Merge patch series "RISC-V: Probe for misaligned access speed"

Evan Green <evan@rivosinc.com> says:

The current setting for the hwprobe bit indicating misaligned access
speed is controlled by a ven

Merge patch series "RISC-V: Probe for misaligned access speed"

Evan Green <evan@rivosinc.com> says:

The current setting for the hwprobe bit indicating misaligned access
speed is controlled by a vendor-specific feature probe function. This is
essentially a per-SoC table we have to maintain on behalf of each vendor
going forward. Let's convert that instead to something we detect at
runtime.

We have two assembly routines at the heart of our probe: one that
does a bunch of word-sized accesses (without aligning its input buffer),
and the other that does byte accesses. If we can move a larger number of
bytes using misaligned word accesses than we can with the same amount of
time doing byte accesses, then we can declare misaligned accesses as
"fast".

The tradeoff of reducing this maintenance burden is boot time. We spend
4-6 jiffies per core doing this measurement (0-2 on jiffie edge
alignment, and 4 on measurement). The timing loop was based on
raid6_choose_gen(), which uses (16+1)*N jiffies (where N is the number
of algorithms). By taking only the fastest iteration out of all
attempts for use in the comparison, variance between runs is very low.
On my THead C906, it looks like this:

[ 0.047563] cpu0: Ratio of byte access time to unaligned word access is 4.34, unaligned accesses are fast

Several others have chimed in with results on slow machines with the
older algorithm, which took all runs into account, including noise like
interrupts. Even with this variation, results indicate that in all cases
(fast, slow, and emulated) the measured numbers are nowhere near each
other (always multiple factors away).

* b4-shazam-merge:
RISC-V: alternative: Remove feature_probe_func
RISC-V: Probe for unaligned access speed

Link: https://lore.kernel.org/r/20230818194136.4084400-1-evan@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

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Merge tag 'v6.5' into next

Sync up with mainline to bring in updates to the shared infrastructure.

RISC-V: alternative: Remove feature_probe_func

Now that we're testing unaligned memory copy and making that
determination generically, there are no more users of the vendor
feature_probe_func(). Whi

RISC-V: alternative: Remove feature_probe_func

Now that we're testing unaligned memory copy and making that
determination generically, there are no more users of the vendor
feature_probe_func(). While I think it's probably going to need to come
back, there are no users right now, so let's remove it until it's
needed.

Signed-off-by: Evan Green <evan@rivosinc.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230818194136.4084400-3-evan@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

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RISC-V: Probe for unaligned access speed

Rather than deferring unaligned access speed determinations to a vendor
function, let's probe them and find out how fast they are. If we
determine that an un

RISC-V: Probe for unaligned access speed

Rather than deferring unaligned access speed determinations to a vendor
function, let's probe them and find out how fast they are. If we
determine that an unaligned word access is faster than N byte accesses,
mark the hardware's unaligned access as "fast". Otherwise, we mark
accesses as slow.

The algorithm itself runs for a fixed amount of jiffies. Within each
iteration it attempts to time a single loop, and then keeps only the best
(fastest) loop it saw. This algorithm was found to have lower variance from
run to run than my first attempt, which counted the total number of
iterations that could be done in that fixed amount of jiffies. By taking
only the best iteration in the loop, assuming at least one loop wasn't
perturbed by an interrupt, we eliminate the effects of interrupts and
other "warm up" factors like branch prediction. The only downside is it
depends on having an rdtime granular and accurate enough to measure a
single copy. If we ever manage to complete a loop in 0 rdtime ticks, we
leave the unaligned setting at UNKNOWN.

There is a slight change in user-visible behavior here. Previously, all
boards except the THead C906 reported misaligned access speed of
UNKNOWN. C906 reported FAST. With this change, since we're now measuring
misaligned access speed on each hart, all RISC-V systems will have this
key set as either FAST or SLOW.

Currently, we don't have a way to confidently measure the difference between
SLOW and EMULATED, so we label anything not fast as SLOW. This will
mislabel some systems that are actually EMULATED as SLOW. When we get
support for delegating misaligned access traps to the kernel (as opposed
to the firmware quietly handling it), we can explicitly test in Linux to
see if unaligned accesses trap. Those systems will start to report
EMULATED, though older (today's) systems without that new SBI mechanism
will continue to report SLOW.

I've updated the documentation for those hwprobe values to reflect
this, specifically: SLOW may or may not be emulated by software, and FAST
represents means being faster than equivalent byte accesses. The change
in documentation is accurate with respect to both the former and current
behavior.

Signed-off-by: Evan Green <evan@rivosinc.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230818194136.4084400-2-evan@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

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Merge branch 'next' into for-linus

Prepare input updates for 6.6 merge window.

Merge drm/drm-next into drm-intel-next

Catching-up with drm-next and drm-intel-gt-next.
It will unblock a code refactor around the platform
definitions (names vs acronyms).

Signed-off-by: Rodrigo V

Merge drm/drm-next into drm-intel-next

Catching-up with drm-next and drm-intel-gt-next.
It will unblock a code refactor around the platform
definitions (names vs acronyms).

Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

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Merge drm/drm-next into drm-intel-gt-next

Need to pull in b3e4aae612ec ("drm/i915/hdcp: Modify hdcp_gsc_message msg sending mechanism") as
a dependency for https://patchwork.freedesktop.org/series/1

Merge drm/drm-next into drm-intel-gt-next

Need to pull in b3e4aae612ec ("drm/i915/hdcp: Modify hdcp_gsc_message msg sending mechanism") as
a dependency for https://patchwork.freedesktop.org/series/121735/

Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

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Merge drm/drm-next into drm-misc-next

Backmerging to get v6.5-rc2.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>

Merge tag 'v6.4' into next

Sync up with mainline to bring in updates to shared infrastructure.

ASoC: Merge v6.5-rc2

Get a similar baseline to my other branches, and fixes for people using
the branch.

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

Cross-merge networking fixes after downstream PR.

No conflicts or adjacent changes.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Merge v6.5-rc1 into drm-misc-fixes

Boris needs 6.5-rc1 in drm-misc-fixes to prevent a conflict.

Signed-off-by: Maxime Ripard <mripard@kernel.org>

Merge tag 'riscv-for-linus-6.5-mw2' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull more RISC-V updates from Palmer Dabbelt:

- A bunch of fixes/cleanups from the first part of th

Merge tag 'riscv-for-linus-6.5-mw2' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull more RISC-V updates from Palmer Dabbelt:

- A bunch of fixes/cleanups from the first part of the merge window,
mostly related to ACPI and vector as those were large

- Some documentation improvements, mostly related to the new code

- The "riscv,isa" DT key is deprecated

- Support for link-time dead code elimination

- Support for minor fault registration in userfaultd

- A handful of cleanups around CMO alternatives

* tag 'riscv-for-linus-6.5-mw2' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (23 commits)
riscv: mm: mark noncoherent_supported as __ro_after_init
riscv: mm: mark CBO relate initialization funcs as __init
riscv: errata: thead: only set cbom size & noncoherent during boot
riscv: Select HAVE_ARCH_USERFAULTFD_MINOR
RISC-V: Document the ISA string parsing rules for ACPI
risc-v: Fix order of IPI enablement vs RCU startup
mm: riscv: fix an unsafe pte read in huge_pte_alloc()
dt-bindings: riscv: deprecate riscv,isa
RISC-V: drop error print from riscv_hartid_to_cpuid()
riscv: Discard vector state on syscalls
riscv: move memblock_allow_resize() after linear mapping is ready
riscv: Enable ARCH_SUSPEND_POSSIBLE for s2idle
riscv: vdso: include vdso/vsyscall.h for vdso_data
selftests: Test RISC-V Vector's first-use handler
riscv: vector: clear V-reg in the first-use trap
riscv: vector: only enable interrupts in the first-use trap
RISC-V: Fix up some vector state related build failures
RISC-V: Document that V registers are clobbered on syscalls
riscv: disable HAVE_LD_DEAD_CODE_DATA_ELIMINATION for LLD
riscv: enable HAVE_LD_DEAD_CODE_DATA_ELIMINATION
...

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risc-v: Fix order of IPI enablement vs RCU startup

Conor reports that risc-v tries to enable IPIs before telling the
core code to enable RCU. With the introduction of the mapple tree
as a backing st

risc-v: Fix order of IPI enablement vs RCU startup

Conor reports that risc-v tries to enable IPIs before telling the
core code to enable RCU. With the introduction of the mapple tree
as a backing store for the irq descriptors, this results in
a very shouty boot sequence, as RCU is legitimately upset.

Restore some sanity by moving the risc_ipi_enable() call after
notify_cpu_starting(), which explicitly enables RCU on the calling
CPU.

Fixes: 832f15f42646 ("RISC-V: Treat IPIs as normal Linux IRQs")
Reported-by: Conor Dooley <conor@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230703-dupe-frying-79ae2ccf94eb@spud
Cc: Anup Patel <apatel@ventanamicro.com>
Cc: Palmer Dabbelt <palmer@rivosinc.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Tested-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230703183126.1567625-1-maz@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

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Merge branch 'master' into mm-hotfixes-stable

Merge tag 'riscv-for-linus-6.5-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull RISC-V updates from Palmer Dabbelt:

- Support for ACPI

- Various cleanups to the ISA string

Merge tag 'riscv-for-linus-6.5-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull RISC-V updates from Palmer Dabbelt:

- Support for ACPI

- Various cleanups to the ISA string parsing, including making them
case-insensitive

- Support for the vector extension

- Support for independent irq/softirq stacks

- Our CPU DT binding now has "unevaluatedProperties: false"

* tag 'riscv-for-linus-6.5-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (78 commits)
riscv: hibernate: remove WARN_ON in save_processor_state
dt-bindings: riscv: cpus: switch to unevaluatedProperties: false
dt-bindings: riscv: cpus: add a ref the common cpu schema
riscv: stack: Add config of thread stack size
riscv: stack: Support HAVE_SOFTIRQ_ON_OWN_STACK
riscv: stack: Support HAVE_IRQ_EXIT_ON_IRQ_STACK
RISC-V: always report presence of extensions formerly part of the base ISA
dt-bindings: riscv: explicitly mention assumption of Zicntr & Zihpm support
RISC-V: remove decrement/increment dance in ISA string parser
RISC-V: rework comments in ISA string parser
RISC-V: validate riscv,isa at boot, not during ISA string parsing
RISC-V: split early & late of_node to hartid mapping
RISC-V: simplify register width check in ISA string parsing
perf: RISC-V: Limit the number of counters returned from SBI
riscv: replace deprecated scall with ecall
riscv: uprobes: Restore thread.bad_cause
riscv: mm: try VMA lock-based page fault handling first
riscv: mm: Pre-allocate PGD entries for vmalloc/modules area
RISC-V: hwprobe: Expose Zba, Zbb, and Zbs
RISC-V: Track ISA extensions per hart
...

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Merge branch 'for-6.5/apple' into for-linus

- improved support for Keychron K8 keyboard (Lasse Brun)

Merge patch series "ISA string parser cleanups"

Conor Dooley <conor@kernel.org> says:

From: Conor Dooley <conor.dooley@microchip.com>

Here are some bits that were discussed with Drew on the "shoul

Merge patch series "ISA string parser cleanups"

Conor Dooley <conor@kernel.org> says:

From: Conor Dooley <conor.dooley@microchip.com>

Here are some bits that were discussed with Drew on the "should we
allow caps" threads that I have now created patches for:
- splitting of riscv_of_processor_hartid() into two distinct functions,
one for use purely during early boot, prior to the establishment of
the possible-cpus mask & another to fit the other current use-cases
- that then allows us to then completely skip some validation of the
hartid in the parser
- the biggest diff in the series is a rework of the comments in the
parser, as I have mostly found the existing (sparse) ones to not be
all that helpful whenever I have to go back and look at it
- from writing the comments, I found a conditional doing a bit of a
dance that I found counter-intuitive, so I've had a go at making that
match what I would expect a little better
- `i` implies 4 other extensions, so add them as extensions and set
them for the craic. Sure why not like...

* b4-shazam-merge:
RISC-V: always report presence of extensions formerly part of the base ISA
dt-bindings: riscv: explicitly mention assumption of Zicntr & Zihpm support
RISC-V: remove decrement/increment dance in ISA string parser
RISC-V: rework comments in ISA string parser
RISC-V: validate riscv,isa at boot, not during ISA string parsing
RISC-V: split early & late of_node to hartid mapping
RISC-V: simplify register width check in ISA string parsing

Link: https://lore.kernel.org/r/20230607-audacity-overhaul-82bb867a825f@spud
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

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RISC-V: split early & late of_node to hartid mapping

Some back and forth with Drew [1] about riscv_fill_hwcap() resulted in
the realisation that it is not very useful to parse the DT & perform
valid

RISC-V: split early & late of_node to hartid mapping

Some back and forth with Drew [1] about riscv_fill_hwcap() resulted in
the realisation that it is not very useful to parse the DT & perform
validation of riscv,isa every time we would like to get the id for a
hart.

Although it is no longer called in riscv_fill_hwcap(),
riscv_of_processor_hartid() is called in several other places.
Notably in setup_smp() it forms part of the logic for filling the mask
of possible CPUs. Since a possible CPU must have passed this basic
validation of riscv,isa, a repeat validation is not required.

Rename riscv_of_processor_id() to riscv_early_of_processor_id(),
which will be called from setup_smp() & introduce a new
riscv_of_processor_id() which makes use of the pre-populated mask of
possible cpus.

Link: https://lore.kernel.org/linux-riscv/xvdswl3iyikwvamny7ikrxo2ncuixshtg3f6uucjahpe3xpc5c@ud4cz4fkg5dj/ [1]
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Sunil V L <sunilvl@ventanamicro.com>
Link: https://lore.kernel.org/r/20230607-glade-pastel-d8cbd9d9f3c6@spud
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

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Merge drm/drm-next into drm-misc-next-fixes

Backmerging to sync drm-misc-next-fixes with drm-misc-next.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>

Merge branch 'drm-next' of git://anongit.freedesktop.org/drm/drm into msm-next-lumag-base

Merge the drm-next tree to pick up the DRM DSC helpers (merged via
drm-intel-next tree). MSM DSC v1.2 patche

Merge branch 'drm-next' of git://anongit.freedesktop.org/drm/drm into msm-next-lumag-base

Merge the drm-next tree to pick up the DRM DSC helpers (merged via
drm-intel-next tree). MSM DSC v1.2 patches depend on these helpers.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

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Merge patch series "riscv: Add vector ISA support"

Andy Chiu <andy.chiu@sifive.com> says:

This is the v21 patch series for adding Vector extension support in
Linux. Please refer to [1] for the intr

Merge patch series "riscv: Add vector ISA support"

Andy Chiu <andy.chiu@sifive.com> says:

This is the v21 patch series for adding Vector extension support in
Linux. Please refer to [1] for the introduction of the patchset. The
v21 patch series was aimed to solve build issues from v19, provide usage
guideline for the prctl interface, and address review comments on v20.

Thank every one who has been reviewing, suggesting on the topic. Hope
this get a step closer to the final merge.

* b4-shazam-merge: (27 commits)
selftests: add .gitignore file for RISC-V hwprobe
selftests: Test RISC-V Vector prctl interface
riscv: Add documentation for Vector
riscv: Enable Vector code to be built
riscv: detect assembler support for .option arch
riscv: Add sysctl to set the default vector rule for new processes
riscv: Add prctl controls for userspace vector management
riscv: hwcap: change ELF_HWCAP to a function
riscv: KVM: Add vector lazy save/restore support
riscv: kvm: Add V extension to KVM ISA
riscv: prevent stack corruption by reserving task_pt_regs(p) early
riscv: signal: validate altstack to reflect Vector
riscv: signal: Report signal frame size to userspace via auxv
riscv: signal: Add sigcontext save/restore for vector
riscv: signal: check fp-reserved words unconditionally
riscv: Add ptrace vector support
riscv: Allocate user's vector context in the first-use trap
riscv: Add task switch support for vector
riscv: Introduce struct/helpers to save/restore per-task Vector state
riscv: Introduce riscv_v_vsize to record size of Vector context
...

Link: https://lore.kernel.org/r/20230605110724.21391-1-andy.chiu@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

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riscv: Introduce riscv_v_vsize to record size of Vector context

This patch is used to detect the size of CPU vector registers and use
riscv_v_vsize to save the size of all the vector registers. It a

riscv: Introduce riscv_v_vsize to record size of Vector context

This patch is used to detect the size of CPU vector registers and use
riscv_v_vsize to save the size of all the vector registers. It assumes all
harts has the same capabilities in a SMP system. If a core detects VLENB
that is different from the boot core, then it warns and turns off V
support for user space.

Co-developed-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Co-developed-by: Vincent Chen <vincent.chen@sifive.com>
Signed-off-by: Vincent Chen <vincent.chen@sifive.com>
Signed-off-by: Greentime Hu <greentime.hu@sifive.com>
Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Heiko Stuebner <heiko.stuebner@vrull.eu>
Tested-by: Heiko Stuebner <heiko.stuebner@vrull.eu>
Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com>
Link: https://lore.kernel.org/r/20230605110724.21391-9-andy.chiu@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

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Merge tag 'v6.4-rc4' into wpan-next/staging

Linux 6.4-rc4

Merge drm/drm-next into drm-intel-gt-next

For conflict avoidance we need the following commit:

c9a9f18d3ad8 drm/i915/huc: use const struct bus_type pointers

Signed-off-by: Tvrtko Ursulin <tvrtko

Merge drm/drm-next into drm-intel-gt-next

For conflict avoidance we need the following commit:

c9a9f18d3ad8 drm/i915/huc: use const struct bus_type pointers

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

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