Unifying the Lunaix's Physical Memory Model (#28)

[lunaix-os.git] / lunaix-os / arch / i386 / mm / pmm.c

diff --git a/lunaix-os/arch/i386/mm/pmm.c b/lunaix-os/arch/i386/mm/pmm.c
new file mode 100644 (file)
index 0000000..7a6ef29
--- /dev/null
+++ b/lunaix-os/arch/i386/mm/pmm.c
@@ -0,0 +1,68 @@
+#include <lunaix/mm/page.h>
+#include <lunaix/mm/pagetable.h>
+
+extern unsigned int __kexec_end[];
+
+void
+pmm_arch_init_pool(struct pmem* memory)
+{
+    pmm_declare_pool(POOL_UNIFIED, 1, memory->list_len);
+}
+
+ptr_t
+pmm_arch_init_remap(struct pmem* memory, struct boot_handoff* bctx)
+{
+    size_t ppfn_total = pfn(bctx->mem.size) + 1;
+    size_t pool_size  = ppfn_total * sizeof(struct ppage);
+    
+    size_t i = 0;
+    struct boot_mmapent* ent;
+    for (; i < bctx->mem.mmap_len; i++) {
+        ent = &bctx->mem.mmap[i];
+        if (free_memregion(ent) && ent->size > pool_size) {
+            goto found;
+        }
+    }
+
+    // fail to find a viable free region to host pplist
+    return 0;
+
+found:;
+    ptr_t kexec_end = to_kphysical(__kexec_end);
+    ptr_t aligned_pplist = MAX(ent->start, kexec_end);
+
+    // FIXME this is a temporary hack, we need a better way to convey
+    //       the mem-map for us to settle the pplist safely
+
+    for (i = 0; i <bctx->mods.mods_num; i++) {
+        aligned_pplist = MAX(aligned_pplist, bctx->mods.entries[i].end);
+    }
+
+    aligned_pplist = napot_upaligned(aligned_pplist, L0T_SIZE);
+
+    if (aligned_pplist + pool_size > ent->start + ent->size) {
+        return 0;
+    }
+
+    // for x86_32, the upper bound of memory requirement for pplist
+    //  is sizeof(struct ppage) * 1MiB. For simplicity (as well as 
+    //  efficiency), we limit the granule to 4M huge page, thus, 
+    //  it will take away at least 4M worth of vm address resource 
+    //  regardless the actual physical memory size
+
+    // anchor the pplist at vmap location (right after kernel)
+    memory->pplist = (struct ppage*)VMAP;
+    memory->list_len = ppfn_total;
+
+    pfn_t nhuge = page_count(pool_size, L0T_SIZE);
+    pte_t* ptep = mkl0tep_va(VMS_SELF, VMAP);
+    pte_t pte   = mkpte(aligned_pplist, KERNEL_DATA);
+    
+    vmm_set_ptes_contig(ptep, pte_mkhuge(pte), L0T_SIZE, nhuge);
+    tlb_flush_kernel(VMAP);
+
+    // shift the actual vmap start address
+    vmap_set_start(VMAP + nhuge * L0T_SIZE);
+
+    return aligned_pplist;
+}
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