84  * memory type of pages that have backing page struct.
86  * X86 PAT supports 4 different memory types:
87  *  - _PAGE_CACHE_MODE_WB
88  *  - _PAGE_CACHE_MODE_WC
89  *  - _PAGE_CACHE_MODE_UC_MINUS
90  *  - _PAGE_CACHE_MODE_WT
104 	unsigned long pg_flags = pg->flags & _PGMT_MASK;  in get_page_memtype()
140 		old_flags = pg->flags;  in set_page_memtype()
142 	} while (cmpxchg(&pg->flags, old_flags, new_flags) != old_flags);  in set_page_memtype()
147 	return -1;  in get_page_memtype()
173 	case PAT_WC:       cache = CM(WC);       cache_mode = "WC  "; break;  in pat_get_cache_mode()
177 	case PAT_UC_MINUS: cache = CM(UC_MINUS); cache_mode = "UC- "; break;  in pat_get_cache_mode()
200 	for (i = 7; i >= 0; i--) {  in __init_cache_modes()
205 	pr_info("x86/PAT: Configuration [0-7]: %s\n", pat_msg);  in __init_cache_modes()
238 		 * PAT on the boot CPU. We have no way to undo PAT.  in pat_ap_init()
261 		 * as No PAT.  in init_cache_modes()
268 		 * No PAT. Emulate the PAT table that corresponds to the two  in init_cache_modes()
279 		 *       10    2    UC-: _PAGE_CACHE_MODE_UC_MINUS  in init_cache_modes()
282 		 * NOTE: When WC or WP is used, it is redirected to UC- per  in init_cache_modes()
293  * pat_init - Initialize PAT MSR and PAT table
295  * This function initializes PAT MSR and PAT table with an OS-defined value
296  * to enable additional cache attributes, WC, WT and WP.
310 	if ((c->x86_vendor == X86_VENDOR_INTEL) &&  in pat_init()
311 	    (((c->x86 == 0x6) && (c->x86_model <= 0xd)) ||  in pat_init()
312 	     ((c->x86 == 0xf) && (c->x86_model <= 0x6)))) {  in pat_init()
325 		 *      001    1    WC : _PAGE_CACHE_MODE_WC  in pat_init()
326 		 *      010    2    UC-: _PAGE_CACHE_MODE_UC_MINUS  in pat_init()
330 		 * NOTE: When WT or WP is used, it is redirected to UC- per  in pat_init()
333 		pat = PAT(0, WB) | PAT(1, WC) | PAT(2, UC_MINUS) | PAT(3, UC) |  in pat_init()
334 		      PAT(4, WB) | PAT(5, WC) | PAT(6, UC_MINUS) | PAT(7, UC);  in pat_init()
351 		 *      001    1    WC : _PAGE_CACHE_MODE_WC  in pat_init()
352 		 *      010    2    UC-: _PAGE_CACHE_MODE_UC_MINUS  in pat_init()
356 		 *      110    6    UC-: Reserved  in pat_init()
362 		pat = PAT(0, WB) | PAT(1, WC) | PAT(2, UC_MINUS) | PAT(3, UC) |  in pat_init()
379  * Does intersection of PAT memory type and MTRR memory type and returns
380  * the resulting memory type as PAT understands it.
382  * The intersection is based on "Effective Memory Type" tables in IA-32
416 	state->not_ram	|= initial_pfn > state->cur_pfn;  in pagerange_is_ram_callback()
417 	state->ram	|= total_nr_pages > 0;  in pagerange_is_ram_callback()
418 	state->cur_pfn	 = initial_pfn + total_nr_pages;  in pagerange_is_ram_callback()
420 	return state->ram && state->not_ram;  in pagerange_is_ram_callback()
427 	unsigned long end_pfn = (end + PAGE_SIZE - 1) >> PAGE_SHIFT;  in pat_pagerange_is_ram()
432 	 * region is tracked as non-RAM. This will allow users of  in pat_pagerange_is_ram()
441 		ret = walk_system_ram_range(start_pfn, end_pfn - start_pfn,  in pat_pagerange_is_ram()
445 	return (ret > 0) ? -1 : (state.ram ? 1 : 0);  in pat_pagerange_is_ram()
450  * The page flags are limited to four types, WB (default), WC, WT and UC-.
451  * WP request fails with -EINVAL, and UC gets redirected to UC-.  Setting
452  * a new memory type is only allowed for a page mapped with the default WB
456  * - Find the memtype of all the pages in the range, look for any conflicts.
457  * - In case of no conflicts, set the new memtype for pages in the range.
469 		return -EINVAL;  in reserve_ram_pages_type()
484 			pr_info("x86/PAT: reserve_ram_pages_type failed [mem %#010Lx-%#010Lx], track 0x%x, req 0x%x\n",  in reserve_ram_pages_type()
485 				start, end - 1, type, req_type);  in reserve_ram_pages_type()
489 			return -EBUSY;  in reserve_ram_pages_type()
523 	 * Decoy addresses are not present for 32-bit builds, see  in sanitize_phys()
533  * - _PAGE_CACHE_MODE_WB
534  * - _PAGE_CACHE_MODE_WC
535  * - _PAGE_CACHE_MODE_UC_MINUS
536  * - _PAGE_CACHE_MODE_UC
537  * - _PAGE_CACHE_MODE_WT
540  * region with req_type. If new_type is non-NULL, function will return
541  * available type in new_type in case of no error. In case of any error
555 		WARN(1, "%s failed: [mem %#010Lx-%#010Lx], req %s\n", __func__,  in reserve_memtype()
556 				start, end - 1, cattr_name(req_type));  in reserve_memtype()
557 		return -EINVAL;  in reserve_memtype()
567 	/* Low ISA region is always mapped WB in page table. No need to track */  in reserve_memtype()
576 	 * optimization for /dev/mem mmap'ers into WB memory (BIOS  in reserve_memtype()
577 	 * tools and ACPI tools). Use WB request for WB memory and use  in reserve_memtype()
592 		return -EINVAL;  in reserve_memtype()
597 		return -ENOMEM;  in reserve_memtype()
599 	new->start	= start;  in reserve_memtype()
600 	new->end	= end;  in reserve_memtype()
601 	new->type	= actual_type;  in reserve_memtype()
607 		pr_info("x86/PAT: reserve_memtype failed [mem %#010Lx-%#010Lx], track %s, req %s\n",  in reserve_memtype()
608 			start, end - 1,  in reserve_memtype()
609 			cattr_name(new->type), cattr_name(req_type));  in reserve_memtype()
618 	dprintk("reserve_memtype added [mem %#010Lx-%#010Lx], track %s, req %s, ret %s\n",  in reserve_memtype()
619 		start, end - 1, cattr_name(new->type), cattr_name(req_type),  in reserve_memtype()
620 		new_type ? cattr_name(*new_type) : "-");  in reserve_memtype()
627 	int err = -EINVAL;  in free_memtype()
637 	/* Low ISA region is always mapped WB. No need to track */  in free_memtype()
648 		return -EINVAL;  in free_memtype()
656 		pr_info("x86/PAT: %s:%d freeing invalid memtype [mem %#010Lx-%#010Lx]\n",  in free_memtype()
657 			current->comm, current->pid, start, end - 1);  in free_memtype()
658 		return -EINVAL;  in free_memtype()
663 	dprintk("free_memtype request [mem %#010Lx-%#010Lx]\n", start, end - 1);  in free_memtype()
670  * lookup_memtype - Looksup the memory type for a physical address
671  * @paddr: physical address of which memory type needs to be looked up
697 		rettype = entry->type;  in lookup_memtype()
706  * pat_pfn_immune_to_uc_mtrr - Check whether the PAT memory type
707  * of @pfn cannot be overridden by UC MTRR memory type.
711  * Returns true, if the PAT memory type of @pfn is UC, UC-, or WC.
725  * io_reserve_memtype - Request a memory type mapping for a region of memory
732  * On failure, returns non-zero
737 	resource_size_t size = end - start;  in io_reserve_memtype()
759 	ret = -EBUSY;  in io_reserve_memtype()
765  * io_free_memtype - Release a memory type mapping for a region of memory
832 	if (file->f_flags & O_DSYNC)  in phys_mem_access_prot_allowed()
841  * Change the memory type for the physial address range in kernel identity
849 	if (base > __pa(high_memory-1))  in kernel_map_sync_memtype()
859 	id_sz = (__pa(high_memory-1) <= base + size) ?  in kernel_map_sync_memtype()
860 				__pa(high_memory) - base :  in kernel_map_sync_memtype()
864 		pr_info("x86/PAT: %s:%d ioremap_change_attr failed %s for [mem %#010Lx-%#010Lx]\n",  in kernel_map_sync_memtype()
865 			current->comm, current->pid,  in kernel_map_sync_memtype()
867 			base, (unsigned long long)(base + size-1));  in kernel_map_sync_memtype()
868 		return -EINVAL;  in kernel_map_sync_memtype()
874  * Internal interface to reserve a range of physical memory with prot.
899 			pr_warn("x86/PAT: %s:%d map pfn RAM range req %s for [mem %#010Lx-%#010Lx], got %s\n",  in reserve_pfn_range()
900 				current->comm, current->pid,  in reserve_pfn_range()
903 				(unsigned long long)(paddr + size - 1),  in reserve_pfn_range()
920 			pr_err("x86/PAT: %s:%d map pfn expected mapping type %s for [mem %#010Lx-%#010Lx], got %s\n",  in reserve_pfn_range()
921 			       current->comm, current->pid,  in reserve_pfn_range()
924 			       (unsigned long long)(paddr + size - 1),  in reserve_pfn_range()
926 			return -EINVAL;  in reserve_pfn_range()
939 		return -EINVAL;  in reserve_pfn_range()
945  * Internal interface to free a range of physical memory.
968 	unsigned long vma_size = vma->vm_end - vma->vm_start;  in track_pfn_copy()
971 	if (vma->vm_flags & VM_PAT) {  in track_pfn_copy()
976 		if (follow_phys(vma, vma->vm_start, 0, &prot, &paddr)) {  in track_pfn_copy()
978 			return -EINVAL;  in track_pfn_copy()
989  * a linear pfn mapping for the entire range, or no vma is provided,
1000 	if (!vma || (addr == vma->vm_start  in track_pfn_remap()
1001 				&& size == (vma->vm_end - vma->vm_start))) {  in track_pfn_remap()
1006 			vma->vm_flags |= VM_PAT;  in track_pfn_remap()
1021 		size -= PAGE_SIZE;  in track_pfn_remap()
1024 			return -EINVAL;  in track_pfn_remap()
1057 	if (vma && !(vma->vm_flags & VM_PAT))  in untrack_pfn()
1063 		if (follow_phys(vma, vma->vm_start, 0, &prot, &paddr)) {  in untrack_pfn()
1068 		size = vma->vm_end - vma->vm_start;  in untrack_pfn()
1072 		vma->vm_flags &= ~VM_PAT;  in untrack_pfn()
1082 	vma->vm_flags &= ~VM_PAT;  in untrack_pfn_moved()
1146 	seq_printf(seq, "%s @ 0x%Lx-0x%Lx\n", cattr_name(print_entry->type),  in memtype_seq_show()
1147 			print_entry->start, print_entry->end);  in memtype_seq_show()