gup_pgd_range() is invoked with disabled interrupts and invokes
__kmap_local_page_prot() via pte_offset_map(), gup_p4d_range().
With HIGHPTE enabled, __kmap_local_page_prot() invokes kmap_high_get()
which uses a spinlock_t via lock_kmap_any(). This leads to an
sleeping-while-atomic error on PREEMPT_RT because spinlock_t becomes a
sleeping lock and must not be acquired in atomic context.
The loop in map_new_virtual() uses wait_queue_head_t for wake up which
also is using a spinlock_t.
Since HIGHPTE is rarely needed at all, turn it off for PREEMPT_RT
to allow the use of get_user_pages_fast().
[arnd: rework patch to turn off HIGHPTE instead of HAVE_PAST_GUP]
Co-developed-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
jump-labels are used to efficiently switch between two possible code
paths. To achieve this, stop_machine() is used to keep the CPU in a
known state while the opcode is modified. The usage of stop_machine()
here leads to large latency spikes which can be observed on PREEMPT_RT.
Jump labels may change the target during runtime and are not restricted
to debug or "configuration/ setup" part of a PREEMPT_RT system where
high latencies could be defined as acceptable.
On 64-bit Arm, it is possible to use jump labels without the
stop_machine() call, which architecturally provides a way to atomically
change one 32-bit instruction word while keeping maintaining consistency,
but this is not generally the case on 32-bit, in particular in thumb2
mode.
Disable jump-label support on a PREEMPT_RT system when SMP is enabled.
[bigeasy: Patch description.]
[arnd: add !SMP case, extend changelog]
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
As of writing, Documentation/Changes states the minimal versions of GNU C
being 8.1, Clang being 15.0.0 and binutils being 2.30. A few Kconfig help
texts are pointing out that specific GCC and Clang versions are needed,
but by now, those pointers to versions, such later than 4.0, later than
4.4, or clang later than 5.0, are obsolete and unlikely to be found by
users configuring their kernel builds anyway.
Drop these outdated remarks in Kconfig help texts referring to older
compiler and binutils versions. No functional change.
Link: https://lkml.kernel.org/r/20251010082138.185752-1-lukas.bulwahn@redhat.com
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@redhat.com>
Cc: Bill Wendling <morbo@google.com>
Cc: Justin Stitt <justinstitt@google.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Russel King <linux@armlinux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Pull ARM development updates from Russell King:
- Use string choices helpers
- Add support for HAVE_FUNCTION_GRAPH_FREGS
* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rmk/linux:
ARM: 9457/1: ftrace: Implement HAVE_FUNCTION_GRAPH_FREGS
ARM: 9456/1: mm: fault: use string choices helper
ARM: 9454/1: kernel: bios32: use string choices helper
ARM: 9451/1: mm: l2x0: use string choices helper
Enable support for ftrace's funcgraph-retval feature by capturing r0-r3
and fp.
Since ARM does not provide its own __arch_ftrace_regs structure,
we instead populate pt_regs with the registers required by ftrace.
Cc: Donglin Peng <pengdonglin@sangfor.com.cn>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Pull Kbuild updates from Nathan Chancellor:
- Extend modules.builtin.modinfo to include module aliases from
MODULE_DEVICE_TABLE for builtin modules so that userspace tools (such
as kmod) can verify that a particular module alias will be handled by
a builtin module
- Bump the minimum version of LLVM for building the kernel to 15.0.0
- Upgrade several userspace API checks in headers_check.pl to errors
- Unify and consolidate CONFIG_WERROR / W=e handling
- Turn assembler and linker warnings into errors with CONFIG_WERROR /
W=e
- Respect CONFIG_WERROR / W=e when building userspace programs
(userprogs)
- Enable -Werror unconditionally when building host programs
(hostprogs)
- Support copy_file_range() and data segment alignment in gen_init_cpio
to improve performance on filesystems that support reflinks such as
btrfs and XFS
- Miscellaneous small changes to scripts and configuration files
* tag 'kbuild-6.18-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux: (47 commits)
modpost: Initialize builtin_modname to stop SIGSEGVs
Documentation: kbuild: note CONFIG_DEBUG_EFI in reproducible builds
kbuild: vmlinux.unstripped should always depend on .vmlinux.export.o
modpost: Create modalias for builtin modules
modpost: Add modname to mod_device_table alias
scsi: Always define blogic_pci_tbl structure
kbuild: extract modules.builtin.modinfo from vmlinux.unstripped
kbuild: keep .modinfo section in vmlinux.unstripped
kbuild: always create intermediate vmlinux.unstripped
s390: vmlinux.lds.S: Reorder sections
KMSAN: Remove tautological checks
objtool: Drop noinstr hack for KCSAN_WEAK_MEMORY
lib/Kconfig.debug: Drop CLANG_VERSION check from DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT
riscv: Remove ld.lld version checks from many TOOLCHAIN_HAS configs
riscv: Unconditionally use linker relaxation
riscv: Remove version check for LTO_CLANG selects
powerpc: Drop unnecessary initializations in __copy_inst_from_kernel_nofault()
mips: Unconditionally select ARCH_HAS_CURRENT_STACK_POINTER
arm64: Remove tautological LLVM Kconfig conditions
ARM: Clean up definition of ARM_HAS_GROUP_RELOCS
...
Pull ARM SoC updates from Arnd Bergmann:
"The at91 power management code and the TI AM33 platform each get a few
updates for robustness, the other changes are just minor cleanups"
* tag 'soc-arm-6.18' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc:
ARM: versatile: clock: convert from round_rate() to determine_rate()
ARM: rockchip: remove REGULATOR conditional to PM
ARM: at91: pm: Remove 2.5V regulator
ARM: OMAP2+: clock: convert from round_rate() to determine_rate()
ARM: OMAP1: clock: convert from round_rate() to determine_rate()
ARM: mach-hpe: Rework support and directory structure
arm: omap2: use string choices helper
ARM: OMAP2+: pm33xx-core: ix device node reference leaks in amx3_idle_init
ARM: OMAP2+: use IS_ERR_OR_NULL() helper
ARM: AM33xx: Implement TI advisory 1.0.36 (EMU0/EMU1 pins state on reset)
ARM: at91: pm: save and restore ACR during PLL disable/enable
ARM: at91: pm: fix MCKx restore routine
ARM: at91: pm: fix .uhp_udp_mask specification for current SoCs
ARM: shmobile: rcar-gen2: Use SZ_256K definition
Pull scheduler updates from Ingo Molnar:
"Core scheduler changes:
- Make migrate_{en,dis}able() inline, to improve performance
(Menglong Dong)
- Move STDL_INIT() functions out-of-line (Peter Zijlstra)
- Unify the SCHED_{SMT,CLUSTER,MC} Kconfig (Peter Zijlstra)
Fair scheduling:
- Defer throttling to when tasks exit to user-space, to reduce the
chance & impact of throttle-preemption with held locks and other
resources (Aaron Lu, Valentin Schneider)
- Get rid of sched_domains_curr_level hack for tl->cpumask(), as the
warning was getting triggered on certain topologies (Peter
Zijlstra)
Misc cleanups & fixes:
- Header cleanups (Menglong Dong)
- Fix race in push_dl_task() (Harshit Agarwal)"
* tag 'sched-core-2025-09-26' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched: Fix some typos in include/linux/preempt.h
sched: Make migrate_{en,dis}able() inline
rcu: Replace preempt.h with sched.h in include/linux/rcupdate.h
arch: Add the macro COMPILE_OFFSETS to all the asm-offsets.c
sched/fair: Do not balance task to a throttled cfs_rq
sched/fair: Do not special case tasks in throttled hierarchy
sched/fair: update_cfs_group() for throttled cfs_rqs
sched/fair: Propagate load for throttled cfs_rq
sched/fair: Get rid of throttled_lb_pair()
sched/fair: Task based throttle time accounting
sched/fair: Switch to task based throttle model
sched/fair: Implement throttle task work and related helpers
sched/fair: Add related data structure for task based throttle
sched: Unify the SCHED_{SMT,CLUSTER,MC} Kconfig
sched: Move STDL_INIT() functions out-of-line
sched/fair: Get rid of sched_domains_curr_level hack for tl->cpumask()
sched/deadline: Fix race in push_dl_task()
The kernel's CFI implementation uses the KCFI ABI specifically, and is
not strictly tied to a particular compiler. In preparation for GCC
supporting KCFI, rename CONFIG_CFI_CLANG to CONFIG_CFI (along with
associated options).
Use new "transitional" Kconfig option for old CONFIG_CFI_CLANG that will
enable CONFIG_CFI during olddefconfig.
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20250923213422.1105654-3-kees@kernel.org
Signed-off-by: Kees Cook <kees@kernel.org>
Having a platform need a mach-* directory should be seen as a negative,
it means the platform needs special non-standard handling. ARM64 support
does not allow mach-* directories at all. While we may not get to that
given all the non-standard architectures we support, we should still try
to get as close as we can and reduce the number of mach directories.
The mach-hpe/ directory and files, provides just one "feature":
having the kernel print the machine name if the DTB does not also contain
a "model" string (which they always do). To reduce the number of mach-*
directories let's do without that feature and remove this directory.
Note, we drop the l2c_aux_mask = ~0 line, but this is safe as
the fallback GENERIC_DT machine has that as the default.
Signed-off-by: Andrew Davis <afd@ti.com>
Link: https://lore.kernel.org/r/20250813170308.290349-1-afd@ti.com
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Pull tracepoint cleanup from Steven Rostedt:
"Remove or hide unused tracepoints
Tracepoints take up memory (around 5K per tracepoint) even when they
are unused. Changes are being made to detect when a tracepoint is
defined but unused and a warning is shown at build. But those changes
are not yet ready for inclusion.
- Fix some of the unused tracepoints that it detected
Some tracepoints were removed and others were hidden by config
settings to match the config settings of where they are
instantiated. Some tracepoints were moved into architecture
specific code as only one architecture used them.
- Call the ftrace_test_filter tracepoint in an unreachable if
statement
The ftrace_test_filter tracepoint which is defined when ftrace
selftests are configured and is used to test the filter logic, but
the tracepoint is not actually called. It is put into an if
statement to not have it get compiled out, but also not warn for
not being used"
* tag 'trace-unused-v6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tracing: sched: Hide numa events under CONFIG_NUMA_BALANCING
powerpc/thp: tracing: Hide hugepage events under CONFIG_PPC_BOOK3S_64
tracing: Call trace_ftrace_test_filter() for the event
tracing: arm: arm64: Hide trace events ipi_raise, ipi_entry and ipi_exit
binder: Remove unused binder lock events
PM: tracing: Hide power_domain_target event under ARCH_OMAP2PLUS
PM: tracing: Hide device_pm_callback events under PM_SLEEP
PM: tracing: Hide psci_domain_idle events under ARM_PSCI_CPUIDLE
PM: cpufreq: powernv/tracing: Move powernv_throttle trace event
alarmtimer: Hide alarmtimer_suspend event when RTC_CLASS is not configured
tracing, AER: Hide PCIe AER event when PCIEAER is not configured
Pull ftrace updates from Steven Rostedt:
- Keep track of when fgraph_ops are registered or not
Keep accounting of when fgraph_ops are registered as if a fgraph_ops
is registered twice it can mess up the accounting and it will not
work as expected later. Trigger a warning if something registers it
twice as to catch bugs before they are found by things just not
working as expected.
- Make DYNAMIC_FTRACE always enabled for architectures that support it
As static ftrace (where all functions are always traced) is very
expensive and only exists to help architectures support ftrace, do
not make it an option. As soon as an architecture supports
DYNAMIC_FTRACE make it use it. This simplifies the code.
- Remove redundant config HAVE_FTRACE_MCOUNT_RECORD
The CONFIG_HAVE_FTRACE_MCOUNT was added to help simplify the
DYNAMIC_FTRACE work, but now every architecture that implements
DYNAMIC_FTRACE also has HAVE_FTRACE_MCOUNT set too, making it
redundant with the HAVE_DYNAMIC_FTRACE.
- Make pid_ptr string size match the comment
In print_graph_proc() the pid_ptr string is of size 11, but the
comment says /* sign + log10(MAX_INT) + '\0' */ which is actually 12.
* tag 'ftrace-v6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tracing: Remove redundant config HAVE_FTRACE_MCOUNT_RECORD
ftrace: Make DYNAMIC_FTRACE always enabled for architectures that support it
fgraph: Keep track of when fgraph_ops are registered or not
fgraph: Make pid_str size match the comment
Pull CRC updates from Eric Biggers:
- Reorganize the architecture-optimized CRC code
It now lives in lib/crc/$(SRCARCH)/ rather than arch/$(SRCARCH)/lib/,
and it is no longer artificially split into separate generic and arch
modules. This allows better inlining and dead code elimination
The generic CRC code is also no longer exported, simplifying the API.
(This mirrors the similar changes to SHA-1 and SHA-2 in lib/crypto/,
which can be found in the "Crypto library updates" pull request)
- Improve crc32c() performance on newer x86_64 CPUs on long messages by
enabling the VPCLMULQDQ optimized code
- Simplify the crypto_shash wrappers for crc32_le() and crc32c()
Register just one shash algorithm for each that uses the (fully
optimized) library functions, instead of unnecessarily providing
direct access to the generic CRC code
- Remove unused and obsolete drivers for hardware CRC engines
- Remove CRC-32 combination functions that are no longer used
- Add kerneldoc for crc32_le(), crc32_be(), and crc32c()
- Convert the crc32() macro to an inline function
* tag 'crc-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiggers/linux: (26 commits)
lib/crc: x86/crc32c: Enable VPCLMULQDQ optimization where beneficial
lib/crc: x86: Reorganize crc-pclmul static_call initialization
lib/crc: crc64: Add include/linux/crc64.h to kernel-api.rst
lib/crc: crc32: Change crc32() from macro to inline function and remove cast
nvmem: layouts: Switch from crc32() to crc32_le()
lib/crc: crc32: Document crc32_le(), crc32_be(), and crc32c()
lib/crc: Explicitly include <linux/export.h>
lib/crc: Remove ARCH_HAS_* kconfig symbols
lib/crc: x86: Migrate optimized CRC code into lib/crc/
lib/crc: sparc: Migrate optimized CRC code into lib/crc/
lib/crc: s390: Migrate optimized CRC code into lib/crc/
lib/crc: riscv: Migrate optimized CRC code into lib/crc/
lib/crc: powerpc: Migrate optimized CRC code into lib/crc/
lib/crc: mips: Migrate optimized CRC code into lib/crc/
lib/crc: loongarch: Migrate optimized CRC code into lib/crc/
lib/crc: arm64: Migrate optimized CRC code into lib/crc/
lib/crc: arm: Migrate optimized CRC code into lib/crc/
lib/crc: Prepare for arch-optimized code in subdirs of lib/crc/
lib/crc: Move files into lib/crc/
lib/crc32: Remove unused combination support
...
Pull hardening updates from Kees Cook:
- Introduce and start using TRAILING_OVERLAP() helper for fixing
embedded flex array instances (Gustavo A. R. Silva)
- mux: Convert mux_control_ops to a flex array member in mux_chip
(Thorsten Blum)
- string: Group str_has_prefix() and strstarts() (Andy Shevchenko)
- Remove KCOV instrumentation from __init and __head (Ritesh Harjani,
Kees Cook)
- Refactor and rename stackleak feature to support Clang
- Add KUnit test for seq_buf API
- Fix KUnit fortify test under LTO
* tag 'hardening-v6.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (22 commits)
sched/task_stack: Add missing const qualifier to end_of_stack()
kstack_erase: Support Clang stack depth tracking
kstack_erase: Add -mgeneral-regs-only to silence Clang warnings
init.h: Disable sanitizer coverage for __init and __head
kstack_erase: Disable kstack_erase for all of arm compressed boot code
x86: Handle KCOV __init vs inline mismatches
arm64: Handle KCOV __init vs inline mismatches
s390: Handle KCOV __init vs inline mismatches
arm: Handle KCOV __init vs inline mismatches
mips: Handle KCOV __init vs inline mismatch
powerpc/mm/book3s64: Move kfence and debug_pagealloc related calls to __init section
configs/hardening: Enable CONFIG_INIT_ON_FREE_DEFAULT_ON
configs/hardening: Enable CONFIG_KSTACK_ERASE
stackleak: Split KSTACK_ERASE_CFLAGS from GCC_PLUGINS_CFLAGS
stackleak: Rename stackleak_track_stack to __sanitizer_cov_stack_depth
stackleak: Rename STACKLEAK to KSTACK_ERASE
seq_buf: Introduce KUnit tests
string: Group str_has_prefix() and strstarts()
kunit/fortify: Add back "volatile" for sizeof() constants
acpi: nfit: intel: avoid multiple -Wflex-array-member-not-at-end warnings
...
Ftrace is tightly coupled with architecture specific code because it
requires the use of trampolines written in assembly. This means that when
a new feature or optimization is made, it must be done for all
architectures. To simplify the approach, CONFIG_HAVE_FTRACE_* configs are
added to denote which architecture has the new enhancement so that other
architectures can still function until they too have been updated.
The CONFIG_HAVE_FTRACE_MCOUNT was added to help simplify the
DYNAMIC_FTRACE work, but now every architecture that implements
DYNAMIC_FTRACE also has HAVE_FTRACE_MCOUNT set too, making it redundant
with the HAVE_DYNAMIC_FTRACE.
Remove the HAVE_FTRACE_MCOUNT config and use DYNAMIC_FTRACE directly where
applicable.
Link: https://lore.kernel.org/all/20250703154916.48e3ada7@gandalf.local.home/
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/20250704104838.27a18690@gandalf.local.home
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
In preparation for adding Clang sanitizer coverage stack depth tracking
that can support stack depth callbacks:
- Add the new top-level CONFIG_KSTACK_ERASE option which will be
implemented either with the stackleak GCC plugin, or with the Clang
stack depth callback support.
- Rename CONFIG_GCC_PLUGIN_STACKLEAK as needed to CONFIG_KSTACK_ERASE,
but keep it for anything specific to the GCC plugin itself.
- Rename all exposed "STACKLEAK" names and files to "KSTACK_ERASE" (named
for what it does rather than what it protects against), but leave as
many of the internals alone as possible to avoid even more churn.
While here, also split "prev_lowest_stack" into CONFIG_KSTACK_ERASE_METRICS,
since that's the only place it is referenced from.
Suggested-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20250717232519.2984886-1-kees@kernel.org
Signed-off-by: Kees Cook <kees@kernel.org>
Move the arm-optimized CRC code from arch/arm/lib/crc* into its new
location in lib/crc/arm/, and wire it up in the new way. This new way
of organizing the CRC code eliminates the need to artificially split the
code for each CRC variant into separate arch and generic modules,
enabling better inlining and dead code elimination. For more details,
see "lib/crc: Prepare for arch-optimized code in subdirs of lib/crc/".
Reviewed-by: "Martin K. Petersen" <martin.petersen@oracle.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: "Jason A. Donenfeld" <Jason@zx2c4.com>
Link: https://lore.kernel.org/r/20250607200454.73587-4-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
ld.lld prior to 21.0.0 does not support using the KEEP keyword within an
overlay description, which may be needed to avoid discarding necessary
sections within an overlay with '--gc-sections', which can be enabled
for the kernel via CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
Disallow CONFIG_LD_DEAD_CODE_DATA_ELIMINATION without support for KEEP
within OVERLAY and introduce a macro, OVERLAY_KEEP, that can be used to
conditionally add KEEP when it is properly supported to avoid breaking
old versions of ld.lld.
Cc: stable@vger.kernel.org
Link: 381599f1fe
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
This commit allows building ARMv7 kernels with Rust support.
The rust core library expects some __eabi_... functions
that are not implemented in the kernel.
Those functions are some float operations and __aeabi_uldivmod.
For now those are implemented with define_panicking_intrinsics!.
This is based on the code by Sven Van Asbroeck from the original
rust branch and inspired by the AArch version by Jamie Cunliffe.
I have tested the rust samples and a custom simple MMIO module
on hardware (De1SoC FPGA + Arm A9 CPU).
Tested-by: Rudraksha Gupta <guptarud@gmail.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Acked-by: Miguel Ojeda <ojeda@kernel.org>
Tested-by: Miguel Ojeda <ojeda@kernel.org>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Christian Schrefl <chrisi.schrefl@gmail.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Pull ARM updates from Russell King:
- fix typos in vfpmodule.c
- drop obsolete VFP accessor fallback for old assemblers
- add cache line identifier register accessor functions
- add cacheinfo support
* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rmk/linux:
ARM: 9440/1: cacheinfo fix format field mask
ARM: 9433/2: implement cacheinfo support
ARM: 9432/2: add CLIDR accessor functions
ARM: 9438/1: assembler: Drop obsolete VFP accessor fallback
ARM: 9437/1: vfp: Fix typographical errors in vfpmodule.c
On ARMv7 / v7m machines read CTR and CLIDR registers to provide
information regarding the cache topology. Earlier machines should
describe full cache topology in the device tree.
Note, this follows the ARM64 cacheinfo support and provides only minimal
support required to bootstrap cache info. All useful properties should
be decribed in Device Tree.
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Now that the minimum supported binutils version is 2.25, we no longer
need a workaround for binutils older than 2.24 for accessing VFP control
registers from assembler.
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Move the arm CRC-T10DIF assembly code into the lib directory and wire it
up to the library interface. This allows it to be used without going
through the crypto API. It remains usable via the crypto API too via
the shash algorithms that use the library interface. Thus all the
arch-specific "shash" code becomes unnecessary and is removed.
Note: to see the diff from arch/arm/crypto/crct10dif-ce-glue.c to
arch/arm/lib/crc-t10dif-glue.c, view this commit with 'git show -M10'.
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20241202012056.209768-6-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Move the arm CRC32 assembly code into the lib directory and wire it up
to the library interface. This allows it to be used without going
through the crypto API. It remains usable via the crypto API too via
the shash algorithms that use the library interface. Thus all the
arch-specific "shash" code becomes unnecessary and is removed.
Note: to see the diff from arch/arm/crypto/crc32-ce-glue.c to
arch/arm/lib/crc32-glue.c, view this commit with 'git show -M10'.
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20241202010844.144356-6-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Pull dma-mapping updates from Christoph Hellwig:
- support DMA zones for arm64 systems where memory starts at > 4GB
(Baruch Siach, Catalin Marinas)
- support direct calls into dma-iommu and thus obsolete dma_map_ops for
many common configurations (Leon Romanovsky)
- add DMA-API tracing (Sean Anderson)
- remove the not very useful return value from various dma_set_* APIs
(Christoph Hellwig)
- misc cleanups and minor optimizations (Chen Y, Yosry Ahmed, Christoph
Hellwig)
* tag 'dma-mapping-6.12-2024-09-19' of git://git.infradead.org/users/hch/dma-mapping:
dma-mapping: reflow dma_supported
dma-mapping: reliably inform about DMA support for IOMMU
dma-mapping: add tracing for dma-mapping API calls
dma-mapping: use IOMMU DMA calls for common alloc/free page calls
dma-direct: optimize page freeing when it is not addressable
dma-mapping: clearly mark DMA ops as an architecture feature
vdpa_sim: don't select DMA_OPS
arm64: mm: keep low RAM dma zone
dma-mapping: don't return errors from dma_set_max_seg_size
dma-mapping: don't return errors from dma_set_seg_boundary
dma-mapping: don't return errors from dma_set_min_align_mask
scsi: check that busses support the DMA API before setting dma parameters
arm64: mm: fix DMA zone when dma-ranges is missing
dma-mapping: direct calls for dma-iommu
dma-mapping: call ->unmap_page and ->unmap_sg unconditionally
arm64: support DMA zone above 4GB
dma-mapping: replace zone_dma_bits by zone_dma_limit
dma-mapping: use bit masking to check VM_DMA_COHERENT
Pull ARM updates from Russell King:
- clean up TTBCR magic numbers and use u32 for this register
- fix clang issue in VFP code leading to kernel oops, caused by
compiler instruction scheduling.
- switch 32-bit Arm to use GENERIC_CPU_DEVICES and use the
arch_cpu_is_hotpluggable() hook.
- pass struct device to arm_iommu_create_mapping() and move over to use
iommu_paging_domain_alloc() rather than iommu_domain_alloc()
- make amba_bustype constant
* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rmk/linux:
ARM: 9418/1: dma-mapping: Use iommu_paging_domain_alloc()
ARM: 9417/1: dma-mapping: Pass device to arm_iommu_create_mapping()
ARM: 9416/1: amba: make amba_bustype constant
ARM: 9412/1: Convert to arch_cpu_is_hotpluggable()
ARM: 9411/1: Switch over to GENERIC_CPU_DEVICES using arch_register_cpu()
ARM: 9410/1: vfp: Use asm volatile in fmrx/fmxr macros
ARM: 9409/1: mmu: Do not use magic number for TTBCR settings
There is a build issue with LD segmentation fault, while
CONFIG_LD_DEAD_CODE_DATA_ELIMINATION is not enabled, as bellow.
scripts/link-vmlinux.sh: line 49: 3796 Segmentation fault
(core dumped) ${ld} ${ldflags} -o ${output} ${wl}--whole-archive
${objs} ${wl}--no-whole-archive ${wl}--start-group
${libs} ${wl}--end-group ${kallsymso} ${btf_vmlinux_bin_o} ${ldlibs}
The error occurs in older versions of the GNU ld with version earlier
than 2.36. It makes most sense to have a minimum LD version as
a dependency for HAVE_LD_DEAD_CODE_DATA_ELIMINATION and eliminate
the impact of ".reloc .text, R_ARM_NONE, ." when
CONFIG_LD_DEAD_CODE_DATA_ELIMINATION is not enabled.
Fixes: ed0f941022 ("ARM: 9404/1: arm32: enable HAVE_LD_DEAD_CODE_DATA_ELIMINATION")
Reported-by: Harith George <mail2hgg@gmail.com>
Tested-by: Harith George <mail2hgg@gmail.com>
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Yuntao Liu <liuyuntao12@huawei.com>
Link: https://lore.kernel.org/all/14e9aefb-88d1-4eee-8288-ef15d4a9b059@gmail.com/
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
DMA ops are a helper for architectures and not for drivers to override
the DMA implementation.
Unfortunately driver authors keep ignoring this. Make the fact more
clear by renaming the symbol to ARCH_HAS_DMA_OPS and having the two drivers
overriding their dma_ops depend on that. These drivers should probably be
marked broken, but we can give them a bit of a grace period for that.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> # for IPU6
Acked-by: Robin Murphy <robin.murphy@arm.com>
Currently, almost all architectures have switched to GENERIC_CPU_DEVICES,
except for arm32. Also switch over to GENERIC_CPU_DEVICES, and provide an
arch_register_cpu() that populates the hotpluggable flag for arm32.
The struct cpu in struct cpuinfo_arm is never used directly, remove
it to use the one GENERIC_CPU_DEVICES provides.
This also has the effect of moving the registration of CPUs from subsys to
driver core initialisation, prior to any initcalls running.
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Pull ARM updates from Russell King:
- ftrace: don't assume stack frames are contiguous in memory
- remove unused mod_inwind_map structure
- spelling fixes
- allow use of LD dead code/data elimination
- fix callchain_trace() return value
- add support for stackleak gcc plugin
- correct some reset asm function prototypes for CFI
[ Missed the merge window because Russell forgot to push out ]
* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rmk/linux:
ARM: 9408/1: mm: CFI: Fix some erroneous reset prototypes
ARM: 9407/1: Add support for STACKLEAK gcc plugin
ARM: 9406/1: Fix callchain_trace() return value
ARM: 9404/1: arm32: enable HAVE_LD_DEAD_CODE_DATA_ELIMINATION
ARM: 9403/1: Alpine: Spelling s/initialiing/initializing/
ARM: 9402/1: Kconfig: Spelling s/Cortex A-/Cortex-A/
ARM: 9400/1: Remove unused struct 'mod_unwind_map'
Pull Kbuild updates from Masahiro Yamada:
- Remove tristate choice support from Kconfig
- Stop using the PROVIDE() directive in the linker script
- Reduce the number of links for the combination of CONFIG_KALLSYMS and
CONFIG_DEBUG_INFO_BTF
- Enable the warning for symbol reference to .exit.* sections by
default
- Fix warnings in RPM package builds
- Improve scripts/make_fit.py to generate a FIT image with separate
base DTB and overlays
- Improve choice value calculation in Kconfig
- Fix conditional prompt behavior in choice in Kconfig
- Remove support for the uncommon EMAIL environment variable in Debian
package builds
- Remove support for the uncommon "name <email>" form for the DEBEMAIL
environment variable
- Raise the minimum supported GNU Make version to 4.0
- Remove stale code for the absolute kallsyms
- Move header files commonly used for host programs to scripts/include/
- Introduce the pacman-pkg target to generate a pacman package used in
Arch Linux
- Clean up Kconfig
* tag 'kbuild-v6.11' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (65 commits)
kbuild: doc: gcc to CC change
kallsyms: change sym_entry::percpu_absolute to bool type
kallsyms: unify seq and start_pos fields of struct sym_entry
kallsyms: add more original symbol type/name in comment lines
kallsyms: use \t instead of a tab in printf()
kallsyms: avoid repeated calculation of array size for markers
kbuild: add script and target to generate pacman package
modpost: use generic macros for hash table implementation
kbuild: move some helper headers from scripts/kconfig/ to scripts/include/
Makefile: add comment to discourage tools/* addition for kernel builds
kbuild: clean up scripts/remove-stale-files
kconfig: recursive checks drop file/lineno
kbuild: rpm-pkg: introduce a simple changelog section for kernel.spec
kallsyms: get rid of code for absolute kallsyms
kbuild: Create INSTALL_PATH directory if it does not exist
kbuild: Abort make on install failures
kconfig: remove 'e1' and 'e2' macros from expression deduplication
kconfig: remove SYMBOL_CHOICEVAL flag
kconfig: add const qualifiers to several function arguments
kconfig: call expr_eliminate_yn() at least once in expr_eliminate_dups()
...
While Documentation/kbuild/kconfig-language.rst provides a brief
explanation, there are recurring confusions regarding the usage of a
prompt followed by 'if <expr>'. This conditional controls _only_ the
prompt.
A typical usage is as follows:
menuconfig BLOCK
bool "Enable the block layer" if EXPERT
default y
When EXPERT=n, the prompt is hidden, but this config entry is still
active, and BLOCK is set to its default value 'y'. This is reasonable
because you are likely want to enable the block device support. When
EXPERT=y, the prompt is shown, allowing you to toggle BLOCK.
Please note that it is different from 'depends on EXPERT', which would
enable and disable the entire config entry.
However, this conditional prompt has never worked in a choice block.
The following two work in the same way: when EXPERT is disabled, the
choice block is entirely disabled.
[Test Code 1]
choice
prompt "choose" if EXPERT
config A
bool "A"
config B
bool "B"
endchoice
[Test Code 2]
choice
prompt "choose"
depends on EXPERT
config A
bool "A"
config B
bool "B"
endchoice
I believe the first case should hide only the prompt, producing the
default:
CONFIG_A=y
# CONFIG_B is not set
The next commit will change (fix) the behavior of the conditional prompt
in choice blocks.
I see several choice blocks wrongly using a conditional prompt, where
'depends on' makes more sense.
To preserve the current behavior, this commit converts such misuses.
I did not touch the following entry in arch/x86/Kconfig:
choice
prompt "Memory split" if EXPERT
default VMSPLIT_3G
This is truly the correct use of the conditional prompt; when EXPERT=n,
this choice block should silently select the reasonable VMSPLIT_3G,
although the resulting PAGE_OFFSET will not be affected anyway.
Presumably, the one in fs/jffs2/Kconfig is also correct, but I converted
it to 'depends on' to avoid any potential behavioral change.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Add the STACKLEAK gcc plugin to arm32 by adding the helper used by
stackleak common code: on_thread_stack(). It initialize the stack with the
poison value before returning from system calls which improves the kernel
security. Additionally, this disables the plugin in EFI stub code and
decompress code, which are out of scope for the protection.
Before the test on Qemu versatilepb board:
# echo STACKLEAK_ERASING > /sys/kernel/debug/provoke-crash/DIRECT
lkdtm: Performing direct entry STACKLEAK_ERASING
lkdtm: XFAIL: stackleak is not supported on this arch (HAVE_ARCH_STACKLEAK=n)
After:
# echo STACKLEAK_ERASING > /sys/kernel/debug/provoke-crash/DIRECT
lkdtm: Performing direct entry STACKLEAK_ERASING
lkdtm: stackleak stack usage:
high offset: 80 bytes
current: 280 bytes
lowest: 696 bytes
tracked: 696 bytes
untracked: 192 bytes
poisoned: 7220 bytes
low offset: 4 bytes
lkdtm: OK: the rest of the thread stack is properly erased
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
The current arm32 architecture does not yet support the
HAVE_LD_DEAD_CODE_DATA_ELIMINATION feature. arm32 is widely used in
embedded scenarios, and enabling this feature would be beneficial for
reducing the size of the kernel image.
In order to make this work, we keep the necessary tables by annotating
them with KEEP, also it requires further changes to linker script to KEEP
some tables and wildcard compiler generated sections into the right place.
When using ld.lld for linking, KEEP is not recognized within the OVERLAY
command, and Ard proposed a concise method to solve this problem.
It boots normally with defconfig, vexpress_defconfig and tinyconfig.
The size comparison of zImage is as follows:
defconfig vexpress_defconfig tinyconfig
5137712 5138024 424192 no dce
5032560 4997824 298384 dce
2.0% 2.7% 29.7% shrink
When using smaller config file, there is a significant reduction in the
size of the zImage.
We also tested this patch on a commercially available single-board
computer, and the comparison is as follows:
a15eb_config
2161384 no dce
2092240 dce
3.2% shrink
The zImage size has been reduced by approximately 3.2%, which is 70KB on
2.1M.
Signed-off-by: Yuntao Liu <liuyuntao12@huawei.com>
Tested-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Fix a misspelling of "Cortex-A9", to make it easier to find which errata
are applicable to Cortex-A9 CPU cores.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Pull mm updates from Andrew Morton:
"The usual shower of singleton fixes and minor series all over MM,
documented (hopefully adequately) in the respective changelogs.
Notable series include:
- Lucas Stach has provided some page-mapping cleanup/consolidation/
maintainability work in the series "mm/treewide: Remove pXd_huge()
API".
- In the series "Allow migrate on protnone reference with
MPOL_PREFERRED_MANY policy", Donet Tom has optimized mempolicy's
MPOL_PREFERRED_MANY mode, yielding almost doubled performance in
one test.
- In their series "Memory allocation profiling" Kent Overstreet and
Suren Baghdasaryan have contributed a means of determining (via
/proc/allocinfo) whereabouts in the kernel memory is being
allocated: number of calls and amount of memory.
- Matthew Wilcox has provided the series "Various significant MM
patches" which does a number of rather unrelated things, but in
largely similar code sites.
- In his series "mm: page_alloc: freelist migratetype hygiene"
Johannes Weiner has fixed the page allocator's handling of
migratetype requests, with resulting improvements in compaction
efficiency.
- In the series "make the hugetlb migration strategy consistent"
Baolin Wang has fixed a hugetlb migration issue, which should
improve hugetlb allocation reliability.
- Liu Shixin has hit an I/O meltdown caused by readahead in a
memory-tight memcg. Addressed in the series "Fix I/O high when
memory almost met memcg limit".
- In the series "mm/filemap: optimize folio adding and splitting"
Kairui Song has optimized pagecache insertion, yielding ~10%
performance improvement in one test.
- Baoquan He has cleaned up and consolidated the early zone
initialization code in the series "mm/mm_init.c: refactor
free_area_init_core()".
- Baoquan has also redone some MM initializatio code in the series
"mm/init: minor clean up and improvement".
- MM helper cleanups from Christoph Hellwig in his series "remove
follow_pfn".
- More cleanups from Matthew Wilcox in the series "Various
page->flags cleanups".
- Vlastimil Babka has contributed maintainability improvements in the
series "memcg_kmem hooks refactoring".
- More folio conversions and cleanups in Matthew Wilcox's series:
"Convert huge_zero_page to huge_zero_folio"
"khugepaged folio conversions"
"Remove page_idle and page_young wrappers"
"Use folio APIs in procfs"
"Clean up __folio_put()"
"Some cleanups for memory-failure"
"Remove page_mapping()"
"More folio compat code removal"
- David Hildenbrand chipped in with "fs/proc/task_mmu: convert
hugetlb functions to work on folis".
- Code consolidation and cleanup work related to GUP's handling of
hugetlbs in Peter Xu's series "mm/gup: Unify hugetlb, part 2".
- Rick Edgecombe has developed some fixes to stack guard gaps in the
series "Cover a guard gap corner case".
- Jinjiang Tu has fixed KSM's behaviour after a fork+exec in the
series "mm/ksm: fix ksm exec support for prctl".
- Baolin Wang has implemented NUMA balancing for multi-size THPs.
This is a simple first-cut implementation for now. The series is
"support multi-size THP numa balancing".
- Cleanups to vma handling helper functions from Matthew Wilcox in
the series "Unify vma_address and vma_pgoff_address".
- Some selftests maintenance work from Dev Jain in the series
"selftests/mm: mremap_test: Optimizations and style fixes".
- Improvements to the swapping of multi-size THPs from Ryan Roberts
in the series "Swap-out mTHP without splitting".
- Kefeng Wang has significantly optimized the handling of arm64's
permission page faults in the series
"arch/mm/fault: accelerate pagefault when badaccess"
"mm: remove arch's private VM_FAULT_BADMAP/BADACCESS"
- GUP cleanups from David Hildenbrand in "mm/gup: consistently call
it GUP-fast".
- hugetlb fault code cleanups from Vishal Moola in "Hugetlb fault
path to use struct vm_fault".
- selftests build fixes from John Hubbard in the series "Fix
selftests/mm build without requiring "make headers"".
- Memory tiering fixes/improvements from Ho-Ren (Jack) Chuang in the
series "Improved Memory Tier Creation for CPUless NUMA Nodes".
Fixes the initialization code so that migration between different
memory types works as intended.
- David Hildenbrand has improved follow_pte() and fixed an errant
driver in the series "mm: follow_pte() improvements and acrn
follow_pte() fixes".
- David also did some cleanup work on large folio mapcounts in his
series "mm: mapcount for large folios + page_mapcount() cleanups".
- Folio conversions in KSM in Alex Shi's series "transfer page to
folio in KSM".
- Barry Song has added some sysfs stats for monitoring multi-size
THP's in the series "mm: add per-order mTHP alloc and swpout
counters".
- Some zswap cleanups from Yosry Ahmed in the series "zswap
same-filled and limit checking cleanups".
- Matthew Wilcox has been looking at buffer_head code and found the
documentation to be lacking. The series is "Improve buffer head
documentation".
- Multi-size THPs get more work, this time from Lance Yang. His
series "mm/madvise: enhance lazyfreeing with mTHP in madvise_free"
optimizes the freeing of these things.
- Kemeng Shi has added more userspace-visible writeback
instrumentation in the series "Improve visibility of writeback".
- Kemeng Shi then sent some maintenance work on top in the series
"Fix and cleanups to page-writeback".
- Matthew Wilcox reduces mmap_lock traffic in the anon vma code in
the series "Improve anon_vma scalability for anon VMAs". Intel's
test bot reported an improbable 3x improvement in one test.
- SeongJae Park adds some DAMON feature work in the series
"mm/damon: add a DAMOS filter type for page granularity access recheck"
"selftests/damon: add DAMOS quota goal test"
- Also some maintenance work in the series
"mm/damon/paddr: simplify page level access re-check for pageout"
"mm/damon: misc fixes and improvements"
- David Hildenbrand has disabled some known-to-fail selftests ni the
series "selftests: mm: cow: flag vmsplice() hugetlb tests as
XFAIL".
- memcg metadata storage optimizations from Shakeel Butt in "memcg:
reduce memory consumption by memcg stats".
- DAX fixes and maintenance work from Vishal Verma in the series
"dax/bus.c: Fixups for dax-bus locking""
* tag 'mm-stable-2024-05-17-19-19' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (426 commits)
memcg, oom: cleanup unused memcg_oom_gfp_mask and memcg_oom_order
selftests/mm: hugetlb_madv_vs_map: avoid test skipping by querying hugepage size at runtime
mm/hugetlb: add missing VM_FAULT_SET_HINDEX in hugetlb_wp
mm/hugetlb: add missing VM_FAULT_SET_HINDEX in hugetlb_fault
selftests: cgroup: add tests to verify the zswap writeback path
mm: memcg: make alloc_mem_cgroup_per_node_info() return bool
mm/damon/core: fix return value from damos_wmark_metric_value
mm: do not update memcg stats for NR_{FILE/SHMEM}_PMDMAPPED
selftests: cgroup: remove redundant enabling of memory controller
Docs/mm/damon/maintainer-profile: allow posting patches based on damon/next tree
Docs/mm/damon/maintainer-profile: change the maintainer's timezone from PST to PT
Docs/mm/damon/design: use a list for supported filters
Docs/admin-guide/mm/damon/usage: fix wrong schemes effective quota update command
Docs/admin-guide/mm/damon/usage: fix wrong example of DAMOS filter matching sysfs file
selftests/damon: classify tests for functionalities and regressions
selftests/damon/_damon_sysfs: use 'is' instead of '==' for 'None'
selftests/damon/_damon_sysfs: find sysfs mount point from /proc/mounts
selftests/damon/_damon_sysfs: check errors from nr_schemes file reads
mm/damon/core: initialize ->esz_bp from damos_quota_init_priv()
selftests/damon: add a test for DAMOS quota goal
...
Support Control Flow Integrity (CFI) when compiling with
CLANG.
In the as-of-writing LLVM CLANG implementation (v17)
the 32-bit ARM platform is supported by the generic CFI
implementation, which isn't tailored specifically for ARM32
but works well enough to enable the feature.
Tested-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
With LPAE enabled, privileged no-access cannot be enforced using CPU
domains as such feature is not available. This patch implements PAN
by disabling TTBR0 page table walks while in kernel mode.
The ARM architecture allows page table walks to be split between TTBR0
and TTBR1. With LPAE enabled, the split is defined by a combination of
TTBCR T0SZ and T1SZ bits. Currently, an LPAE-enabled kernel uses TTBR0
for user addresses and TTBR1 for kernel addresses with the VMSPLIT_2G
and VMSPLIT_3G configurations. The main advantage for the 3:1 split is
that TTBR1 is reduced to 2 levels, so potentially faster TLB refill
(though usually the first level entries are already cached in the TLB).
The PAN support on LPAE-enabled kernels uses TTBR0 when running in user
space or in kernel space during user access routines (TTBCR T0SZ and
T1SZ are both 0). When running user accesses are disabled in kernel
mode, TTBR0 page table walks are disabled by setting TTBCR.EPD0. TTBR1
is used for kernel accesses (including loadable modules; anything
covered by swapper_pg_dir) by reducing the TTBCR.T0SZ to the minimum
(2^(32-7) = 32MB). To avoid user accesses potentially hitting stale TLB
entries, the ASID is switched to 0 (reserved) by setting TTBCR.A1 and
using the ASID value in TTBR1. The difference from a non-PAN kernel is
that with the 3:1 memory split, TTBR1 always uses 3 levels of page
tables.
As part of the change we are using preprocessor elif definied() clauses
so balance these clauses by converting relevant precedingt ifdef
clauses to if defined() clauses.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Florian Fainelli <florian.fainelli@broadcom.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Pull ARM updates from Russell King:
- remove a misuse of kernel-doc comment
- use "Call trace:" for backtraces like other architectures
- implement copy_from_kernel_nofault_allowed() to fix a LKDTM test
- add a "cut here" line for prefetch aborts
- remove unnecessary Kconfing entry for FRAME_POINTER
- remove iwmmxy support for PJ4/PJ4B cores
- use bitfield helpers in ptrace to improve readabililty
- check if folio is reserved before flushing
* tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm:
ARM: 9359/1: flush: check if the folio is reserved for no-mapping addresses
ARM: 9354/1: ptrace: Use bitfield helpers
ARM: 9352/1: iwmmxt: Remove support for PJ4/PJ4B cores
ARM: 9353/1: remove unneeded entry for CONFIG_FRAME_POINTER
ARM: 9351/1: fault: Add "cut here" line for prefetch aborts
ARM: 9350/1: fault: Implement copy_from_kernel_nofault_allowed()
ARM: 9349/1: unwind: Add missing "Call trace:" line
ARM: 9334/1: mm: init: remove misuse of kernel-doc comment
