (for sigreturn helpers).
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
In preparation for arm64 supporting ftrace built on other compiler
options, let's have the arm64 Makefiles remove the $(CC_FLAGS_FTRACE)
flags, whatever these may be, rather than assuming '-pg'.
There should be no functional change as a result of this patch.
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Torsten Duwe <duwe@suse.de>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Use the standard obj-$(CONFIG_...) syntex. The behavior is still the
same.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Add an arm64-specific prctl to allow a thread to reinitialize its
pointer authentication keys to random values. This can be useful when
exec() is not used for starting new processes, to ensure that different
processes still have different keys.
Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Ard Biesheuvel