RISC-V: detect virtual address space at runtime using hwprobe#1296
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aurel32 wants to merge 1 commit into
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RISC-V: detect virtual address space at runtime using hwprobe#1296aurel32 wants to merge 1 commit into
aurel32 wants to merge 1 commit into
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res2k
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May 18, 2026
The virtual address space on RISC-V is currently detected at build time by parsing /proc/cpuinfo. This works when the binary runs on the same hardware it was built, however running such a binary on a system with a larger address space just causes a segmentation fault. Replace the build time check with a runtime detection using the hwprobe interface (available since Linux 6.11, commit c9b8cd139c1d "riscv: hwprobe export highest virtual userspace address"), with a fallback to parsing /proc/cpuinfo on older kernels.
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The virtual address space on RISC-V is currently detected at build time by parsing /proc/cpuinfo. This works when the binary runs on the same hardware it was built, however running such a binary on a system with a larger address space just causes a segmentation fault.
Replace the build time check with a runtime detection using the hwprobe interface (available since Linux 6.11, commit c9b8cd139c1d "riscv: hwprobe export highest virtual userspace address"). For older kernels, fallback to the default 48 bits. This is suboptimal on SV39 MMUs but still works.