Commit Graph

370 Commits

Author SHA1 Message Date
Guo Ren 163e76cc6e
riscv: stack: Support HAVE_IRQ_EXIT_ON_IRQ_STACK
Add independent irq stacks for percpu to prevent kernel stack overflows.
It is also compatible with VMAP_STACK by arch_alloc_vmap_stack.

Tested-by: Jisheng Zhang <jszhang@kernel.org>
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
Cc: Clément Léger <cleger@rivosinc.com>
Link: https://lore.kernel.org/r/20230614013018.2168426-2-guoren@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-06-22 10:38:35 -07:00
Palmer Dabbelt d5e45e810e
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>
2023-06-08 07:17:09 -07:00
Guo Ren fa8e7cce55
riscv: Enable Vector code to be built
This patch adds configs for building Vector code. First it detects the
reqired toolchain support for building the code. Then it provides an
option setting whether Vector is implicitly enabled to userspace.

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Co-developed-by: Greentime Hu <greentime.hu@sifive.com>
Signed-off-by: Greentime Hu <greentime.hu@sifive.com>
Co-developed-by: Andy Chiu <andy.chiu@sifive.com>
Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230605110724.21391-25-andy.chiu@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-06-08 07:16:56 -07:00
Andy Chiu e4bb020f3d
riscv: detect assembler support for .option arch
Some extensions use .option arch directive to selectively enable certain
extensions in parts of its assembly code. For example, Zbb uses it to
inform assmebler to emit bit manipulation instructions. However,
supporting of this directive only exist on GNU assembler and has not
landed on clang at the moment, making TOOLCHAIN_HAS_ZBB depend on
AS_IS_GNU.

While it is still under review at https://reviews.llvm.org/D123515, the
upcoming Vector patch also requires this feature in assembler. Thus,
provide Kconfig AS_HAS_OPTION_ARCH to detect such feature. Then
TOOLCHAIN_HAS_XXX will be turned on automatically when the feature land.

Suggested-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Heiko Stuebner <heiko.stuebner@vrull.eu>
Tested-by: Heiko Stuebner <heiko.stuebner@vrull.eu>
Link: https://lore.kernel.org/r/20230605110724.21391-24-andy.chiu@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-06-08 07:16:55 -07:00
Sunil V L a91a9ffbd3
RISC-V: Add support to build the ACPI core
Enable ACPI core for RISC-V after adding architecture-specific
interfaces and header files required to build the ACPI core.

1) Couple of header files are required unconditionally by the ACPI
core. Add empty acenv.h and cpu.h header files.

2) If CONFIG_PCI is enabled, a few PCI related interfaces need to
be provided by the architecture. Define dummy interfaces for now
so that build succeeds. Actual implementation will be added when
PCI support is added for ACPI along with external interrupt
controller support.

3) A few globals and memory mapping related functions specific
to the architecture need to be provided.

Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com>
Link: https://lore.kernel.org/r/20230515054928.2079268-7-sunilvl@ventanamicro.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-06-01 08:45:01 -07:00
Linus Torvalds 982365a8f5 RISC-V Patches for the 6.4 Merge Window, Part 2
* Support for hibernation.
 * .rela.dyn has been moved to init.
 * A fix for the SBI probing to allow for implementation-defined
   behavior.
 * Various other fixes and cleanups throughout the tree.
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Merge tag 'riscv-for-linus-6.4-mw2' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull more RISC-V updates from Palmer Dabbelt:

 - Support for hibernation

 - The .rela.dyn section has been moved to the init area

 - A fix for the SBI probing to allow for implementation-defined
   behavior

 - Various other fixes and cleanups throughout the tree

* tag 'riscv-for-linus-6.4-mw2' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  RISC-V: include cpufeature.h in cpufeature.c
  riscv: Move .rela.dyn to the init sections
  dt-bindings: riscv: explicitly mention assumption of Zicsr & Zifencei support
  riscv: compat_syscall_table: Fixup compile warning
  RISC-V: fixup in-flight collision with ARCH_WANT_OPTIMIZE_VMEMMAP rename
  RISC-V: fix sifive and thead section mismatches in errata
  RISC-V: Align SBI probe implementation with spec
  riscv: mm: remove redundant parameter of create_fdt_early_page_table
  riscv: Adjust dependencies of HAVE_DYNAMIC_FTRACE selection
  RISC-V: Add arch functions to support hibernation/suspend-to-disk
  RISC-V: mm: Enable huge page support to kernel_page_present() function
  RISC-V: Factor out common code of __cpu_resume_enter()
  RISC-V: Change suspend_save_csrs and suspend_restore_csrs to public function
2023-05-05 12:23:33 -07:00
Conor Dooley 26b0812f4c
RISC-V: fixup in-flight collision with ARCH_WANT_OPTIMIZE_VMEMMAP rename
Lukas warned that ARCH_WANT_HUGETLB_PAGE_OPTIMIZE_VMEMMAP had been
renamed in the mm tree & that RISC-V would need a fixup as part of the
merge. The warning was missed however, and RISC-V is selecting the
orphaned Kconfig option.

Fixes: 89d77f71f4 ("Merge tag 'riscv-for-linus-6.4-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux")
Reported-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>.
Link: https://lore.kernel.org/linux-riscv/CAKXUXMyVeg2kQK_edKHtMD3eADrDK_PKhCSVkMrLDdYgTQQ5rg@mail.gmail.com/
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com>
Link: https://lore.kernel.org/r/20230429-trilogy-jolly-12bf5c53d62d@spud
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-04-29 15:33:10 -07:00
Palmer Dabbelt 38dab744f7
Merge patch series "RISC-V Hibernation Support"
Sia Jee Heng <jeeheng.sia@starfivetech.com> says:

This series adds RISC-V Hibernation/suspend to disk support.
Low level Arch functions were created to support hibernation.
swsusp_arch_suspend() relies code from __cpu_suspend_enter() to write
cpu state onto the stack, then calling swsusp_save() to save the memory
image.

Arch specific hibernation header is implemented and is utilized by the
arch_hibernation_header_restore() and arch_hibernation_header_save()
functions. The arch specific hibernation header consists of satp, hartid,
and the cpu_resume address. The kernel built version is also need to be
saved into the hibernation image header to making sure only the same
kernel is restore when resume.

swsusp_arch_resume() creates a temporary page table that covering only
the linear map. It copies the restore code to a 'safe' page, then start to
restore the memory image. Once completed, it restores the original
kernel's page table. It then calls into __hibernate_cpu_resume()
to restore the CPU context. Finally, it follows the normal hibernation
path back to the hibernation core.

To enable hibernation/suspend to disk into RISCV, the below config
need to be enabled:
- CONFIG_HIBERNATION
- CONFIG_ARCH_HIBERNATION_HEADER
- CONFIG_ARCH_HIBERNATION_POSSIBLE

At high-level, this series includes the following changes:
1) Change suspend_save_csrs() and suspend_restore_csrs()
   to public function as these functions are common to
   suspend/hibernation. (patch 1)
2) Refactor the common code in the __cpu_resume_enter() function and
   __hibernate_cpu_resume() function. The common code are used by
   hibernation and suspend. (patch 2)
3) Enhance kernel_page_present() function to support huge page. (patch 3)
4) Add arch/riscv low level functions to support
   hibernation/suspend to disk. (patch 4)

* b4-shazam-merge:
  RISC-V: Add arch functions to support hibernation/suspend-to-disk
  RISC-V: mm: Enable huge page support to kernel_page_present() function
  RISC-V: Factor out common code of __cpu_resume_enter()
  RISC-V: Change suspend_save_csrs and suspend_restore_csrs to public function

Link: https://lore.kernel.org/r/20230330064321.1008373-1-jeeheng.sia@starfivetech.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-04-29 11:27:33 -07:00
Nathan Chancellor b3d6bdfea2
riscv: Adjust dependencies of HAVE_DYNAMIC_FTRACE selection
When building allmodconfig with clang and its integrated assembler and
linking with a version of GNU ld prior to 2.36, the following link error
occurs:

  riscv64-linux-gnu-ld: .init.data has both ordered [`__patchable_function_entries' in init/main.o] and unordered [`.init_array.0' in kernel/trace/trace_benchmark.o] sections
  riscv64-linux-gnu-ld: final link failed: bad value

This is the same error addressed by commit 45bd895180 ("arm64: Improve
HAVE_DYNAMIC_FTRACE_WITH_REGS selection for clang") for arm64. See that
changelog for a full description of why this error occurs with this
combination of tools.

In a similar manner as that change, restrict the
CONFIG_HAVE_DYNAMIC_FTRACE selection to combinations of tools known to
work so that there are no errors.

Link: https://github.com/ClangBuiltLinux/linux/issues/1817
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230404-riscv-dynamic-ftrace-checks-clang-v1-1-0ce296b7d423@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-04-29 11:27:32 -07:00
Sia Jee Heng c031721001
RISC-V: Add arch functions to support hibernation/suspend-to-disk
Low level Arch functions were created to support hibernation.
swsusp_arch_suspend() relies code from __cpu_suspend_enter() to write
cpu state onto the stack, then calling swsusp_save() to save the memory
image.

Arch specific hibernation header is implemented and is utilized by the
arch_hibernation_header_restore() and arch_hibernation_header_save()
functions. The arch specific hibernation header consists of satp, hartid,
and the cpu_resume address. The kernel built version is also need to be
saved into the hibernation image header to making sure only the same
kernel is restore when resume.

swsusp_arch_resume() creates a temporary page table that covering only
the linear map. It copies the restore code to a 'safe' page, then start
to restore the memory image. Once completed, it restores the original
kernel's page table. It then calls into __hibernate_cpu_resume()
to restore the CPU context. Finally, it follows the normal hibernation
path back to the hibernation core.

To enable hibernation/suspend to disk into RISCV, the below config
need to be enabled:
- CONFIG_HIBERNATION
- CONFIG_ARCH_HIBERNATION_HEADER
- CONFIG_ARCH_HIBERNATION_POSSIBLE

Signed-off-by: Sia Jee Heng <jeeheng.sia@starfivetech.com>
Reviewed-by: Ley Foon Tan <leyfoon.tan@starfivetech.com>
Reviewed-by: Mason Huo <mason.huo@starfivetech.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Link: https://lore.kernel.org/r/20230330064321.1008373-5-jeeheng.sia@starfivetech.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-04-29 11:25:13 -07:00
Linus Torvalds b28e6315a0 dma-mapping updates for Linux 6.4
- fix a PageHighMem check in dma-coherent initialization (Doug Berger)
  - clean up the coherency defaul initialiation (Jiaxun Yang)
  - add cacheline to user/kernel dma-debug space dump messages
    (Desnes Nunes, Geert Uytterhoeve)
  - swiotlb statistics improvements (Michael Kelley)
  - misc cleanups (Petr Tesarik)
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Merge tag 'dma-mapping-6.4-2023-04-28' of git://git.infradead.org/users/hch/dma-mapping

Pull dma-mapping updates from Christoph Hellwig:

 - fix a PageHighMem check in dma-coherent initialization (Doug Berger)

 - clean up the coherency defaul initialiation (Jiaxun Yang)

 - add cacheline to user/kernel dma-debug space dump messages (Desnes
   Nunes, Geert Uytterhoeve)

 - swiotlb statistics improvements (Michael Kelley)

 - misc cleanups (Petr Tesarik)

* tag 'dma-mapping-6.4-2023-04-28' of git://git.infradead.org/users/hch/dma-mapping:
  swiotlb: Omit total_used and used_hiwater if !CONFIG_DEBUG_FS
  swiotlb: track and report io_tlb_used high water marks in debugfs
  swiotlb: fix debugfs reporting of reserved memory pools
  swiotlb: relocate PageHighMem test away from rmem_swiotlb_setup
  of: address: always use dma_default_coherent for default coherency
  dma-mapping: provide CONFIG_ARCH_DMA_DEFAULT_COHERENT
  dma-mapping: provide a fallback dma_default_coherent
  dma-debug: Use %pa to format phys_addr_t
  dma-debug: add cacheline to user/kernel space dump messages
  dma-debug: small dma_debug_entry's comment and variable name updates
  dma-direct: cleanup parameters to dma_direct_optimal_gfp_mask
2023-04-29 10:29:57 -07:00
Linus Torvalds 89d77f71f4 RISC-V Patches for the 6.4 Merge Window, Part 1
* Support for runtime detection of the Svnapot extension.
 * Support for Zicboz when clearing pages.
 * We've moved to GENERIC_ENTRY.
 * Support for !MMU on rv32 systems.
 * The linear region is now mapped via huge pages.
 * Support for building relocatable kernels.
 * Support for the hwprobe interface.
 * Various fixes and cleanups throughout the tree.
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Merge tag 'riscv-for-linus-6.4-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull RISC-V updates from Palmer Dabbelt:

 - Support for runtime detection of the Svnapot extension

 - Support for Zicboz when clearing pages

 - We've moved to GENERIC_ENTRY

 - Support for !MMU on rv32 systems

 - The linear region is now mapped via huge pages

 - Support for building relocatable kernels

 - Support for the hwprobe interface

 - Various fixes and cleanups throughout the tree

* tag 'riscv-for-linus-6.4-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (57 commits)
  RISC-V: hwprobe: Explicity check for -1 in vdso init
  RISC-V: hwprobe: There can only be one first
  riscv: Allow to downgrade paging mode from the command line
  dt-bindings: riscv: add sv57 mmu-type
  RISC-V: hwprobe: Remove __init on probe_vendor_features()
  riscv: Use --emit-relocs in order to move .rela.dyn in init
  riscv: Check relocations at compile time
  powerpc: Move script to check relocations at compile time in scripts/
  riscv: Introduce CONFIG_RELOCATABLE
  riscv: Move .rela.dyn outside of init to avoid empty relocations
  riscv: Prepare EFI header for relocatable kernels
  riscv: Unconditionnally select KASAN_VMALLOC if KASAN
  riscv: Fix ptdump when KASAN is enabled
  riscv: Fix EFI stub usage of KASAN instrumented strcmp function
  riscv: Move DTB_EARLY_BASE_VA to the kernel address space
  riscv: Rework kasan population functions
  riscv: Split early and final KASAN population functions
  riscv: Use PUD/P4D/PGD pages for the linear mapping
  riscv: Move the linear mapping creation in its own function
  riscv: Get rid of riscv_pfn_base variable
  ...
2023-04-28 16:55:39 -07:00
Linus Torvalds 53b5e72b9d asm-generic updates for 6.4
These are various cleanups, fixing a number of uapi header files to no
 longer reference CONFIG_* symbols, and one patch that introduces the
 new CONFIG_HAS_IOPORT symbol for architectures that provide working
 inb()/outb() macros, as a preparation for adding driver dependencies
 on those in the following release.
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Merge tag 'asm-generic-6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic

Pull asm-generic updates from Arnd Bergmann:
 "These are various cleanups, fixing a number of uapi header files to no
  longer reference CONFIG_* symbols, and one patch that introduces the
  new CONFIG_HAS_IOPORT symbol for architectures that provide working
  inb()/outb() macros, as a preparation for adding driver dependencies
  on those in the following release"

* tag 'asm-generic-6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic:
  Kconfig: introduce HAS_IOPORT option and select it as necessary
  scripts: Update the CONFIG_* ignore list in headers_install.sh
  pktcdvd: Remove CONFIG_CDROM_PKTCDVD_WCACHE from uapi header
  Move bp_type_idx to include/linux/hw_breakpoint.h
  Move ep_take_care_of_epollwakeup() to fs/eventpoll.c
  Move COMPAT_ATM_ADDPARTY to net/atm/svc.c
2023-04-25 12:22:11 -07:00
Thomas Gleixner f37202aa6e irqchip changes for 6.4
- Large RISC-V IPI rework to make way for a new interrupt
   architecture
 
 - More Loongarch fixes from Lianmin Lv, fixing issues in the so
   called "dual-bridge" systems.
 
 - Workaround for the nvidia T241 chip that gets confused in
   3 and 4 socket configurations, leading to the GIC
   malfunctionning in some contexts
 
 - Drop support for non-firmware driven GIC configurarations
   now that the old ARM11MP Cavium board is gone
 
 - Workaround for the Rockchip 3588 chip that doesn't
   correctly deal with the shareability attributes.
 
 - Replace uses of of_find_property() with the more appropriate
   of_property_read_bool()
 
 - Make bcm-6345-l1 request its MMIO region
 
 - Add suspend support to the SiFive PLIC
 
 - Drop support for stih415, stih416 and stid127 platforms
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Merge tag 'irqchip-6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms into irq/core

Pull irqchip changes from Marc Zyngier:

 - Large RISC-V IPI rework to make way for a new interrupt
   architecture

 - More Loongarch fixes from Lianmin Lv, fixing issues in the so
   called "dual-bridge" systems.

 - Workaround for the nvidia T241 chip that gets confused in
   3 and 4 socket configurations, leading to the GIC
   malfunctionning in some contexts

 - Drop support for non-firmware driven GIC configurarations
   now that the old ARM11MP Cavium board is gone

 - Workaround for the Rockchip 3588 chip that doesn't
   correctly deal with the shareability attributes.

 - Replace uses of of_find_property() with the more appropriate
   of_property_read_bool()

 - Make bcm-6345-l1 request its MMIO region

 - Add suspend support to the SiFive PLIC

 - Drop support for stih415, stih416 and stid127 platforms

Link: https://lore.kernel.org/lkml/20230421132104.3021536-1-maz@kernel.org
2023-04-21 17:30:57 +02:00
Palmer Dabbelt 310c33dc7a
Merge patch series "Introduce 64b relocatable kernel"
Alexandre Ghiti <alexghiti@rivosinc.com> says:

After multiple attempts, this patchset is now based on the fact that the
64b kernel mapping was moved outside the linear mapping.

The first patch allows to build relocatable kernels but is not selected
by default. That patch is a requirement for KASLR.
The second and third patches take advantage of an already existing powerpc
script that checks relocations at compile-time, and uses it for riscv.

* b4-shazam-merge:
  riscv: Use --emit-relocs in order to move .rela.dyn in init
  riscv: Check relocations at compile time
  powerpc: Move script to check relocations at compile time in scripts/
  riscv: Introduce CONFIG_RELOCATABLE
  riscv: Move .rela.dyn outside of init to avoid empty relocations
  riscv: Prepare EFI header for relocatable kernels

Link: https://lore.kernel.org/r/20230329045329.64565-1-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-04-19 07:47:45 -07:00
Alexandre Ghiti 39b3307294
riscv: Introduce CONFIG_RELOCATABLE
This config allows to compile 64b kernel as PIE and to relocate it at
any virtual address at runtime: this paves the way to KASLR.
Runtime relocation is possible since relocation metadata are embedded into
the kernel.

Note that relocating at runtime introduces an overhead even if the
kernel is loaded at the same address it was linked at and that the compiler
options are those used in arm64 which uses the same RELA relocation
format.

Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20230329045329.64565-4-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-04-19 07:46:30 -07:00
Palmer Dabbelt 2667e3673f
Merge patch series "RISC-V kasan rework"
Alexandre Ghiti <alexghiti@rivosinc.com> says:

As described in patch 2, our current kasan implementation is intricate,
so I tried to simplify the implementation and mimic what arm64/x86 are
doing.

In addition it fixes UEFI bootflow with a kasan kernel and kasan inline
instrumentation: all kasan configurations were tested on a large ubuntu
kernel with success with KASAN_KUNIT_TEST and KASAN_MODULE_TEST.

inline ubuntu config + uefi:
 sv39: OK
 sv48: OK
 sv57: OK

outline ubuntu config + uefi:
 sv39: OK
 sv48: OK
 sv57: OK

Actually 1 test always fails with KASAN_KUNIT_TEST that I have to check:
KASAN failure expected in "set_bit(nr, addr)", but none occurrred

Note that Palmer recently proposed to remove COMMAND_LINE_SIZE from the
userspace abi
https://lore.kernel.org/lkml/20221211061358.28035-1-palmer@rivosinc.com/T/
so that we can finally increase the command line to fit all kasan kernel
parameters.

All of this should hopefully fix the syzkaller riscv build that has been
failing for a few months now, any test is appreciated and if I can help
in any way, please ask.

* b4-shazam-merge:
  riscv: Unconditionnally select KASAN_VMALLOC if KASAN
  riscv: Fix ptdump when KASAN is enabled
  riscv: Fix EFI stub usage of KASAN instrumented strcmp function
  riscv: Move DTB_EARLY_BASE_VA to the kernel address space
  riscv: Rework kasan population functions
  riscv: Split early and final KASAN population functions

Link: https://lore.kernel.org/r/20230203075232.274282-1-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-04-19 07:24:56 -07:00
Alexandre Ghiti 864046c512
riscv: Unconditionnally select KASAN_VMALLOC if KASAN
If KASAN is enabled, VMAP_STACK depends on KASAN_VMALLOC so enable
KASAN_VMALLOC with KASAN so that we can enable VMAP_STACK by default.

Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Reviewed-by: Björn Töpel <bjorn@rivosinc.com>
Link: https://lore.kernel.org/r/20230203075232.274282-7-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-04-19 07:24:54 -07:00
Conor Dooley 5464912cfa
RISC-V: align ISA extension Kconfig help text with each other
Other extensions only capitalise the first letter in the text visible
in Kconfig menus, and provide a short comment about the extension's
meaning. Do the same for Svnapot & Svpbmt.

The precedent for capitalisation in the Kconfig text was set by Zicbom
& sorta followed for Zicboz. The RVI styling used for multi-letter
extensions only capitalises the first letter, so do the same here.
If nothing else, my OCD likes it when the extensions follow a consistent
pattern.

While editing one of the lines, reformat the "spelling" of 64-bit.

Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Link: https://lore.kernel.org/r/20230405-pucker-cogwheel-3a999a94a2f2@wendy
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-04-18 20:37:21 -07:00
Song Shuai 8bf7b3b667
riscv: Kconfig: enable SCHED_MC kconfig
RISC-V now builds the sched domain based on the simple possible map.

Enable SCHED_MC to make the building based on cpu_coregroup_mask()
which also takes care of the NUMA and cores with LLC.

Signed-off-by: Song Shuai <suagrfillet@gmail.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230310110336.970985-1-suagrfillet@gmail.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-04-18 20:35:43 -07:00
Palmer Dabbelt eb04e72b34
Merge patch series "RISC-V Hardware Probing User Interface"
Evan Green <evan@rivosinc.com> says:

There's been a bunch of off-list discussions about this, including at
Plumbers.  The original plan was to do something involving providing an
ISA string to userspace, but ISA strings just aren't sufficient for a
stable ABI any more: in order to parse an ISA string users need the
version of the specifications that the string is written to, the version
of each extension (sometimes at a finer granularity than the RISC-V
releases/versions encode), and the expected use case for the ISA string
(ie, is it a U-mode or M-mode string).  That's a lot of complexity to
try and keep ABI compatible and it's probably going to continue to grow,
as even if there's no more complexity in the specifications we'll have
to deal with the various ISA string parsing oddities that end up all
over userspace.

Instead this patch set takes a very different approach and provides a set
of key/value pairs that encode various bits about the system.  The big
advantage here is that we can clearly define what these mean so we can
ensure ABI stability, but it also allows us to encode information that's
unlikely to ever appear in an ISA string (see the misaligned access
performance, for example).  The resulting interface looks a lot like
what arm64 and x86 do, and will hopefully fit well into something like
ACPI in the future.

The actual user interface is a syscall, with a vDSO function in front of
it. The vDSO function can answer some queries without a syscall at all,
and falls back to the syscall for cases it doesn't have answers to.
Currently we prepopulate it with an array of answers for all keys and
a CPU set of "all CPUs". This can be adjusted as necessary to provide
fast answers to the most common queries.

An example series in glibc exposing this syscall and using it in an
ifunc selector for memcpy can be found at [1].

I was asked about the performance delta between this and something like
sysfs. I created a small test program and ran it on a Nezha D1
Allwinner board. Doing each operation 100000 times and dividing, these
operations take the following amount of time:
 - open()+read()+close() of /sys/kernel/cpu_byteorder: 3.8us
 - access("/sys/kernel/cpu_byteorder", R_OK): 1.3us
 - riscv_hwprobe() vDSO and syscall: .0094us
 - riscv_hwprobe() vDSO with no syscall: 0.0091us

These numbers get farther apart if we query multiple keys, as sysfs will
scale linearly with the number of keys, where the dedicated syscall
stays the same. To frame these numbers, I also did a tight
fork/exec/wait loop, which I measured as 4.8ms. So doing 4
open/read/close operations is a delta of about 0.3%, versus a single vDSO
call is a delta of essentially zero.

[1] https://patchwork.ozlabs.org/project/glibc/list/?series=343050

* b4-shazam-merge:
  RISC-V: Add hwprobe vDSO function and data
  selftests: Test the new RISC-V hwprobe interface
  RISC-V: hwprobe: Support probing of misaligned access performance
  RISC-V: hwprobe: Add support for RISCV_HWPROBE_BASE_BEHAVIOR_IMA
  RISC-V: Add a syscall for HW probing
  RISC-V: Move struct riscv_cpuinfo to new header

Link: https://lore.kernel.org/r/20230407231103.2622178-1-evan@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-04-18 19:49:51 -07:00
Evan Green aa5af0aa90
RISC-V: Add hwprobe vDSO function and data
Add a vDSO function __vdso_riscv_hwprobe, which can sit in front of the
riscv_hwprobe syscall and answer common queries. We stash a copy of
static answers for the "all CPUs" case in the vDSO data page. This data
is private to the vDSO, so we can decide later to change what's stored
there or under what conditions we defer to the syscall. Currently all
data can be discovered at boot, so the vDSO function answers all queries
when the cpumask is set to the "all CPUs" hint.

There's also a boolean in the data that lets the vDSO function know that
all CPUs are the same. In that case, the vDSO will also answer queries
for arbitrary CPU masks in addition to the "all CPUs" hint.

Signed-off-by: Evan Green <evan@rivosinc.com>
Link: https://lore.kernel.org/r/20230407231103.2622178-7-evan@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-04-18 15:48:18 -07:00
Anup Patel 832f15f426 RISC-V: Treat IPIs as normal Linux IRQs
Currently, the RISC-V kernel provides arch specific hooks (i.e.
struct riscv_ipi_ops) to register IPI handling methods. The stats
gathering of IPIs is also arch specific in the RISC-V kernel.

Other architectures (such as ARM, ARM64, and MIPS) have moved away
from custom arch specific IPI handling methods. Currently, these
architectures have Linux irqchip drivers providing a range of Linux
IRQ numbers to be used as IPIs and IPI triggering is done using
generic IPI APIs. This approach allows architectures to treat IPIs
as normal Linux IRQs and IPI stats gathering is done by the generic
Linux IRQ subsystem.

We extend the RISC-V IPI handling as-per above approach so that arch
specific IPI handling methods (struct riscv_ipi_ops) can be removed
and the IPI handling is done through the Linux IRQ subsystem.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230328035223.1480939-4-apatel@ventanamicro.com
2023-04-08 11:26:24 +01:00
Jiaxun Yang c00a60d6f4 of: address: always use dma_default_coherent for default coherency
As for now all arches have dma_default_coherent reflecting default
DMA coherency for of devices, so there is no need to have a standalone
config option.

Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Signed-off-by: Christoph Hellwig <hch@lst.de>
2023-04-07 07:38:28 +02:00
Niklas Schnelle fcbfe8121a
Kconfig: introduce HAS_IOPORT option and select it as necessary
We introduce a new HAS_IOPORT Kconfig option to indicate support for I/O
Port access. In a future patch HAS_IOPORT=n will disable compilation of
the I/O accessor functions inb()/outb() and friends on architectures
which can not meaningfully support legacy I/O spaces such as s390.

The following architectures do not select HAS_IOPORT:

* ARC
* C-SKY
* Hexagon
* Nios II
* OpenRISC
* s390
* User-Mode Linux
* Xtensa

All other architectures select HAS_IOPORT at least conditionally.

The "depends on" relations on HAS_IOPORT in drivers as well as ifdefs
for HAS_IOPORT specific sections will be added in subsequent patches on
a per subsystem basis.

Co-developed-by: Arnd Bergmann <arnd@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@kernel.org>
Acked-by: Johannes Berg <johannes@sipsolutions.net> # for ARCH=um
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2023-04-05 22:15:19 +02:00
Conor Dooley d34a6b715a
RISC-V: convert new selectors of RISCV_ALTERNATIVE to dependencies
for-next contains two additional extensions that select
RISCV_ALTERNATIVE. RISCV_ALTERNATIVE no longer needs to be selected by
individual config options as it is now selected for !XIP_KERNEL builds
by the top level RISCV option.
These extensions rely on the alternative framework, so convert the
"select"s to "depends on"s instead.

Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Link: https://lore.kernel.org/r/20230324121240.3594777-1-conor.dooley@microchip.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-29 12:27:01 -07:00
Palmer Dabbelt be693ef2a4
Merge patch series "RISC-V: Fixes for riscv_has_extension[un]likely()'s alternative dependency"
Conor Dooley <conor.dooley@microchip.com> says:

Here's my attempt at fixing both the use of an FPU on XIP kernels and
the issue that Jason ran into where CONFIG_FPU, which needs the
alternatives frame work for has_fpu() checks, could be enabled without
the alternatives actually being present.

For the former, a "slow" fallback that does not use alternatives is
added to riscv_has_extension_[un]likely() that can be used with XIP.
Obviously, we want to make use of Jisheng's alternatives based approach
where possible, so any users of riscv_has_extension_[un]likely() will
want to make sure that they select RISCV_ALTERNATIVE.
If they don't however, they'll hit the fallback path which (should,
sparing a silly mistake from me!) behave in the same way, thus
succeeding silently. Sounds like a

To prevent "depends on !XIP_KERNEL; select RISCV_ALTERNATIVE" spreading
like the plague through the various places that want to check for the
presence of extensions, and sidestep the potential silent "success"
mentioned above, all users RISCV_ALTERNATIVE are converted from selects
to dependencies, with the option being selected for all !XIP_KERNEL
builds.

I know that the VDSO was a key place that Jisheng wanted to use the new
helper rather than static branches, and I think the fallback path
should not cause issues there.

See the thread at [1] for the prior discussion.

1 - https://lore.kernel.org/linux-riscv/20230128172856.3814-1-jszhang@kernel.org/T/#m21390d570997145d31dd8bb95002fd61f99c6573

[Palmer: these were also merged into fixes, but there's a cleanup that
depends on the merge so I'm taking it into for-next as well.]

* b4-shazam-merge:
  RISC-V: always select RISCV_ALTERNATIVE for non-xip kernels
  RISC-V: add non-alternative fallback for riscv_has_extension_[un]likely()

Link: https://lore.kernel.org/r/20230324100538.3514663-1-conor.dooley@microchip.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

* commit '1ee7fc3f4d0a93831a20d5566f203d5ad6d44de8':
  RISC-V: always select RISCV_ALTERNATIVE for non-xip kernels
  RISC-V: add non-alternative fallback for riscv_has_extension_[un]likely()
2023-03-29 12:26:38 -07:00
Palmer Dabbelt 4622f15909
Merge patch series "RISC-V: Fixes for riscv_has_extension[un]likely()'s alternative dependency"
Conor Dooley <conor.dooley@microchip.com> says:

Here's my attempt at fixing both the use of an FPU on XIP kernels and
the issue that Jason ran into where CONFIG_FPU, which needs the
alternatives frame work for has_fpu() checks, could be enabled without
the alternatives actually being present.

For the former, a "slow" fallback that does not use alternatives is
added to riscv_has_extension_[un]likely() that can be used with XIP.
Obviously, we want to make use of Jisheng's alternatives based approach
where possible, so any users of riscv_has_extension_[un]likely() will
want to make sure that they select RISCV_ALTERNATIVE.
If they don't however, they'll hit the fallback path which (should,
sparing a silly mistake from me!) behave in the same way, thus
succeeding silently. Sounds like a

To prevent "depends on !XIP_KERNEL; select RISCV_ALTERNATIVE" spreading
like the plague through the various places that want to check for the
presence of extensions, and sidestep the potential silent "success"
mentioned above, all users RISCV_ALTERNATIVE are converted from selects
to dependencies, with the option being selected for all !XIP_KERNEL
builds.

I know that the VDSO was a key place that Jisheng wanted to use the new
helper rather than static branches, and I think the fallback path
should not cause issues there.

See the thread at [1] for the prior discussion.

1 - https://lore.kernel.org/linux-riscv/20230128172856.3814-1-jszhang@kernel.org/T/#m21390d570997145d31dd8bb95002fd61f99c6573

[Palmer: merging in the fixes as a branch as there's some features that
depend on it.]

* b4-shazam-merge:
  RISC-V: always select RISCV_ALTERNATIVE for non-xip kernels
  RISC-V: add non-alternative fallback for riscv_has_extension_[un]likely()

Link: https://lore.kernel.org/r/20230324100538.3514663-1-conor.dooley@microchip.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-29 12:23:00 -07:00
Conor Dooley 1ee7fc3f4d
RISC-V: always select RISCV_ALTERNATIVE for non-xip kernels
When moving switch_to's has_fpu() over to using
riscv_has_extension_likely() rather than static branches, the FPU code
gained a dependency on the alternatives framework.
That dependency has now been removed, as riscv_has_extension_ikely() now
contains a fallback path, using __riscv_isa_extension_available(), but
if CONFIG_RISCV_ALTERNATIVE isn't selected when CONFIG_FPU is, has_fpu()
checks will not benefit from the "fast path" that the alternatives
framework provides.

We want to ensure that alternatives are available whenever
riscv_has_extension_[un]likely() is used, rather than silently falling
back to the slow path, but rather than rely on selecting
RISCV_ALTERNATIVE in the myriad of locations that may use
riscv_has_extension_[un]likely(), select it (almost) always instead by
adding it to the main RISCV config entry.
xip kernels cannot make use of the alternatives framework, so it is not
enabled for those configurations, although this is the status quo.

All current sites that select RISCV_ALTERNATIVE are converted to
dependencies on the option instead. The explicit dependencies on
!XIP_KERNEL can be dropped, as RISCV_ALTERNATIVE is not user selectable.

Fixes: 702e64550b ("riscv: fpu: switch has_fpu() to riscv_has_extension_likely()")
Link: https://lore.kernel.org/all/ZBruFRwt3rUVngPu@zx2c4.com/
Reported-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Jason A. Donenfeld <Jason@zx2c4.com>
Link: https://lore.kernel.org/r/20230324100538.3514663-3-conor.dooley@microchip.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-29 11:48:39 -07:00
Palmer Dabbelt e97be4fbc1
Merge patch series "Add RISC-V 32 NOMMU support"
Jesse Taube <mr.bossman075@gmail.com> says:

This patch-set aims to add NOMMU support to RV32.
Many people want to build simple emulators or HDL
models of RISC-V this patch makes it possible to
run linux on them.

Yimin Gu is the original author of this set.
Submitted here:
https://lists.buildroot.org/pipermail/buildroot/2022-November/656134.html

Though Jesse T rewrote the Dconf.

* b4-shazam-merge:
  riscv: configs: Add nommu PHONY defconfig for RV32
  riscv: Kconfig: Allow RV32 to build with no MMU

Link: https://lore.kernel.org/r/20230301002657.352637-1-Mr.Bossman075@gmail.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-27 16:27:49 -07:00
Yimin Gu b5e2c507b0
riscv: Kconfig: Allow RV32 to build with no MMU
Some RISC-V 32bit cores do not have an MMU, and the kernel should be
able to build for them. This patch enables the RV32 to be built with
no MMU support.

Signed-off-by: Yimin Gu <ustcymgu@gmail.com>
CC: Jesse Taube <Mr.Bossman075@gmail.com>
Tested-by: Waldemar Brodkorb <wbx@openadk.org>
Signed-off-by: Jesse Taube <Mr.Bossman075@gmail.com>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230301002657.352637-3-Mr.Bossman075@gmail.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-27 16:27:46 -07:00
Palmer Dabbelt e45d6a52fe
Merge patch series "riscv: Add GENERIC_ENTRY support"
guoren@kernel.org <guoren@kernel.org> says:

From: Guo Ren <guoren@linux.alibaba.com>

The patches convert riscv to use the generic entry infrastructure from
kernel/entry/*. Some optimization for entry.S with new .macro and merge
ret_from_kernel_thread into ret_from_fork.

* b4-shazam-merge:
  riscv: entry: Consolidate general regs saving/restoring
  riscv: entry: Consolidate ret_from_kernel_thread into ret_from_fork
  riscv: entry: Remove extra level wrappers of trace_hardirqs_{on,off}
  riscv: entry: Convert to generic entry
  riscv: entry: Add noinstr to prevent instrumentation inserted
  riscv: ptrace: Remove duplicate operation

Link: https://lore.kernel.org/r/20230222033021.983168-1-guoren@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-24 13:34:43 -07:00
Nathan Chancellor e89c2e815e
riscv: Handle zicsr/zifencei issues between clang and binutils
There are two related issues that appear in certain combinations with
clang and GNU binutils.

The first occurs when a version of clang that supports zicsr or zifencei
via '-march=' [1] (i.e, >= 17.x) is used in combination with a version
of GNU binutils that do not recognize zicsr and zifencei in the
'-march=' value (i.e., < 2.36):

  riscv64-linux-gnu-ld: -march=rv64i2p0_m2p0_a2p0_c2p0_zicsr2p0_zifencei2p0: Invalid or unknown z ISA extension: 'zifencei'
  riscv64-linux-gnu-ld: failed to merge target specific data of file fs/efivarfs/file.o
  riscv64-linux-gnu-ld: -march=rv64i2p0_m2p0_a2p0_c2p0_zicsr2p0_zifencei2p0: Invalid or unknown z ISA extension: 'zifencei'
  riscv64-linux-gnu-ld: failed to merge target specific data of file fs/efivarfs/super.o

The second occurs when a version of clang that does not support zicsr or
zifencei via '-march=' (i.e., <= 16.x) is used in combination with a
version of GNU as that defaults to a newer ISA base spec, which requires
specifying zicsr and zifencei in the '-march=' value explicitly (i.e, >=
2.38):

  ../arch/riscv/kernel/kexec_relocate.S: Assembler messages:
  ../arch/riscv/kernel/kexec_relocate.S:147: Error: unrecognized opcode `fence.i', extension `zifencei' required
  clang-12: error: assembler command failed with exit code 1 (use -v to see invocation)

This is the same issue addressed by commit 6df2a016c0 ("riscv: fix
build with binutils 2.38") (see [2] for additional information) but
older versions of clang miss out on it because the cc-option check
fails:

  clang-12: error: invalid arch name 'rv64imac_zicsr_zifencei', unsupported standard user-level extension 'zicsr'
  clang-12: error: invalid arch name 'rv64imac_zicsr_zifencei', unsupported standard user-level extension 'zicsr'

To resolve the first issue, only attempt to add zicsr and zifencei to
the march string when using the GNU assembler 2.38 or newer, which is
when the default ISA spec was updated, requiring these extensions to be
specified explicitly. LLVM implements an older version of the base
specification for all currently released versions, so these instructions
are available as part of the 'i' extension. If LLVM's implementation is
updated in the future, a CONFIG_AS_IS_LLVM condition can be added to
CONFIG_TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI.

To resolve the second issue, use version 2.2 of the base ISA spec when
using an older version of clang that does not support zicsr or zifencei
via '-march=', as that is the spec version most compatible with the one
clang/LLVM implements and avoids the need to specify zicsr and zifencei
explicitly due to still being a part of 'i'.

[1]: 22e199e6af
[2]: https://lore.kernel.org/ZAxT7T9Xy1Fo3d5W@aurel32.net/

Cc: stable@vger.kernel.org
Link: https://github.com/ClangBuiltLinux/linux/issues/1808
Co-developed-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230313-riscv-zicsr-zifencei-fiasco-v1-1-dd1b7840a551@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-23 12:52:49 -07:00
Guo Ren f0bddf5058
riscv: entry: Convert to generic entry
This patch converts riscv to use the generic entry infrastructure from
kernel/entry/*. The generic entry makes maintainers' work easier and
codes more elegant. Here are the changes:

 - More clear entry.S with handle_exception and ret_from_exception
 - Get rid of complex custom signal implementation
 - Move syscall procedure from assembly to C, which is much more
   readable.
 - Connect ret_from_fork & ret_from_kernel_thread to generic entry.
 - Wrap with irqentry_enter/exit and syscall_enter/exit_from_user_mode
 - Use the standard preemption code instead of custom

Suggested-by: Huacai Chen <chenhuacai@kernel.org>
Reviewed-by: Björn Töpel <bjorn@rivosinc.com>
Tested-by: Yipeng Zou <zouyipeng@huawei.com>
Tested-by: Jisheng Zhang <jszhang@kernel.org>
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
Cc: Ben Hutchings <ben@decadent.org.uk>
Link: https://lore.kernel.org/r/20230222033021.983168-5-guoren@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-23 08:47:00 -07:00
Palmer Dabbelt 4b740779ac
Merge patch series "RISC-V: Apply Zicboz to clear_page"
Andrew Jones <ajones@ventanamicro.com> says:

When the Zicboz extension is available we can more rapidly zero naturally
aligned Zicboz block sized chunks of memory. As pages are always page
aligned and are larger than any Zicboz block size will be, then
clear_page() appears to be a good candidate for the extension. While cycle
count and energy consumption should also be considered, we can be pretty
certain that implementing clear_page() with the Zicboz extension is a win
by comparing the new dynamic instruction count with its current count[1].
Doing so we see that the new count is just over a quarter of the old count
(see patch6's commit message for more details).

For those of you who reviewed v1[2], you may be looking for the memset()
patches. As pointed out in v1, and a couple follow-up emails, it's not
clear that patching memset() is a win yet. When I get a chance to test
on real hardware with a comprehensive benchmark collection then I can
post the memset() patches separately (assuming the benchmarks show it's
worthwhile).

* b4-shazam-merge:
  RISC-V: KVM: Expose Zicboz to the guest
  RISC-V: KVM: Provide UAPI for Zicboz block size
  RISC-V: Use Zicboz in clear_page when available
  RISC-V: cpufeatures: Put the upper 16 bits of patch ID to work
  RISC-V: Add Zicboz detection and block size parsing
  dt-bindings: riscv: Document cboz-block-size
  RISC-V: Factor out body of riscv_init_cbom_blocksize loop
  RISC-V: alternatives: Support patching multiple insns in assembly

Link: https://lore.kernel.org/r/20230224162631.405473-1-ajones@ventanamicro.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-15 07:11:08 -07:00
Andrew Jones ab0f77465e
RISC-V: Use Zicboz in clear_page when available
Using memset() to zero a 4K page takes 563 total instructions, where
20 are branches. clear_page(), with Zicboz and a 64 byte block size,
takes 169 total instructions, where 4 are branches and 33 are nops.
Even though the block size is a variable, thanks to alternatives, we
can still implement a Duff device without having to do any preliminary
calculations. This is achieved by using the alternatives' cpufeature
value (the upper 16 bits of patch_id). The value used is the maximum
zicboz block size order accepted at the patch site. This enables us
to stop patching / unrolling when 4K bytes have been zeroed (we would
loop and continue after 4K if the page size would be larger)

For 4K pages, unrolling 16 times allows block sizes of 64 and 128 to
only loop a few times and larger block sizes to not loop at all. Since
cbo.zero doesn't take an offset, we also need an 'add' after each
instruction, making the loop body 112 to 160 bytes. Hopefully this
is small enough to not cause icache misses.

Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230224162631.405473-7-ajones@ventanamicro.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-14 21:26:06 -07:00
Palmer Dabbelt 73bde0ca0a
Merge patch series "riscv: alternative/cpufeature related cleanups"
Andrew Jones <ajones@ventanamicro.com> says:

This series has no intended functional change. These cleanups were
found while renaming errata_id to patch_id in order to better
convey that its purpose is larger than errata (it's also for
cpufeatures).

* b4-shazam-merge:
  riscv: cpufeature: Drop errata_list.h and other unused includes
  riscv: lib: Include hwcap.h directly
  riscv: alternatives: Rename errata_id to patch_id
  riscv: alternatives: Remove unnecessary define and unused struct
  riscv: Rename Kconfig.erratas to Kconfig.errata
  riscv: Clarify RISCV_ALTERNATIVE help text

Link: https://lore.kernel.org/r/20230224154601.88163-1-ajones@ventanamicro.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-14 20:51:34 -07:00
Andrew Jones ff19a8dee1
riscv: alternatives: Rename errata_id to patch_id
Alternatives are used for both errata and cpufeatures. Use a more
generic name, 'patch_id', as in "ID of code patching site", to
avoid confusion when alternatives are used for cpufeatures.

Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Heiko Stuebner <heiko.stuebner@vrull.eu>
Link: https://lore.kernel.org/r/20230224154601.88163-5-ajones@ventanamicro.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-14 20:51:23 -07:00
Andrew Jones a3d095ac00
riscv: Rename Kconfig.erratas to Kconfig.errata
Errata is already plural for erratum. Rename it to make the
grammar gooder.

Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Heiko Stuebner <heiko.stuebner@vrull.eu>
Link: https://lore.kernel.org/r/20230224154601.88163-3-ajones@ventanamicro.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-14 20:51:21 -07:00
Andrew Jones 099122af4e
riscv: Clarify RISCV_ALTERNATIVE help text
Clarify RISCV_ALTERNATIVE's help text by pointing out that code
patching is not only done at boot time, but also module load time.
Also point out that this is the minimal possible overhead.

Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
Link: https://lore.kernel.org/r/20230224154601.88163-2-ajones@ventanamicro.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-14 20:51:20 -07:00
Palmer Dabbelt 4a4c459872
Merge patch series "riscv, mm: detect svnapot cpu support at runtime"
Qinglin Pan <panqinglin00@gmail.com> says:

Svnapot is a RISC-V extension for marking contiguous 4K pages as a non-4K
page. This patch set is for using Svnapot in hugetlb fs and huge vmap.

This patchset adds a Kconfig item for using Svnapot in
"Platform type"->"SVNAPOT extension support". Its default value is on,
and people can set it off if they don't allow kernel to detect Svnapot
hardware support and leverage it.

Tested on:
  - qemu rv64 with "Svnapot support" off and svnapot=true.
  - qemu rv64 with "Svnapot support" on and svnapot=true.
  - qemu rv64 with "Svnapot support" off and svnapot=false.
  - qemu rv64 with "Svnapot support" on and svnapot=false.

* b4-shazam-merge:
  riscv: mm: support Svnapot in huge vmap
  riscv: mm: support Svnapot in hugetlb page
  riscv: mm: modify pte format for Svnapot

Link: https://lore.kernel.org/r/20230209131647.17245-1-panqinglin00@gmail.com
[Palmer: fix up the feature ordering in the merge]
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-09 18:13:45 -08:00
Qinglin Pan 82a1a1f3bf
riscv: mm: support Svnapot in hugetlb page
Svnapot can be used to support 64KB hugetlb page, so it can become a new
option when using hugetlbfs. Add a basic implementation of hugetlb page,
and support 64KB as a size in it by using Svnapot.

For test, boot kernel with command line contains "default_hugepagesz=64K
hugepagesz=64K hugepages=20" and run a simple test like this:

tools/testing/selftests/vm/map_hugetlb 1 16

And it should be passed.

Signed-off-by: Qinglin Pan <panqinglin00@gmail.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Link: https://lore.kernel.org/r/20230209131647.17245-3-panqinglin00@gmail.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-07 19:39:16 -08:00
Qinglin Pan 23ad288aaf
riscv: mm: modify pte format for Svnapot
Add one alternative to enable/disable svnapot support, enable this static
key when "svnapot" is in the "riscv,isa" field of fdt and SVNAPOT compile
option is set. It will influence the behavior of has_svnapot. All code
dependent on svnapot should make sure that has_svnapot return true firstly.

Modify PTE definition for Svnapot, and creates some functions in pgtable.h
to mark a PTE as napot and check if it is a Svnapot PTE. Until now, only
64KB napot size is supported in spec, so some macros has only 64KB version.

Signed-off-by: Qinglin Pan <panqinglin00@gmail.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Link: https://lore.kernel.org/r/20230209131647.17245-2-panqinglin00@gmail.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-07 19:39:15 -08:00
Linus Torvalds 01687e7c93 RISC-V Patches for the 6.3 Merge Window, Part 1
There's a bunch of fixes/cleanups throughout the tree as usual, but we
 also have a handful of new features.
 
 * Various improvements to the extension detection and alternative
   patching infrastructure.
 * Zbb-optimized string routines.
 * Support for cpu-capacity in the RISC-V DT bindings.
 * Zicbom no longer depends on toolchain support.
 * Some performance and code size improvements to ftrace.
 * Support for ARCH_WANT_LD_ORPHAN_WARN.
 * Oops now contain the faulting instruction.
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Merge tag 'riscv-for-linus-6.3-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull RISC-V updates from Palmer Dabbelt:
 "There's a bunch of fixes/cleanups throughout the tree as usual, but we
  also have a handful of new features:

   - Various improvements to the extension detection and alternative
     patching infrastructure

   - Zbb-optimized string routines

   - Support for cpu-capacity in the RISC-V DT bindings

   - Zicbom no longer depends on toolchain support

   - Some performance and code size improvements to ftrace

   - Support for ARCH_WANT_LD_ORPHAN_WARN

   - Oops now contain the faulting instruction"

* tag 'riscv-for-linus-6.3-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (67 commits)
  RISC-V: add a spin_shadow_stack declaration
  riscv: mm: hugetlb: Enable ARCH_WANT_HUGETLB_PAGE_OPTIMIZE_VMEMMAP
  riscv: Add header include guards to insn.h
  riscv: alternative: proceed one more instruction for auipc/jalr pair
  riscv: Avoid enabling interrupts in die()
  riscv, mm: Perform BPF exhandler fixup on page fault
  RISC-V: take text_mutex during alternative patching
  riscv: hwcap: Don't alphabetize ISA extension IDs
  RISC-V: fix ordering of Zbb extension
  riscv: jump_label: Fixup unaligned arch_static_branch function
  RISC-V: Only provide the single-letter extensions in HWCAP
  riscv: mm: fix regression due to update_mmu_cache change
  scripts/decodecode: Add support for RISC-V
  riscv: Add instruction dump to RISC-V splats
  riscv: select ARCH_WANT_LD_ORPHAN_WARN for !XIP_KERNEL
  riscv: vmlinux.lds.S: explicitly catch .init.bss sections from EFI stub
  riscv: vmlinux.lds.S: explicitly catch .riscv.attributes sections
  riscv: vmlinux.lds.S: explicitly catch .rela.dyn symbols
  riscv: lds: define RUNTIME_DISCARD_EXIT
  RISC-V: move some stray __RISCV_INSN_FUNCS definitions from kprobes
  ...
2023-02-25 11:14:08 -08:00
Guo Ren a3c7d6b642
riscv: mm: hugetlb: Enable ARCH_WANT_HUGETLB_PAGE_OPTIMIZE_VMEMMAP
Add HVO support for RISC-V; see commit 6be24bed9d ("mm: hugetlb:
introduce a new config HUGETLB_PAGE_FREE_VMEMMAP"). This patch is
similar to commit 1e63ac088f ("arm64: mm: hugetlb: enable
HUGETLB_PAGE_FREE_VMEMMAP for arm64"), and riscv's motivation is the
same as arm64. The current riscv was ready to enable HVO after fixup,
ref commit d33deda095 ("riscv/mm: hugepage's PG_dcache_clean flag
is only set in head page").

See Documentation/mm/vmemmap_dedup.rst for more details.

The HugeTLB VmemmapvOptimization (HVO) defaults to off in Kconfig.

Here is the riscv test log:
cat /proc/sys/vm/hugetlb_optimize_vmemmap
echo 8 > /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages
mount -t hugetlbfs none test/ -o pagesize=2048k
<Try some simple hugetlb test in test dir, no problem found.>

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
Link: https://lore.kernel.org/linux-riscv/1F5AF29D-708A-483B-A29F-CAEE6F554866@linux.dev/
Acked-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Link: https://lore.kernel.org/r/20230201015259.3222524-1-guoren@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-02-21 17:28:12 -08:00
Palmer Dabbelt f3af3b0039
Merge patch series "riscv: improve link and support ARCH_WANT_LD_ORPHAN_WARN"
Jisheng Zhang <jszhang@kernel.org> says:

This series tries to improve link time handling of riscv:
patch1 adds the missing RUNTIME_DISCARD_EXIT as suggested by Masahiro.

Similar as other architectures such as x86, arm64 and so on, enable
ARCH_WANT_LD_ORPHAN_WARN to enable linker orphan warnings to prevent
from missing any new sections in future. So the following two patches
are preparation ones, and the last patch finally selects
ARCH_WANT_LD_ORPHAN_WARN

* b4-shazam-merge:
  riscv: select ARCH_WANT_LD_ORPHAN_WARN for !XIP_KERNEL
  riscv: vmlinux.lds.S: explicitly catch .init.bss sections from EFI stub
  riscv: vmlinux.lds.S: explicitly catch .riscv.attributes sections
  riscv: vmlinux.lds.S: explicitly catch .rela.dyn symbols
  riscv: lds: define RUNTIME_DISCARD_EXIT

Link: https://lore.kernel.org/r/20230119155417.2600-1-jszhang@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-02-21 17:21:49 -08:00
Jisheng Zhang f4b71bff8d
riscv: select ARCH_WANT_LD_ORPHAN_WARN for !XIP_KERNEL
Now, after that all the sections are explicitly described and
declared in vmlinux.lds.S, we can enable ld orphan warnings for
!XIP_KERNEL to prevent from missing any new sections in future.

Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230119155417.2600-6-jszhang@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-02-21 16:29:07 -08:00
Palmer Dabbelt ec6311919e
Merge patch series "riscv: Optimize function trace"
guoren@kernel.org <guoren@kernel.org> says:

From: Guo Ren <guoren@linux.alibaba.com>

The previous ftrace detour implementation fc76b8b8011 ("riscv: Using
PATCHABLE_FUNCTION_ENTRY instead of MCOUNT") contain three problems.

 - The most horrible bug is preemption panic which found by Andy [1].
   Let's disable preemption for ftrace first, and Andy could continue
   the ftrace preemption work.
 - The "-fpatchable-function-entry= CFLAG" wasted code size
   !RISCV_ISA_C.
 - The ftrace detour implementation wasted code size.
 - When livepatching, the trampoline (ftrace_regs_caller) would not
   return to <func_prolog+12> but would rather jump to the new function.
   So, "REG_L ra, -SZREG(sp)" would not run and the original return
   address would not be restored. The kernel is likely to hang or crash
   as a result. (Found by Evgenii Shatokhin [4])

[Palmer: The first three patches in this series are pretty concrete
fixes, so I'm pulling them ahead of the rest of the series.]

* b4-shazam-merge:
  riscv: ftrace: Reduce the detour code size to half
  riscv: ftrace: Remove wasted nops for !RISCV_ISA_C
  riscv: ftrace: Fixup panic by disabling preemption

Link: https://lore.kernel.org/r/20230112090603.1295340-1-guoren@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-02-15 10:59:54 -08:00
Andy Chiu 8547649981
riscv: ftrace: Fixup panic by disabling preemption
In RISCV, we must use an AUIPC + JALR pair to encode an immediate,
forming a jump that jumps to an address over 4K. This may cause errors
if we want to enable kernel preemption and remove dependency from
patching code with stop_machine(). For example, if a task was switched
out on auipc. And, if we changed the ftrace function before it was
switched back, then it would jump to an address that has updated 11:0
bits mixing with previous XLEN:12 part.

p: patched area performed by dynamic ftrace
ftrace_prologue:
p|      REG_S   ra, -SZREG(sp)
p|      auipc   ra, 0x? ------------> preempted
					...
				change ftrace function
					...
p|      jalr    -?(ra) <------------- switched back
p|      REG_L   ra, -SZREG(sp)
func:
	xxx
	ret

Fixes: afc76b8b80 ("riscv: Using PATCHABLE_FUNCTION_ENTRY instead of MCOUNT")
Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
Link: https://lore.kernel.org/r/20230112090603.1295340-2-guoren@kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-02-15 10:58:09 -08:00
Palmer Dabbelt 9a5c09dd97
Merge patch series "Remove toolchain dependencies for Zicbom"
Conor Dooley <conor@kernel.org> says:

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

I've yoinked patch 1 from Drew's series adding support for Zicboz &
attached two more patches here that remove the need for, and then drop
the toolchain support checks for Zicbom. The goal is to remove the need
for checking the presence of toolchain Zicbom support in the work being
done to support non instruction based CMOs [1].

I've tested compliation on a number of different configurations with
the Zicbom config option enabled. The important ones to call out I
guess are:
- clang/llvm 14 w/ LLVM=1 which doesn't support Zicbom atm.
- gcc 11 w/ binutils 2.37 which doesn't support Zicbom atm either.
- clang/llvm 15 w/ LLVM=1 BUT with binutils 2.37's ld. This is the
  configuration that prompted adding the LD checks as cc/as supports
  Zicbom, but ld doesn't [2].
- gcc 12 w/ binutils 2.39 & clang 15 w/ LLVM=1, both of these supported
  Zicbom before and still do.

I also checked building the THEAD errata etc with
CONFIG_RISCV_ISA_ZICBOM disabled, and there were no build issues there
either.

* b4-shazam-merge:
  RISC-V: remove toolchain version checks for Zicbom
  RISC-V: replace cbom instructions with an insn-def
  RISC-V: insn-def: Add I-type insn-def

Link: https://lore.kernel.org/r/20230108163356.3063839-1-conor@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-02-14 21:33:27 -08:00