-/*
- * Called once VM is fully initialized so that we can release unused
- * sections of low memory to the general pool.
- * Also complete the set-up of identity-mapped sections of the kernel:
- * 1) write-protect kernel text
- * 2) map kernel text using large pages if possible
- * 3) read and write-protect page zero (for K32)
- * 4) map the global page at the appropriate virtual address.
- *
- * Use of large pages
- * ------------------
- * To effectively map and write-protect all kernel text pages, the text
- * must be 2M-aligned at the base, and the data section above must also be
- * 2M-aligned. That is, there's padding below and above. This is achieved
- * through linker directives. Large pages are used only if this alignment
- * exists (and not overriden by the -kernel_text_page_4K boot-arg). The
- * memory layout is:
- *
- * : :
- * | __DATA |
- * sdata: ================== 2Meg
- * | |
- * | zero-padding |
- * | |
- * etext: ------------------
- * | |
- * : :
- * | |
- * | __TEXT |
- * | |
- * : :
- * | |
- * stext: ================== 2Meg
- * | |
- * | zero-padding |
- * | |
- * eHIB: ------------------
- * | __HIB |
- * : :
- *
- * Prior to changing the mapping from 4K to 2M, the zero-padding pages
- * [eHIB,stext] and [etext,sdata] are ml_static_mfree()'d. Then all the
- * 4K pages covering [stext,etext] are coalesced as 2M large pages.
- * The now unused level-1 PTE pages are also freed.
- */
-void
-pmap_lowmem_finalize(void)
-{
- spl_t spl;
- int i;
-
- /* Check the kernel is linked at the expected base address */
- if (i386_btop(kvtophys((vm_offset_t) &IdlePML4)) !=
- I386_KERNEL_IMAGE_BASE_PAGE)
- panic("pmap_lowmem_finalize() unexpected kernel base address");
-
- /*
- * Free all pages in pmap regions below the base:
- * rdar://6332712
- * We can't free all the pages to VM that EFI reports available.
- * Pages in the range 0xc0000-0xff000 aren't safe over sleep/wake.
- * There's also a size miscalculation here: pend is one page less
- * than it should be but this is not fixed to be backwards
- * compatible.
- * Due to this current EFI limitation, we take only the first
- * entry in the memory region table. However, the loop is retained
- * (with the intended termination criteria commented out) in the
- * hope that some day we can free all low-memory ranges.
- * This loop assumes the first range does not span the kernel
- * image base & avail_start. We skip this process on systems
- * with "kernel reserved" ranges, as the low memory reclamation
- * is handled in the initial memory map processing loop on
- * such systems.
- */
- for (i = 0;
-// pmap_memory_regions[i].end <= I386_KERNEL_IMAGE_BASE_PAGE;
- i < 1 && (pmap_reserved_ranges == 0);
- i++) {
- vm_offset_t pbase = (vm_offset_t)i386_ptob(pmap_memory_regions[i].base);
- vm_offset_t pend = (vm_offset_t)i386_ptob(pmap_memory_regions[i].end);
-// vm_offset_t pend = i386_ptob(pmap_memory_regions[i].end+1);
-
- DBG("ml_static_mfree(%p,%p) for pmap region %d\n",
- (void *) ml_static_ptovirt(pbase),
- (void *) (pend - pbase), i);
- ml_static_mfree(ml_static_ptovirt(pbase), pend - pbase);
- }
-
- /*
- * If text and data are both 2MB-aligned,
- * we can map text with large-pages,
- * unless the -kernel_text_ps_4K boot-arg overrides.
- */
- if ((stext & I386_LPGMASK) == 0 && (sdata & I386_LPGMASK) == 0) {
- kprintf("Kernel text is 2MB aligned");
- kernel_text_ps_4K = FALSE;
- if (PE_parse_boot_argn("-kernel_text_ps_4K",
- &kernel_text_ps_4K,
- sizeof (kernel_text_ps_4K)))
- kprintf(" but will be mapped with 4K pages\n");
- else
- kprintf(" and will be mapped with 2M pages\n");
- }
-
- (void) PE_parse_boot_argn("wpkernel", &wpkernel, sizeof (wpkernel));
- if (wpkernel)
- kprintf("Kernel text %p-%p to be write-protected\n",
- (void *) stext, (void *) etext);
-
- spl = splhigh();
-
- /*
- * Scan over text if mappings are to be changed:
- * - Remap kernel text readonly unless the "wpkernel" boot-arg is 0
- * - Change to large-pages if possible and not overriden.
- */
- if (kernel_text_ps_4K && wpkernel) {
- vm_offset_t myva;
- for (myva = stext; myva < etext; myva += PAGE_SIZE) {
- pt_entry_t *ptep;
-
- ptep = pmap_pte(kernel_pmap, (vm_map_offset_t)myva);
- if (ptep)
- pmap_store_pte(ptep, *ptep & ~INTEL_PTE_RW);
- }
- }
-
- if (!kernel_text_ps_4K) {
- vm_offset_t myva;
-
- /*
- * Release zero-filled page padding used for 2M-alignment.
- */
- DBG("ml_static_mfree(%p,%p) for padding below text\n",
- (void *) eHIB, (void *) (stext - eHIB));
- ml_static_mfree(eHIB, stext - eHIB);
- DBG("ml_static_mfree(%p,%p) for padding above text\n",
- (void *) etext, (void *) (sdata - etext));
- ml_static_mfree(etext, sdata - etext);
-
- /*
- * Coalesce text pages into large pages.
- */
- for (myva = stext; myva < sdata; myva += I386_LPGBYTES) {
- pt_entry_t *ptep;
- vm_offset_t pte_phys;
- pt_entry_t *pdep;
- pt_entry_t pde;
-
- pdep = pmap_pde(kernel_pmap, (vm_map_offset_t)myva);
- ptep = pmap_pte(kernel_pmap, (vm_map_offset_t)myva);
- DBG("myva: %p pdep: %p ptep: %p\n",
- (void *) myva, (void *) pdep, (void *) ptep);
- if ((*ptep & INTEL_PTE_VALID) == 0)
- continue;
- pte_phys = (vm_offset_t)(*ptep & PG_FRAME);
- pde = *pdep & PTMASK; /* page attributes from pde */
- pde |= INTEL_PTE_PS; /* make it a 2M entry */
- pde |= pte_phys; /* take page frame from pte */
-
- if (wpkernel)
- pde &= ~INTEL_PTE_RW;
- DBG("pmap_store_pte(%p,0x%llx)\n",
- (void *)pdep, pde);
- pmap_store_pte(pdep, pde);
-
- /*
- * Free the now-unused level-1 pte.
- * Note: ptep is a virtual address to the pte in the
- * recursive map. We can't use this address to free
- * the page. Instead we need to compute its address
- * in the Idle PTEs in "low memory".
- */
- vm_offset_t vm_ptep = (vm_offset_t) KPTphys
- + (pte_phys >> PTPGSHIFT);
- DBG("ml_static_mfree(%p,0x%x) for pte\n",
- (void *) vm_ptep, PAGE_SIZE);
- ml_static_mfree(vm_ptep, PAGE_SIZE);
- }
-
- /* Change variable read by sysctl machdep.pmap */
- pmap_kernel_text_ps = I386_LPGBYTES;
- }
-
-#if defined(__i386__)
- /* no matter what, kernel page zero is not accessible */
- pmap_store_pte(pmap_pte(kernel_pmap, 0), INTEL_PTE_INVALID);
-#endif
-
- /* map lowmem global page into fixed addr */
- pt_entry_t *pte = NULL;
- if (0 == (pte = pmap_pte(kernel_pmap,
- VM_MIN_KERNEL_LOADED_ADDRESS + 0x2000)))
- panic("lowmem pte");
- /* make sure it is defined on page boundary */
- assert(0 == ((vm_offset_t) &lowGlo & PAGE_MASK));
- pmap_store_pte(pte, kvtophys((vm_offset_t)&lowGlo)
- | INTEL_PTE_REF
- | INTEL_PTE_MOD
- | INTEL_PTE_WIRED
- | INTEL_PTE_VALID
- | INTEL_PTE_RW);
- splx(spl);
- flush_tlb();
-}
-
projects / apple / xnu.git / blobdiff