en Copyright 2015 Java http://kernelsources.org:8080/source/history/linux/arch/riscv/lib/strchr.S#feff82eb5f4075d541990d0ba60dad14ea83ea9b Merge tag 'riscv-for-linus-7.1-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linuxPull RISC-V updates from Paul Walmsley: "There is one significant change outside arch/riscv in this pull request: the addition of a set of KUnit tests for strlen(), strnlen(), and strrchr(). Otherwise, the most notable changes are to add some RISC-V-specific string function implementations, to remove XIP kernel support, to add hardware error exception handling, and to optimize our runtime unaligned access speed testing. A few comments on the motivation for removing XIP support. It's been broken in the RISC-V kernel for months. The code is not easy to maintain. Furthermore, for XIP support to truly be useful for RISC-V, we think that compile-time feature switches would need to be added for many of the RISC-V ISA features and microarchitectural properties that are currently implemented with runtime patching. No one has stepped forward to take responsibility for that work, so many of us think it's best to remove it until clear use cases and champions emerge. Summary: - Add Kunit correctness testing and microbenchmarks for strlen(), strnlen(), and strrchr() - Add RISC-V-specific strnlen(), strchr(), strrchr() implementations - Add hardware error exception handling - Clean up and optimize our unaligned access probe code - Enable HAVE_IOREMAP_PROT to be able to use generic_access_phys() - Remove XIP kernel support - Warn when addresses outside the vmemmap range are passed to vmemmap_populate() - Update the ACPI FADT revision check to warn if it's not at least ACPI v6.6, which is when key RISC-V-specific tables were added to the specification - Increase COMMAND_LINE_SIZE to 2048 to match ARM64, x86, PowerPC, etc. - Make kaslr_offset() a static inline function, since there's no need for it to show up in the symbol table - Add KASLR offset and SATP to the VMCOREINFO ELF notes to improve kdump support - Add Makefile cleanup rule for vdso_cfi copied source files, and add a .gitignore for the build artifacts in that directory - Remove some redundant ifdefs that check Kconfig macros - Add missing SPDX license tag to the CFI selftest - Simplify UTS_MACHINE assignment in the RISC-V Makefile - Clarify some unclear comments and remove some superfluous comments - Fix various English typos across the RISC-V codebase"* tag 'riscv-for-linus-7.1-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (31 commits) riscv: Remove support for XIP kernel riscv: Reuse compare_unaligned_access() in check_vector_unaligned_access() riscv: Split out compare_unaligned_access() riscv: Reuse measure_cycles() in check_vector_unaligned_access() riscv: Split out measure_cycles() for reuse riscv: Clean up & optimize unaligned scalar access probe riscv: lib: add strrchr() implementation riscv: lib: add strchr() implementation riscv: lib: add strnlen() implementation lib/string_kunit: extend benchmarks to strnlen() and chr searches lib/string_kunit: add performance benchmark for strlen() lib/string_kunit: add correctness test for strrchr() lib/string_kunit: add correctness test for strnlen() lib/string_kunit: add correctness test for strlen() riscv: vdso_cfi: Add .gitignore for build artifacts riscv: vdso_cfi: Add clean rule for copied sources riscv: enable HAVE_IOREMAP_PROT riscv: mm: WARN_ON() for bad addresses in vmemmap_populate() riscv: acpi: update FADT revision check to 6.6 riscv: add hardware error trap handler support ... List of files: /linux/arch/riscv/lib/strchr.S Fri, 24 Apr 2026 19:00:37 +0200 Linus Torvalds <torvalds@linux-foundation.org> http://kernelsources.org:8080/source/history/linux/arch/riscv/lib/strchr.S#adf542133960d402f63c976b00e46be4d986d4c3 riscv: lib: add strchr() implementationAdd an assembly implementation of strchr() for RISC-V.By eliminating stack frame management (prologue/epilogue) and optimizingthe function entries, the assembly version provides significant relativegains for short strings where the fixed overhead of the C function ismost prominent. As string length increases, performance converges withthe generic C implementation.Benchmark results (QEMU TCG, rv64): Length | Original (MB/s) | Optimized (MB/s) | Improvement -------|-----------------|------------------|------------ 1 B | 21 | 22 | +4.8% 7 B | 113 | 121 | +7.1% 16 B | 195 | 202 | +3.6% 512 B | 376 | 389 | +3.5% 4096 B | 394 | 393 | -0.3%Signed-off-by: Feng Jiang <jiangfeng@kylinos.cn>Tested-by: Joel Stanley <joel@jms.id.au>Link: https://patch.msgid.link/20260130025018.172925-8-jiangfeng@kylinos.cnSigned-off-by: Paul Walmsley <pjw@kernel.org> List of files: /linux/arch/riscv/lib/strchr.S Sat, 04 Apr 2026 03:28:47 +0200 Feng Jiang <jiangfeng@kylinos.cn>