* for-next/sve-state:
arm64/fp: Use a struct to pass data to fpsimd_bind_state_to_cpu()
arm64/sve: Leave SVE enabled on syscall if we don't context switch
arm64/fpsimd: SME no longer requires SVE register state
arm64/fpsimd: Load FP state based on recorded data type
arm64/fpsimd: Stop using TIF_SVE to manage register saving in KVM
arm64/fpsimd: Have KVM explicitly say which FP registers to save
arm64/fpsimd: Track the saved FPSIMD state type separately to TIF_SVE
KVM: arm64: Discard any SVE state when entering KVM guests
* for-next/selftests:
kselftest/arm64: Allow epoll_wait() to return more than one result
kselftest/arm64: Don't drain output while spawning children
kselftest/arm64: Hold fp-stress children until they're all spawned
kselftest/arm64: Set test names prior to starting children
kselftest/arm64: Use preferred form for predicate load/stores
kselftest/arm64: fix array_size.cocci warning
kselftest/arm64: fix array_size.cocci warning
kselftest/arm64: Print ASCII version of unknown signal frame magic values
kselftest/arm64: Remove validation of extra_context from TODO
kselftest/arm64: Provide progress messages when signalling children
kselftest/arm64: Check that all children are producing output in fp-stress
* for-next/kprobes:
arm64: kprobes: Return DBG_HOOK_ERROR if kprobes can not handle a BRK
arm64: kprobes: Let arch do_page_fault() fix up page fault in user handler
arm64: Prohibit instrumentation on arch_stack_walk()
* for-next/kdump:
arm64: kdump: Support crashkernel=X fall back to reserve region above DMA zones
arm64: kdump: Provide default size when crashkernel=Y,low is not specified
* for-next/cpufeature:
kselftest/arm64: Add SVE 2.1 to hwcap test
arm64/hwcap: Add support for SVE 2.1
kselftest/arm64: Add FEAT_RPRFM to the hwcap test
arm64/hwcap: Add support for FEAT_RPRFM
kselftest/arm64: Add FEAT_CSSC to the hwcap selftest
arm64/hwcap: Add support for FEAT_CSSC
arm64: Enable data independent timing (DIT) in the kernel
Return DBG_HOOK_ERROR if kprobes can not handle a BRK because it
fails to find a kprobe corresponding to the address.
Since arm64 kprobes uses stop_machine based text patching for removing
BRK, it ensures all running kprobe_break_handler() is done at that point.
And after removing the BRK, it removes the kprobe from its hash list.
Thus, if the kprobe_break_handler() fails to find kprobe from hash list,
there is a bug.
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/166994753273.439920.6629626290560350760.stgit@devnote3
Signed-off-by: Will Deacon <will@kernel.org>
When everything is starting up we are likely to have a lot of child
processes producing output at once. This means that we can reduce
overhead a bit by allowing epoll_wait() to return more than one
descriptor at once, it cuts down on the number of system calls we need
to do which on virtual platforms where the syscall overhead is a bit
more noticable and we're likely to have a lot more children active can
make a small but noticable difference.
On physical platforms the relatively small number of processes being run
and vastly improved speeds push the effects of this change into the
noise.
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20221129215926.442895-4-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
At present fp-stress has a bit of a thundering herd problem since the
children it spawns start running immediately, meaning that they can start
starving the parent process of CPU before it has even started all the
children. This is much more severe on virtual platforms since they tend to
support far more SVE and SME vector lengths, be slower in general and for
some have issues with performance when simulating multiple CPUs.
We can mitigate this problem by having all the child processes block before
starting the test program, meaning that we at least have all the child
processes started before we start heavily using CPU. We still have the same
load issues while waiting for the actual stress test programs to start up
and produce output but they're at least all ready to go before that kicks
in, resulting in substantial reductions in overall runtime on some of the
severely affected systems. One test was showing about 20% improvement.
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20221129215926.442895-2-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
For reasons that are unclear to this reader fpsimd_bind_state_to_cpu()
populates the struct fpsimd_last_state_struct that it uses to store the
active floating point state for KVM guests by passing an argument for
each member of the structure. As the richness of the architecture increases
this is resulting in a function with a rather large number of arguments
which isn't ideal.
Simplify the interface by using the struct directly as the single argument
for the function, renaming it as we lift the definition into the header.
This could be built on further to reduce the work we do adding storage for
new FP state in various places but for now it just simplifies this one
interface.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221115094640.112848-9-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
The syscall ABI says that the SVE register state not shared with FPSIMD
may not be preserved on syscall, and this is the only mechanism we have
in the ABI to stop tracking the extra SVE state for a process. Currently
we do this unconditionally by means of disabling SVE for the process on
syscall, causing userspace to take a trap to EL1 if it uses SVE again.
These extra traps result in a noticeable overhead for using SVE instead
of FPSIMD in some workloads, especially for simple syscalls where we can
return directly to userspace and would not otherwise need to update the
floating point registers. Tests with fp-pidbench show an approximately
70% overhead on a range of implementations when SVE is in use - while
this is an extreme and entirely artificial benchmark it is clear that
there is some useful room for improvement here.
Now that we have the ability to track the decision about what to save
seprately to TIF_SVE we can improve things by leaving TIF_SVE enabled on
syscall but only saving the FPSIMD registers if we are in a syscall.
This means that if we need to restore the register state from memory
(eg, after a context switch or kernel mode NEON) we will drop TIF_SVE
and reenable traps for userspace but if we can just return to userspace
then traps will remain disabled.
Since our current implementation and hence ABI has the effect of zeroing
all the SVE register state not shared with FPSIMD on syscall we replace
the disabling of TIF_SVE with a flush of the non-shared register state,
this means that there is still some overhead for syscalls when SVE is in
use but it is very much reduced.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221115094640.112848-8-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
Now that we are recording the type of floating point register state we
are saving when we write the register state out to memory we can use
that information when we load from memory to decide which format to
load, bringing TIF_SVE into line with what we saved rather than relying
on TIF_SVE to determine what to load.
The SME state details are already recorded directly in the saved
SVCR and handled based on the information there.
Since we are not changing any of the save paths there should be no
functional change from this patch, further patches will make use of this
to optimise and clarify the code.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221115094640.112848-6-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
Now that we are explicitly telling the host FP code which register state
it needs to save we can remove the manipulation of TIF_SVE from the KVM
code, simplifying it and allowing us to optimise our handling of normal
tasks. Remove the manipulation of TIF_SVE from KVM and instead rely on
to_save to ensure we save the correct data for it.
There should be no functional or performance impact from this change.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221115094640.112848-5-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
In order to avoid needlessly saving and restoring the guest registers KVM
relies on the host FPSMID code to save the guest registers when we context
switch away from the guest. This is done by binding the KVM guest state to
the CPU on top of the task state that was originally there, then carefully
managing the TIF_SVE flag for the task to cause the host to save the full
SVE state when needed regardless of the needs of the host task. This works
well enough but isn't terribly direct about what is going on and makes it
much more complicated to try to optimise what we're doing with the SVE
register state.
Let's instead have KVM pass in the register state it wants saving when it
binds to the CPU. We introduce a new FP_STATE_CURRENT for use
during normal task binding to indicate that we should base our
decisions on the current task. This should not be used when
actually saving. Ideally we might want to use a separate enum for
the type to save but this enum and the enum values would then
need to be named which has problems with clarity and ambiguity.
In order to ease any future debugging that might be required this patch
does not actually update any of the decision making about what to save,
it merely starts tracking the new information and warns if the requested
state is not what we would otherwise have decided to save.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221115094640.112848-4-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
When we save the state for the floating point registers this can be done
in the form visible through either the FPSIMD V registers or the SVE Z and
P registers. At present we track which format is currently used based on
TIF_SVE and the SME streaming mode state but particularly in the SVE case
this limits our options for optimising things, especially around syscalls.
Introduce a new enum which we place together with saved floating point
state in both thread_struct and the KVM guest state which explicitly
states which format is active and keep it up to date when we change it.
At present we do not use this state except to verify that it has the
expected value when loading the state, future patches will introduce
functional changes.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221115094640.112848-3-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
Since 8383741ab2 (KVM: arm64: Get rid of host SVE tracking/saving)
KVM has not tracked the host SVE state, relying on the fact that we
currently disable SVE whenever we perform a syscall. This may not be true
in future since performance optimisation may result in us keeping SVE
enabled in order to avoid needing to take access traps to reenable it.
Handle this by clearing TIF_SVE and converting the stored task state to
FPSIMD format when preparing to run the guest. This is done with a new
call fpsimd_kvm_prepare() to keep the direct state manipulation
functions internal to fpsimd.c.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221115094640.112848-2-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
The PMU support to filter the TLP when counting the bandwidth with below
options:
- only count the TLP headers
- only count the TLP payloads
- count both TLP headers and payloads
In the current driver it's default to count the TLP payloads only, which
will have an implicity side effects that on the traffic only have header
only TLPs, we'll get no data.
Make this user configuration through "len_mode" parameter and make it
default to count both TLP headers and payloads when user not specified.
Also update the documentation for it.
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
Link: https://lore.kernel.org/r/20221117084136.53572-5-yangyicong@huawei.com
Signed-off-by: Will Deacon <will@kernel.org>
Some configurations (i.e., 64k + LVA/LPA) can tolerate a physical
placement of the kernel image outside of the 48-bit addressable region,
but given that the loader has no way of knowing whether or not the image
in question supports LVA/LPA, it currently has no choice but to place it
below the 48-bit mark.
Once we add support for LPA2, which allows 52-bit physical and virtual
addressing when using 4k or 16k pages, but in way that relies on
increasing the number of paging levels, there will be more variety in
the configurations that may or may not support this.
So redefine bit #3 in the Image header as 'must be placed within 48-bit
addressable memory', as this is the current de facto meaning.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20221122170249.2453853-1-ardb@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
The build test robot pointer out that there's a build failure when:
CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS=y
CONFIG_DYNAMIC_FTRACE_WITH_ARGS=n
... due to some mismatched ifdeffery, some of which checks
CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS, and some of which checks
CONFIG_DYNAMIC_FTRACE_WITH_ARGS, leading to some missing definitions expected
by the core code when CONFIG_DYNAMIC_FTRACE=n and consequently
CONFIG_DYNAMIC_FTRACE_WITH_ARGS=n.
There's really not much point in supporting CONFIG_DYNAMIC_FTRACE=n (AKA
static ftrace). All supported toolchains allow us to implement
DYNAMIC_FTRACE, distributions all prefer DYNAMIC_FTRACE, and both
powerpc and s390 removed support for static ftrace in commits:
0c0c52306f ("powerpc: Only support DYNAMIC_FTRACE not static")
5d6a016349 ("s390/ftrace: enforce DYNAMIC_FTRACE if FUNCTION_TRACER is selected")
... and according to Steven, static ftrace is only supported on x86 to
allow testing that the core code still functions in this configuration.
Given that, let's simplify matters by removing arm64's support for
static ftrace. This avoids the problem originally reported, and leaves
us with less code to maintain.
Fixes: 26299b3f6b ("ftrace: arm64: move from REGS to ARGS")
Link: https://lore.kernel.org/r/202211212249.livTPi3Y-lkp@intel.com
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/20221122163624.1225912-1-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
The driver misses including <linux/io.h>, which causes a compilation
error with x86_64 'allmodconfig':
drivers/perf/amlogic/meson_g12_ddr_pmu.c: In function 'dmc_g12_get_freq_quick':
drivers/perf/amlogic/meson_g12_ddr_pmu.c:135:15: error: implicit declaration of function 'readl' [-Werror=implicit-function-declaration]
135 | val = readl(info->pll_reg);
| ^~~~~
drivers/perf/amlogic/meson_g12_ddr_pmu.c: In function 'dmc_g12_counter_enable':
drivers/perf/amlogic/meson_g12_ddr_pmu.c:204:9: error: implicit declaration of function 'writel' [-Werror=implicit-function-declaration]
204 | writel(clock_count, info->ddr_reg[0] + DMC_MON_G12_TIMER);
| ^~~~~~
Add the missing header to fix the build.
Fixes: 2016e2113d ("perf/amlogic: Add support for Amlogic meson G12 SoC DDR PMU driver")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Jiucheng Xu <jiucheng.xu@amlogic.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20221122084028.572494-1-jiucheng.xu@amlogic.com
Signed-off-by: Will Deacon <will@kernel.org>
If a Cortex-A715 cpu sees a page mapping permissions change from executable
to non-executable, it may corrupt the ESR_ELx and FAR_ELx registers, on the
next instruction abort caused by permission fault.
Only user-space does executable to non-executable permission transition via
mprotect() system call which calls ptep_modify_prot_start() and ptep_modify
_prot_commit() helpers, while changing the page mapping. The platform code
can override these helpers via __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION.
Work around the problem via doing a break-before-make TLB invalidation, for
all executable user space mappings, that go through mprotect() system call.
This overrides ptep_modify_prot_start() and ptep_modify_prot_commit(), via
defining HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION on the platform thus giving
an opportunity to intercept user space exec mappings, and do the necessary
TLB invalidation. Similar interceptions are also implemented for HugeTLB.
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20221116140915.356601-3-anshuman.khandual@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
