From ed285c9fc665e262ed21c7bf5734acb2b7a532db Mon Sep 17 00:00:00 2001 From: hachem Date: Fri, 25 Sep 2026 11:31:59 +0200 Subject: feat: load + run native ELF binaries --- kernel/vmm.rv | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) create mode 100644 kernel/vmm.rv (limited to 'kernel/vmm.rv') diff --git a/kernel/vmm.rv b/kernel/vmm.rv new file mode 100644 index 0000000..d6673b3 --- /dev/null +++ b/kernel/vmm.rv @@ -0,0 +1,24 @@ +# build the 4-level page tables for one user page +# everything here only writes small entries we construct, so it's f64-safe +const PTE_ADDR = 0x000FFFFFFFFFF000 + +fn pte_idx(virt, level) (virt shr (12 + 9 * level)) band 0x1ff + +# next-level table phys under entry `i` of table `tbl`, creating it if absent +fn next_table(tbl, i) do + const slot = tbl + i * 8 + const entry = mem_read(slot, 8) + if (entry band 1) != 0 return entry band PTE_ADDR + const frame = frame_alloc() + mem_zero(frame, 4096) + mem_write(slot, frame bor 7, 8) # present | write | user + frame +end + +fn as_map(pml4, virt, phys, flags) do + const pdpt = next_table(pml4, pte_idx(virt, 3)) + const pd = next_table(pdpt, pte_idx(virt, 2)) + const pt = next_table(pd, pte_idx(virt, 1)) + mem_write(pt + pte_idx(virt, 0) * 8, (phys band PTE_ADDR) bor flags bor 1, 8) + invlpg(virt) +end -- cgit v1.3