1 // SPDX-License-Identifier: GPL-2.0-or-later
4 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
6 * Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
7 * and Cort Dougan (PReP) (cort@cs.nmt.edu)
8 * Copyright (C) 1996 Paul Mackerras
10 * Derived from "arch/i386/mm/init.c"
11 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
13 * Dave Engebretsen <engebret@us.ibm.com>
14 * Rework for PPC64 port.
19 #include <linux/signal.h>
20 #include <linux/sched.h>
21 #include <linux/kernel.h>
22 #include <linux/errno.h>
23 #include <linux/string.h>
24 #include <linux/types.h>
25 #include <linux/mman.h>
27 #include <linux/swap.h>
28 #include <linux/stddef.h>
29 #include <linux/vmalloc.h>
30 #include <linux/init.h>
31 #include <linux/delay.h>
32 #include <linux/highmem.h>
33 #include <linux/idr.h>
34 #include <linux/nodemask.h>
35 #include <linux/module.h>
36 #include <linux/poison.h>
37 #include <linux/memblock.h>
38 #include <linux/hugetlb.h>
39 #include <linux/slab.h>
40 #include <linux/of_fdt.h>
41 #include <linux/libfdt.h>
42 #include <linux/memremap.h>
43 #include <linux/memory.h>
45 #include <asm/pgalloc.h>
50 #include <asm/mmu_context.h>
52 #include <linux/uaccess.h>
54 #include <asm/machdep.h>
57 #include <asm/processor.h>
58 #include <asm/mmzone.h>
59 #include <asm/cputable.h>
60 #include <asm/sections.h>
61 #include <asm/iommu.h>
63 #include <asm/hugetlb.h>
65 #include <mm/mmu_decl.h>
67 #ifdef CONFIG_SPARSEMEM_VMEMMAP
69 * Given an address within the vmemmap, determine the page that
70 * represents the start of the subsection it is within. Note that we have to
71 * do this by hand as the proffered address may not be correctly aligned.
72 * Subtraction of non-aligned pointers produces undefined results.
74 static struct page
* __meminit
vmemmap_subsection_start(unsigned long vmemmap_addr
)
76 unsigned long start_pfn
;
77 unsigned long offset
= vmemmap_addr
- ((unsigned long)(vmemmap
));
79 /* Return the pfn of the start of the section. */
80 start_pfn
= (offset
/ sizeof(struct page
)) & PAGE_SUBSECTION_MASK
;
81 return pfn_to_page(start_pfn
);
85 * Since memory is added in sub-section chunks, before creating a new vmemmap
86 * mapping, the kernel should check whether there is an existing memmap mapping
87 * covering the new subsection added. This is needed because kernel can map
88 * vmemmap area using 16MB pages which will cover a memory range of 16G. Such
89 * a range covers multiple subsections (2M)
91 * If any subsection in the 16G range mapped by vmemmap is valid we consider the
92 * vmemmap populated (There is a page table entry already present). We can't do
93 * a page table lookup here because with the hash translation we don't keep
94 * vmemmap details in linux page table.
96 int __meminit
vmemmap_populated(unsigned long vmemmap_addr
, int vmemmap_map_size
)
99 unsigned long vmemmap_end
= vmemmap_addr
+ vmemmap_map_size
;
100 start
= vmemmap_subsection_start(vmemmap_addr
);
102 for (; (unsigned long)start
< vmemmap_end
; start
+= PAGES_PER_SUBSECTION
)
104 * pfn valid check here is intended to really check
105 * whether we have any subsection already initialized
108 if (pfn_valid(page_to_pfn(start
)))
115 * vmemmap virtual address space management does not have a traditional page
116 * table to track which virtual struct pages are backed by physical mapping.
117 * The virtual to physical mappings are tracked in a simple linked list
118 * format. 'vmemmap_list' maintains the entire vmemmap physical mapping at
119 * all times where as the 'next' list maintains the available
120 * vmemmap_backing structures which have been deleted from the
121 * 'vmemmap_global' list during system runtime (memory hotplug remove
122 * operation). The freed 'vmemmap_backing' structures are reused later when
123 * new requests come in without allocating fresh memory. This pointer also
124 * tracks the allocated 'vmemmap_backing' structures as we allocate one
125 * full page memory at a time when we dont have any.
127 struct vmemmap_backing
*vmemmap_list
;
128 static struct vmemmap_backing
*next
;
131 * The same pointer 'next' tracks individual chunks inside the allocated
132 * full page during the boot time and again tracks the freed nodes during
133 * runtime. It is racy but it does not happen as they are separated by the
134 * boot process. Will create problem if some how we have memory hotplug
135 * operation during boot !!
138 static int num_freed
;
140 static __meminit
struct vmemmap_backing
* vmemmap_list_alloc(int node
)
142 struct vmemmap_backing
*vmem_back
;
143 /* get from freed entries first */
152 /* allocate a page when required and hand out chunks */
154 next
= vmemmap_alloc_block(PAGE_SIZE
, node
);
155 if (unlikely(!next
)) {
159 num_left
= PAGE_SIZE
/ sizeof(struct vmemmap_backing
);
167 static __meminit
int vmemmap_list_populate(unsigned long phys
,
171 struct vmemmap_backing
*vmem_back
;
173 vmem_back
= vmemmap_list_alloc(node
);
174 if (unlikely(!vmem_back
)) {
175 pr_debug("vmemap list allocation failed\n");
179 vmem_back
->phys
= phys
;
180 vmem_back
->virt_addr
= start
;
181 vmem_back
->list
= vmemmap_list
;
183 vmemmap_list
= vmem_back
;
187 bool altmap_cross_boundary(struct vmem_altmap
*altmap
, unsigned long start
,
188 unsigned long page_size
)
190 unsigned long nr_pfn
= page_size
/ sizeof(struct page
);
191 unsigned long start_pfn
= page_to_pfn((struct page
*)start
);
193 if ((start_pfn
+ nr_pfn
- 1) > altmap
->end_pfn
)
196 if (start_pfn
< altmap
->base_pfn
)
202 static int __meminit
__vmemmap_populate(unsigned long start
, unsigned long end
, int node
,
203 struct vmem_altmap
*altmap
)
206 unsigned long page_size
= 1 << mmu_psize_defs
[mmu_vmemmap_psize
].shift
;
208 /* Align to the page size of the linear mapping. */
209 start
= ALIGN_DOWN(start
, page_size
);
211 pr_debug("vmemmap_populate %lx..%lx, node %d\n", start
, end
, node
);
213 for (; start
< end
; start
+= page_size
) {
218 * This vmemmap range is backing different subsections. If any
219 * of that subsection is marked valid, that means we already
220 * have initialized a page table covering this range and hence
221 * the vmemmap range is populated.
223 if (vmemmap_populated(start
, page_size
))
227 * Allocate from the altmap first if we have one. This may
228 * fail due to alignment issues when using 16MB hugepages, so
229 * fall back to system memory if the altmap allocation fail.
231 if (altmap
&& !altmap_cross_boundary(altmap
, start
, page_size
)) {
232 p
= vmemmap_alloc_block_buf(page_size
, node
, altmap
);
234 pr_debug("altmap block allocation failed, falling back to system memory");
239 p
= vmemmap_alloc_block_buf(page_size
, node
, NULL
);
240 altmap_alloc
= false;
245 if (vmemmap_list_populate(__pa(p
), start
, node
)) {
247 * If we don't populate vmemap list, we don't have
248 * the ability to free the allocated vmemmap
249 * pages in section_deactivate. Hence free them
252 int nr_pfns
= page_size
>> PAGE_SHIFT
;
253 unsigned long page_order
= get_order(page_size
);
256 vmem_altmap_free(altmap
, nr_pfns
);
258 free_pages((unsigned long)p
, page_order
);
262 pr_debug(" * %016lx..%016lx allocated at %p\n",
263 start
, start
+ page_size
, p
);
265 rc
= vmemmap_create_mapping(start
, page_size
, __pa(p
));
267 pr_warn("%s: Unable to create vmemmap mapping: %d\n",
276 int __meminit
vmemmap_populate(unsigned long start
, unsigned long end
, int node
,
277 struct vmem_altmap
*altmap
)
280 #ifdef CONFIG_PPC_BOOK3S_64
282 return radix__vmemmap_populate(start
, end
, node
, altmap
);
285 return __vmemmap_populate(start
, end
, node
, altmap
);
288 #ifdef CONFIG_MEMORY_HOTPLUG
289 static unsigned long vmemmap_list_free(unsigned long start
)
291 struct vmemmap_backing
*vmem_back
, *vmem_back_prev
;
293 vmem_back_prev
= vmem_back
= vmemmap_list
;
295 /* look for it with prev pointer recorded */
296 for (; vmem_back
; vmem_back
= vmem_back
->list
) {
297 if (vmem_back
->virt_addr
== start
)
299 vmem_back_prev
= vmem_back
;
302 if (unlikely(!vmem_back
))
305 /* remove it from vmemmap_list */
306 if (vmem_back
== vmemmap_list
) /* remove head */
307 vmemmap_list
= vmem_back
->list
;
309 vmem_back_prev
->list
= vmem_back
->list
;
311 /* next point to this freed entry */
312 vmem_back
->list
= next
;
316 return vmem_back
->phys
;
319 static void __ref
__vmemmap_free(unsigned long start
, unsigned long end
,
320 struct vmem_altmap
*altmap
)
322 unsigned long page_size
= 1 << mmu_psize_defs
[mmu_vmemmap_psize
].shift
;
323 unsigned long page_order
= get_order(page_size
);
324 unsigned long alt_start
= ~0, alt_end
= ~0;
325 unsigned long base_pfn
;
327 start
= ALIGN_DOWN(start
, page_size
);
329 alt_start
= altmap
->base_pfn
;
330 alt_end
= altmap
->base_pfn
+ altmap
->reserve
+ altmap
->free
;
333 pr_debug("vmemmap_free %lx...%lx\n", start
, end
);
335 for (; start
< end
; start
+= page_size
) {
336 unsigned long nr_pages
, addr
;
340 * We have already marked the subsection we are trying to remove
341 * invalid. So if we want to remove the vmemmap range, we
342 * need to make sure there is no subsection marked valid
345 if (vmemmap_populated(start
, page_size
))
348 addr
= vmemmap_list_free(start
);
352 page
= pfn_to_page(addr
>> PAGE_SHIFT
);
353 nr_pages
= 1 << page_order
;
354 base_pfn
= PHYS_PFN(addr
);
356 if (base_pfn
>= alt_start
&& base_pfn
< alt_end
) {
357 vmem_altmap_free(altmap
, nr_pages
);
358 } else if (PageReserved(page
)) {
359 /* allocated from bootmem */
360 if (page_size
< PAGE_SIZE
) {
362 * this shouldn't happen, but if it is
363 * the case, leave the memory there
368 free_reserved_page(page
++);
371 free_pages((unsigned long)(__va(addr
)), page_order
);
374 vmemmap_remove_mapping(start
, page_size
);
378 void __ref
vmemmap_free(unsigned long start
, unsigned long end
,
379 struct vmem_altmap
*altmap
)
381 #ifdef CONFIG_PPC_BOOK3S_64
383 return radix__vmemmap_free(start
, end
, altmap
);
385 return __vmemmap_free(start
, end
, altmap
);
389 void register_page_bootmem_memmap(unsigned long section_nr
,
390 struct page
*start_page
, unsigned long size
)
394 #endif /* CONFIG_SPARSEMEM_VMEMMAP */
396 #ifdef CONFIG_PPC_BOOK3S_64
397 unsigned int mmu_lpid_bits
;
398 #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
399 EXPORT_SYMBOL_GPL(mmu_lpid_bits
);
401 unsigned int mmu_pid_bits
;
403 static bool disable_radix
= !IS_ENABLED(CONFIG_PPC_RADIX_MMU_DEFAULT
);
405 static int __init
parse_disable_radix(char *p
)
411 else if (kstrtobool(p
, &val
))
418 early_param("disable_radix", parse_disable_radix
);
421 * If we're running under a hypervisor, we need to check the contents of
422 * /chosen/ibm,architecture-vec-5 to see if the hypervisor is willing to do
423 * radix. If not, we clear the radix feature bit so we fall back to hash.
425 static void __init
early_check_vec5(void)
427 unsigned long root
, chosen
;
432 root
= of_get_flat_dt_root();
433 chosen
= of_get_flat_dt_subnode_by_name(root
, "chosen");
434 if (chosen
== -FDT_ERR_NOTFOUND
) {
435 cur_cpu_spec
->mmu_features
&= ~MMU_FTR_TYPE_RADIX
;
438 vec5
= of_get_flat_dt_prop(chosen
, "ibm,architecture-vec-5", &size
);
440 cur_cpu_spec
->mmu_features
&= ~MMU_FTR_TYPE_RADIX
;
443 if (size
<= OV5_INDX(OV5_MMU_SUPPORT
)) {
444 cur_cpu_spec
->mmu_features
&= ~MMU_FTR_TYPE_RADIX
;
448 /* Check for supported configuration */
449 mmu_supported
= vec5
[OV5_INDX(OV5_MMU_SUPPORT
)] &
450 OV5_FEAT(OV5_MMU_SUPPORT
);
451 if (mmu_supported
== OV5_FEAT(OV5_MMU_RADIX
)) {
452 /* Hypervisor only supports radix - check enabled && GTSE */
453 if (!early_radix_enabled()) {
454 pr_warn("WARNING: Ignoring cmdline option disable_radix\n");
456 if (!(vec5
[OV5_INDX(OV5_RADIX_GTSE
)] &
457 OV5_FEAT(OV5_RADIX_GTSE
))) {
458 cur_cpu_spec
->mmu_features
&= ~MMU_FTR_GTSE
;
460 cur_cpu_spec
->mmu_features
|= MMU_FTR_GTSE
;
461 /* Do radix anyway - the hypervisor said we had to */
462 cur_cpu_spec
->mmu_features
|= MMU_FTR_TYPE_RADIX
;
463 } else if (mmu_supported
== OV5_FEAT(OV5_MMU_HASH
)) {
464 /* Hypervisor only supports hash - disable radix */
465 cur_cpu_spec
->mmu_features
&= ~MMU_FTR_TYPE_RADIX
;
466 cur_cpu_spec
->mmu_features
&= ~MMU_FTR_GTSE
;
470 static int __init
dt_scan_mmu_pid_width(unsigned long node
,
471 const char *uname
, int depth
,
476 const char *type
= of_get_flat_dt_prop(node
, "device_type", NULL
);
478 /* We are scanning "cpu" nodes only */
479 if (type
== NULL
|| strcmp(type
, "cpu") != 0)
482 /* Find MMU LPID, PID register size */
483 prop
= of_get_flat_dt_prop(node
, "ibm,mmu-lpid-bits", &size
);
484 if (prop
&& size
== 4)
485 mmu_lpid_bits
= be32_to_cpup(prop
);
487 prop
= of_get_flat_dt_prop(node
, "ibm,mmu-pid-bits", &size
);
488 if (prop
&& size
== 4)
489 mmu_pid_bits
= be32_to_cpup(prop
);
491 if (!mmu_pid_bits
&& !mmu_lpid_bits
)
498 * Outside hotplug the kernel uses this value to map the kernel direct map
499 * with radix. To be compatible with older kernels, let's keep this value
500 * as 16M which is also SECTION_SIZE with SPARSEMEM. We can ideally map
501 * things with 1GB size in the case where we don't support hotplug.
503 #ifndef CONFIG_MEMORY_HOTPLUG
504 #define DEFAULT_MEMORY_BLOCK_SIZE SZ_16M
506 #define DEFAULT_MEMORY_BLOCK_SIZE MIN_MEMORY_BLOCK_SIZE
509 static void update_memory_block_size(unsigned long *block_size
, unsigned long mem_size
)
511 unsigned long min_memory_block_size
= DEFAULT_MEMORY_BLOCK_SIZE
;
513 for (; *block_size
> min_memory_block_size
; *block_size
>>= 2) {
514 if ((mem_size
& *block_size
) == 0)
519 static int __init
probe_memory_block_size(unsigned long node
, const char *uname
, int
523 unsigned long *block_size
= (unsigned long *)data
;
524 const __be32
*reg
, *endp
;
530 * If we have dynamic-reconfiguration-memory node, use the
533 if (strcmp(uname
, "ibm,dynamic-reconfiguration-memory") == 0) {
537 prop
= of_get_flat_dt_prop(node
, "ibm,lmb-size", &l
);
539 if (!prop
|| l
< dt_root_size_cells
* sizeof(__be32
))
541 * Nothing in the device tree
543 *block_size
= DEFAULT_MEMORY_BLOCK_SIZE
;
545 *block_size
= of_read_number(prop
, dt_root_size_cells
);
547 * We have found the final value. Don't probe further.
552 * Find all the device tree nodes of memory type and make sure
553 * the area can be mapped using the memory block size value
554 * we end up using. We start with 1G value and keep reducing
555 * it such that we can map the entire area using memory_block_size.
556 * This will be used on powernv and older pseries that don't
557 * have ibm,lmb-size node.
558 * For ex: with P5 we can end up with
561 * This will end up using 64MB memory block size value.
563 type
= of_get_flat_dt_prop(node
, "device_type", NULL
);
564 if (type
== NULL
|| strcmp(type
, "memory") != 0)
567 reg
= of_get_flat_dt_prop(node
, "linux,usable-memory", &l
);
569 reg
= of_get_flat_dt_prop(node
, "reg", &l
);
573 endp
= reg
+ (l
/ sizeof(__be32
));
574 while ((endp
- reg
) >= (dt_root_addr_cells
+ dt_root_size_cells
)) {
575 const char *compatible
;
578 dt_mem_next_cell(dt_root_addr_cells
, ®
);
579 size
= dt_mem_next_cell(dt_root_size_cells
, ®
);
582 update_memory_block_size(block_size
, size
);
586 * ibm,coherent-device-memory with linux,usable-memory = 0
587 * Force 256MiB block size. Work around for GPUs on P9 PowerNV
588 * linux,usable-memory == 0 implies driver managed memory and
589 * we can't use large memory block size due to hotplug/unplug
592 compatible
= of_get_flat_dt_prop(node
, "compatible", NULL
);
593 if (compatible
&& !strcmp(compatible
, "ibm,coherent-device-memory")) {
594 if (*block_size
> SZ_256M
)
595 *block_size
= SZ_256M
;
597 * We keep 256M as the upper limit with GPU present.
602 /* continue looking for other memory device types */
607 * start with 1G memory block size. Early init will
608 * fix this with correct value.
610 unsigned long memory_block_size __ro_after_init
= 1UL << 30;
611 static void __init
early_init_memory_block_size(void)
614 * We need to do memory_block_size probe early so that
615 * radix__early_init_mmu() can use this as limit for
618 of_scan_flat_dt(probe_memory_block_size
, &memory_block_size
);
621 void __init
mmu_early_init_devtree(void)
623 bool hvmode
= !!(mfmsr() & MSR_HV
);
625 /* Disable radix mode based on kernel command line. */
627 if (IS_ENABLED(CONFIG_PPC_64S_HASH_MMU
))
628 cur_cpu_spec
->mmu_features
&= ~MMU_FTR_TYPE_RADIX
;
630 pr_warn("WARNING: Ignoring cmdline option disable_radix\n");
633 of_scan_flat_dt(dt_scan_mmu_pid_width
, NULL
);
634 if (hvmode
&& !mmu_lpid_bits
) {
635 if (early_cpu_has_feature(CPU_FTR_ARCH_207S
))
636 mmu_lpid_bits
= 12; /* POWER8-10 */
638 mmu_lpid_bits
= 10; /* POWER7 */
641 if (early_cpu_has_feature(CPU_FTR_ARCH_300
))
642 mmu_pid_bits
= 20; /* POWER9-10 */
646 * Check /chosen/ibm,architecture-vec-5 if running as a guest.
647 * When running bare-metal, we can use radix if we like
648 * even though the ibm,architecture-vec-5 property created by
649 * skiboot doesn't have the necessary bits set.
654 early_init_memory_block_size();
656 if (early_radix_enabled()) {
657 radix__early_init_devtree();
660 * We have finalized the translation we are going to use by now.
661 * Radix mode is not limited by RMA / VRMA addressing.
662 * Hence don't limit memblock allocations.
664 ppc64_rma_size
= ULONG_MAX
;
665 memblock_set_current_limit(MEMBLOCK_ALLOC_ANYWHERE
);
667 hash__early_init_devtree();
669 if (IS_ENABLED(CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
))
670 hugetlbpage_init_defaultsize();
672 if (!(cur_cpu_spec
->mmu_features
& MMU_FTR_HPTE_TABLE
) &&
673 !(cur_cpu_spec
->mmu_features
& MMU_FTR_TYPE_RADIX
))
674 panic("kernel does not support any MMU type offered by platform");
676 #endif /* CONFIG_PPC_BOOK3S_64 */