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JinRui
248dbaf777
The RISC-V ISA manual specifies that Zfh implies Zfhmin, a normative rule clarified in https://github.com/riscv/riscv-isa-manual/pull/3070. Zvfh likewise implies Zvfhmin, as stated by the vector extension specification. The kernel currently reports ZFH and ZFHMIN (and ZVFH and ZVFHMIN) as independent hwprobe bits derived only from what the device tree declares. Platforms that declare just "zfh" (Zfh being a superset that already contains all Zfhmin instructions) therefore report RISCV_HWPROBE_EXT_ZFHMIN=0, which breaks userspace RVA23 conformance checks (e.g. snapd installing core26 on riscv64). Use the existing superset mechanism to set the implied subset bits: - zfh implies zfhmin - zvfh implies zvfhmin Add a hwprobe selftest asserting the implication holds and update the hwprobe documentation accordingly. This is complementary to the rva23u64 base behavior discussion: the RVA23 conformance query proposed there is derived from the per-extension bits fixed here, so correct EXT_0 reporting is a prerequisite for it to work on harts whose device tree declares only "zfh". Tested on a RISC-V QEMU VM whose device tree only declares "zfh" and "zvfh": with this change both /proc/cpuinfo and the hwprobe RISCV_HWPROBE_KEY_IMA_EXT_0 bitmap report ZFHMIN and ZVFHMIN, and the hwprobe selftest (including the new implication check) passes. Link: https://lore.kernel.org/kvm-riscv/20260206002349.96740-1-andrew.jones@oss.qualcomm.com/ Signed-off-by: JinRui <jinrui@haiwei.tech> Link: https://patch.msgid.link/7190E4DB338251C3+20260811081513.2849980-1-jinrui@haiwei.tech [pjw@kernel.org: trimmed superfluous blank line in tags] Signed-off-by: Paul Walmsley <pjw@kernel.org>