1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Initialize MMU support.
4  *
5  * Copyright (C) 1998-2003 Hewlett-Packard Co
6  *	David Mosberger-Tang <davidm@hpl.hp.com>
7  */
8 #include <linux/kernel.h>
9 #include <linux/init.h>
10 
11 #include <linux/dma-map-ops.h>
12 #include <linux/dmar.h>
13 #include <linux/efi.h>
14 #include <linux/elf.h>
15 #include <linux/memblock.h>
16 #include <linux/mm.h>
17 #include <linux/sched/signal.h>
18 #include <linux/mmzone.h>
19 #include <linux/module.h>
20 #include <linux/personality.h>
21 #include <linux/reboot.h>
22 #include <linux/slab.h>
23 #include <linux/swap.h>
24 #include <linux/proc_fs.h>
25 #include <linux/bitops.h>
26 #include <linux/kexec.h>
27 #include <linux/swiotlb.h>
28 
29 #include <asm/dma.h>
30 #include <asm/efi.h>
31 #include <asm/io.h>
32 #include <asm/numa.h>
33 #include <asm/patch.h>
34 #include <asm/pgalloc.h>
35 #include <asm/sal.h>
36 #include <asm/sections.h>
37 #include <asm/tlb.h>
38 #include <linux/uaccess.h>
39 #include <asm/unistd.h>
40 #include <asm/mca.h>
41 
42 extern void ia64_tlb_init (void);
43 
44 unsigned long MAX_DMA_ADDRESS = PAGE_OFFSET + 0x100000000UL;
45 
46 struct page *zero_page_memmap_ptr;	/* map entry for zero page */
47 EXPORT_SYMBOL(zero_page_memmap_ptr);
48 
49 void
__ia64_sync_icache_dcache(pte_t pte)50 __ia64_sync_icache_dcache (pte_t pte)
51 {
52 	unsigned long addr;
53 	struct page *page;
54 
55 	page = pte_page(pte);
56 	addr = (unsigned long) page_address(page);
57 
58 	if (test_bit(PG_arch_1, &page->flags))
59 		return;				/* i-cache is already coherent with d-cache */
60 
61 	flush_icache_range(addr, addr + page_size(page));
62 	set_bit(PG_arch_1, &page->flags);	/* mark page as clean */
63 }
64 
65 /*
66  * Since DMA is i-cache coherent, any (complete) pages that were written via
67  * DMA can be marked as "clean" so that lazy_mmu_prot_update() doesn't have to
68  * flush them when they get mapped into an executable vm-area.
69  */
arch_dma_mark_clean(phys_addr_t paddr,size_t size)70 void arch_dma_mark_clean(phys_addr_t paddr, size_t size)
71 {
72 	unsigned long pfn = PHYS_PFN(paddr);
73 
74 	do {
75 		set_bit(PG_arch_1, &pfn_to_page(pfn)->flags);
76 	} while (++pfn <= PHYS_PFN(paddr + size - 1));
77 }
78 
79 inline void
ia64_set_rbs_bot(void)80 ia64_set_rbs_bot (void)
81 {
82 	unsigned long stack_size = rlimit_max(RLIMIT_STACK) & -16;
83 
84 	if (stack_size > MAX_USER_STACK_SIZE)
85 		stack_size = MAX_USER_STACK_SIZE;
86 	current->thread.rbs_bot = PAGE_ALIGN(current->mm->start_stack - stack_size);
87 }
88 
89 /*
90  * This performs some platform-dependent address space initialization.
91  * On IA-64, we want to setup the VM area for the register backing
92  * store (which grows upwards) and install the gateway page which is
93  * used for signal trampolines, etc.
94  */
95 void
ia64_init_addr_space(void)96 ia64_init_addr_space (void)
97 {
98 	struct vm_area_struct *vma;
99 
100 	ia64_set_rbs_bot();
101 
102 	/*
103 	 * If we're out of memory and kmem_cache_alloc() returns NULL, we simply ignore
104 	 * the problem.  When the process attempts to write to the register backing store
105 	 * for the first time, it will get a SEGFAULT in this case.
106 	 */
107 	vma = vm_area_alloc(current->mm);
108 	if (vma) {
109 		vma_set_anonymous(vma);
110 		vma->vm_start = current->thread.rbs_bot & PAGE_MASK;
111 		vma->vm_end = vma->vm_start + PAGE_SIZE;
112 		vma->vm_flags = VM_DATA_DEFAULT_FLAGS|VM_GROWSUP|VM_ACCOUNT;
113 		vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
114 		mmap_write_lock(current->mm);
115 		if (insert_vm_struct(current->mm, vma)) {
116 			mmap_write_unlock(current->mm);
117 			vm_area_free(vma);
118 			return;
119 		}
120 		mmap_write_unlock(current->mm);
121 	}
122 
123 	/* map NaT-page at address zero to speed up speculative dereferencing of NULL: */
124 	if (!(current->personality & MMAP_PAGE_ZERO)) {
125 		vma = vm_area_alloc(current->mm);
126 		if (vma) {
127 			vma_set_anonymous(vma);
128 			vma->vm_end = PAGE_SIZE;
129 			vma->vm_page_prot = __pgprot(pgprot_val(PAGE_READONLY) | _PAGE_MA_NAT);
130 			vma->vm_flags = VM_READ | VM_MAYREAD | VM_IO |
131 					VM_DONTEXPAND | VM_DONTDUMP;
132 			mmap_write_lock(current->mm);
133 			if (insert_vm_struct(current->mm, vma)) {
134 				mmap_write_unlock(current->mm);
135 				vm_area_free(vma);
136 				return;
137 			}
138 			mmap_write_unlock(current->mm);
139 		}
140 	}
141 }
142 
143 void
free_initmem(void)144 free_initmem (void)
145 {
146 	free_reserved_area(ia64_imva(__init_begin), ia64_imva(__init_end),
147 			   -1, "unused kernel");
148 }
149 
150 void __init
free_initrd_mem(unsigned long start,unsigned long end)151 free_initrd_mem (unsigned long start, unsigned long end)
152 {
153 	/*
154 	 * EFI uses 4KB pages while the kernel can use 4KB or bigger.
155 	 * Thus EFI and the kernel may have different page sizes. It is
156 	 * therefore possible to have the initrd share the same page as
157 	 * the end of the kernel (given current setup).
158 	 *
159 	 * To avoid freeing/using the wrong page (kernel sized) we:
160 	 *	- align up the beginning of initrd
161 	 *	- align down the end of initrd
162 	 *
163 	 *  |             |
164 	 *  |=============| a000
165 	 *  |             |
166 	 *  |             |
167 	 *  |             | 9000
168 	 *  |/////////////|
169 	 *  |/////////////|
170 	 *  |=============| 8000
171 	 *  |///INITRD////|
172 	 *  |/////////////|
173 	 *  |/////////////| 7000
174 	 *  |             |
175 	 *  |KKKKKKKKKKKKK|
176 	 *  |=============| 6000
177 	 *  |KKKKKKKKKKKKK|
178 	 *  |KKKKKKKKKKKKK|
179 	 *  K=kernel using 8KB pages
180 	 *
181 	 * In this example, we must free page 8000 ONLY. So we must align up
182 	 * initrd_start and keep initrd_end as is.
183 	 */
184 	start = PAGE_ALIGN(start);
185 	end = end & PAGE_MASK;
186 
187 	if (start < end)
188 		printk(KERN_INFO "Freeing initrd memory: %ldkB freed\n", (end - start) >> 10);
189 
190 	for (; start < end; start += PAGE_SIZE) {
191 		if (!virt_addr_valid(start))
192 			continue;
193 		free_reserved_page(virt_to_page(start));
194 	}
195 }
196 
197 /*
198  * This installs a clean page in the kernel's page table.
199  */
200 static struct page * __init
put_kernel_page(struct page * page,unsigned long address,pgprot_t pgprot)201 put_kernel_page (struct page *page, unsigned long address, pgprot_t pgprot)
202 {
203 	pgd_t *pgd;
204 	p4d_t *p4d;
205 	pud_t *pud;
206 	pmd_t *pmd;
207 	pte_t *pte;
208 
209 	pgd = pgd_offset_k(address);		/* note: this is NOT pgd_offset()! */
210 
211 	{
212 		p4d = p4d_alloc(&init_mm, pgd, address);
213 		if (!p4d)
214 			goto out;
215 		pud = pud_alloc(&init_mm, p4d, address);
216 		if (!pud)
217 			goto out;
218 		pmd = pmd_alloc(&init_mm, pud, address);
219 		if (!pmd)
220 			goto out;
221 		pte = pte_alloc_kernel(pmd, address);
222 		if (!pte)
223 			goto out;
224 		if (!pte_none(*pte))
225 			goto out;
226 		set_pte(pte, mk_pte(page, pgprot));
227 	}
228   out:
229 	/* no need for flush_tlb */
230 	return page;
231 }
232 
233 static void __init
setup_gate(void)234 setup_gate (void)
235 {
236 	struct page *page;
237 
238 	/*
239 	 * Map the gate page twice: once read-only to export the ELF
240 	 * headers etc. and once execute-only page to enable
241 	 * privilege-promotion via "epc":
242 	 */
243 	page = virt_to_page(ia64_imva(__start_gate_section));
244 	put_kernel_page(page, GATE_ADDR, PAGE_READONLY);
245 #ifdef HAVE_BUGGY_SEGREL
246 	page = virt_to_page(ia64_imva(__start_gate_section + PAGE_SIZE));
247 	put_kernel_page(page, GATE_ADDR + PAGE_SIZE, PAGE_GATE);
248 #else
249 	put_kernel_page(page, GATE_ADDR + PERCPU_PAGE_SIZE, PAGE_GATE);
250 	/* Fill in the holes (if any) with read-only zero pages: */
251 	{
252 		unsigned long addr;
253 
254 		for (addr = GATE_ADDR + PAGE_SIZE;
255 		     addr < GATE_ADDR + PERCPU_PAGE_SIZE;
256 		     addr += PAGE_SIZE)
257 		{
258 			put_kernel_page(ZERO_PAGE(0), addr,
259 					PAGE_READONLY);
260 			put_kernel_page(ZERO_PAGE(0), addr + PERCPU_PAGE_SIZE,
261 					PAGE_READONLY);
262 		}
263 	}
264 #endif
265 	ia64_patch_gate();
266 }
267 
268 static struct vm_area_struct gate_vma;
269 
gate_vma_init(void)270 static int __init gate_vma_init(void)
271 {
272 	vma_init(&gate_vma, NULL);
273 	gate_vma.vm_start = FIXADDR_USER_START;
274 	gate_vma.vm_end = FIXADDR_USER_END;
275 	gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC;
276 	gate_vma.vm_page_prot = __P101;
277 
278 	return 0;
279 }
280 __initcall(gate_vma_init);
281 
get_gate_vma(struct mm_struct * mm)282 struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
283 {
284 	return &gate_vma;
285 }
286 
in_gate_area_no_mm(unsigned long addr)287 int in_gate_area_no_mm(unsigned long addr)
288 {
289 	if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
290 		return 1;
291 	return 0;
292 }
293 
in_gate_area(struct mm_struct * mm,unsigned long addr)294 int in_gate_area(struct mm_struct *mm, unsigned long addr)
295 {
296 	return in_gate_area_no_mm(addr);
297 }
298 
ia64_mmu_init(void * my_cpu_data)299 void ia64_mmu_init(void *my_cpu_data)
300 {
301 	unsigned long pta, impl_va_bits;
302 	extern void tlb_init(void);
303 
304 #ifdef CONFIG_DISABLE_VHPT
305 #	define VHPT_ENABLE_BIT	0
306 #else
307 #	define VHPT_ENABLE_BIT	1
308 #endif
309 
310 	/*
311 	 * Check if the virtually mapped linear page table (VMLPT) overlaps with a mapped
312 	 * address space.  The IA-64 architecture guarantees that at least 50 bits of
313 	 * virtual address space are implemented but if we pick a large enough page size
314 	 * (e.g., 64KB), the mapped address space is big enough that it will overlap with
315 	 * VMLPT.  I assume that once we run on machines big enough to warrant 64KB pages,
316 	 * IMPL_VA_MSB will be significantly bigger, so this is unlikely to become a
317 	 * problem in practice.  Alternatively, we could truncate the top of the mapped
318 	 * address space to not permit mappings that would overlap with the VMLPT.
319 	 * --davidm 00/12/06
320 	 */
321 #	define pte_bits			3
322 #	define mapped_space_bits	(3*(PAGE_SHIFT - pte_bits) + PAGE_SHIFT)
323 	/*
324 	 * The virtual page table has to cover the entire implemented address space within
325 	 * a region even though not all of this space may be mappable.  The reason for
326 	 * this is that the Access bit and Dirty bit fault handlers perform
327 	 * non-speculative accesses to the virtual page table, so the address range of the
328 	 * virtual page table itself needs to be covered by virtual page table.
329 	 */
330 #	define vmlpt_bits		(impl_va_bits - PAGE_SHIFT + pte_bits)
331 #	define POW2(n)			(1ULL << (n))
332 
333 	impl_va_bits = ffz(~(local_cpu_data->unimpl_va_mask | (7UL << 61)));
334 
335 	if (impl_va_bits < 51 || impl_va_bits > 61)
336 		panic("CPU has bogus IMPL_VA_MSB value of %lu!\n", impl_va_bits - 1);
337 	/*
338 	 * mapped_space_bits - PAGE_SHIFT is the total number of ptes we need,
339 	 * which must fit into "vmlpt_bits - pte_bits" slots. Second half of
340 	 * the test makes sure that our mapped space doesn't overlap the
341 	 * unimplemented hole in the middle of the region.
342 	 */
343 	if ((mapped_space_bits - PAGE_SHIFT > vmlpt_bits - pte_bits) ||
344 	    (mapped_space_bits > impl_va_bits - 1))
345 		panic("Cannot build a big enough virtual-linear page table"
346 		      " to cover mapped address space.\n"
347 		      " Try using a smaller page size.\n");
348 
349 
350 	/* place the VMLPT at the end of each page-table mapped region: */
351 	pta = POW2(61) - POW2(vmlpt_bits);
352 
353 	/*
354 	 * Set the (virtually mapped linear) page table address.  Bit
355 	 * 8 selects between the short and long format, bits 2-7 the
356 	 * size of the table, and bit 0 whether the VHPT walker is
357 	 * enabled.
358 	 */
359 	ia64_set_pta(pta | (0 << 8) | (vmlpt_bits << 2) | VHPT_ENABLE_BIT);
360 
361 	ia64_tlb_init();
362 
363 #ifdef	CONFIG_HUGETLB_PAGE
364 	ia64_set_rr(HPAGE_REGION_BASE, HPAGE_SHIFT << 2);
365 	ia64_srlz_d();
366 #endif
367 }
368 
register_active_ranges(u64 start,u64 len,int nid)369 int __init register_active_ranges(u64 start, u64 len, int nid)
370 {
371 	u64 end = start + len;
372 
373 #ifdef CONFIG_KEXEC
374 	if (start > crashk_res.start && start < crashk_res.end)
375 		start = crashk_res.end;
376 	if (end > crashk_res.start && end < crashk_res.end)
377 		end = crashk_res.start;
378 #endif
379 
380 	if (start < end)
381 		memblock_add_node(__pa(start), end - start, nid, MEMBLOCK_NONE);
382 	return 0;
383 }
384 
385 int
find_max_min_low_pfn(u64 start,u64 end,void * arg)386 find_max_min_low_pfn (u64 start, u64 end, void *arg)
387 {
388 	unsigned long pfn_start, pfn_end;
389 #ifdef CONFIG_FLATMEM
390 	pfn_start = (PAGE_ALIGN(__pa(start))) >> PAGE_SHIFT;
391 	pfn_end = (PAGE_ALIGN(__pa(end - 1))) >> PAGE_SHIFT;
392 #else
393 	pfn_start = GRANULEROUNDDOWN(__pa(start)) >> PAGE_SHIFT;
394 	pfn_end = GRANULEROUNDUP(__pa(end - 1)) >> PAGE_SHIFT;
395 #endif
396 	min_low_pfn = min(min_low_pfn, pfn_start);
397 	max_low_pfn = max(max_low_pfn, pfn_end);
398 	return 0;
399 }
400 
401 /*
402  * Boot command-line option "nolwsys" can be used to disable the use of any light-weight
403  * system call handler.  When this option is in effect, all fsyscalls will end up bubbling
404  * down into the kernel and calling the normal (heavy-weight) syscall handler.  This is
405  * useful for performance testing, but conceivably could also come in handy for debugging
406  * purposes.
407  */
408 
409 static int nolwsys __initdata;
410 
411 static int __init
nolwsys_setup(char * s)412 nolwsys_setup (char *s)
413 {
414 	nolwsys = 1;
415 	return 1;
416 }
417 
418 __setup("nolwsys", nolwsys_setup);
419 
420 void __init
mem_init(void)421 mem_init (void)
422 {
423 	int i;
424 
425 	BUG_ON(PTRS_PER_PGD * sizeof(pgd_t) != PAGE_SIZE);
426 	BUG_ON(PTRS_PER_PMD * sizeof(pmd_t) != PAGE_SIZE);
427 	BUG_ON(PTRS_PER_PTE * sizeof(pte_t) != PAGE_SIZE);
428 
429 	/*
430 	 * This needs to be called _after_ the command line has been parsed but
431 	 * _before_ any drivers that may need the PCI DMA interface are
432 	 * initialized or bootmem has been freed.
433 	 */
434 	do {
435 #ifdef CONFIG_INTEL_IOMMU
436 		detect_intel_iommu();
437 		if (iommu_detected)
438 			break;
439 #endif
440 		swiotlb_init(true, SWIOTLB_VERBOSE);
441 	} while (0);
442 
443 #ifdef CONFIG_FLATMEM
444 	BUG_ON(!mem_map);
445 #endif
446 
447 	set_max_mapnr(max_low_pfn);
448 	high_memory = __va(max_low_pfn * PAGE_SIZE);
449 	memblock_free_all();
450 
451 	/*
452 	 * For fsyscall entrypoints with no light-weight handler, use the ordinary
453 	 * (heavy-weight) handler, but mark it by setting bit 0, so the fsyscall entry
454 	 * code can tell them apart.
455 	 */
456 	for (i = 0; i < NR_syscalls; ++i) {
457 		extern unsigned long fsyscall_table[NR_syscalls];
458 		extern unsigned long sys_call_table[NR_syscalls];
459 
460 		if (!fsyscall_table[i] || nolwsys)
461 			fsyscall_table[i] = sys_call_table[i] | 1;
462 	}
463 	setup_gate();
464 }
465 
466 #ifdef CONFIG_MEMORY_HOTPLUG
arch_add_memory(int nid,u64 start,u64 size,struct mhp_params * params)467 int arch_add_memory(int nid, u64 start, u64 size,
468 		    struct mhp_params *params)
469 {
470 	unsigned long start_pfn = start >> PAGE_SHIFT;
471 	unsigned long nr_pages = size >> PAGE_SHIFT;
472 	int ret;
473 
474 	if (WARN_ON_ONCE(params->pgprot.pgprot != PAGE_KERNEL.pgprot))
475 		return -EINVAL;
476 
477 	ret = __add_pages(nid, start_pfn, nr_pages, params);
478 	if (ret)
479 		printk("%s: Problem encountered in __add_pages() as ret=%d\n",
480 		       __func__,  ret);
481 
482 	return ret;
483 }
484 
arch_remove_memory(u64 start,u64 size,struct vmem_altmap * altmap)485 void arch_remove_memory(u64 start, u64 size, struct vmem_altmap *altmap)
486 {
487 	unsigned long start_pfn = start >> PAGE_SHIFT;
488 	unsigned long nr_pages = size >> PAGE_SHIFT;
489 
490 	__remove_pages(start_pfn, nr_pages, altmap);
491 }
492 #endif
493