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git://git.kernel.org/pub/scm/linux/kernel/git/crng/random
Pull more random number generator updates from Jason Donenfeld:
"This time with some large scale treewide cleanups.
The intent of this pull is to clean up the way callers fetch random
integers. The current rules for doing this right are:
- If you want a secure or an insecure random u64, use get_random_u64()
- If you want a secure or an insecure random u32, use get_random_u32()
The old function prandom_u32() has been deprecated for a while
now and is just a wrapper around get_random_u32(). Same for
get_random_int().
- If you want a secure or an insecure random u16, use get_random_u16()
- If you want a secure or an insecure random u8, use get_random_u8()
- If you want secure or insecure random bytes, use get_random_bytes().
The old function prandom_bytes() has been deprecated for a while
now and has long been a wrapper around get_random_bytes()
- If you want a non-uniform random u32, u16, or u8 bounded by a
certain open interval maximum, use prandom_u32_max()
I say "non-uniform", because it doesn't do any rejection sampling
or divisions. Hence, it stays within the prandom_*() namespace, not
the get_random_*() namespace.
I'm currently investigating a "uniform" function for 6.2. We'll see
what comes of that.
By applying these rules uniformly, we get several benefits:
- By using prandom_u32_max() with an upper-bound that the compiler
can prove at compile-time is ≤65536 or ≤256, internally
get_random_u16() or get_random_u8() is used, which wastes fewer
batched random bytes, and hence has higher throughput.
- By using prandom_u32_max() instead of %, when the upper-bound is
not a constant, division is still avoided, because
prandom_u32_max() uses a faster multiplication-based trick instead.
- By using get_random_u16() or get_random_u8() in cases where the
return value is intended to indeed be a u16 or a u8, we waste fewer
batched random bytes, and hence have higher throughput.
This series was originally done by hand while I was on an airplane
without Internet. Later, Kees and I worked on retroactively figuring
out what could be done with Coccinelle and what had to be done
manually, and then we split things up based on that.
So while this touches a lot of files, the actual amount of code that's
hand fiddled is comfortably small"
* tag 'random-6.1-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random:
prandom: remove unused functions
treewide: use get_random_bytes() when possible
treewide: use get_random_u32() when possible
treewide: use get_random_{u8,u16}() when possible, part 2
treewide: use get_random_{u8,u16}() when possible, part 1
treewide: use prandom_u32_max() when possible, part 2
treewide: use prandom_u32_max() when possible, part 1
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Rather than incurring a division or requesting too many random bytes for
the given range, use the prandom_u32_max() function, which only takes
the minimum required bytes from the RNG and avoids divisions. This was
done mechanically with this coccinelle script:
@basic@
expression E;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
typedef u64;
@@
(
- ((T)get_random_u32() % (E))
+ prandom_u32_max(E)
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- ((T)get_random_u32() & ((E) - 1))
+ prandom_u32_max(E * XXX_MAKE_SURE_E_IS_POW2)
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- ((u64)(E) * get_random_u32() >> 32)
+ prandom_u32_max(E)
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- ((T)get_random_u32() & ~PAGE_MASK)
+ prandom_u32_max(PAGE_SIZE)
)
@multi_line@
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
identifier RAND;
expression E;
@@
- RAND = get_random_u32();
... when != RAND
- RAND %= (E);
+ RAND = prandom_u32_max(E);
// Find a potential literal
@literal_mask@
expression LITERAL;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
position p;
@@
((T)get_random_u32()@p & (LITERAL))
// Add one to the literal.
@script:python add_one@
literal << literal_mask.LITERAL;
RESULT;
@@
value = None
if literal.startswith('0x'):
value = int(literal, 16)
elif literal[0] in '123456789':
value = int(literal, 10)
if value is None:
print("I don't know how to handle %s" % (literal))
cocci.include_match(False)
elif value == 2**32 - 1 or value == 2**31 - 1 or value == 2**24 - 1 or value == 2**16 - 1 or value == 2**8 - 1:
print("Skipping 0x%x for cleanup elsewhere" % (value))
cocci.include_match(False)
elif value & (value + 1) != 0:
print("Skipping 0x%x because it's not a power of two minus one" % (value))
cocci.include_match(False)
elif literal.startswith('0x'):
coccinelle.RESULT = cocci.make_expr("0x%x" % (value + 1))
else:
coccinelle.RESULT = cocci.make_expr("%d" % (value + 1))
// Replace the literal mask with the calculated result.
@plus_one@
expression literal_mask.LITERAL;
position literal_mask.p;
expression add_one.RESULT;
identifier FUNC;
@@
- (FUNC()@p & (LITERAL))
+ prandom_u32_max(RESULT)
@collapse_ret@
type T;
identifier VAR;
expression E;
@@
{
- T VAR;
- VAR = (E);
- return VAR;
+ return E;
}
@drop_var@
type T;
identifier VAR;
@@
{
- T VAR;
... when != VAR
}
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Yury Norov <yury.norov@gmail.com>
Reviewed-by: KP Singh <kpsingh@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz> # for ext4 and sbitmap
Reviewed-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> # for drbd
Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Heiko Carstens <hca@linux.ibm.com> # for s390
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # for mmc
Acked-by: Darrick J. Wong <djwong@kernel.org> # for xfs
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
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Only x86 has own release_thread(), introduce a new weak release_thread()
function to clean empty definitions in other ARCHs.
Link: https://lkml.kernel.org/r/20220819014406.32266-1-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: Guo Ren <guoren@kernel.org> [csky]
Acked-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Brian Cain <bcain@quicinc.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> [powerpc]
Acked-by: Stafford Horne <shorne@gmail.com> [openrisc]
Acked-by: Catalin Marinas <catalin.marinas@arm.com> [arm64]
Acked-by: Huacai Chen <chenhuacai@kernel.org> [LoongArch]
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Chris Zankel <chris@zankel.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Guo Ren <guoren@kernel.org> [csky]
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Richard Henderson <richard.henderson@linaro.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: Will Deacon <will@kernel.org>
Cc: Xuerui Wang <kernel@xen0n.name>
Cc: Yoshinori Sato <ysato@users.osdn.me>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull kthread updates from Eric Biederman:
"This updates init and user mode helper tasks to be ordinary user mode
tasks.
Commit 40966e316f86 ("kthread: Ensure struct kthread is present for
all kthreads") caused init and the user mode helper threads that call
kernel_execve to have struct kthread allocated for them. This struct
kthread going away during execve in turned made a use after free of
struct kthread possible.
Here, commit 343f4c49f243 ("kthread: Don't allocate kthread_struct for
init and umh") is enough to fix the use after free and is simple
enough to be backportable.
The rest of the changes pass struct kernel_clone_args to clean things
up and cause the code to make sense.
In making init and the user mode helpers tasks purely user mode tasks
I ran into two complications. The function task_tick_numa was
detecting tasks without an mm by testing for the presence of
PF_KTHREAD. The initramfs code in populate_initrd_image was using
flush_delayed_fput to ensuere the closing of all it's file descriptors
was complete, and flush_delayed_fput does not work in a userspace
thread.
I have looked and looked and more complications and in my code review
I have not found any, and neither has anyone else with the code
sitting in linux-next"
* tag 'kthread-cleanups-for-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
sched: Update task_tick_numa to ignore tasks without an mm
fork: Stop allowing kthreads to call execve
fork: Explicitly set PF_KTHREAD
init: Deal with the init process being a user mode process
fork: Generalize PF_IO_WORKER handling
fork: Explicity test for idle tasks in copy_thread
fork: Pass struct kernel_clone_args into copy_thread
kthread: Don't allocate kthread_struct for init and umh
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Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new sys-off API.
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Add fn and fn_arg members into struct kernel_clone_args and test for
them in copy_thread (instead of testing for PF_KTHREAD | PF_IO_WORKER).
This allows any task that wants to be a user space task that only runs
in kernel mode to use this functionality.
The code on x86 is an exception and still retains a PF_KTHREAD test
because x86 unlikely everything else handles kthreads slightly
differently than user space tasks that start with a function.
The functions that created tasks that start with a function
have been updated to set ".fn" and ".fn_arg" instead of
".stack" and ".stack_size". These functions are fork_idle(),
create_io_thread(), kernel_thread(), and user_mode_thread().
Link: https://lkml.kernel.org/r/20220506141512.516114-4-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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With io_uring we have started supporting tasks that are for most
purposes user space tasks that exclusively run code in kernel mode.
The kernel task that exec's init and tasks that exec user mode
helpers are also user mode tasks that just run kernel code
until they call kernel execve.
Pass kernel_clone_args into copy_thread so these oddball
tasks can be supported more cleanly and easily.
v2: Fix spelling of kenrel_clone_args on h8300
Link: https://lkml.kernel.org/r/20220506141512.516114-2-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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Fix following coccicheck error:
./arch/arm64/kernel/process.c:322:2-23: alloc with no test, possible model on line 326
Here should be dst->thread.sve_state.
Fixes: 8bd7f91c03d8 ("arm64/sme: Implement traps and syscall handling for SME")
Signed-off-by: Wan Jiabing <wanjiabing@vivo.com>
Reviwed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220426113054.630983-1-wanjiabing@vivo.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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By default all SME operations in userspace will trap. When this happens
we allocate storage space for the SME register state, set up the SVE
registers and disable traps. We do not need to initialize ZA since the
architecture guarantees that it will be zeroed when enabled and when we
trap ZA is disabled.
On syscall we exit streaming mode if we were previously in it and ensure
that all but the lower 128 bits of the registers are zeroed while
preserving the state of ZA. This follows the aarch64 PCS for SME, ZA
state is preserved over a function call and streaming mode is exited.
Since the traps for SME do not distinguish between streaming mode SVE
and ZA usage if ZA is in use rather than reenabling traps we instead
zero the parts of the SVE registers not shared with FPSIMD and leave SME
enabled, this simplifies handling SME traps. If ZA is not in use then we
reenable SME traps and fall through to normal handling of SVE.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20220419112247.711548-17-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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In SME the use of both streaming SVE mode and ZA are tracked through
PSTATE.SM and PSTATE.ZA, visible through the system register SVCR. In
order to context switch the floating point state for SME we need to
context switch the contents of this register as part of context
switching the floating point state.
Since changing the vector length exits streaming SVE mode and disables
ZA we also make sure we update SVCR appropriately when setting vector
length, and similarly ensure that new threads have streaming SVE mode
and ZA disabled.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20220419112247.711548-14-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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The Scalable Matrix Extension introduces support for a new thread specific
data register TPIDR2 intended for use by libc. The kernel must save the
value of TPIDR2 on context switch and should ensure that all new threads
start off with a default value of 0. Add a field to the thread_struct to
store TPIDR2 and context switch it with the other thread specific data.
In case there are future extensions which also use TPIDR2 we introduce
system_supports_tpidr2() and use that rather than system_supports_sme()
for TPIDR2 handling.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20220419112247.711548-13-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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As pointed out by Evgenii Stepanov one potential issue with the new ABI for
enabling asymmetric is that if there are multiple places where MTE is
configured in a process, some of which were compiled with the old prctl.h
and some of which were compiled with the new prctl.h, there may be problems
keeping track of which MTE modes are requested. For example some code may
disable only sync and async modes leaving asymmetric mode enabled when it
intended to fully disable MTE.
In order to avoid such mishaps remove asymmetric mode from the prctl(),
instead implicitly allowing it if both sync and async modes are requested.
This should not disrupt userspace since a process requesting both may
already see a mix of sync and async modes due to differing defaults between
CPUs or changes in default while the process is running but it does mean
that userspace is unable to explicitly request asymmetric mode without
changing the system default for CPUs.
Reported-by: Evgenii Stepanov <eugenis@google.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Evgenii Stepanov <eugenis@google.com>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Joey Gouly <joey.gouly@arm.com>
Cc: Branislav Rankov <branislav.rankov@arm.com>
Link: https://lore.kernel.org/r/20220309131200.112637-1-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
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The architecture provides an asymmetric mode for MTE where tag mismatches
are checked asynchronously for stores but synchronously for loads. Allow
userspace processes to select this and make it available as a default mode
via the existing per-CPU sysfs interface.
Since there PR_MTE_TCF_ values are a bitmask (allowing the kernel to choose
between the multiple modes) and there are no free bits adjacent to the
existing PR_MTE_TCF_ bits the set of bits used to specify the mode becomes
disjoint. Programs using the new interface should be aware of this and
programs that do not use it will not see any change in behaviour.
When userspace requests two possible modes but the system default for the
CPU is the third mode (eg, default is synchronous but userspace requests
either asynchronous or asymmetric) the preference order is:
ASYMM > ASYNC > SYNC
This situation is not currently possible since there are only two modes and
it is mandatory to have a system default so there could be no ambiguity and
there is no ABI change. The chosen order is basically arbitrary as we do not
have a clear metric for what is better here.
If userspace requests specifically asymmetric mode via the prctl() and the
system does not support it then we will return an error, this mirrors
how we handle the case where userspace enables MTE on a system that does
not support MTE at all and the behaviour that will be seen if running on
an older kernel that does not support userspace use of asymmetric mode.
Attempts to set asymmetric mode as the default mode will result in an error
if the system does not support it.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Vincenzo Frascino <Vincenzo.Frascino@arm.com>
Tested-by: Branislav Rankov <branislav.rankov@arm.com>
Link: https://lore.kernel.org/r/20220216173224.2342152-5-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
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'for-next/stacktrace', 'for-next/xor-neon', 'for-next/kasan', 'for-next/armv8_7-fp', 'for-next/atomics', 'for-next/bti', 'for-next/sve', 'for-next/kselftest' and 'for-next/kcsan', remote-tracking branch 'arm64/for-next/perf' into for-next/core
* arm64/for-next/perf: (32 commits)
arm64: perf: Don't register user access sysctl handler multiple times
drivers: perf: marvell_cn10k: fix an IS_ERR() vs NULL check
perf/smmuv3: Fix unused variable warning when CONFIG_OF=n
arm64: perf: Support new DT compatibles
arm64: perf: Simplify registration boilerplate
arm64: perf: Support Denver and Carmel PMUs
drivers/perf: hisi: Add driver for HiSilicon PCIe PMU
docs: perf: Add description for HiSilicon PCIe PMU driver
dt-bindings: perf: Add YAML schemas for Marvell CN10K LLC-TAD pmu bindings
drivers: perf: Add LLC-TAD perf counter support
perf/smmuv3: Synthesize IIDR from CoreSight ID registers
perf/smmuv3: Add devicetree support
dt-bindings: Add Arm SMMUv3 PMCG binding
perf/arm-cmn: Add debugfs topology info
perf/arm-cmn: Add CI-700 Support
dt-bindings: perf: arm-cmn: Add CI-700
perf/arm-cmn: Support new IP features
perf/arm-cmn: Demarcate CMN-600 specifics
perf/arm-cmn: Move group validation data off-stack
perf/arm-cmn: Optimise DTC counter accesses
...
* for-next/misc:
: Miscellaneous patches
arm64: Use correct method to calculate nomap region boundaries
arm64: Drop outdated links in comments
arm64: errata: Fix exec handling in erratum 1418040 workaround
arm64: Unhash early pointer print plus improve comment
asm-generic: introduce io_stop_wc() and add implementation for ARM64
arm64: remove __dma_*_area() aliases
docs/arm64: delete a space from tagged-address-abi
arm64/fp: Add comments documenting the usage of state restore functions
arm64: mm: Use asid feature macro for cheanup
arm64: mm: Rename asid2idx() to ctxid2asid()
arm64: kexec: reduce calls to page_address()
arm64: extable: remove unused ex_handler_t definition
arm64: entry: Use SDEI event constants
arm64: Simplify checking for populated DT
arm64/kvm: Fix bitrotted comment for SVE handling in handle_exit.c
* for-next/cache-ops-dzp:
: Avoid DC instructions when DCZID_EL0.DZP == 1
arm64: mte: DC {GVA,GZVA} shouldn't be used when DCZID_EL0.DZP == 1
arm64: clear_page() shouldn't use DC ZVA when DCZID_EL0.DZP == 1
* for-next/stacktrace:
: Unify the arm64 unwind code
arm64: Make some stacktrace functions private
arm64: Make dump_backtrace() use arch_stack_walk()
arm64: Make profile_pc() use arch_stack_walk()
arm64: Make return_address() use arch_stack_walk()
arm64: Make __get_wchan() use arch_stack_walk()
arm64: Make perf_callchain_kernel() use arch_stack_walk()
arm64: Mark __switch_to() as __sched
arm64: Add comment for stack_info::kr_cur
arch: Make ARCH_STACKWALK independent of STACKTRACE
* for-next/xor-neon:
: Use SHA3 instructions to speed up XOR
arm64/xor: use EOR3 instructions when available
* for-next/kasan:
: Log potential KASAN shadow aliases
arm64: mm: log potential KASAN shadow alias
arm64: mm: use die_kernel_fault() in do_mem_abort()
* for-next/armv8_7-fp:
: Add HWCAPS for ARMv8.7 FEAT_AFP amd FEAT_RPRES
arm64: cpufeature: add HWCAP for FEAT_RPRES
arm64: add ID_AA64ISAR2_EL1 sys register
arm64: cpufeature: add HWCAP for FEAT_AFP
* for-next/atomics:
: arm64 atomics clean-ups and codegen improvements
arm64: atomics: lse: define RETURN ops in terms of FETCH ops
arm64: atomics: lse: improve constraints for simple ops
arm64: atomics: lse: define ANDs in terms of ANDNOTs
arm64: atomics lse: define SUBs in terms of ADDs
arm64: atomics: format whitespace consistently
* for-next/bti:
: BTI clean-ups
arm64: Ensure that the 'bti' macro is defined where linkage.h is included
arm64: Use BTI C directly and unconditionally
arm64: Unconditionally override SYM_FUNC macros
arm64: Add macro version of the BTI instruction
arm64: ftrace: add missing BTIs
arm64: kexec: use __pa_symbol(empty_zero_page)
arm64: update PAC description for kernel
* for-next/sve:
: SVE code clean-ups and refactoring in prepararation of Scalable Matrix Extensions
arm64/sve: Minor clarification of ABI documentation
arm64/sve: Generalise vector length configuration prctl() for SME
arm64/sve: Make sysctl interface for SVE reusable by SME
* for-next/kselftest:
: arm64 kselftest additions
kselftest/arm64: Add pidbench for floating point syscall cases
kselftest/arm64: Add a test program to exercise the syscall ABI
kselftest/arm64: Allow signal tests to trigger from a function
kselftest/arm64: Parameterise ptrace vector length information
* for-next/kcsan:
: Enable KCSAN for arm64
arm64: Enable KCSAN
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The erratum 1418040 workaround enables CNTVCT_EL1 access trapping in EL0
when executing compat threads. The workaround is applied when switching
between tasks, but the need for the workaround could also change at an
exec(), when a non-compat task execs a compat binary or vice versa. Apply
the workaround in arch_setup_new_exec().
This leaves a small window of time between SET_PERSONALITY and
arch_setup_new_exec where preemption could occur and confuse the old
workaround logic that compares TIF_32BIT between prev and next. Instead, we
can just read cntkctl to make sure it's in the state that the next task
needs. I measured cntkctl read time to be about the same as a mov from a
general-purpose register on N1. Update the workaround logic to examine the
current value of cntkctl instead of the previous task's compat state.
Fixes: d49f7d7376d0 ("arm64: Move handling of erratum 1418040 into C code")
Cc: <stable@vger.kernel.org> # 5.9.x
Signed-off-by: D Scott Phillips <scott@os.amperecomputing.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211220234114.3926-1-scott@os.amperecomputing.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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To enable RELIABLE_STACKTRACE and LIVEPATCH on arm64, we need to
substantially rework arm64's unwinding code. As part of this, we want to
minimize the set of unwind interfaces we expose, and avoid open-coding
of unwind logic outside of stacktrace.c.
Currently, __get_wchan() walks the stack of a blocked task by calling
start_backtrace() with the task's saved PC and FP values, and iterating
unwind steps using unwind_frame(). The initialization is functionally
equivalent to calling arch_stack_walk() with the blocked task, which
will start with the task's saved PC and FP values.
Currently __get_wchan() always performs an initial unwind step, which
will stkip __switch_to(), but as this is now marked as a __sched
function, this no longer needs special handling and will be skipped in
the same way as other sched functions.
Make __get_wchan() use arch_stack_walk(). This simplifies __get_wchan(),
and in future will alow us to make unwind_frame() private to
stacktrace.c. At the same time, we can simplify the try_get_task_stack()
check and avoid the unnecessary `stack_page` variable.
The change to the skipping logic means we may terminate one frame
earlier than previously where there are an excessive number of sched
functions in the trace, but this isn't seen in practice, and wchan is
best-effort anyway, so this should not be a problem.
Other than the above, there should be no functional change as a result
of this patch.
Signed-off-by: Madhavan T. Venkataraman <madvenka@linux.microsoft.com>
[Mark: rebase atop wchan changes, elaborate commit message, fix includes]
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20211129142849.3056714-6-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Unlike most architectures (and only in keeping with powerpc), arm64 has
a non __sched() function on the path to our cpu_switch_to() assembly
function.
It is expected that for a blocked task, in_sched_functions() can be used
to skip all functions between the raw context switch assembly and the
scheduler functions that call into __switch_to(). This is the behaviour
expected by stack_trace_consume_entry_nosched(), and the behaviour we'd
like to have such that we an simplify arm64's __get_wchan()
implementation to use arch_stack_walk().
This patch mark's arm64's __switch_to as __sched. This *will not* change
the behaviour of arm64's current __get_wchan() implementation, which
always performs an initial unwind step which skips __switch_to(). This
*will* change the behaviour of stack_trace_consume_entry_nosched() and
stack_trace_save_tsk() to match their expected behaviour on blocked
tasks, skipping all scheduler-internal functions including
__switch_to().
Other than the above, there should be no functional change as a result
of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Madhavan T. Venkataraman <madvenka@linux.microsoft.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will@kernel.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20211129142849.3056714-4-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Having a stable wchan means the process must be blocked and for it to
stay that way while performing stack unwinding.
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> [arm]
Tested-by: Mark Rutland <mark.rutland@arm.com> [arm64]
Link: https://lkml.kernel.org/r/20211008111626.332092234@infradead.org
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__stack_chk_guard is setup once while init stage and never changed
after that.
Although the modification of this variable at runtime will usually
cause the kernel to crash (so does the attacker), it should be marked
as __ro_after_init, and it should not affect performance if it is
placed in the ro_after_init section.
Signed-off-by: Dan Li <ashimida@linux.alibaba.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/1631612642-102881-1-git-send-email-ashimida@linux.alibaba.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Remove all but the first include of linux/sched.h from process.c
Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Lv Ruyi <lv.ruyi@zte.com.cn>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20210902011126.29828-1-lv.ruyi@zte.com.cn
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:
- Add -s option (strict mode) to merge_config.sh to make it fail when
any symbol is redefined.
- Show a warning if a different compiler is used for building external
modules.
- Infer --target from ARCH for CC=clang to let you cross-compile the
kernel without CROSS_COMPILE.
- Make the integrated assembler default (LLVM_IAS=1) for CC=clang.
- Add <linux/stdarg.h> to the kernel source instead of borrowing
<stdarg.h> from the compiler.
- Add Nick Desaulniers as a Kbuild reviewer.
- Drop stale cc-option tests.
- Fix the combination of CONFIG_TRIM_UNUSED_KSYMS and CONFIG_LTO_CLANG
to handle symbols in inline assembly.
- Show a warning if 'FORCE' is missing for if_changed rules.
- Various cleanups
* tag 'kbuild-v5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (39 commits)
kbuild: redo fake deps at include/ksym/*.h
kbuild: clean up objtool_args slightly
modpost: get the *.mod file path more simply
checkkconfigsymbols.py: Fix the '--ignore' option
kbuild: merge vmlinux_link() between ARCH=um and other architectures
kbuild: do not remove 'linux' link in scripts/link-vmlinux.sh
kbuild: merge vmlinux_link() between the ordinary link and Clang LTO
kbuild: remove stale *.symversions
kbuild: remove unused quiet_cmd_update_lto_symversions
gen_compile_commands: extract compiler command from a series of commands
x86: remove cc-option-yn test for -mtune=
arc: replace cc-option-yn uses with cc-option
s390: replace cc-option-yn uses with cc-option
ia64: move core-y in arch/ia64/Makefile to arch/ia64/Kbuild
sparc: move the install rule to arch/sparc/Makefile
security: remove unneeded subdir-$(CONFIG_...)
kbuild: sh: remove unused install script
kbuild: Fix 'no symbols' warning when CONFIG_TRIM_UNUSD_KSYMS=y
kbuild: Switch to 'f' variants of integrated assembler flag
kbuild: Shuffle blank line to improve comment meaning
...
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* tip/sched/arm64: (785 commits)
Documentation: arm64: describe asymmetric 32-bit support
arm64: Remove logic to kill 32-bit tasks on 64-bit-only cores
arm64: Hook up cmdline parameter to allow mismatched 32-bit EL0
arm64: Advertise CPUs capable of running 32-bit applications in sysfs
arm64: Prevent offlining first CPU with 32-bit EL0 on mismatched system
arm64: exec: Adjust affinity for compat tasks with mismatched 32-bit EL0
arm64: Implement task_cpu_possible_mask()
sched: Introduce dl_task_check_affinity() to check proposed affinity
sched: Allow task CPU affinity to be restricted on asymmetric systems
sched: Split the guts of sched_setaffinity() into a helper function
sched: Introduce task_struct::user_cpus_ptr to track requested affinity
sched: Reject CPU affinity changes based on task_cpu_possible_mask()
cpuset: Cleanup cpuset_cpus_allowed_fallback() use in select_fallback_rq()
cpuset: Honour task_cpu_possible_mask() in guarantee_online_cpus()
cpuset: Don't use the cpu_possible_mask as a last resort for cgroup v1
sched: Introduce task_cpu_possible_mask() to limit fallback rq selection
sched: Cgroup SCHED_IDLE support
sched/topology: Skip updating masks for non-online nodes
Linux 5.14-rc6
lib: use PFN_PHYS() in devmem_is_allowed()
...
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remote-tracking branch 'arm64/for-next/perf' into for-next/core
* arm64/for-next/perf:
arm64/perf: Replace '0xf' instances with ID_AA64DFR0_PMUVER_IMP_DEF
* for-next/mte:
: Miscellaneous MTE improvements.
arm64/cpufeature: Optionally disable MTE via command-line
arm64: kasan: mte: remove redundant mte_report_once logic
arm64: kasan: mte: use a constant kernel GCR_EL1 value
arm64: avoid double ISB on kernel entry
arm64: mte: optimize GCR_EL1 modification on kernel entry/exit
Documentation: document the preferred tag checking mode feature
arm64: mte: introduce a per-CPU tag checking mode preference
arm64: move preemption disablement to prctl handlers
arm64: mte: change ASYNC and SYNC TCF settings into bitfields
arm64: mte: rename gcr_user_excl to mte_ctrl
arm64: mte: avoid TFSRE0_EL1 related operations unless in async mode
* for-next/misc:
: Miscellaneous updates.
arm64: Do not trap PMSNEVFR_EL1
arm64: mm: fix comment typo of pud_offset_phys()
arm64: signal32: Drop pointless call to sigdelsetmask()
arm64/sve: Better handle failure to allocate SVE register storage
arm64: Document the requirement for SCR_EL3.HCE
arm64: head: avoid over-mapping in map_memory
arm64/sve: Add a comment documenting the binutils needed for SVE asm
arm64/sve: Add some comments for sve_save/load_state()
arm64: replace in_irq() with in_hardirq()
arm64: mm: Fix TLBI vs ASID rollover
arm64: entry: Add SYM_CODE annotation for __bad_stack
arm64: fix typo in a comment
arm64: move the (z)install rules to arch/arm64/Makefile
arm64/sve: Make fpsimd_bind_task_to_cpu() static
arm64: unnecessary end 'return;' in void functions
arm64/sme: Document boot requirements for SME
arm64: use __func__ to get function name in pr_err
arm64: SSBS/DIT: print SSBS and DIT bit when printing PSTATE
arm64: cpufeature: Use defined macro instead of magic numbers
arm64/kexec: Test page size support with new TGRAN range values
* for-next/kselftest:
: Kselftest additions for arm64.
kselftest/arm64: signal: Add a TODO list for signal handling tests
kselftest/arm64: signal: Add test case for SVE register state in signals
kselftest/arm64: signal: Verify that signals can't change the SVE vector length
kselftest/arm64: signal: Check SVE signal frame shows expected vector length
kselftest/arm64: signal: Support signal frames with SVE register data
kselftest/arm64: signal: Add SVE to the set of features we can check for
kselftest/arm64: pac: Fix skipping of tests on systems without PAC
kselftest/arm64: mte: Fix misleading output when skipping tests
kselftest/arm64: Add a TODO list for floating point tests
kselftest/arm64: Add tests for SVE vector configuration
kselftest/arm64: Validate vector lengths are set in sve-probe-vls
kselftest/arm64: Provide a helper binary and "library" for SVE RDVL
kselftest/arm64: Ignore check_gcr_el1_cswitch binary
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The scheduler now knows enough about these braindead systems to place
32-bit tasks accordingly, so throw out the safety checks and allow the
ret-to-user path to avoid do_notify_resume() if there is nothing to do.
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20210730112443.23245-16-will@kernel.org
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When exec'ing a 32-bit task on a system with mismatched support for
32-bit EL0, try to ensure that it starts life on a CPU that can actually
run it.
Similarly, when exec'ing a 64-bit task on such a system, try to restore
the old affinity mask if it was previously restricted.
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Reviewed-by: Quentin Perret <qperret@google.com>
Link: https://lore.kernel.org/r/20210730112443.23245-12-will@kernel.org
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Delete/fixup few includes in anticipation of global -isystem compile
option removal.
Note: crypto/aegis128-neon-inner.c keeps <stddef.h> due to redefinition
of uintptr_t error (one definition comes from <stddef.h>, another from
<linux/types.h>).
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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The current code to print PSTATE when generating backtraces does not
include SSBS bit and DIT bit, so add this information.
Cc: Vladimir Murzin <vladimir.murzin@arm.com>
Cc: Will Deacon <will@kernel.org>
Reviewed-by: Vladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: Lingyan Huang <huanglingyan2@huawei.com>
Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.com>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/1626920436-54816-1-git-send-email-zhangshaokun@hisilicon.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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In the next patch, we will start reading sctlr_user from
mte_update_sctlr_user and subsequently writing a new value based on the
task's TCF setting and potentially the per-CPU TCF preference. This
means that we need to be careful to disable preemption around any
code sequences that read from sctlr_user and subsequently write to
sctlr_user and/or SCTLR_EL1, so that we don't end up writing a stale
value (based on the previous CPU's TCF preference) to either of them.
We currently have four such sequences, in the prctl handlers for
PR_SET_TAGGED_ADDR_CTRL and PR_PAC_SET_ENABLED_KEYS, as well as in
the task initialization code that resets the prctl settings. Change
the prctl handlers to disable preemption in the handlers themselves
rather than the functions that they call, and change the task
initialization code to call the respective prctl handlers instead of
setting sctlr_user directly.
As a result of this change, we no longer need the helper function
set_task_sctlr_el1, nor does its behavior make sense any more, so
remove it.
Signed-off-by: Peter Collingbourne <pcc@google.com>
Link: https://linux-review.googlesource.com/id/Ic0e8a0c00bb47d786c1e8011df0b7fe99bee4bb5
Link: https://lore.kernel.org/r/20210727205300.2554659-4-pcc@google.com
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Pull ARM development updates from Russell King:
- Make it clear __swp_entry_to_pte() uses PTE_TYPE_FAULT
- Updates for setting vmalloc size via command line to resolve an issue
with the 8MiB hole not properly being accounted for, and clean up the
code.
- ftrace support for module PLTs
- Spelling fixes
- kbuild updates for removing generated files and pattern rules for
generating files
- Clang/llvm updates
- Change the way the kernel is mapped, placing it in vmalloc space
instead.
- Remove arm_pm_restart from arm and aarch64.
* tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm: (29 commits)
ARM: 9098/1: ftrace: MODULE_PLT: Fix build problem without DYNAMIC_FTRACE
ARM: 9097/1: mmu: Declare section start/end correctly
ARM: 9096/1: Remove arm_pm_restart()
ARM: 9095/1: ARM64: Remove arm_pm_restart()
ARM: 9094/1: Register with kernel restart handler
ARM: 9093/1: drivers: firmwapsci: Register with kernel restart handler
ARM: 9092/1: xen: Register with kernel restart handler
ARM: 9091/1: Revert "mm: qsd8x50: Fix incorrect permission faults"
ARM: 9090/1: Map the lowmem and kernel separately
ARM: 9089/1: Define kernel physical section start and end
ARM: 9088/1: Split KERNEL_OFFSET from PAGE_OFFSET
ARM: 9087/1: kprobes: test-thumb: fix for LLVM_IAS=1
ARM: 9086/1: syscalls: use pattern rules to generate syscall headers
ARM: 9085/1: remove unneeded abi parameter to syscallnr.sh
ARM: 9084/1: simplify the build rule of mach-types.h
ARM: 9083/1: uncompress: atags_to_fdt: Spelling s/REturn/Return/
ARM: 9082/1: [v2] mark prepare_page_table as __init
ARM: 9079/1: ftrace: Add MODULE_PLTS support
ARM: 9078/1: Add warn suppress parameter to arm_gen_branch_link()
ARM: 9077/1: PLT: Move struct plt_entries definition to header
...
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git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 updates from Will Deacon:
"There's a reasonable amount here and the juicy details are all below.
It's worth noting that the MTE/KASAN changes strayed outside of our
usual directories due to core mm changes and some associated changes
to some other architectures; Andrew asked for us to carry these [1]
rather that take them via the -mm tree.
Summary:
- Optimise SVE switching for CPUs with 128-bit implementations.
- Fix output format from SVE selftest.
- Add support for versions v1.2 and 1.3 of the SMC calling
convention.
- Allow Pointer Authentication to be configured independently for
kernel and userspace.
- PMU driver cleanups for managing IRQ affinity and exposing event
attributes via sysfs.
- KASAN optimisations for both hardware tagging (MTE) and out-of-line
software tagging implementations.
- Relax frame record alignment requirements to facilitate 8-byte
alignment with KASAN and Clang.
- Cleanup of page-table definitions and removal of unused memory
types.
- Reduction of ARCH_DMA_MINALIGN back to 64 bytes.
- Refactoring of our instruction decoding routines and addition of
some missing encodings.
- Move entry code moved into C and hardened against harmful compiler
instrumentation.
- Update booting requirements for the FEAT_HCX feature, added to v8.7
of the architecture.
- Fix resume from idle when pNMI is being used.
- Additional CPU sanity checks for MTE and preparatory changes for
systems where not all of the CPUs support 32-bit EL0.
- Update our kernel string routines to the latest Cortex Strings
implementation.
- Big cleanup of our cache maintenance routines, which were
confusingly named and inconsistent in their implementations.
- Tweak linker flags so that GDB can understand vmlinux when using
RELR relocations.
- Boot path cleanups to enable early initialisation of per-cpu
operations needed by KCSAN.
- Non-critical fixes and miscellaneous cleanup"
* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (150 commits)
arm64: tlb: fix the TTL value of tlb_get_level
arm64: Restrict undef hook for cpufeature registers
arm64/mm: Rename ARM64_SWAPPER_USES_SECTION_MAPS
arm64: insn: avoid circular include dependency
arm64: smp: Bump debugging information print down to KERN_DEBUG
drivers/perf: fix the missed ida_simple_remove() in ddr_perf_probe()
perf/arm-cmn: Fix invalid pointer when access dtc object sharing the same IRQ number
arm64: suspend: Use cpuidle context helpers in cpu_suspend()
PSCI: Use cpuidle context helpers in psci_cpu_suspend_enter()
arm64: Convert cpu_do_idle() to using cpuidle context helpers
arm64: Add cpuidle context save/restore helpers
arm64: head: fix code comments in set_cpu_boot_mode_flag
arm64: mm: drop unused __pa(__idmap_text_start)
arm64: mm: fix the count comments in compute_indices
arm64/mm: Fix ttbr0 values stored in struct thread_info for software-pan
arm64: mm: Pass original fault address to handle_mm_fault()
arm64/mm: Drop SECTION_[SHIFT|SIZE|MASK]
arm64/mm: Use CONT_PMD_SHIFT for ARM64_MEMSTART_SHIFT
arm64/mm: Drop SWAPPER_INIT_MAP_SIZE
arm64: Conditionally configure PTR_AUTH key of the kernel.
...
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The never-ending entry.S refactoring continues, putting us in a much
better place wrt compiler instrumentation whilst moving more of the code
into C.
* for-next/entry:
arm64: idle: don't instrument idle code with KCOV
arm64: entry: don't instrument entry code with KCOV
arm64: entry: make NMI entry/exit functions static
arm64: entry: split SDEI entry
arm64: entry: split bad stack entry
arm64: entry: fold el1_inv() into el1h_64_sync_handler()
arm64: entry: handle all vectors with C
arm64: entry: template the entry asm functions
arm64: entry: improve bad_mode()
arm64: entry: move bad_mode() to entry-common.c
arm64: entry: consolidate EL1 exception returns
arm64: entry: organise entry vectors consistently
arm64: entry: organise entry handlers consistently
arm64: entry: convert IRQ+FIQ handlers to C
arm64: entry: add a call_on_irq_stack helper
arm64: entry: move NMI preempt logic to C
arm64: entry: move arm64_preempt_schedule_irq to entry-common.c
arm64: entry: convert SError handlers to C
arm64: entry: unmask IRQ+FIQ after EL0 handling
arm64: remove redundant local_daif_mask() in bad_mode()
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Fix resume from idle when pNMI is being used.
* for-next/cpuidle:
arm64: suspend: Use cpuidle context helpers in cpu_suspend()
PSCI: Use cpuidle context helpers in psci_cpu_suspend_enter()
arm64: Convert cpu_do_idle() to using cpuidle context helpers
arm64: Add cpuidle context save/restore helpers
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Additional CPU sanity checks for MTE and preparatory changes for systems
where not all of the CPUs support 32-bit EL0.
* for-next/cpufeature:
arm64: Restrict undef hook for cpufeature registers
arm64: Kill 32-bit applications scheduled on 64-bit-only CPUs
KVM: arm64: Kill 32-bit vCPUs on systems with mismatched EL0 support
arm64: Allow mismatched 32-bit EL0 support
arm64: cpuinfo: Split AArch32 registers out into a separate struct
arm64: Check if GMID_EL1.BS is the same on all CPUs
arm64: Change the cpuinfo_arm64 member type for some sysregs to u64
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Replace a bunch of 'p->state == TASK_RUNNING' with a new helper:
task_is_running(p).
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Davidlohr Bueso <dave@stgolabs.net>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20210611082838.222401495@infradead.org
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Now that we have helpers that are aware of the pseudo-NMI
feature, introduce them to cpu_do_idle(). This allows for
some nice cleanup.
No functional change intended.
Tested-by: Valentin Schneider <valentin.schneider@arm.com>
Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210615111227.2454465-3-maz@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
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All users of arm_pm_restart() have been converted to use the kernel
restart handler.
Acked-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
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Scheduling a 32-bit application on a 64-bit-only CPU is a bad idea.
Ensure that 32-bit applications always take the slow-path when returning
to userspace on a system with mismatched support at EL0, so that we can
avoid trying to run on a 64-bit-only CPU and force a SIGKILL instead.
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20210608180313.11502-5-will@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
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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>
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Subsequent patches will pull more of the IRQ entry handling into C. To
keep this in one place, let's move arm64_preempt_schedule_irq() into
entry-common.c along with the other entry management functions.
We no longer need to include <linux/lockdep.h> in process.c, so the
include directive is removed.
There should be no functional change as a result of this patch.
Reviewed-by Joey Gouly <joey.gouly@arm.com>
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/20210607094624.34689-5-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
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Reliable stacktracing requires that we identify when a stacktrace is
terminated early. We can do this by ensuring all tasks have a final
frame record at a known location on their task stack, and checking
that this is the final frame record in the chain.
We'd like to use task_pt_regs(task)->stackframe as the final frame
record, as this is already setup upon exception entry from EL0. For
kernel tasks we need to consistently reserve the pt_regs and point x29
at this, which we can do with small changes to __primary_switched,
__secondary_switched, and copy_process().
Since the final frame record must be at a specific location, we must
create the final frame record in __primary_switched and
__secondary_switched rather than leaving this to start_kernel and
secondary_start_kernel. Thus, __primary_switched and
__secondary_switched will now show up in stacktraces for the idle tasks.
Since the final frame record is now identified by its location rather
than by its contents, we identify it at the start of unwind_frame(),
before we read any values from it.
External debuggers may terminate the stack trace when FP == 0. In the
pt_regs->stackframe, the PC is 0 as well. So, stack traces taken in the
debugger may print an extra record 0x0 at the end. While this is not
pretty, this does not do any harm. This is a small price to pay for
having reliable stack trace termination in the kernel. That said, gdb
does not show the extra record probably because it uses DWARF and not
frame pointers for stack traces.
Signed-off-by: Madhavan T. Venkataraman <madvenka@linux.microsoft.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
[Mark: rebase, use ASM_BUG(), update comments, update commit message]
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20210510110026.18061-1-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull more arm64 updates from Catalin Marinas:
"A mix of fixes and clean-ups that turned up too late for the first
pull request:
- Restore terminal stack frame records. Their previous removal caused
traces which cross secondary_start_kernel to terminate one entry
too late, with a spurious "0" entry.
- Fix boot warning with pseudo-NMI due to the way we manipulate the
PMR register.
- ACPI fixes: avoid corruption of interrupt mappings on watchdog
probe failure (GTDT), prevent unregistering of GIC SGIs.
- Force SPARSEMEM_VMEMMAP as the only memory model, it saves with
having to test all the other combinations.
- Documentation fixes and updates: tagged address ABI exceptions on
brk/mmap/mremap(), event stream frequency, update booting
requirements on the configuration of traps"
* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
arm64: kernel: Update the stale comment
arm64: Fix the documented event stream frequency
arm64: entry: always set GIC_PRIO_PSR_I_SET during entry
arm64: Explicitly document boot requirements for SVE
arm64: Explicitly require that FPSIMD instructions do not trap
arm64: Relax booting requirements for configuration of traps
arm64: cpufeatures: use min and max
arm64: stacktrace: restore terminal records
arm64/vdso: Discard .note.gnu.property sections in vDSO
arm64: doc: Add brk/mmap/mremap() to the Tagged Address ABI Exceptions
psci: Remove unneeded semicolon
ACPI: irq: Prevent unregistering of GIC SGIs
ACPI: GTDT: Don't corrupt interrupt mappings on watchdow probe failure
arm64: Show three registers per line
arm64: remove HAVE_DEBUG_BUGVERBOSE
arm64: alternative: simplify passing alt_region
arm64: Force SPARSEMEM_VMEMMAP as the only memory management model
arm64: vdso32: drop -no-integrated-as flag
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git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 updates from Catalin Marinas:
- MTE asynchronous support for KASan. Previously only synchronous
(slower) mode was supported. Asynchronous is faster but does not
allow precise identification of the illegal access.
- Run kernel mode SIMD with softirqs disabled. This allows using NEON
in softirq context for crypto performance improvements. The
conditional yield support is modified to take softirqs into account
and reduce the latency.
- Preparatory patches for Apple M1: handle CPUs that only have the VHE
mode available (host kernel running at EL2), add FIQ support.
- arm64 perf updates: support for HiSilicon PA and SLLC PMU drivers,
new functions for the HiSilicon HHA and L3C PMU, cleanups.
- Re-introduce support for execute-only user permissions but only when
the EPAN (Enhanced Privileged Access Never) architecture feature is
available.
- Disable fine-grained traps at boot and improve the documented boot
requirements.
- Support CONFIG_KASAN_VMALLOC on arm64 (only with KASAN_GENERIC).
- Add hierarchical eXecute Never permissions for all page tables.
- Add arm64 prctl(PR_PAC_{SET,GET}_ENABLED_KEYS) allowing user programs
to control which PAC keys are enabled in a particular task.
- arm64 kselftests for BTI and some improvements to the MTE tests.
- Minor improvements to the compat vdso and sigpage.
- Miscellaneous cleanups.
* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (86 commits)
arm64/sve: Add compile time checks for SVE hooks in generic functions
arm64/kernel/probes: Use BUG_ON instead of if condition followed by BUG.
arm64: pac: Optimize kernel entry/exit key installation code paths
arm64: Introduce prctl(PR_PAC_{SET,GET}_ENABLED_KEYS)
arm64: mte: make the per-task SCTLR_EL1 field usable elsewhere
arm64/sve: Remove redundant system_supports_sve() tests
arm64: fpsimd: run kernel mode NEON with softirqs disabled
arm64: assembler: introduce wxN aliases for wN registers
arm64: assembler: remove conditional NEON yield macros
kasan, arm64: tests supports for HW_TAGS async mode
arm64: mte: Report async tag faults before suspend
arm64: mte: Enable async tag check fault
arm64: mte: Conditionally compile mte_enable_kernel_*()
arm64: mte: Enable TCO in functions that can read beyond buffer limits
kasan: Add report for async mode
arm64: mte: Drop arch_enable_tagging()
kasan: Add KASAN mode kernel parameter
arm64: mte: Add asynchronous mode support
arm64: Get rid of CONFIG_ARM64_VHE
arm64: Cope with CPUs stuck in VHE mode
...
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Displaying two registers per line takes 15 lines. That improves to just
10 lines if we display three registers per line, which reduces the amount
of information lost when oopses are cut off. It stays within 80 columns
and matches x86-64.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20210420172245.3679077-1-willy@infradead.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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* for-next/pac-set-get-enabled-keys:
: Introduce arm64 prctl(PR_PAC_{SET,GET}_ENABLED_KEYS).
arm64: pac: Optimize kernel entry/exit key installation code paths
arm64: Introduce prctl(PR_PAC_{SET,GET}_ENABLED_KEYS)
arm64: mte: make the per-task SCTLR_EL1 field usable elsewhere
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The kernel does not use any keys besides IA so we don't need to
install IB/DA/DB/GA on kernel exit if we arrange to install them
on task switch instead, which we can expect to happen an order of
magnitude less often.
Furthermore we can avoid installing the user IA in the case where the
user task has IA disabled and just leave the kernel IA installed. This
also lets us avoid needing to install IA on kernel entry.
On an Apple M1 under a hypervisor, the overhead of kernel entry/exit
has been measured to be reduced by 15.6ns in the case where IA is
enabled, and 31.9ns in the case where IA is disabled.
Signed-off-by: Peter Collingbourne <pcc@google.com>
Link: https://linux-review.googlesource.com/id/Ieddf6b580d23c9e0bed45a822dabe72d2ffc9a8e
Link: https://lore.kernel.org/r/2d653d055f38f779937f2b92f8ddd5cf9e4af4f4.1616123271.git.pcc@google.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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This change introduces a prctl that allows the user program to control
which PAC keys are enabled in a particular task. The main reason
why this is useful is to enable a userspace ABI that uses PAC to
sign and authenticate function pointers and other pointers exposed
outside of the function, while still allowing binaries conforming
to the ABI to interoperate with legacy binaries that do not sign or
authenticate pointers.
The idea is that a dynamic loader or early startup code would issue
this prctl very early after establishing that a process may load legacy
binaries, but before executing any PAC instructions.
This change adds a small amount of overhead to kernel entry and exit
due to additional required instruction sequences.
On a DragonBoard 845c (Cortex-A75) with the powersave governor, the
overhead of similar instruction sequences was measured as 4.9ns when
simulating the common case where IA is left enabled, or 43.7ns when
simulating the uncommon case where IA is disabled. These numbers can
be seen as the worst case scenario, since in more realistic scenarios
a better performing governor would be used and a newer chip would be
used that would support PAC unlike Cortex-A75 and would be expected
to be faster than Cortex-A75.
On an Apple M1 under a hypervisor, the overhead of the entry/exit
instruction sequences introduced by this patch was measured as 0.3ns
in the case where IA is left enabled, and 33.0ns in the case where
IA is disabled.
Signed-off-by: Peter Collingbourne <pcc@google.com>
Reviewed-by: Dave Martin <Dave.Martin@arm.com>
Link: https://linux-review.googlesource.com/id/Ibc41a5e6a76b275efbaa126b31119dc197b927a5
Link: https://lore.kernel.org/r/d6609065f8f40397a4124654eb68c9f490b4d477.1616123271.git.pcc@google.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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In an upcoming change we are going to introduce per-task SCTLR_EL1
bits for PAC. Move the existing per-task SCTLR_EL1 field out of the
MTE-specific code so that we will be able to use it from both the
PAC and MTE code paths and make the task switching code more efficient.
Signed-off-by: Peter Collingbourne <pcc@google.com>
Link: https://linux-review.googlesource.com/id/Ic65fac78a7926168fa68f9e8da591c9e04ff7278
Link: https://lore.kernel.org/r/13d725cb8e741950fb9d6e64b2cd9bd54ff7c3f9.1616123271.git.pcc@google.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Fix GCC warnings reported when building with "-Wmissing-prototypes":
arch/arm64/kernel/process.c:261:6: warning: no previous prototype for '__show_regs' [-Wmissing-prototypes]
261 | void __show_regs(struct pt_regs *regs)
| ^~~~~~~~~~~
arch/arm64/kernel/process.c:307:6: warning: no previous prototype for '__show_regs_alloc_free' [-Wmissing-prototypes]
307 | void __show_regs_alloc_free(struct pt_regs *regs)
| ^~~~~~~~~~~~~~~~~~~~~~
arch/arm64/kernel/process.c:365:5: warning: no previous prototype for 'arch_dup_task_struct' [-Wmissing-prototypes]
365 | int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
| ^~~~~~~~~~~~~~~~~~~~
arch/arm64/kernel/process.c:546:41: warning: no previous prototype for '__switch_to' [-Wmissing-prototypes]
546 | __notrace_funcgraph struct task_struct *__switch_to(struct task_struct *prev,
| ^~~~~~~~~~~
arch/arm64/kernel/process.c:710:25: warning: no previous prototype for 'arm64_preempt_schedule_irq' [-Wmissing-prototypes]
710 | asmlinkage void __sched arm64_preempt_schedule_irq(void)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~
Link: https://lore.kernel.org/lkml/202103192250.AennsfXM-lkp@intel.com
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Maninder Singh <maninder1.s@samsung.com>
Link: https://lore.kernel.org/r/1616568899-986-1-git-send-email-maninder1.s@samsung.com
Signed-off-by: Will Deacon <will@kernel.org>
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Apple SoCs (A11 and newer) have some interrupt sources hardwired to the
FIQ line. We implement support for this by simply treating IRQs and FIQs
the same way in the interrupt vectors.
To support these systems, the FIQ mask bit needs to be kept in sync with
the IRQ mask bit, so both kinds of exceptions are masked together. No
other platforms should be delivering FIQ exceptions right now, and we
already unmask FIQ in normal process context, so this should not have an
effect on other systems - if spurious FIQs were arriving, they would
already panic the kernel.
Signed-off-by: Hector Martin <marcan@marcan.st>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Hector Martin <marcan@marcan.st>
Cc: James Morse <james.morse@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20210315115629.57191-6-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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