linux/arch/riscv/Makefile, branch master

arch/riscv: add dual vdso creation logic and select vdso based on hw

2026-01-29T09:38:40Z

Shadow stack instructions are taken from the Zimop ISA extension, which is mandated on RVA23. Any userspace with shadow stack instructions in it will fault on hardware that doesn't have support for Zimop. Thus, a shadow stack-enabled userspace can't be run on hardware that doesn't support Zimop. It's not known how Linux userspace providers will respond to this kind of binary fragmentation. In order to keep kernel portable across different hardware, 'arch/riscv/kernel/vdso_cfi' is created which has Makefile logic to compile 'arch/riscv/kernel/vdso' sources with CFI flags, and 'arch/riscv/kernel/vdso.c' is modified to select the appropriate vdso depending on whether the underlying CPU implements the Zimop extension. Since the offset of vdso symbols will change due to having two different vdso binaries, there is added logic to include a new generated vdso offset header and dynamically select the offset (like for rt_sigreturn). Signed-off-by: Deepak Gupta Acked-by: Charles Mirabile Tested-by: Andreas Korb # QEMU, custom CVA6 Tested-by: Valentin Haudiquet Link: https://patch.msgid.link/20251112-v5_user_cfi_series-v23-24-b55691eacf4f@rivosinc.com [pjw@kernel.org: cleaned up patch description] Signed-off-by: Paul Walmsley

arch/riscv: compile vdso with landing pad and shadow stack note

2026-01-29T09:38:40Z

User mode tasks compiled with Zicfilp may call indirectly into the vdso (like hwprobe indirect calls). Add support for compiling landing pads into the vdso. Landing pad instructions in the vdso will be no-ops for tasks which have not enabled landing pads. Furthermore, add support for the C sources of the vdso to be compiled with shadow stack and landing pads enabled as well. Landing pad and shadow stack instructions are emitted only when the VDSO_CFI cflags option is defined during compile. Signed-off-by: Jim Shu Reviewed-by: Zong Li Signed-off-by: Deepak Gupta Tested-by: Andreas Korb # QEMU, custom CVA6 Tested-by: Valentin Haudiquet Link: https://patch.msgid.link/20251112-v5_user_cfi_series-v23-23-b55691eacf4f@rivosinc.com [pjw@kernel.org: cleaned up patch description, issues reported by checkpatch] Signed-off-by: Paul Walmsley

riscv: Remove redundant judgment for the default build target

2025-11-08T00:39:07Z

The value of KBUILD_IMAGE is derived from $(boot-image-y), so there's no need for redundant checks before this. Signed-off-by: Feng Jiang Reviewed-by: Emil Renner Berthing Link: https://lore.kernel.org/r/20251029094429.553842-2-jiangfeng@kylinos.cn Signed-off-by: Paul Walmsley

riscv: Build loader.bin exclusively for Canaan K210

2025-11-08T00:39:06Z

According to the explanation in commit ef10bdf9c3e6 ("riscv: Kconfig.socs: Split ARCH_CANAAN and SOC_CANAAN_K210"), loader.bin is a special feature of the Canaan K210 and is not applicable to other SoCs. Fixes: e79dfcbfb902 ("riscv: make image compression configurable") Signed-off-by: Feng Jiang Reviewed-by: Emil Renner Berthing Link: https://lore.kernel.org/r/20251029094429.553842-1-jiangfeng@kylinos.cn Signed-off-by: Paul Walmsley

riscv: Unconditionally use linker relaxation

2025-08-28T23:58:45Z

Now that the minimum supported version of LLVM for building the kernel has been bumped to 15.0.0, CONFIG_RISCV_USE_LINKER_RELAXATION will always be enabled, so it can be removed. Acked-by: Alexandre Ghiti Link: https://lore.kernel.org/r/20250821-bump-min-llvm-ver-15-v2-8-635f3294e5f0@kernel.org Signed-off-by: Nathan Chancellor

riscv: Implement HAVE_DYNAMIC_FTRACE_WITH_CALL_OPS

2025-06-05T18:09:30Z

This patch enables support for DYNAMIC_FTRACE_WITH_CALL_OPS on RISC-V. This allows each ftrace callsite to provide an ftrace_ops to the common ftrace trampoline, allowing each callsite to invoke distinct tracer functions without the need to fall back to list processing or to allocate custom trampolines for each callsite. This significantly speeds up cases where multiple distinct trace functions are used and callsites are mostly traced by a single tracer. The idea and most of the implementation is taken from the ARM64's implementation of the same feature. The idea is to place a pointer to the ftrace_ops as a literal at a fixed offset from the function entry point, which can be recovered by the common ftrace trampoline. We use -fpatchable-function-entry to reserve 8 bytes above the function entry by emitting 2 4 byte or 4 2 byte nops depending on the presence of CONFIG_RISCV_ISA_C. These 8 bytes are patched at runtime with a pointer to the associated ftrace_ops for that callsite. Functions are aligned to 8 bytes to make sure that the accesses to this literal are atomic. This approach allows for directly invoking ftrace_ops::func even for ftrace_ops which are dynamically-allocated (or part of a module), without going via ftrace_ops_list_func. We've benchamrked this with the ftrace_ops sample module on Spacemit K1 Jupiter: Without this patch: baseline (Linux rivos 6.14.0-09584-g7d06015d936c #3 SMP Sat Mar 29 +-----------------------+-----------------+----------------------------+ | Number of tracers | Total time (ns) | Per-call average time | |-----------------------+-----------------+----------------------------| | Relevant | Irrelevant | 100000 calls | Total (ns) | Overhead (ns) | |----------+------------+-----------------+------------+---------------| | 0 | 0 | 1357958 | 13 | - | | 0 | 1 | 1302375 | 13 | - | | 0 | 2 | 1302375 | 13 | - | | 0 | 10 | 1379084 | 13 | - | | 0 | 100 | 1302458 | 13 | - | | 0 | 200 | 1302333 | 13 | - | |----------+------------+-----------------+------------+---------------| | 1 | 0 | 13677833 | 136 | 123 | | 1 | 1 | 18500916 | 185 | 172 | | 1 | 2 | 22856459 | 228 | 215 | | 1 | 10 | 58824709 | 588 | 575 | | 1 | 100 | 505141584 | 5051 | 5038 | | 1 | 200 | 1580473126 | 15804 | 15791 | |----------+------------+-----------------+------------+---------------| | 1 | 0 | 13561000 | 135 | 122 | | 2 | 0 | 19707292 | 197 | 184 | | 10 | 0 | 67774750 | 677 | 664 | | 100 | 0 | 714123125 | 7141 | 7128 | | 200 | 0 | 1918065668 | 19180 | 19167 | +----------+------------+-----------------+------------+---------------+ Note: per-call overhead is estimated relative to the baseline case with 0 relevant tracers and 0 irrelevant tracers. With this patch: v4-rc4 (Linux rivos 6.14.0-09598-gd75747611c93 #4 SMP Sat Mar 29 +-----------------------+-----------------+----------------------------+ | Number of tracers | Total time (ns) | Per-call average time | |-----------------------+-----------------+----------------------------| | Relevant | Irrelevant | 100000 calls | Total (ns) | Overhead (ns) | |----------+------------+-----------------+------------+---------------| | 0 | 0 | 1459917 | 14 | - | | 0 | 1 | 1408000 | 14 | - | | 0 | 2 | 1383792 | 13 | - | | 0 | 10 | 1430709 | 14 | - | | 0 | 100 | 1383791 | 13 | - | | 0 | 200 | 1383750 | 13 | - | |----------+------------+-----------------+------------+---------------| | 1 | 0 | 5238041 | 52 | 38 | | 1 | 1 | 5228542 | 52 | 38 | | 1 | 2 | 5325917 | 53 | 40 | | 1 | 10 | 5299667 | 52 | 38 | | 1 | 100 | 5245250 | 52 | 39 | | 1 | 200 | 5238459 | 52 | 39 | |----------+------------+-----------------+------------+---------------| | 1 | 0 | 5239083 | 52 | 38 | | 2 | 0 | 19449417 | 194 | 181 | | 10 | 0 | 67718584 | 677 | 663 | | 100 | 0 | 709840708 | 7098 | 7085 | | 200 | 0 | 2203580626 | 22035 | 22022 | +----------+------------+-----------------+------------+---------------+ Note: per-call overhead is estimated relative to the baseline case with 0 relevant tracers and 0 irrelevant tracers. As can be seen from the above: a) Whenever there is a single relevant tracer function associated with a tracee, the overhead of invoking the tracer is constant, and does not scale with the number of tracers which are *not* associated with that tracee. b) The overhead for a single relevant tracer has dropped to ~1/3 of the overhead prior to this series (from 122ns to 38ns). This is largely due to permitting calls to dynamically-allocated ftrace_ops without going through ftrace_ops_list_func. Signed-off-by: Puranjay Mohan [update kconfig, asm, refactor] Signed-off-by: Andy Chiu Tested-by: Björn Töpel Link: https://lore.kernel.org/r/20250407180838.42877-10-andybnac@gmail.com Signed-off-by: Alexandre Ghiti Signed-off-by: Palmer Dabbelt

Merge tag 'kbuild-v6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

2025-04-05T22:46:50Z

Pull Kbuild updates from Masahiro Yamada: - Improve performance in gendwarfksyms - Remove deprecated EXTRA_*FLAGS and KBUILD_ENABLE_EXTRA_GCC_CHECKS - Support CONFIG_HEADERS_INSTALL for ARCH=um - Use more relative paths to sources files for better reproducibility - Support the loong64 Debian architecture - Add Kbuild bash completion - Introduce intermediate vmlinux.unstripped for architectures that need static relocations to be stripped from the final vmlinux - Fix versioning in Debian packages for -rc releases - Treat missing MODULE_DESCRIPTION() as an error - Convert Nios2 Makefiles to use the generic rule for built-in DTB - Add debuginfo support to the RPM package * tag 'kbuild-v6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (40 commits) kbuild: rpm-pkg: build a debuginfo RPM kconfig: merge_config: use an empty file as initfile nios2: migrate to the generic rule for built-in DTB rust: kbuild: skip `--remap-path-prefix` for `rustdoc` kbuild: pacman-pkg: hardcode module installation path kbuild: deb-pkg: don't set KBUILD_BUILD_VERSION unconditionally modpost: require a MODULE_DESCRIPTION() kbuild: make all file references relative to source root x86: drop unnecessary prefix map configuration kbuild: deb-pkg: add comment about future removal of KDEB_COMPRESS kbuild: Add a help message for "headers" kbuild: deb-pkg: remove "version" variable in mkdebian kbuild: deb-pkg: fix versioning for -rc releases Documentation/kbuild: Fix indentation in modules.rst example x86: Get rid of Makefile.postlink kbuild: Create intermediate vmlinux build with relocations preserved kbuild: Introduce Kconfig symbol for linking vmlinux with relocations kbuild: link-vmlinux.sh: Make output file name configurable kbuild: do not generate .tmp_vmlinux*.map when CONFIG_VMLINUX_MAP=y Revert "kheaders: Ignore silly-rename files" ...

riscv: Remove duplicate CONFIG_PAGE_OFFSET definition

2025-03-26T22:56:38Z

This definition is already provided by include/generated/autoconf.h, so it does not need to be provided on the command line. Signed-off-by: Samuel Holland Reviewed-by: Jesse Taube Link: https://lore.kernel.org/r/20241026171441.3047904-2-samuel.holland@sifive.com Signed-off-by: Palmer Dabbelt

kbuild: Introduce Kconfig symbol for linking vmlinux with relocations

2025-03-16T15:29:50Z

Some architectures build vmlinux with static relocations preserved, but strip them again from the final vmlinux image. Arch specific tools consume these static relocations in order to construct relocation tables for KASLR. The fact that vmlinux is created, consumed and subsequently updated goes against the typical, declarative paradigm used by Make, which is based on rules and dependencies. So as a first step towards cleaning this up, introduce a Kconfig symbol to declare that the arch wants to consume the static relocations emitted into vmlinux. This will be wired up further in subsequent patches. Signed-off-by: Ard Biesheuvel Signed-off-by: Masahiro Yamada

Merge tag 'kbuild-v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

2024-11-30T21:41:50Z

Pull Kbuild updates from Masahiro Yamada: - Add generic support for built-in boot DTB files - Enable TAB cycling for dialog buttons in nconfig - Fix issues in streamline_config.pl - Refactor Kconfig - Add support for Clang's AutoFDO (Automatic Feedback-Directed Optimization) - Add support for Clang's Propeller, a profile-guided optimization. - Change the working directory to the external module directory for M= builds - Support building external modules in a separate output directory - Enable objtool for *.mod.o and additional kernel objects - Use lz4 instead of deprecated lz4c - Work around a performance issue with "git describe" - Refactor modpost * tag 'kbuild-v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (85 commits) kbuild: rename .tmp_vmlinux.kallsyms0.syms to .tmp_vmlinux0.syms gitignore: Don't ignore 'tags' directory kbuild: add dependency from vmlinux to resolve_btfids modpost: replace tdb_hash() with hash_str() kbuild: deb-pkg: add python3:native to build dependency genksyms: reduce indentation in export_symbol() modpost: improve error messages in device_id_check() modpost: rename alias symbol for MODULE_DEVICE_TABLE() modpost: rename variables in handle_moddevtable() modpost: move strstarts() to modpost.h modpost: convert do_usb_table() to a generic handler modpost: convert do_of_table() to a generic handler modpost: convert do_pnp_device_entry() to a generic handler modpost: convert do_pnp_card_entries() to a generic handler modpost: call module_alias_printf() from all do_*_entry() functions modpost: pass (struct module *) to do_*_entry() functions modpost: remove DEF_FIELD_ADDR_VAR() macro modpost: deduplicate MODULE_ALIAS() for all drivers modpost: introduce module_alias_printf() helper modpost: remove unnecessary check in do_acpi_entry() ...