Commit Graph

563 Commits

Author SHA1 Message Date
Linus Torvalds
c4bb3a2d64 ARM:
* Fixes.
 
 RISC-V:
 
 * Svade and Svadu (accessed and dirty bit) extension support for host and
   guest.  This was acked on the mailing list by the RISC-V maintainer, see
   https://patchew.org/linux/20240726084931.28924-1-yongxuan.wang@sifive.com/.
 -----BEGIN PGP SIGNATURE-----
 
 iQFIBAABCAAyFiEE8TM4V0tmI4mGbHaCv/vSX3jHroMFAmdKS0QUHHBib256aW5p
 QHJlZGhhdC5jb20ACgkQv/vSX3jHroP7hggAmt5CJesFGIuDwQgJX1KuNWAS84AX
 Oq5SPZLH0XjE5YDm6AusSzvbtOhRM6mARU5/iqMRE6Mqpf4MXpP9tOo6xaDiL7+m
 bOFsDYEO73WQyrIfFUCZ7dXiTbDVtQfNH8Z1yQwHPsa1d+WDYY3tLbCe5qCdqYMF
 JDiB7K0cQzPDmhCwf3Zf8mW2ZRI0QsTqiuFUfVGGNgFDspWfBFBqkLCkrMNmbp9z
 ye375oKb2VCe6OBJCY+Nl6tdoBUkz+CtZDCxkxuh0Uk4NmsUC9JMye9iwgU9DuI7
 nagFuvpUGcgbZvrx1ly47TL+wcEFLwnBJ0xBZTGIgVoZHj/wX9GM+tSgIw==
 =semZ
 -----END PGP SIGNATURE-----

Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull more kvm updates from Paolo Bonzini:

 - ARM fixes

 - RISC-V Svade and Svadu (accessed and dirty bit) extension support for
   host and guest

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: riscv: selftests: Add Svade and Svadu Extension to get-reg-list test
  RISC-V: KVM: Add Svade and Svadu Extensions Support for Guest/VM
  dt-bindings: riscv: Add Svade and Svadu Entries
  RISC-V: Add Svade and Svadu Extensions Support
  KVM: arm64: Use MDCR_EL2.HPME to evaluate overflow of hyp counters
  KVM: arm64: Ignore PMCNTENSET_EL0 while checking for overflow status
  KVM: arm64: Mark set_sysreg_masks() as inline to avoid build failure
  KVM: arm64: vgic-its: Add stronger type-checking to the ITS entry sizes
  KVM: arm64: vgic: Kill VGIC_MAX_PRIVATE definition
  KVM: arm64: vgic: Make vgic_get_irq() more robust
  KVM: arm64: vgic-v3: Sanitise guest writes to GICR_INVLPIR
2024-11-30 14:51:08 -08:00
Linus Torvalds
91dbbe6c9f RISC-V Paches for the 6.13 Merge Window, Part 1
* Support for pointer masking in userspace,
 * Support for probing vector misaligned access performance.
 * Support for qspinlock on systems with Zacas and Zabha.
 -----BEGIN PGP SIGNATURE-----
 
 iQJHBAABCAAxFiEEKzw3R0RoQ7JKlDp6LhMZ81+7GIkFAmdHNu4THHBhbG1lckBk
 YWJiZWx0LmNvbQAKCRAuExnzX7sYiZW7D/oCjSIdBHZ6OJN8vATRn2FoHedMgKzE
 8OF0EXX85+PNmznxzyUirPerfQPcog5422vCKLUR5h8QD0x3wdMH8gUaV0Wa11k8
 ldXlV903k7gJLtJMnww2Eiha7kds5XpNWsWBTU0sBAxt2mMUE2VlloBY5YM/fitJ
 3TUihA7vyic5J0H3H4VrkuEoFnN4Xl9WclbwCYFg0uKmiogqXCe5LKey5/JjLpDR
 2DdFe/7PRjQMuUNVrNO4Vm+/YD1nwRdg5ukvIl42KINHWKyn1hl23cKsFobrilw5
 GyMbTzP4hBhy3kpX+zjWPpvTyoHSww7iJK6AvkvgQk/gua8M6abLJheachY/Ciz1
 lJy4okB8H2LtZwMYlJiIXBQzKE1qCwNA1/m24y8SUYQXvjxwGZxaPXAyWvvqBxOP
 /q/jQYfCiQi/h7BncMv9F8cxkU3J8cglzmxTKlM5Rf5YKdOzMyf4t0sm2pPsFX2l
 V4xjZQNMDJ1IHGnRbeMTOqHN6iKymyj8BKph5kATO5W9gq4tWXRSEIPfuGJMq2jq
 T64RweOdHlBPhiXu4hMmRXgT2rNBfTuaqEsVgXAZWkPmqum9uDPjBBiJ89bQO6pk
 dJl7jVJ27HKSd4zLwnxSGCsVahirF4CCtULRam08500Gfz6dEarD7shZznd86cEg
 QiBXqK5W6IWyJw==
 =ND+J
 -----END PGP SIGNATURE-----

Merge tag 'riscv-for-linus-6.13-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull RISC-v updates from Palmer Dabbelt:

 - Support for pointer masking in userspace

 - Support for probing vector misaligned access performance

 - Support for qspinlock on systems with Zacas and Zabha

* tag 'riscv-for-linus-6.13-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (38 commits)
  RISC-V: Remove unnecessary include from compat.h
  riscv: Fix default misaligned access trap
  riscv: Add qspinlock support
  dt-bindings: riscv: Add Ziccrse ISA extension description
  riscv: Add ISA extension parsing for Ziccrse
  asm-generic: ticket-lock: Add separate ticket-lock.h
  asm-generic: ticket-lock: Reuse arch_spinlock_t of qspinlock
  riscv: Implement xchg8/16() using Zabha
  riscv: Implement arch_cmpxchg128() using Zacas
  riscv: Improve zacas fully-ordered cmpxchg()
  riscv: Implement cmpxchg8/16() using Zabha
  dt-bindings: riscv: Add Zabha ISA extension description
  riscv: Implement cmpxchg32/64() using Zacas
  riscv: Do not fail to build on byte/halfword operations with Zawrs
  riscv: Move cpufeature.h macros into their own header
  KVM: riscv: selftests: Add Smnpm and Ssnpm to get-reg-list test
  RISC-V: KVM: Allow Smnpm and Ssnpm extensions for guests
  riscv: hwprobe: Export the Supm ISA extension
  riscv: selftests: Add a pointer masking test
  riscv: Allow ptrace control of the tagged address ABI
  ...
2024-11-27 11:19:09 -08:00
Paolo Bonzini
4d911c7abe KVM/riscv changes for 6.13 part #2
- Svade and Svadu extension support for Host and Guest/VM
 -----BEGIN PGP SIGNATURE-----
 
 iQIzBAABCgAdFiEEZdn75s5e6LHDQ+f/rUjsVaLHLAcFAmc/KesACgkQrUjsVaLH
 LAcuuQ/9Gv8qezVw5TiV3BiusRns50PVIVZA12lrLLXrjiUzuo0zbIRTozeZbTzb
 0HMuS8isfgNkRmj35ZXQ1nzeckf3GN3j0f/TYeAVDUCj5sARimcRzSL+k9KC62aW
 NxvmHsq+y4jlCr7V4viy9pkHrj2oNO4m6HhiAtgXfATXWYRtKOTkEKVYIPg3c77D
 U7FeUEA1ege6xKK5U+v2gpIZHOXv13RaXQqmZ3j+JfDyzIhakYSKE/mRslX3z4ch
 9SKSUt2PqustyT5qdmM1jt9+q6k1QQw2fWWnxJb6AGsmDfwkEEvPKuok74TUDVPa
 V4mnesTIf8wPjzw4n5XSqf5i+67WuNjBBtxMWhWGmcfpLbC9y0gE+lTaRZrXU7fL
 66VXVDK7YhTsWCJ9sJfRXnGAOtHcIp20lQwemdRYCSMRbD8I6OWwfBbXfo3pUo85
 8mCZtstySXAyr2pnfX44kuav70D46qWyiTm0o4WSVeCExtny0qslJLmKoYgjsB+T
 7eJCrpxcmsTXBMYST6AXiAg5GUVj4DoCzMDT2DcsGoa2DM1RLc8qlwSrsD4jdSdF
 Jc8HSOc54mSUvaE31LWwd1YJiQ20Nh8kfv5nmO7m9LB6ADiZOL1yL7tTsSxrMWSg
 l0lgJbjTRYTPVghXR/kkAD7jXEthWAFJ5knv5CT2bb6Qx7uWPpk=
 =juLq
 -----END PGP SIGNATURE-----

Merge tag 'kvm-riscv-6.13-2' of https://github.com/kvm-riscv/linux into HEAD

KVM/riscv changes for 6.13 part #2

- Svade and Svadu extension support for Host and Guest/VM
2024-11-27 12:00:28 -05:00
Paolo Bonzini
c1668520c9 RISC-V Paches for the 6.13 Merge Window, Part 1
* Support for pointer masking in userspace,
 * Support for probing vector misaligned access performance.
 * Support for qspinlock on systems with Zacas and Zabha.
 -----BEGIN PGP SIGNATURE-----
 
 iQJHBAABCAAxFiEEKzw3R0RoQ7JKlDp6LhMZ81+7GIkFAmdHNu4THHBhbG1lckBk
 YWJiZWx0LmNvbQAKCRAuExnzX7sYiZW7D/oCjSIdBHZ6OJN8vATRn2FoHedMgKzE
 8OF0EXX85+PNmznxzyUirPerfQPcog5422vCKLUR5h8QD0x3wdMH8gUaV0Wa11k8
 ldXlV903k7gJLtJMnww2Eiha7kds5XpNWsWBTU0sBAxt2mMUE2VlloBY5YM/fitJ
 3TUihA7vyic5J0H3H4VrkuEoFnN4Xl9WclbwCYFg0uKmiogqXCe5LKey5/JjLpDR
 2DdFe/7PRjQMuUNVrNO4Vm+/YD1nwRdg5ukvIl42KINHWKyn1hl23cKsFobrilw5
 GyMbTzP4hBhy3kpX+zjWPpvTyoHSww7iJK6AvkvgQk/gua8M6abLJheachY/Ciz1
 lJy4okB8H2LtZwMYlJiIXBQzKE1qCwNA1/m24y8SUYQXvjxwGZxaPXAyWvvqBxOP
 /q/jQYfCiQi/h7BncMv9F8cxkU3J8cglzmxTKlM5Rf5YKdOzMyf4t0sm2pPsFX2l
 V4xjZQNMDJ1IHGnRbeMTOqHN6iKymyj8BKph5kATO5W9gq4tWXRSEIPfuGJMq2jq
 T64RweOdHlBPhiXu4hMmRXgT2rNBfTuaqEsVgXAZWkPmqum9uDPjBBiJ89bQO6pk
 dJl7jVJ27HKSd4zLwnxSGCsVahirF4CCtULRam08500Gfz6dEarD7shZznd86cEg
 QiBXqK5W6IWyJw==
 =ND+J
 -----END PGP SIGNATURE-----

Merge tag 'riscv-for-linus-6.13-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux into HEAD

RISC-V Paches for the 6.13 Merge Window, Part 1

* Support for pointer masking in userspace,
* Support for probing vector misaligned access performance.
* Support for qspinlock on systems with Zacas and Zabha.
2024-11-27 11:49:44 -05:00
Yong-Xuan Wang
94a7734d09 RISC-V: Add Svade and Svadu Extensions Support
Svade and Svadu extensions represent two schemes for managing the PTE A/D
bits. When the PTE A/D bits need to be set, Svade extension intdicates
that a related page fault will be raised. In contrast, the Svadu extension
supports hardware updating of PTE A/D bits. Since the Svade extension is
mandatory and the Svadu extension is optional in RVA23 profile, by default
the M-mode firmware will enable the Svadu extension in the menvcfg CSR
when only Svadu is present in DT.

This patch detects Svade and Svadu extensions from DT and adds
arch_has_hw_pte_young() to enable optimization in MGLRU and
__wp_page_copy_user() when we have the PTE A/D bits hardware updating
support.

Co-developed-by: Jinyu Tang <tjytimi@163.com>
Signed-off-by: Jinyu Tang <tjytimi@163.com>
Signed-off-by: Yong-Xuan Wang <yongxuan.wang@sifive.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Link: https://lore.kernel.org/r/20240726084931.28924-2-yongxuan.wang@sifive.com
Signed-off-by: Anup Patel <anup@brainfault.org>
2024-11-21 17:40:06 +05:30
Linus Torvalds
0352387523 First step of consolidating the VDSO data page handling:
The VDSO data page handling is architecture specific for historical
   reasons, but there is no real technical reason to do so.
 
   Aside of that VDSO data has become a dump ground for various mechanisms
   and fail to provide a clear separation of the functionalities.
 
   Clean this up by:
 
     * consolidating the VDSO page data by getting rid of architecture
       specific warts especially in x86 and PowerPC.
 
     * removing the last includes of header files which are pulling in other
       headers outside of the VDSO namespace.
 
     * seperating timekeeping and other VDSO data accordingly.
 
   Further consolidation of the VDSO page handling is done in subsequent
   changes scheduled for the next merge window.
 
   This also lays the ground for expanding the VDSO time getters for
   independent PTP clocks in a generic way without making every architecture
   add support seperately.
 -----BEGIN PGP SIGNATURE-----
 
 iQJHBAABCgAxFiEEQp8+kY+LLUocC4bMphj1TA10mKEFAmc7kyoTHHRnbHhAbGlu
 dXRyb25peC5kZQAKCRCmGPVMDXSYoVBjD/9awdN2YeCGIM9rlHIktUdNRmRSL2SL
 6av1CPffN5DenONYTXWrDYPkC4yfjUwIs8H57uzFo10yA7RQ/Qfq+O68k5GnuFew
 jvpmmYSZ6TT21AmAaCIhn+kdl9YbEJFvN2AWH85Bl29k9FGB04VzJlQMMjfEZ1a5
 Mhwv+cfYNuPSZmU570jcxW2XgbyTWlLZBByXX/Tuz9bwpmtszba507bvo45x6gIP
 twaWNzrsyJpdXfMrfUnRiChN8jHlDN7I6fgQvpsoRH5FOiVwIFo0Ip2rKbk+ONfD
 W/rcU5oeqRIxRVDHzf2Sv8WPHMCLRv01ZHBcbJOtgvZC3YiKgKYoeEKabu9ZL1BH
 6VmrxjYOBBFQHOYAKPqBuS7BgH5PmtMbDdSZXDfRaAKaCzhCRysdlWW7z48r2R//
 zPufb7J6Tle23AkuZWhFjvlGgSBl4zxnTFn31HYOyQps3TMI4y50Z2DhE/EeU8a6
 DRl8/k1KQVDUZ6udJogS5kOr1J8pFtUPrA2uhR8UyLdx7YKiCzcdO1qWAjtXlVe8
 oNpzinU+H9bQqGe9IyS7kCG9xNaCRZNkln5Q1WfnkTzg5f6ihfaCvIku3l4bgVpw
 3HmcxYiC6RxQB+ozwN7hzCCKT4L9aMhr/457TNOqRkj2Elw3nvJ02L4aI86XAKLE
 jwO9Fkp9qcCxCw==
 =q5eD
 -----END PGP SIGNATURE-----

Merge tag 'timers-vdso-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull vdso data page handling updates from Thomas Gleixner:
 "First steps of consolidating the VDSO data page handling.

  The VDSO data page handling is architecture specific for historical
  reasons, but there is no real technical reason to do so.

  Aside of that VDSO data has become a dump ground for various
  mechanisms and fail to provide a clear separation of the
  functionalities.

  Clean this up by:

   - consolidating the VDSO page data by getting rid of architecture
     specific warts especially in x86 and PowerPC.

   - removing the last includes of header files which are pulling in
     other headers outside of the VDSO namespace.

   - seperating timekeeping and other VDSO data accordingly.

  Further consolidation of the VDSO page handling is done in subsequent
  changes scheduled for the next merge window.

  This also lays the ground for expanding the VDSO time getters for
  independent PTP clocks in a generic way without making every
  architecture add support seperately"

* tag 'timers-vdso-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (42 commits)
  x86/vdso: Add missing brackets in switch case
  vdso: Rename struct arch_vdso_data to arch_vdso_time_data
  powerpc: Split systemcfg struct definitions out from vdso
  powerpc: Split systemcfg data out of vdso data page
  powerpc: Add kconfig option for the systemcfg page
  powerpc/pseries/lparcfg: Use num_possible_cpus() for potential processors
  powerpc/pseries/lparcfg: Fix printing of system_active_processors
  powerpc/procfs: Propagate error of remap_pfn_range()
  powerpc/vdso: Remove offset comment from 32bit vdso_arch_data
  x86/vdso: Split virtual clock pages into dedicated mapping
  x86/vdso: Delete vvar.h
  x86/vdso: Access vdso data without vvar.h
  x86/vdso: Move the rng offset to vsyscall.h
  x86/vdso: Access rng vdso data without vvar.h
  x86/vdso: Access timens vdso data without vvar.h
  x86/vdso: Allocate vvar page from C code
  x86/vdso: Access rng data from kernel without vvar
  x86/vdso: Place vdso_data at beginning of vvar page
  x86/vdso: Use __arch_get_vdso_data() to access vdso data
  x86/mm/mmap: Remove arch_vma_name()
  ...
2024-11-19 16:09:13 -08:00
Linus Torvalds
3f020399e4 Scheduler changes for v6.13:
- Core facilities:
 
     - Add the "Lazy preemption" model (CONFIG_PREEMPT_LAZY=y), which optimizes
       fair-class preemption by delaying preemption requests to the
       tick boundary, while working as full preemption for RR/FIFO/DEADLINE
       classes. (Peter Zijlstra)
 
         - x86: Enable Lazy preemption (Peter Zijlstra)
         - riscv: Enable Lazy preemption (Jisheng Zhang)
 
     - Initialize idle tasks only once (Thomas Gleixner)
 
     - sched/ext: Remove sched_fork() hack (Thomas Gleixner)
 
  - Fair scheduler:
     - Optimize the PLACE_LAG when se->vlag is zero (Huang Shijie)
 
  - Idle loop:
       Optimize the generic idle loop by removing unnecessary
       memory barrier (Zhongqiu Han)
 
  - RSEQ:
     - Improve cache locality of RSEQ concurrency IDs for
       intermittent workloads (Mathieu Desnoyers)
 
  - Waitqueues:
     - Make wake_up_{bit,var} less fragile (Neil Brown)
 
  - PSI:
     - Pass enqueue/dequeue flags to psi callbacks directly (Johannes Weiner)
 
  - Preparatory patches for proxy execution:
     - core: Add move_queued_task_locked helper (Connor O'Brien)
     - core: Consolidate pick_*_task to task_is_pushable helper (Connor O'Brien)
     - core: Split out __schedule() deactivate task logic into a helper (John Stultz)
     - core: Split scheduler and execution contexts (Peter Zijlstra)
     - locking/mutex: Make mutex::wait_lock irq safe (Juri Lelli)
     - locking/mutex: Expose __mutex_owner() (Juri Lelli)
     - locking/mutex: Remove wakeups from under mutex::wait_lock (Peter Zijlstra)
 
  - Misc fixes and cleanups:
     - core: Remove unused __HAVE_THREAD_FUNCTIONS hook support (David Disseldorp)
     - core: Update the comment for TIF_NEED_RESCHED_LAZY (Sebastian Andrzej Siewior)
     - wait: Remove unused bit_wait_io_timeout (Dr. David Alan Gilbert)
     - fair: remove the DOUBLE_TICK feature (Huang Shijie)
     - fair: fix the comment for PREEMPT_SHORT (Huang Shijie)
     - uclamp: Fix unnused variable warning (Christian Loehle)
     - rt: No PREEMPT_RT=y for all{yes,mod}config
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
 -----BEGIN PGP SIGNATURE-----
 
 iQJFBAABCgAvFiEEBpT5eoXrXCwVQwEKEnMQ0APhK1gFAmc7fnQRHG1pbmdvQGtl
 cm5lbC5vcmcACgkQEnMQ0APhK1hZTBAAozVdWA2m51aNa67HvAZta/olmrIagVbW
 inwbTgqa8b+UfeWEuKOfrZr5khjEh6pLgR3dBTib1uH6xxYj/Okds+qbPWSBPVLh
 yzavlm/zJZM1U1XtxE3eyVfqWik4GrY7DoIMDQQr+YH7rNXonJeJkll38OI2E5MC
 q3Q01qyMo8RJJX8qkf3f8ObOoP/51NsVniTw0Zb2fzEhXz8FjezLlxk6cMfgSkJG
 lg9gfIwUZ7Xg5neRo4kJcc3Ht31KYOhWSiupBJzRD1hss/N/AybvMcTX/Cm8d07w
 HIAdDDAn84o46miFo/a0V/hsJZ72idWbqxVJUCtaezrpOUiFkG+uInRvG/ynr0lF
 5dEI9f+6PUw8Nc7L72IyHkobjPqS2IefSaxYYCBKmxMX2qrenfTor/pKiWzzhBIl
 rX3MZSuUJ8NjV4rNGD/qXRM1IsMJrsDwxDyv+sRec3XdH33x286ds6aAUEPDQ6N7
 96VS0sOKcNUJN8776ErNjlIxRl8HTlpkaO3nZlQIfXgTlXUpRvOuKbEWqP+606lo
 oANgJTKgUhgJPWZnvmdRxDjSiOp93QcImjus9i1tN81FGiEDleONsJUxu2Di1E5+
 s1nCiytjq+cdvzCqFyiOZUh+g6kSZ4yXxNgLg2UvbXzX1zOeUQT3WtyKUhMPXhU8
 esh1TgbUbpE=
 =Zcqj
 -----END PGP SIGNATURE-----

Merge tag 'sched-core-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler updates from Ingo Molnar:
 "Core facilities:

   - Add the "Lazy preemption" model (CONFIG_PREEMPT_LAZY=y), which
     optimizes fair-class preemption by delaying preemption requests to
     the tick boundary, while working as full preemption for
     RR/FIFO/DEADLINE classes. (Peter Zijlstra)
        - x86: Enable Lazy preemption (Peter Zijlstra)
        - riscv: Enable Lazy preemption (Jisheng Zhang)

   - Initialize idle tasks only once (Thomas Gleixner)

   - sched/ext: Remove sched_fork() hack (Thomas Gleixner)

  Fair scheduler:

   - Optimize the PLACE_LAG when se->vlag is zero (Huang Shijie)

  Idle loop:

   - Optimize the generic idle loop by removing unnecessary memory
     barrier (Zhongqiu Han)

  RSEQ:

   - Improve cache locality of RSEQ concurrency IDs for intermittent
     workloads (Mathieu Desnoyers)

  Waitqueues:

   - Make wake_up_{bit,var} less fragile (Neil Brown)

  PSI:

   - Pass enqueue/dequeue flags to psi callbacks directly (Johannes
     Weiner)

  Preparatory patches for proxy execution:

   - Add move_queued_task_locked helper (Connor O'Brien)

   - Consolidate pick_*_task to task_is_pushable helper (Connor O'Brien)

   - Split out __schedule() deactivate task logic into a helper (John
     Stultz)

   - Split scheduler and execution contexts (Peter Zijlstra)

   - Make mutex::wait_lock irq safe (Juri Lelli)

   - Expose __mutex_owner() (Juri Lelli)

   - Remove wakeups from under mutex::wait_lock (Peter Zijlstra)

  Misc fixes and cleanups:

   - Remove unused __HAVE_THREAD_FUNCTIONS hook support (David
     Disseldorp)

   - Update the comment for TIF_NEED_RESCHED_LAZY (Sebastian Andrzej
     Siewior)

   - Remove unused bit_wait_io_timeout (Dr. David Alan Gilbert)

   - remove the DOUBLE_TICK feature (Huang Shijie)

   - fix the comment for PREEMPT_SHORT (Huang Shijie)

   - Fix unnused variable warning (Christian Loehle)

   - No PREEMPT_RT=y for all{yes,mod}config"

* tag 'sched-core-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (33 commits)
  sched, x86: Update the comment for TIF_NEED_RESCHED_LAZY.
  sched: No PREEMPT_RT=y for all{yes,mod}config
  riscv: add PREEMPT_LAZY support
  sched, x86: Enable Lazy preemption
  sched: Enable PREEMPT_DYNAMIC for PREEMPT_RT
  sched: Add Lazy preemption model
  sched: Add TIF_NEED_RESCHED_LAZY infrastructure
  sched/ext: Remove sched_fork() hack
  sched: Initialize idle tasks only once
  sched: psi: pass enqueue/dequeue flags to psi callbacks directly
  sched/uclamp: Fix unnused variable warning
  sched: Split scheduler and execution contexts
  sched: Split out __schedule() deactivate task logic into a helper
  sched: Consolidate pick_*_task to task_is_pushable helper
  sched: Add move_queued_task_locked helper
  locking/mutex: Expose __mutex_owner()
  locking/mutex: Make mutex::wait_lock irq safe
  locking/mutex: Remove wakeups from under mutex::wait_lock
  sched: Improve cache locality of RSEQ concurrency IDs for intermittent workloads
  sched: idle: Optimize the generic idle loop by removing needless memory barrier
  ...
2024-11-19 14:16:06 -08:00
Dave Vasilevsky
31daa34315 crash, powerpc: default to CRASH_DUMP=n on PPC_BOOK3S_32
Fixes boot failures on 6.9 on PPC_BOOK3S_32 machines using Open Firmware. 
On these machines, the kernel refuses to boot from non-zero
PHYSICAL_START, which occurs when CRASH_DUMP is on.

Since most PPC_BOOK3S_32 machines boot via Open Firmware, it should
default to off for them.  Users booting via some other mechanism can still
turn it on explicitly.

Does not change the default on any other architectures for the
time being.

Link: https://lkml.kernel.org/r/20240917163720.1644584-1-dave@vasilevsky.ca
Fixes: 75bc255a74 ("crash: clean up kdump related config items")
Signed-off-by: Dave Vasilevsky <dave@vasilevsky.ca>
Reported-by: Reimar Döffinger <Reimar.Doeffinger@gmx.de>
Closes: https://lists.debian.org/debian-powerpc/2024/07/msg00001.html
Acked-by: Michael Ellerman <mpe@ellerman.id.au>	[powerpc]
Acked-by: Baoquan He <bhe@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Reimar Döffinger <Reimar.Doeffinger@gmx.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-11-14 22:43:48 -08:00
Palmer Dabbelt
64f7b77f0b
Merge patch series "Zacas/Zabha support and qspinlocks"
Alexandre Ghiti <alexghiti@rivosinc.com> says:

This implements [cmp]xchgXX() macros using Zacas and Zabha extensions
and finally uses those newly introduced macros to add support for
qspinlocks: note that this implementation of qspinlocks satisfies the
forward progress guarantee.

It also uses Ziccrse to provide the qspinlock implementation.

Thanks to Guo and Leonardo for their work!

* b4-shazam-merge: (1314 commits)
  riscv: Add qspinlock support
  dt-bindings: riscv: Add Ziccrse ISA extension description
  riscv: Add ISA extension parsing for Ziccrse
  asm-generic: ticket-lock: Add separate ticket-lock.h
  asm-generic: ticket-lock: Reuse arch_spinlock_t of qspinlock
  riscv: Implement xchg8/16() using Zabha
  riscv: Implement arch_cmpxchg128() using Zacas
  riscv: Improve zacas fully-ordered cmpxchg()
  riscv: Implement cmpxchg8/16() using Zabha
  dt-bindings: riscv: Add Zabha ISA extension description
  riscv: Implement cmpxchg32/64() using Zacas
  riscv: Do not fail to build on byte/halfword operations with Zawrs
  riscv: Move cpufeature.h macros into their own header

Link: https://lore.kernel.org/r/20241103145153.105097-1-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-11-11 07:35:09 -08:00
Alexandre Ghiti
ab83647fad
riscv: Add qspinlock support
In order to produce a generic kernel, a user can select
CONFIG_COMBO_SPINLOCKS which will fallback at runtime to the ticket
spinlock implementation if Zabha or Ziccrse are not present.

Note that we can't use alternatives here because the discovery of
extensions is done too late and we need to start with the qspinlock
implementation because the ticket spinlock implementation would pollute
the spinlock value, so let's use static keys.

This is largely based on Guo's work and Leonardo reviews at [1].

Link: https://lore.kernel.org/linux-riscv/20231225125847.2778638-1-guoren@kernel.org/ [1]
Signed-off-by: Guo Ren <guoren@kernel.org>
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Reviewed-by: Andrea Parri <parri.andrea@gmail.com>
Link: https://lore.kernel.org/r/20241103145153.105097-14-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-11-11 07:33:20 -08:00
Alexandre Ghiti
f7bd2be766
riscv: Implement arch_cmpxchg128() using Zacas
Now that Zacas is supported in the kernel, let's use the double word
atomic version of amocas to improve the SLUB allocator.

Note that we have to select fixed registers, otherwise gcc fails to pick
even registers and then produces a reserved encoding which fails to
assemble.

Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Andrea Parri <parri.andrea@gmail.com>
Link: https://lore.kernel.org/r/20241103145153.105097-8-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-11-11 07:33:14 -08:00
Alexandre Ghiti
1658ef4314
riscv: Implement cmpxchg8/16() using Zabha
This adds runtime support for Zabha in cmpxchg8/16() operations.

Note that in the absence of Zacas support in the toolchain, CAS
instructions from Zabha won't be used.

Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Andrea Parri <parri.andrea@gmail.com>
Link: https://lore.kernel.org/r/20241103145153.105097-6-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-11-11 07:33:12 -08:00
Alexandre Ghiti
38acdee32d
riscv: Implement cmpxchg32/64() using Zacas
This adds runtime support for Zacas in cmpxchg operations.

Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Andrea Parri <parri.andrea@gmail.com>
Link: https://lore.kernel.org/r/20241103145153.105097-4-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-11-11 07:33:10 -08:00
Jisheng Zhang
22aaec357c riscv: add PREEMPT_LAZY support
riscv has switched to GENERIC_ENTRY, so adding PREEMPT_LAZY is as simple
as adding TIF_NEED_RESCHED_LAZY related definitions and enabling
ARCH_HAS_PREEMPT_LAZY.

[bigeasy: Replace old PREEMPT_AUTO bits with new PREEMPT_LAZY ]

Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Link: https://lkml.kernel.org/r/20241021151257.102296-4-bigeasy@linutronix.de
2024-11-05 12:55:39 +01:00
Nam Cao
a812eee0b6 vdso: Rename struct arch_vdso_data to arch_vdso_time_data
The struct arch_vdso_data is only about vdso time data. So rename it to
arch_vdso_time_data to make it obvious.
Non time-related data will be migrated out of these structs soon.

Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Heiko Carstens <hca@linux.ibm.com> # s390
Link: https://lore.kernel.org/all/20241010-vdso-generic-base-v1-28-b64f0842d512@linutronix.de
2024-11-02 12:37:36 +01:00
Conor Dooley
33549fcf37
RISC-V: disallow gcc + rust builds
During the discussion before supporting rust on riscv, it was decided
not to support gcc yet, due to differences in extension handling
compared to llvm (only the version of libclang matching the c compiler
is supported). Recently Jason Montleon reported [1] that building with
gcc caused build issues, due to unsupported arguments being passed to
libclang. After some discussion between myself and Miguel, it is better
to disable gcc + rust builds to match the original intent, and
subsequently support it when an appropriate set of extensions can be
deduced from the version of libclang.

Closes: https://lore.kernel.org/all/20240917000848.720765-2-jmontleo@redhat.com/ [1]
Link: https://lore.kernel.org/all/20240926-battering-revolt-6c6a7827413e@spud/ [2]
Fixes: 70a57b2472 ("RISC-V: enable building 64-bit kernels with rust support")
Cc: stable@vger.kernel.org
Reported-by: Jason Montleon <jmontleo@redhat.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Acked-by: Miguel Ojeda <ojeda@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20241001-playlist-deceiving-16ece2f440f5@spud
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-10-25 06:18:37 -07:00
Palmer Dabbelt
075fde5818
Merge patch series "riscv: Userspace pointer masking and tagged address ABI"
Samuel Holland <samuel.holland@sifive.com> says:

RISC-V defines three extensions for pointer masking[1]:
 - Smmpm: configured in M-mode, affects M-mode
 - Smnpm: configured in M-mode, affects the next lower mode (S or U-mode)
 - Ssnpm: configured in S-mode, affects the next lower mode (VS, VU, or U-mode)

This series adds support for configuring Smnpm or Ssnpm (depending on
which privilege mode the kernel is running in) to allow pointer masking
in userspace (VU or U-mode), extending the PR_SET_TAGGED_ADDR_CTRL API
from arm64. Unlike arm64 TBI, userspace pointer masking is not enabled
by default on RISC-V. Additionally, the tag width (referred to as PMLEN)
is variable, so userspace needs to ask the kernel for a specific tag
width, which is interpreted as a lower bound on the number of tag bits.

This series also adds support for a tagged address ABI similar to arm64
and x86. Since accesses from the kernel to user memory use the kernel's
pointer masking configuration, not the user's, the kernel must untag
user pointers in software before dereferencing them. And since the tag
width is variable, as with LAM on x86, it must be kept the same across
all threads in a process so untagged_addr_remote() can work.

[1]: https://github.com/riscv/riscv-j-extension/raw/d70011dde6c2/zjpm-spec.pdf

* b4-shazam-merge:
  KVM: riscv: selftests: Add Smnpm and Ssnpm to get-reg-list test
  RISC-V: KVM: Allow Smnpm and Ssnpm extensions for guests
  riscv: hwprobe: Export the Supm ISA extension
  riscv: selftests: Add a pointer masking test
  riscv: Allow ptrace control of the tagged address ABI
  riscv: Add support for the tagged address ABI
  riscv: Add support for userspace pointer masking
  riscv: Add CSR definitions for pointer masking
  riscv: Add ISA extension parsing for pointer masking
  dt-bindings: riscv: Add pointer masking ISA extensions

Link: https://lore.kernel.org/r/20241016202814.4061541-1-samuel.holland@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-10-24 14:13:03 -07:00
Samuel Holland
09d6775f50
riscv: Add support for userspace pointer masking
RISC-V supports pointer masking with a variable number of tag bits
(which is called "PMLEN" in the specification) and which is configured
at the next higher privilege level.

Wire up the PR_SET_TAGGED_ADDR_CTRL and PR_GET_TAGGED_ADDR_CTRL prctls
so userspace can request a lower bound on the number of tag bits and
determine the actual number of tag bits. As with arm64's
PR_TAGGED_ADDR_ENABLE, the pointer masking configuration is
thread-scoped, inherited on clone() and fork() and cleared on execve().

Reviewed-by: Charlie Jenkins <charlie@rivosinc.com>
Tested-by: Charlie Jenkins <charlie@rivosinc.com>
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Link: https://lore.kernel.org/r/20241016202814.4061541-5-samuel.holland@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-10-24 14:12:55 -07:00
Jesse Taube
e7c9d66e31
RISC-V: Report vector unaligned access speed hwprobe
Detect if vector misaligned accesses are faster or slower than
equivalent vector byte accesses. This is useful for usermode to know
whether vector byte accesses or vector misaligned accesses have a better
bandwidth for operations like memcpy.

Signed-off-by: Jesse Taube <jesse@rivosinc.com>
Reviewed-by: Charlie Jenkins <charlie@rivosinc.com>
Link: https://lore.kernel.org/r/20241017-jesse_unaligned_vector-v10-5-5b33500160f8@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-10-18 12:38:34 -07:00
Jesse Taube
d1703dc7bc
RISC-V: Detect unaligned vector accesses supported
Run an unaligned vector access to test if the system supports
vector unaligned access. Add the result to a new key in hwprobe.
This is useful for usermode to know if vector misaligned accesses are
supported and if they are faster or slower than equivalent byte accesses.

Signed-off-by: Jesse Taube <jesse@rivosinc.com>
Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
Link: https://lore.kernel.org/r/20241017-jesse_unaligned_vector-v10-4-5b33500160f8@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-10-18 12:38:33 -07:00
Jesse Taube
c05a62c925
RISC-V: Replace RISCV_MISALIGNED with RISCV_SCALAR_MISALIGNED
Replace RISCV_MISALIGNED with RISCV_SCALAR_MISALIGNED to allow
for the addition of RISCV_VECTOR_MISALIGNED in a later patch.

Signed-off-by: Jesse Taube <jesse@rivosinc.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Charlie Jenkins <charlie@rivosinc.com>
Reviewed-by: Evan Green <evan@rivosinc.com>
Link: https://lore.kernel.org/r/20241017-jesse_unaligned_vector-v10-3-5b33500160f8@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-10-18 12:38:32 -07:00
Alexandre Ghiti
cfb10de185
riscv: Fix kernel stack size when KASAN is enabled
We use Kconfig to select the kernel stack size, doubling the default
size if KASAN is enabled.

But that actually only works if KASAN is selected from the beginning,
meaning that if KASAN config is added later (for example using
menuconfig), CONFIG_THREAD_SIZE_ORDER won't be updated, keeping the
default size, which is not enough for KASAN as reported in [1].

So fix this by moving the logic to compute the right kernel stack into a
header.

Fixes: a7555f6b62 ("riscv: stack: Add config of thread stack size")
Reported-by: syzbot+ba9eac24453387a9d502@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/000000000000eb301906222aadc2@google.com/ [1]
Cc: stable@vger.kernel.org
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20240917150328.59831-1-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-10-01 13:08:11 -07:00
Linus Torvalds
5701725692 Rust changes for v6.12
Toolchain and infrastructure:
 
  - Support 'MITIGATION_{RETHUNK,RETPOLINE,SLS}' (which cleans up objtool
    warnings), teach objtool about 'noreturn' Rust symbols and mimic
    '___ADDRESSABLE()' for 'module_{init,exit}'. With that, we should be
    objtool-warning-free, so enable it to run for all Rust object files.
 
  - KASAN (no 'SW_TAGS'), KCFI and shadow call sanitizer support.
 
  - Support 'RUSTC_VERSION', including re-config and re-build on change.
 
  - Split helpers file into several files in a folder, to avoid conflicts
    in it. Eventually those files will be moved to the right places with
    the new build system. In addition, remove the need to manually export
    the symbols defined there, reusing existing machinery for that.
 
  - Relax restriction on configurations with Rust + GCC plugins to just
    the RANDSTRUCT plugin.
 
 'kernel' crate:
 
  - New 'list' module: doubly-linked linked list for use with reference
    counted values, which is heavily used by the upcoming Rust Binder.
    This includes 'ListArc' (a wrapper around 'Arc' that is guaranteed
    unique for the given ID), 'AtomicTracker' (tracks whether a 'ListArc'
    exists using an atomic), 'ListLinks' (the prev/next pointers for an
    item in a linked list), 'List' (the linked list itself), 'Iter' (an
    iterator over a 'List'), 'Cursor' (a cursor into a 'List' that allows
    to remove elements), 'ListArcField' (a field exclusively owned by a
    'ListArc'), as well as support for heterogeneous lists.
 
  - New 'rbtree' module: red-black tree abstractions used by the upcoming
    Rust Binder. This includes 'RBTree' (the red-black tree itself),
    'RBTreeNode' (a node), 'RBTreeNodeReservation' (a memory reservation
    for a node), 'Iter' and 'IterMut' (immutable and mutable iterators),
    'Cursor' (bidirectional cursor that allows to remove elements), as
    well as an entry API similar to the Rust standard library one.
 
  - 'init' module: add 'write_[pin_]init' methods and the 'InPlaceWrite'
    trait. Add the 'assert_pinned!' macro.
 
  - 'sync' module: implement the 'InPlaceInit' trait for 'Arc' by
    introducing an associated type in the trait.
 
  - 'alloc' module: add 'drop_contents' method to 'BoxExt'.
 
  - 'types' module: implement the 'ForeignOwnable' trait for
    'Pin<Box<T>>' and improve the trait's documentation. In addition,
    add the 'into_raw' method to the 'ARef' type.
 
  - 'error' module: in preparation for the upcoming Rust support for
    32-bit architectures, like arm, locally allow Clippy lint for those.
 
 Documentation:
 
  - https://rust.docs.kernel.org has been announced, so link to it.
 
  - Enable rustdoc's "jump to definition" feature, making its output a
    bit closer to the experience in a cross-referencer.
 
  - Debian Testing now also provides recent Rust releases (outside of
    the freeze period), so add it to the list.
 
 MAINTAINERS:
 
  - Trevor is joining as reviewer of the "RUST" entry.
 
 And a few other small bits.
 -----BEGIN PGP SIGNATURE-----
 
 iQIzBAABCgAdFiEEPjU5OPd5QIZ9jqqOGXyLc2htIW0FAmbzNz4ACgkQGXyLc2ht
 IW3muA/9HcPL0QqVB5+SqSRqcatmrFU/wq8Oaa6Z/No0JaynqyikK+R1WNokUd/5
 WpQi4PC1OYV+ekyAuWdkooKmaSqagH5r53XlezNw+cM5zo8y7p0otVlbepQ0t3Ky
 pVEmfDRIeSFXsKrg91BJUKyJf70TQlgSggDVCExlanfOjPz88C1+s3EcJ/XWYGKQ
 cRk/XDdbF5eNaldp2MriVF0fw7XktgIrmVzxt/z0lb4PE7RaCAnO6gSQI+90Vb2d
 zvyOYKS4AkqE3suFvDIIUlPUv+8XbACj0c4wvBZHH5uZGTbgWUffqygJ45GqChEt
 c4fS/+E8VaM1z0EvxNczC0nQkfLwkTc1mgbP+sG3VZJMPVCJ2zQan1/ond7GqCpw
 pt6uQaGvDsAvllm7sbiAIVaAY81icqyYWKfNBXLLEL7DhY5je5Wq+E83XQ8d5u5F
 EuapnZhW3y12d6UCsSe9bD8W45NFoWHPXky1TzT+whTxnX1yH9YsPXbJceGSbbgd
 Lw3GmUtZx2bVAMToVjNFD2lPA3OmPY1e2lk0jwzTuQrEXfnZYuzbjqs3YUijb7xR
 AlsWfIb0IHBwHWpB7da24ezqWP2VD4eaDdD8/+LmDSj6XLngxMNWRLKmXT000eTW
 vIFP9GJrvag2R3YFPhrurgGpRsp8HUTLtvcZROxp2JVQGQ7Z4Ww=
 =52BN
 -----END PGP SIGNATURE-----

Merge tag 'rust-6.12' of https://github.com/Rust-for-Linux/linux

Pull Rust updates from Miguel Ojeda:
 "Toolchain and infrastructure:

   - Support 'MITIGATION_{RETHUNK,RETPOLINE,SLS}' (which cleans up
     objtool warnings), teach objtool about 'noreturn' Rust symbols and
     mimic '___ADDRESSABLE()' for 'module_{init,exit}'. With that, we
     should be objtool-warning-free, so enable it to run for all Rust
     object files.

   - KASAN (no 'SW_TAGS'), KCFI and shadow call sanitizer support.

   - Support 'RUSTC_VERSION', including re-config and re-build on
     change.

   - Split helpers file into several files in a folder, to avoid
     conflicts in it. Eventually those files will be moved to the right
     places with the new build system. In addition, remove the need to
     manually export the symbols defined there, reusing existing
     machinery for that.

   - Relax restriction on configurations with Rust + GCC plugins to just
     the RANDSTRUCT plugin.

  'kernel' crate:

   - New 'list' module: doubly-linked linked list for use with reference
     counted values, which is heavily used by the upcoming Rust Binder.

     This includes 'ListArc' (a wrapper around 'Arc' that is guaranteed
     unique for the given ID), 'AtomicTracker' (tracks whether a
     'ListArc' exists using an atomic), 'ListLinks' (the prev/next
     pointers for an item in a linked list), 'List' (the linked list
     itself), 'Iter' (an iterator over a 'List'), 'Cursor' (a cursor
     into a 'List' that allows to remove elements), 'ListArcField' (a
     field exclusively owned by a 'ListArc'), as well as support for
     heterogeneous lists.

   - New 'rbtree' module: red-black tree abstractions used by the
     upcoming Rust Binder.

     This includes 'RBTree' (the red-black tree itself), 'RBTreeNode' (a
     node), 'RBTreeNodeReservation' (a memory reservation for a node),
     'Iter' and 'IterMut' (immutable and mutable iterators), 'Cursor'
     (bidirectional cursor that allows to remove elements), as well as
     an entry API similar to the Rust standard library one.

   - 'init' module: add 'write_[pin_]init' methods and the
     'InPlaceWrite' trait. Add the 'assert_pinned!' macro.

   - 'sync' module: implement the 'InPlaceInit' trait for 'Arc' by
     introducing an associated type in the trait.

   - 'alloc' module: add 'drop_contents' method to 'BoxExt'.

   - 'types' module: implement the 'ForeignOwnable' trait for
     'Pin<Box<T>>' and improve the trait's documentation. In addition,
     add the 'into_raw' method to the 'ARef' type.

   - 'error' module: in preparation for the upcoming Rust support for
     32-bit architectures, like arm, locally allow Clippy lint for
     those.

  Documentation:

   - https://rust.docs.kernel.org has been announced, so link to it.

   - Enable rustdoc's "jump to definition" feature, making its output a
     bit closer to the experience in a cross-referencer.

   - Debian Testing now also provides recent Rust releases (outside of
     the freeze period), so add it to the list.

  MAINTAINERS:

   - Trevor is joining as reviewer of the "RUST" entry.

  And a few other small bits"

* tag 'rust-6.12' of https://github.com/Rust-for-Linux/linux: (54 commits)
  kasan: rust: Add KASAN smoke test via UAF
  kbuild: rust: Enable KASAN support
  rust: kasan: Rust does not support KHWASAN
  kbuild: rust: Define probing macros for rustc
  kasan: simplify and clarify Makefile
  rust: cfi: add support for CFI_CLANG with Rust
  cfi: add CONFIG_CFI_ICALL_NORMALIZE_INTEGERS
  rust: support for shadow call stack sanitizer
  docs: rust: include other expressions in conditional compilation section
  kbuild: rust: replace proc macros dependency on `core.o` with the version text
  kbuild: rust: rebuild if the version text changes
  kbuild: rust: re-run Kconfig if the version text changes
  kbuild: rust: add `CONFIG_RUSTC_VERSION`
  rust: avoid `box_uninit_write` feature
  MAINTAINERS: add Trevor Gross as Rust reviewer
  rust: rbtree: add `RBTree::entry`
  rust: rbtree: add cursor
  rust: rbtree: add mutable iterator
  rust: rbtree: add iterator
  rust: rbtree: add red-black tree implementation backed by the C version
  ...
2024-09-25 10:25:40 -07:00
Linus Torvalds
97d8894b6f RISC-V Patches for the 6.12 Merge Window, Part 1
* Support for using Zkr to seed KASLR.
 * Support for IPI-triggered CPU backtracing.
 * Support for generic CPU vulnerabilities reporting to userspace.
 * A few cleanups for missing licenses.
 * The size limit on the XIP kernel has been removed.
 * Support for tracing userspace stacks.
 * Support for the Svvptc extension.
 * Various cleanups and fixes throughout the tree.
 -----BEGIN PGP SIGNATURE-----
 
 iQJHBAABCAAxFiEEKzw3R0RoQ7JKlDp6LhMZ81+7GIkFAmbykZITHHBhbG1lckBk
 YWJiZWx0LmNvbQAKCRAuExnzX7sYiTDLEACABTPlMX+Ke1lMYWj6MLBTXMSlQJ6w
 TKLVk3slp4POPsd+ViWy4J6EJDpCkNp6iK30Bv4AGainA3RJnbS7neKYy+MTw0ZV
 pJWTn73sxHeF+APnZ+geFYcmyteL/SZplgHgwLipFaojs7i/+tOvLFRRD3LueCz6
 Q6Muvke9R5uN6LL3tUrmIhJeyZjOwJtKEYoRz6Fo5Tq3RRK0VHYZkdpqRQ86rr9U
 yNbRNlBLlANstq8xjtiwm22ImPGIsvvhs0AvFft0H72zhf3Tfy0VcTLlDJYwkdKN
 Bz59v4N4jg1ajXuAsj4/BQdj5uRkzJNZ3Yq1yvMmGI+2UV1tInHEMeZi63+4gs8F
 0FYCziA+j6/08u8v8CrwdDOpJ9Iq/NMV6359bt5ySu3rM6QnPRGnHGkv4Ptk9Oyh
 sSPiuHS8YxpRBOB8xXNp5xFipTZ4+65VqCz253pAsbbp5aZ/o9Jw/bbBFFWcSsRZ
 tV2xhELVzPiC7dowfYkQhcNZOLlCaJ/Mvo2nMOtjbUwzaXkcjIRcYEy7+dTlfXyr
 3h5sStjWAKEmtLEvCYSI+lAT544tbV1x+lCMJGuvztapsTMtAP4GpQKblXl5qqnV
 L+VWIPJV1elI26H/p/Max9Z1s48NtfwoJSRL7Rnaya6uJ3iWG/BtajHlFbvgOkJf
 ObPZ//Yr9e91gg==
 =zDwL
 -----END PGP SIGNATURE-----

Merge tag 'riscv-for-linus-6.12-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull RISC-V updates from Palmer Dabbelt:

 - Support using Zkr to seed KASLR

 - Support IPI-triggered CPU backtracing

 - Support for generic CPU vulnerabilities reporting to userspace

 - A few cleanups for missing licenses

 - The size limit on the XIP kernel has been removed

 - Support for tracing userspace stacks

 - Support for the Svvptc extension

 - Various cleanups and fixes throughout the tree

* tag 'riscv-for-linus-6.12-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (47 commits)
  crash: Fix riscv64 crash memory reserve dead loop
  perf/riscv-sbi: Add platform specific firmware event handling
  tools: Optimize ring buffer for riscv
  tools: Add riscv barrier implementation
  RISC-V: Don't have MAX_PHYSMEM_BITS exceed phys_addr_t
  ACPI: NUMA: initialize all values of acpi_early_node_map to NUMA_NO_NODE
  riscv: Enable bitops instrumentation
  riscv: Omit optimized string routines when using KASAN
  ACPI: RISCV: Make acpi_numa_get_nid() to be static
  riscv: Randomize lower bits of stack address
  selftests: riscv: Allow mmap test to compile on 32-bit
  riscv: Make riscv_isa_vendor_ext_andes array static
  riscv: Use LIST_HEAD() to simplify code
  riscv: defconfig: Disable RZ/Five peripheral support
  RISC-V: Implement kgdb_roundup_cpus() to enable future NMI Roundup
  riscv: avoid Imbalance in RAS
  riscv: cacheinfo: Add back init_cache_level() function
  riscv: Remove unused _TIF_WORK_MASK
  drivers/perf: riscv: Remove redundant macro check
  riscv: define ILLEGAL_POINTER_VALUE for 64bit
  ...
2024-09-24 10:59:17 -07:00
Linus Torvalds
7856a56541 Many singleton patches - please see the various changelogs for details.
Quite a lot of nilfs2 work this time around.
 
 Notable patch series in this pull request are:
 
 "mul_u64_u64_div_u64: new implementation" by Nicolas Pitre, with
 assistance from Uwe Kleine-König.  Reimplement mul_u64_u64_div_u64() to
 provide (much) more accurate results.  The current implementation was
 causing Uwe some issues in the PWM drivers.
 
 "xz: Updates to license, filters, and compression options" from Lasse
 Collin.  Miscellaneous maintenance and kinor feature work to the xz
 decompressor.
 
 "Fix some GDB command error and add some GDB commands" from Kuan-Ying Lee.
 Fixes and enhancements to the gdb scripts.
 
 "treewide: add missing MODULE_DESCRIPTION() macros" from Jeff Johnson.
 Adds lots of MODULE_DESCRIPTIONs, thus fixing lots of warnings about this.
 
 "nilfs2: add support for some common ioctls" from Ryusuke Konishi.  Adds
 various commonly-available ioctls to nilfs2.
 
 "This series fixes a number of formatting issues in kernel doc comments"
 from Ryusuke Konishi does that.
 
 "nilfs2: prevent unexpected ENOENT propagation" from Ryusuke Konishi.  Fix
 issues where -ENOENT was being unintentionally and inappropriately
 returned to userspace.
 
 "nilfs2: assorted cleanups" from Huang Xiaojia.
 
 "nilfs2: fix potential issues with empty b-tree nodes" from Ryusuke
 Konishi fixes some issues which can occur on corrupted nilfs2 filesystems.
 
 "scripts/decode_stacktrace.sh: improve error reporting and usability" from
 Luca Ceresoli does those things.
 -----BEGIN PGP SIGNATURE-----
 
 iHUEABYIAB0WIQTTMBEPP41GrTpTJgfdBJ7gKXxAjgUCZu7dpAAKCRDdBJ7gKXxA
 jsPqAPwMDEZyKlfSw7QioEHNHDkmkbP7VYCYR0CbUnppbztwpAD8D37aVbWQ+UzM
 3nnOq3W2Pc2o/20zqi8Upf1mnvUrygQ=
 =/NWE
 -----END PGP SIGNATURE-----

Merge tag 'mm-nonmm-stable-2024-09-21-07-52' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull non-MM updates from Andrew Morton:
 "Many singleton patches - please see the various changelogs for
  details.

  Quite a lot of nilfs2 work this time around.

  Notable patch series in this pull request are:

   - "mul_u64_u64_div_u64: new implementation" by Nicolas Pitre, with
     assistance from Uwe Kleine-König. Reimplement mul_u64_u64_div_u64()
     to provide (much) more accurate results. The current implementation
     was causing Uwe some issues in the PWM drivers.

   - "xz: Updates to license, filters, and compression options" from
     Lasse Collin. Miscellaneous maintenance and kinor feature work to
     the xz decompressor.

   - "Fix some GDB command error and add some GDB commands" from
     Kuan-Ying Lee. Fixes and enhancements to the gdb scripts.

   - "treewide: add missing MODULE_DESCRIPTION() macros" from Jeff
     Johnson. Adds lots of MODULE_DESCRIPTIONs, thus fixing lots of
     warnings about this.

   - "nilfs2: add support for some common ioctls" from Ryusuke Konishi.
     Adds various commonly-available ioctls to nilfs2.

   - "This series fixes a number of formatting issues in kernel doc
     comments" from Ryusuke Konishi does that.

   - "nilfs2: prevent unexpected ENOENT propagation" from Ryusuke
     Konishi. Fix issues where -ENOENT was being unintentionally and
     inappropriately returned to userspace.

   - "nilfs2: assorted cleanups" from Huang Xiaojia.

   - "nilfs2: fix potential issues with empty b-tree nodes" from Ryusuke
     Konishi fixes some issues which can occur on corrupted nilfs2
     filesystems.

   - "scripts/decode_stacktrace.sh: improve error reporting and
     usability" from Luca Ceresoli does those things"

* tag 'mm-nonmm-stable-2024-09-21-07-52' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (103 commits)
  list: test: increase coverage of list_test_list_replace*()
  list: test: fix tests for list_cut_position()
  proc: use __auto_type more
  treewide: correct the typo 'retun'
  ocfs2: cleanup return value and mlog in ocfs2_global_read_info()
  nilfs2: remove duplicate 'unlikely()' usage
  nilfs2: fix potential oob read in nilfs_btree_check_delete()
  nilfs2: determine empty node blocks as corrupted
  nilfs2: fix potential null-ptr-deref in nilfs_btree_insert()
  user_namespace: use kmemdup_array() instead of kmemdup() for multiple allocation
  tools/mm: rm thp_swap_allocator_test when make clean
  squashfs: fix percpu address space issues in decompressor_multi_percpu.c
  lib: glob.c: added null check for character class
  nilfs2: refactor nilfs_segctor_thread()
  nilfs2: use kthread_create and kthread_stop for the log writer thread
  nilfs2: remove sc_timer_task
  nilfs2: do not repair reserved inode bitmap in nilfs_new_inode()
  nilfs2: eliminate the shared counter and spinlock for i_generation
  nilfs2: separate inode type information from i_state field
  nilfs2: use the BITS_PER_LONG macro
  ...
2024-09-21 08:20:50 -07:00
Sebastian Andrzej Siewior
2638e4e6b1 riscv: Allow to enable PREEMPT_RT.
It is really time.

riscv has all the required architecture related changes, that have been
identified over time, in order to enable PREEMPT_RT. With the recent
printk changes, the last known road block has been addressed.

Allow to enable PREEMPT_RT on riscv.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Nam Cao <namcao@linutronix.de> # Visionfive 2
Link: https://lore.kernel.org/all/20240906111841.562402-4-bigeasy@linutronix.de
2024-09-17 11:06:08 +02:00
Palmer Dabbelt
9b2863e2cc
Merge patch series "riscv: select ARCH_USE_SYM_ANNOTATIONS"
Jisheng Zhang <jszhang@kernel.org> says:

commit 76329c6939 ("riscv: Use SYM_*() assembly macros instead
of deprecated ones"), most riscv has been to converted the new style
SYM_ assembler annotations. The remaining one is sifive's
errata_cip_453.S, so convert to new style SYM_ annotations as well.
After that select ARCH_USE_SYM_ANNOTATIONS.

* b4-shazam-merge:
  riscv: select ARCH_USE_SYM_ANNOTATIONS
  riscv: errata: sifive: Use SYM_*() assembly macros

Link: https://lore.kernel.org/r/20240709160536.3690-1-jszhang@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-09-15 20:15:49 -07:00
Palmer Dabbelt
f25170a053
Merge patch series "riscv: stacktrace: Add USER_STACKTRACE support"
Jinjie Ruan <ruanjinjie@huawei.com> says:

Add RISC-V USER_STACKTRACE support, and fix the fp alignment bug
in perf_callchain_user() by the way as Björn pointed out.

* b4-shazam-merge:
  riscv: stacktrace: Add USER_STACKTRACE support
  riscv: Fix fp alignment bug in perf_callchain_user()

Link: https://lore.kernel.org/r/20240708032847.2998158-1-ruanjinjie@huawei.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-09-15 20:15:47 -07:00
Jisheng Zhang
5c178472af
riscv: define ILLEGAL_POINTER_VALUE for 64bit
This is used in poison.h for poison pointer offset. Based on current
SV39, SV48 and SV57 vm layout, 0xdead000000000000 is a proper value
that is not mappable, this can avoid potentially turning an oops to
an expolit.

Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Fixes: fbe934d69e ("RISC-V: Build Infrastructure")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240705170210.3236-1-jszhang@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-09-15 20:15:40 -07:00
Jisheng Zhang
7c9d980e46
riscv: select ARCH_USE_SYM_ANNOTATIONS
Now, riscv has been converted to the new style SYM_ assembler
annotations. So select ARCH_USE_SYM_ANNOTATIONS to ensure the
deprecated macros such as ENTRY(), END(), WEAK() and so on are not
available and we don't regress.

Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Reviewed-By: Clément Léger <cleger@rivosinc.com>
Link: https://lore.kernel.org/r/20240709160536.3690-3-jszhang@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-09-15 00:03:23 -07:00
Jinjie Ruan
1a74833182
riscv: stacktrace: Add USER_STACKTRACE support
Currently, userstacktrace is unsupported for riscv. So use the
perf_callchain_user() code as blueprint to implement the
arch_stack_walk_user() which add userstacktrace support on riscv.
Meanwhile, we can use arch_stack_walk_user() to simplify the implementation
of perf_callchain_user().

A ftrace test case is shown as below:

	# cd /sys/kernel/debug/tracing
	# echo 1 > options/userstacktrace
	# echo 1 > options/sym-userobj
	# echo 1 > events/sched/sched_process_fork/enable
	# cat trace
	......
	            bash-178     [000] ...1.    97.968395: sched_process_fork: comm=bash pid=178 child_comm=bash child_pid=231
	            bash-178     [000] ...1.    97.970075: <user stack trace>
	 => /lib/libc.so.6[+0xb5090]

Also a simple perf test is ok as below:

	# perf record -e cpu-clock --call-graph fp top
	# perf report --call-graph

	.....
	[[31m  66.54%[[m     0.00%  top      [kernel.kallsyms]            [k] ret_from_exception
            |
            ---ret_from_exception
               |
               |--[[31m58.97%[[m--do_trap_ecall_u
               |          |
               |          |--[[31m17.34%[[m--__riscv_sys_read
               |          |          ksys_read
               |          |          |
               |          |           --[[31m16.88%[[m--vfs_read
               |          |                     |
               |          |                     |--[[31m10.90%[[m--seq_read

Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Tested-by: Jinjie Ruan <ruanjinjie@huawei.com>
Cc: Björn Töpel <bjorn@kernel.org>
Link: https://lore.kernel.org/r/20240708032847.2998158-3-ruanjinjie@huawei.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-09-14 23:57:16 -07:00
Alice Ryhl
d077242d68 rust: support for shadow call stack sanitizer
Add all of the flags that are needed to support the shadow call stack
(SCS) sanitizer with Rust, and updates Kconfig to allow only
configurations that work.

The -Zfixed-x18 flag is required to use SCS on arm64, and requires rustc
version 1.80.0 or greater. This restriction is reflected in Kconfig.

When CONFIG_DYNAMIC_SCS is enabled, the build will be configured to
include unwind tables in the build artifacts. Dynamic SCS uses the
unwind tables at boot to find all places that need to be patched. The
-Cforce-unwind-tables=y flag ensures that unwind tables are available
for Rust code.

In non-dynamic mode, the -Zsanitizer=shadow-call-stack flag is what
enables the SCS sanitizer. Using this flag requires rustc version 1.82.0
or greater on the targets used by Rust in the kernel. This restriction
is reflected in Kconfig.

It is possible to avoid the requirement of rustc 1.80.0 by using
-Ctarget-feature=+reserve-x18 instead of -Zfixed-x18. However, this flag
emits a warning during the build, so this patch does not add support for
using it and instead requires 1.80.0 or greater.

The dependency is placed on `select HAVE_RUST` to avoid a situation
where enabling Rust silently turns off the sanitizer. Instead, turning
on the sanitizer results in Rust being disabled. We generally do not
want changes to CONFIG_RUST to result in any mitigations being changed
or turned off.

At the time of writing, rustc 1.82.0 only exists via the nightly release
channel. There is a chance that the -Zsanitizer=shadow-call-stack flag
will end up needing 1.83.0 instead, but I think it is small.

Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Kees Cook <kees@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20240829-shadow-call-stack-v7-1-2f62a4432abf@google.com
[ Fixed indentation using spaces. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-09-13 00:03:14 +02:00
Rafael J. Wysocki
45de40574f Merge branch 'acpi-riscv'
Merge ACPI and irqchip updates related to external interrupt controller
support on RISC-V:

 - Add ACPI device enumeration support for interrupt controller probing
   including taking dependencies into account (Sunil V L).

 - Implement ACPI-based interrupt controller probing on RISC-V (Sunil V L).

 - Add ACPI support for AIA in riscv-intc and add ACPI support to
   riscv-imsic, riscv-aplic, and sifive-plic (Sunil V L).

* acpi-riscv:
  irqchip/sifive-plic: Add ACPI support
  irqchip/riscv-aplic: Add ACPI support
  irqchip/riscv-imsic: Add ACPI support
  irqchip/riscv-imsic-state: Create separate function for DT
  irqchip/riscv-intc: Add ACPI support for AIA
  ACPI: RISC-V: Implement function to add implicit dependencies
  ACPI: RISC-V: Initialize GSI mapping structures
  ACPI: RISC-V: Implement function to reorder irqchip probe entries
  ACPI: RISC-V: Implement PCI related functionality
  ACPI: pci_link: Clear the dependencies after probe
  ACPI: bus: Add RINTC IRQ model for RISC-V
  ACPI: scan: Define weak function to populate dependencies
  ACPI: scan: Add RISC-V interrupt controllers to honor list
  ACPI: scan: Refactor dependency creation
  ACPI: bus: Add acpi_riscv_init() function
  ACPI: scan: Add a weak arch_sort_irqchip_probe() to order the IRQCHIP probe
  arm64: PCI: Migrate ACPI related functions to pci-acpi.c
2024-09-11 21:44:22 +02:00
Anton Blanchard
5ba7a75a53
riscv: Fix toolchain vector detection
A recent change to gcc flags rv64iv as no longer valid:

   cc1: sorry, unimplemented: Currently the 'V' implementation
   requires the 'M' extension

and as a result vector support is disabled. Fix this by adding m
to our toolchain vector detection code.

Signed-off-by: Anton Blanchard <antonb@tenstorrent.com>
Fixes: fa8e7cce55 ("riscv: Enable Vector code to be built")
Link: https://lore.kernel.org/r/20240819001131.1738806-1-antonb@tenstorrent.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-09-03 07:57:05 -07:00
Lasse Collin
ab4ce9831a riscv: boot: add Image.xz support
The Image.* targets existed for other compressors already.  Bootloader
support is needed for decompression.

This is for CONFIG_EFI_ZBOOT=n. With CONFIG_EFI_ZBOOT=y, XZ was already
available.

Comparision with Linux 6.10 RV64GC tinyconfig (in KiB):

    1027 Image
     594 Image.gz
     541 Image.zst
     510 Image.lzma
     474 Image.xz

Link: https://lkml.kernel.org/r/20240721133633.47721-17-lasse.collin@tukaani.org
Signed-off-by: Lasse Collin <lasse.collin@tukaani.org>
Reviewed-by: Emil Renner Berthing <emil.renner.berthing@canonical.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Jules Maselbas <jmaselbas@zdiv.net>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Joel Stanley <joel@jms.id.au>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Jubin Zhong <zhongjubin@huawei.com>
Cc: Krzysztof Kozlowski <krzk@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Rui Li <me@lirui.org>
Cc: Sam James <sam@gentoo.org>
Cc: Simon Glass <sjg@chromium.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-01 20:43:27 -07:00
Sunil V L
01415e78cf ACPI: RISC-V: Implement PCI related functionality
Replace the dummy implementation for PCI related functions with actual
implementation. This needs ECAM and MCFG CONFIG options to be enabled
for RISC-V.

Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
Tested-by: Björn Töpel <bjorn@rivosinc.com>
Link: https://patch.msgid.link/20240812005929.113499-10-sunilvl@ventanamicro.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2024-08-27 15:48:35 +02:00
Jinjie Ruan
0e3f3649d4
riscv: Enable generic CPU vulnerabilites support
Currently x86, ARM and ARM64 support generic CPU vulnerabilites, but
RISC-V not, such as:

	# cd /sys/devices/system/cpu/vulnerabilities/
x86:
	# cat spec_store_bypass
		Mitigation: Speculative Store Bypass disabled via prctl and seccomp
	# cat meltdown
		Not affected

ARM64:

	# cat spec_store_bypass
		Mitigation: Speculative Store Bypass disabled via prctl and seccomp
	# cat meltdown
		Mitigation: PTI

RISC-V:

	# cat /sys/devices/system/cpu/vulnerabilities
	# ... No such file or directory

As SiFive RISC-V Core IP offerings are not affected by Meltdown and
Spectre, it can use the default weak function as below:

	# cat spec_store_bypass
		Not affected
	# cat meltdown
		Not affected

Link: https://www.sifive.cn/blog/sifive-statement-on-meltdown-and-spectre

Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Link: https://lore.kernel.org/r/20240703022732.2068316-1-ruanjinjie@huawei.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-08-14 17:44:34 -07:00
Linus Torvalds
c9f33436d8 RISC-V Patches for the 6.11 Merge Window, Part 2
* Support for NUMA (via SRAT and SLIT), console output (via SPCR), and
   cache info (via PPTT) on ACPI-based systems.
 * The trap entry/exit code no longer breaks the return address stack
   predictor on many systems, which results in an improvement to trap
   latency.
 * Support for HAVE_ARCH_STACKLEAK.
 * The sv39 linear map has been extended to support 128GiB mappings.
 * The frequency of the mtime CSR is now visible via hwprobe.
 -----BEGIN PGP SIGNATURE-----
 
 iQJHBAABCAAxFiEEKzw3R0RoQ7JKlDp6LhMZ81+7GIkFAmaj2EYTHHBhbG1lckBk
 YWJiZWx0LmNvbQAKCRAuExnzX7sYiVG3D/9kNHTI09iPDJd6fTChE3cpMxy7xXXE
 URX3Avu+gYsJmIbYyg4RnQ8FGFN7icKBCrQqs7JmLliU0NU+YMcCcjsJA2QaivbD
 VAlaex1qNcvNGteHrpbqhr3Zs4zw8GlBkB3KFTLyPAp61bybGo0a/A5ONJ7ScQIW
 RWHewAPgb86cQ0Q34JpO87TqvMM0KMvhQP5dip+olaFjLRBzhXmGFZfHqA80kTWl
 0ytYclVCHZMtO/5mnQpuIOVs1IKw9L4wa0sivOQF0iLTqfKDFALa6yZsThHA/w3e
 JVuBAdQhcPZ3fgO2fUfJPlW16GmRC2/tdiFg5NFw8k4vo7DYBwX55ztPKXqDrJDM
 8ah85IeLiPar/A/uHdn6bPjK+aGMuzklKF50r62XXAc2fL8mza1sdvKCVOy2EOLn
 JyGI9c/10KpvN/DW8g7hPefhvbx4+tCKkFcPqf++VQha6W8cQdCKi+Li0Pm8TTnp
 XPQjIvSlDDG1Pl4ofgBSFoyB8pkBXNzvv8NZp+YYtnqSOLAKaZuP+KwA8TwHdvGM
 pdCXcL3KHiLy4/pJWEoNTutD0mbJ7PUIb2P/KkjqYDgp4F1n0Hg+/aeSIp+7a4Pv
 yTBctIGxrlriQMIdtWCR8tyhcPP4pDpGYkW0K15EE16G0NK0fjD89LEXYqT6ae2R
 C0QgiwnVe/eopg==
 =zeUn
 -----END PGP SIGNATURE-----

Merge tag 'riscv-for-linus-6.11-mw2' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull more RISC-V updates from Palmer Dabbelt:

 - Support for NUMA (via SRAT and SLIT), console output (via SPCR), and
   cache info (via PPTT) on ACPI-based systems.

 - The trap entry/exit code no longer breaks the return address stack
   predictor on many systems, which results in an improvement to trap
   latency.

 - Support for HAVE_ARCH_STACKLEAK.

 - The sv39 linear map has been extended to support 128GiB mappings.

 - The frequency of the mtime CSR is now visible via hwprobe.

* tag 'riscv-for-linus-6.11-mw2' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (21 commits)
  RISC-V: Provide the frequency of time CSR via hwprobe
  riscv: Extend sv39 linear mapping max size to 128G
  riscv: enable HAVE_ARCH_STACKLEAK
  riscv: signal: Remove unlikely() from WARN_ON() condition
  riscv: Improve exception and system call latency
  RISC-V: Select ACPI PPTT drivers
  riscv: cacheinfo: initialize cacheinfo's level and type from ACPI PPTT
  riscv: cacheinfo: remove the useless input parameter (node) of ci_leaf_init()
  RISC-V: ACPI: Enable SPCR table for console output on RISC-V
  riscv: boot: remove duplicated targets line
  trace: riscv: Remove deprecated kprobe on ftrace support
  riscv: cpufeature: Extract common elements from extension checking
  riscv: Introduce vendor variants of extension helpers
  riscv: Add vendor extensions to /proc/cpuinfo
  riscv: Extend cpufeature.c to detect vendor extensions
  RISC-V: run savedefconfig for defconfig
  RISC-V: hwprobe: sort EXT_KEY()s in hwprobe_isa_ext0() alphabetically
  ACPI: NUMA: replace pr_info with pr_debug in arch_acpi_numa_init
  ACPI: NUMA: change the ACPI_NUMA to a hidden option
  ACPI: NUMA: Add handler for SRAT RINTC affinity structure
  ...
2024-07-27 10:14:34 -07:00
Palmer Dabbelt
3aa1a7d013
Merge patch series "RISC-V: Select ACPI PPTT drivers"
This series adds support for ACPI PPTT via cacheinfo.

* b4-shazam-merge:
  RISC-V: Select ACPI PPTT drivers
  riscv: cacheinfo: initialize cacheinfo's level and type from ACPI PPTT
  riscv: cacheinfo: remove the useless input parameter (node) of ci_leaf_init()

Link: https://lore.kernel.org/r/20240617131425.7526-1-cuiyunhui@bytedance.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-07-26 05:50:49 -07:00
Palmer Dabbelt
ec1dc56b54
Merge patch "Enable SPCR table for console output on RISC-V"
Sia Jee Heng <jeeheng.sia@starfivetech.com> says:

The ACPI SPCR code has been used to enable console output for ARM64 and
X86. The same code can be reused for RISC-V. Furthermore, SPCR table is
mandated for headless system as outlined in the RISC-V BRS
Specification, chapter 6.

* b4-shazam-merge:
  RISC-V: ACPI: Enable SPCR table for console output on RISC-V

Link: https://lore.kernel.org/r/20240502073751.102093-1-jeeheng.sia@starfivetech.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-07-26 05:50:48 -07:00
Jisheng Zhang
b5db73fb18
riscv: enable HAVE_ARCH_STACKLEAK
Add support for the stackleak feature. Whenever the kernel returns to user
space the kernel stack is filled with a poison value.

At the same time, disables the plugin in EFI stub code because EFI stub
is out of scope for the protection.

Tested on qemu and milkv duo:
/ # echo STACKLEAK_ERASING > /sys/kernel/debug/provoke-crash/DIRECT
[   38.675575] lkdtm: Performing direct entry STACKLEAK_ERASING
[   38.678448] lkdtm: stackleak stack usage:
[   38.678448]   high offset: 288 bytes
[   38.678448]   current:     496 bytes
[   38.678448]   lowest:      1328 bytes
[   38.678448]   tracked:     1328 bytes
[   38.678448]   untracked:   448 bytes
[   38.678448]   poisoned:    14312 bytes
[   38.678448]   low offset:  8 bytes
[   38.689887] lkdtm: OK: the rest of the thread stack is properly erased

Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Reviewed-by: Charlie Jenkins <charlie@rivosinc.com>
Link: https://lore.kernel.org/r/20240623235316.2010-1-jszhang@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-07-26 05:50:47 -07:00
Yunhui Cui
66381d3677
RISC-V: Select ACPI PPTT drivers
After adding ACPI support to populate_cache_leaves(), RISC-V can build
cacheinfo through the ACPI PPTT table, thus enabling the ACPI_PPTT
configuration.

Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>
Reviewed-by: Jeremy Linton <jeremy.linton@arm.com>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Reviewed-by: Sunil V L <sunilvl@ventanamicro.com>
Link: https://lore.kernel.org/r/20240617131425.7526-3-cuiyunhui@bytedance.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-07-24 07:39:37 -07:00
Sia Jee Heng
38738947db
RISC-V: ACPI: Enable SPCR table for console output on RISC-V
The ACPI SPCR code has been used to enable console output for ARM64 and
X86. The same code can be reused for RISC-V. Furthermore, SPCR table is
mandated for headless system as outlined in the RISC-V BRS
Specification, chapter 6.

Signed-off-by: Sia Jee Heng <jeeheng.sia@starfivetech.com>
Reviewed-by: Sunil V L <sunilvl@ventanamicro.com>
Link: https://lore.kernel.org/r/20240502073751.102093-2-jeeheng.sia@starfivetech.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-07-24 07:33:37 -07:00
Jinjie Ruan
3308172276
trace: riscv: Remove deprecated kprobe on ftrace support
Since commit 7caa976546 ("ftrace: riscv: move from REGS to ARGS"),
kprobe on ftrace is not supported by riscv, because riscv's support for
FTRACE_WITH_REGS has been replaced with support for FTRACE_WITH_ARGS, and
KPROBES_ON_FTRACE will be supplanted by FPROBES. So remove the deprecated
kprobe on ftrace support, which is misunderstood.

Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Link: https://lore.kernel.org/r/20240613111347.1745379-1-ruanjinjie@huawei.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-07-24 06:14:05 -07:00
Linus Torvalds
ca83c61cb3 Kbuild updates for v6.11
- Remove tristate choice support from Kconfig
 
  - Stop using the PROVIDE() directive in the linker script
 
  - Reduce the number of links for the combination of CONFIG_DEBUG_INFO_BTF
    and CONFIG_KALLSYMS
 
  - Enable the warning for symbol reference to .exit.* sections by default
 
  - Fix warnings in RPM package builds
 
  - Improve scripts/make_fit.py to generate a FIT image with separate base
    DTB and overlays
 
  - Improve choice value calculation in Kconfig
 
  - Fix conditional prompt behavior in choice in Kconfig
 
  - Remove support for the uncommon EMAIL environment variable in Debian
    package builds
 
  - Remove support for the uncommon "name <email>" form for the DEBEMAIL
    environment variable
 
  - Raise the minimum supported GNU Make version to 4.0
 
  - Remove stale code for the absolute kallsyms
 
  - Move header files commonly used for host programs to scripts/include/
 
  - Introduce the pacman-pkg target to generate a pacman package used in
    Arch Linux
 
  - Clean up Kconfig
 -----BEGIN PGP SIGNATURE-----
 
 iQJJBAABCgAzFiEEbmPs18K1szRHjPqEPYsBB53g2wYFAmagBLUVHG1hc2FoaXJv
 eUBrZXJuZWwub3JnAAoJED2LAQed4NsGmoUQAJ8pnURs0g+Rcyk6bdY/qtXBYkS+
 nXpIK1ssFgRRgAQdeszYtvBqLFzb0wRCSie87G1AriD/JkVVTjCCY1For1y+vs0u
 a7HfxitHhZpPyZW/T+WMQ3LViNccpkx+DFAcoRH8xOY/XPEJKVUby332jOIXMuyg
 +NKIELQJVsLhcDofTUGb5VfIQektw219n5c4jKjXdNk4ZtE24xCRM5X528ZebwWJ
 RZhMvJ968PyIH1IRXvNt6dsKBxoGIwPP8IO6yW9hzHaNsBqt7MGSChSel7r1VKpk
 iwCNApJvEiVBe5wvTSVOVro7/8p/AZ70CQAqnMJV+dNnRqtGqW7NvL6XAjZRJgJJ
 Uxe5NSrXgQd3FtqfcbXLetBgp9zGVt328nHm1HXHR5rFsvoOiTvO7hHPbhA+OoWJ
 fs+jHzEXdAMRgsNrczPWU5Svq6MgGe4v8HBf0m8N1Uy65t/O+z9ti2QAw7kIFlbu
 /VSFNjw4CHmNxGhnH0khCMsy85FwVIt9Ux+2d6IEc0gP8S1Qa1HgHGAoVI4U51eS
 9dxEPVJNPOugaIVHheuS3wimEO6wzaJcQHn4IXaasMA7P6Yo4G/jiGoy4cb9qPTM
 Hb+GaOltUy7vDoG4D2LSym8zR8rdKwbIf/5psdZrq/IWVKq5p+p7KWs3aOykSoM7
 o6Hb532Ioalhm8je
 =BYu7
 -----END PGP SIGNATURE-----

Merge tag 'kbuild-v6.11' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild updates from Masahiro Yamada:

 - Remove tristate choice support from Kconfig

 - Stop using the PROVIDE() directive in the linker script

 - Reduce the number of links for the combination of CONFIG_KALLSYMS and
   CONFIG_DEBUG_INFO_BTF

 - Enable the warning for symbol reference to .exit.* sections by
   default

 - Fix warnings in RPM package builds

 - Improve scripts/make_fit.py to generate a FIT image with separate
   base DTB and overlays

 - Improve choice value calculation in Kconfig

 - Fix conditional prompt behavior in choice in Kconfig

 - Remove support for the uncommon EMAIL environment variable in Debian
   package builds

 - Remove support for the uncommon "name <email>" form for the DEBEMAIL
   environment variable

 - Raise the minimum supported GNU Make version to 4.0

 - Remove stale code for the absolute kallsyms

 - Move header files commonly used for host programs to scripts/include/

 - Introduce the pacman-pkg target to generate a pacman package used in
   Arch Linux

 - Clean up Kconfig

* tag 'kbuild-v6.11' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (65 commits)
  kbuild: doc: gcc to CC change
  kallsyms: change sym_entry::percpu_absolute to bool type
  kallsyms: unify seq and start_pos fields of struct sym_entry
  kallsyms: add more original symbol type/name in comment lines
  kallsyms: use \t instead of a tab in printf()
  kallsyms: avoid repeated calculation of array size for markers
  kbuild: add script and target to generate pacman package
  modpost: use generic macros for hash table implementation
  kbuild: move some helper headers from scripts/kconfig/ to scripts/include/
  Makefile: add comment to discourage tools/* addition for kernel builds
  kbuild: clean up scripts/remove-stale-files
  kconfig: recursive checks drop file/lineno
  kbuild: rpm-pkg: introduce a simple changelog section for kernel.spec
  kallsyms: get rid of code for absolute kallsyms
  kbuild: Create INSTALL_PATH directory if it does not exist
  kbuild: Abort make on install failures
  kconfig: remove 'e1' and 'e2' macros from expression deduplication
  kconfig: remove SYMBOL_CHOICEVAL flag
  kconfig: add const qualifiers to several function arguments
  kconfig: call expr_eliminate_yn() at least once in expr_eliminate_dups()
  ...
2024-07-23 14:32:21 -07:00
Palmer Dabbelt
b9a603da42
Merge patch series "riscv: Separate vendor extensions from standard extensions"
Charlie Jenkins <charlie@rivosinc.com> says:

All extensions, both standard and vendor, live in one struct
"riscv_isa_ext". There is currently one vendor extension, xandespmu, but
it is likely that more vendor extensions will be added to the kernel in
the future. As more vendor extensions (and standard extensions) are
added, riscv_isa_ext will become more bloated with a mix of vendor and
standard extensions.

This also allows each vendor to be conditionally enabled through
Kconfig.

* b4-shazam-merge:
  riscv: cpufeature: Extract common elements from extension checking
  riscv: Introduce vendor variants of extension helpers
  riscv: Add vendor extensions to /proc/cpuinfo
  riscv: Extend cpufeature.c to detect vendor extensions

Link: https://lore.kernel.org/r/20240719-support_vendor_extensions-v3-0-0af7587bbec0@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-07-22 15:37:01 -07:00
Charlie Jenkins
23c996fc2b
riscv: Extend cpufeature.c to detect vendor extensions
Instead of grouping all vendor extensions into the same riscv_isa_ext
that standard instructions use, create a struct
"riscv_isa_vendor_ext_data_list" that allows each vendor to maintain
their vendor extensions independently of the standard extensions.
xandespmu is currently the only vendor extension so that is the only
extension that is affected by this change.

An additional benefit of this is that the extensions of each vendor can
be conditionally enabled. A config RISCV_ISA_VENDOR_EXT_ANDES has been
added to allow for that.

Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Andy Chiu <andy.chiu@sifive.com>
Tested-by: Yu Chien Peter Lin <peterlin@andestech.com>
Reviewed-by: Yu Chien Peter Lin <peterlin@andestech.com>
Link: https://lore.kernel.org/r/20240719-support_vendor_extensions-v3-1-0af7587bbec0@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-07-22 15:36:54 -07:00
Linus Torvalds
f557af081d RISC-V Patches for the 6.11 Merge Window, Part 1
* Support for various new ISA extensions:
     * The Zve32[xf] and Zve64[xfd] sub-extensios of the vector
       extension.
     * Zimop and Zcmop for may-be-operations.
     * The Zca, Zcf, Zcd and Zcb sub-extensions of the C extension.
     * Zawrs,
 * riscv,cpu-intc is now dtschema.
 * A handful of performance improvements and cleanups to text patching.
 * Support for memory hot{,un}plug
 * The highest user-allocatable virtual address is now visible in
   hwprobe.
 -----BEGIN PGP SIGNATURE-----
 
 iQJHBAABCAAxFiEEKzw3R0RoQ7JKlDp6LhMZ81+7GIkFAmabIGETHHBhbG1lckBk
 YWJiZWx0LmNvbQAKCRAuExnzX7sYiQe8D/9QPCaOnoP5OCZbwjkRBwaVxyknNyD0
 l+YNXk7Jk3B/oaOv3d7Bz+uWt1SG4j4jkfyuGJ81StZykp4/R7T823TZrPhog9VX
 IJm580MtvE49I2i1qJ+ZQti9wpiM+80lFnyMCzY6S7rrM9m62tKgUpARZcWoA55P
 iUo5bku99TYCcU2k1pnPrNSPQvVpECpv7tG0PwKpQd5DiYjbPp+aw5cQWN+izdOB
 6raOZ0buzP7McszvO/gcJs+kuHwrp0JSRvNxc2pwYZ0lx00p3hSV8UdtIMlI9Qm/
 z3gkQGHwc6UVMPHo1x0Gr5ShUTCI/iSwy4/7aY4NNXF6Sj99b8alt9GcbYqNAE7V
 k7sibCR7dhL4ods/GFMmzR7cQYlwlwtO+/ILak7rXhNvA32Xy1WUABguhP9ElTmw
 1ZS2hnRv6wc7MA2V7HBamf5mPXM6HQyC3oKy3njzDSJdiGIG7aa+TOfRAD+L/1Du
 QjIrKp6XcPIsZNjh8H3nMDVJ0VvDNnS4d4LbfNQc23VPzf57kFUqbli1pS0hBjFT
 ELEItH9dgSx+T5Qebdy/QMC3RG8Yc1IUdw6VQ7Jny/uCCEZNq+VZ+bXxspMmswCp
 sUIyDplJTJfRt3G2OxK0b95x6oj8jbaJOQfv6PBF71dDBsChg8eXFVJ2NDrX4Bvr
 h2MPK7vGBtFz8w==
 =+ICi
 -----END PGP SIGNATURE-----

Merge tag 'riscv-for-linus-6.11-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull RISC-V updates from Palmer Dabbelt:

 - Support for various new ISA extensions:
     * The Zve32[xf] and Zve64[xfd] sub-extensios of the vector
       extension
     * Zimop and Zcmop for may-be-operations
     * The Zca, Zcf, Zcd and Zcb sub-extensions of the C extension
     * Zawrs

 - riscv,cpu-intc is now dtschema

 - A handful of performance improvements and cleanups to text patching

 - Support for memory hot{,un}plug

 - The highest user-allocatable virtual address is now visible in
   hwprobe

* tag 'riscv-for-linus-6.11-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (58 commits)
  riscv: lib: relax assembly constraints in hweight
  riscv: set trap vector earlier
  KVM: riscv: selftests: Add Zawrs extension to get-reg-list test
  KVM: riscv: Support guest wrs.nto
  riscv: hwprobe: export Zawrs ISA extension
  riscv: Add Zawrs support for spinlocks
  dt-bindings: riscv: Add Zawrs ISA extension description
  riscv: Provide a definition for 'pause'
  riscv: hwprobe: export highest virtual userspace address
  riscv: Improve sbi_ecall() code generation by reordering arguments
  riscv: Add tracepoints for SBI calls and returns
  riscv: Optimize crc32 with Zbc extension
  riscv: Enable DAX VMEMMAP optimization
  riscv: mm: Add support for ZONE_DEVICE
  virtio-mem: Enable virtio-mem for RISC-V
  riscv: Enable memory hotplugging for RISC-V
  riscv: mm: Take memory hotplug read-lock during kernel page table dump
  riscv: mm: Add memory hotplugging support
  riscv: mm: Add pfn_to_kaddr() implementation
  riscv: mm: Refactor create_linear_mapping_range() for memory hot add
  ...
2024-07-20 09:11:27 -07:00
Masahiro Yamada
b9d73218d7 treewide: change conditional prompt for choices to 'depends on'
While Documentation/kbuild/kconfig-language.rst provides a brief
explanation, there are recurring confusions regarding the usage of a
prompt followed by 'if <expr>'. This conditional controls _only_ the
prompt.

A typical usage is as follows:

    menuconfig BLOCK
            bool "Enable the block layer" if EXPERT
            default y

When EXPERT=n, the prompt is hidden, but this config entry is still
active, and BLOCK is set to its default value 'y'. This is reasonable
because you are likely want to enable the block device support. When
EXPERT=y, the prompt is shown, allowing you to toggle BLOCK.

Please note that it is different from 'depends on EXPERT', which would
enable and disable the entire config entry.

However, this conditional prompt has never worked in a choice block.

The following two work in the same way: when EXPERT is disabled, the
choice block is entirely disabled.

[Test Code 1]

    choice
            prompt "choose" if EXPERT

    config A
            bool "A"

    config B
            bool "B"

    endchoice

[Test Code 2]

    choice
            prompt "choose"
            depends on EXPERT

    config A
            bool "A"

    config B
            bool "B"

    endchoice

I believe the first case should hide only the prompt, producing the
default:

   CONFIG_A=y
   # CONFIG_B is not set

The next commit will change (fix) the behavior of the conditional prompt
in choice blocks.

I see several choice blocks wrongly using a conditional prompt, where
'depends on' makes more sense.

To preserve the current behavior, this commit converts such misuses.

I did not touch the following entry in arch/x86/Kconfig:

    choice
            prompt "Memory split" if EXPERT
            default VMSPLIT_3G

This is truly the correct use of the conditional prompt; when EXPERT=n,
this choice block should silently select the reasonable VMSPLIT_3G,
although the resulting PAGE_OFFSET will not be affected anyway.

Presumably, the one in fs/jffs2/Kconfig is also correct, but I converted
it to 'depends on' to avoid any potential behavioral change.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2024-07-16 01:08:37 +09:00
Palmer Dabbelt
5ee121a393
Merge patch series "riscv: Apply Zawrs when available"
Andrew Jones <ajones@ventanamicro.com> says:

Zawrs provides two instructions (wrs.nto and wrs.sto), where both are
meant to allow the hart to enter a low-power state while waiting on a
store to a memory location. The instructions also both wait an
implementation-defined "short" duration (unless the implementation
terminates the stall for another reason). The difference is that while
wrs.sto will terminate when the duration elapses, wrs.nto, depending on
configuration, will either just keep waiting or an ILL exception will be
raised. Linux will use wrs.nto, so if platforms have an implementation
which falls in the "just keep waiting" category (which is not expected),
then it should _not_ advertise Zawrs in the hardware description.

Like wfi (and with the same {m,h}status bits to configure it), when
wrs.nto is configured to raise exceptions it's expected that the higher
privilege level will see the instruction was a wait instruction, do
something, and then resume execution following the instruction. For
example, KVM does configure exceptions for wfi (hstatus.VTW=1) and
therefore also for wrs.nto. KVM does this for wfi since it's better to
allow other tasks to be scheduled while a VCPU waits for an interrupt.
For waits such as those where wrs.nto/sto would be used, which are
typically locks, it is also a good idea for KVM to be involved, as it
can attempt to schedule the lock holding VCPU.

This series starts with Christoph's addition of the riscv
smp_cond_load_relaxed function which applies wrs.sto when available.
That patch has been reworked to use wrs.nto and to use the same approach
as Arm for the wait loop, since we can't have arbitrary C code between
the load-reserved and the wrs. Then, hwprobe support is added (since the
instructions are also usable from usermode), and finally KVM is
taught about wrs.nto, allowing guests to see and use the Zawrs
extension.

We still don't have test results from hardware, and it's not possible to
prove that using Zawrs is a win when testing on QEMU, not even when
oversubscribing VCPUs to guests. However, it is possible to use KVM
selftests to force a scenario where we can prove Zawrs does its job and
does it well. [4] is a test which does this and, on my machine, without
Zawrs it takes 16 seconds to complete and with Zawrs it takes 0.25
seconds.

This series is also available here [1]. In order to use QEMU for testing
a build with [2] is needed. In order to enable guests to use Zawrs with
KVM using kvmtool, the branch at [3] may be used.

[1] https://github.com/jones-drew/linux/commits/riscv/zawrs-v3/
[2] https://lore.kernel.org/all/20240312152901.512001-2-ajones@ventanamicro.com/
[3] https://github.com/jones-drew/kvmtool/commits/riscv/zawrs/
[4] cb2beccebc

Link: https://lore.kernel.org/r/20240426100820.14762-8-ajones@ventanamicro.com

* b4-shazam-merge:
  KVM: riscv: selftests: Add Zawrs extension to get-reg-list test
  KVM: riscv: Support guest wrs.nto
  riscv: hwprobe: export Zawrs ISA extension
  riscv: Add Zawrs support for spinlocks
  dt-bindings: riscv: Add Zawrs ISA extension description
  riscv: Provide a definition for 'pause'

Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-07-12 08:55:29 -07:00