1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * PPC Huge TLB Page Support for Book3E MMU
4  *
5  * Copyright (C) 2009 David Gibson, IBM Corporation.
6  * Copyright (C) 2011 Becky Bruce, Freescale Semiconductor
7  *
8  */
9 #include <linux/mm.h>
10 #include <linux/hugetlb.h>
11 
12 #include <asm/mmu.h>
13 
14 #ifdef CONFIG_PPC64
15 #include <asm/paca.h>
16 
17 static inline int tlb1_next(void)
18 {
19 	struct paca_struct *paca = get_paca();
20 	struct tlb_core_data *tcd;
21 	int this, next;
22 
23 	tcd = paca->tcd_ptr;
24 	this = tcd->esel_next;
25 
26 	next = this + 1;
27 	if (next >= tcd->esel_max)
28 		next = tcd->esel_first;
29 
30 	tcd->esel_next = next;
31 	return this;
32 }
33 
34 static inline void book3e_tlb_lock(void)
35 {
36 	struct paca_struct *paca = get_paca();
37 	unsigned long tmp;
38 	int token = smp_processor_id() + 1;
39 
40 	/*
41 	 * Besides being unnecessary in the absence of SMT, this
42 	 * check prevents trying to do lbarx/stbcx. on e5500 which
43 	 * doesn't implement either feature.
44 	 */
45 	if (!cpu_has_feature(CPU_FTR_SMT))
46 		return;
47 
48 	asm volatile(".machine push;"
49 		     ".machine e6500;"
50 		     "1: lbarx %0, 0, %1;"
51 		     "cmpwi %0, 0;"
52 		     "bne 2f;"
53 		     "stbcx. %2, 0, %1;"
54 		     "bne 1b;"
55 		     "b 3f;"
56 		     "2: lbzx %0, 0, %1;"
57 		     "cmpwi %0, 0;"
58 		     "bne 2b;"
59 		     "b 1b;"
60 		     "3:"
61 		     ".machine pop;"
62 		     : "=&r" (tmp)
63 		     : "r" (&paca->tcd_ptr->lock), "r" (token)
64 		     : "memory");
65 }
66 
67 static inline void book3e_tlb_unlock(void)
68 {
69 	struct paca_struct *paca = get_paca();
70 
71 	if (!cpu_has_feature(CPU_FTR_SMT))
72 		return;
73 
74 	isync();
75 	paca->tcd_ptr->lock = 0;
76 }
77 #else
78 static inline int tlb1_next(void)
79 {
80 	int index, ncams;
81 
82 	ncams = mfspr(SPRN_TLB1CFG) & TLBnCFG_N_ENTRY;
83 
84 	index = this_cpu_read(next_tlbcam_idx);
85 
86 	/* Just round-robin the entries and wrap when we hit the end */
87 	if (unlikely(index == ncams - 1))
88 		__this_cpu_write(next_tlbcam_idx, tlbcam_index);
89 	else
90 		__this_cpu_inc(next_tlbcam_idx);
91 
92 	return index;
93 }
94 
95 static inline void book3e_tlb_lock(void)
96 {
97 }
98 
99 static inline void book3e_tlb_unlock(void)
100 {
101 }
102 #endif
103 
104 static inline int book3e_tlb_exists(unsigned long ea, unsigned long pid)
105 {
106 	int found = 0;
107 
108 	mtspr(SPRN_MAS6, pid << 16);
109 	asm volatile(
110 		"tlbsx	0,%1\n"
111 		"mfspr	%0,0x271\n"
112 		"srwi	%0,%0,31\n"
113 		: "=&r"(found) : "r"(ea));
114 
115 	return found;
116 }
117 
118 static void
119 book3e_hugetlb_preload(struct vm_area_struct *vma, unsigned long ea, pte_t pte)
120 {
121 	unsigned long mas1, mas2;
122 	u64 mas7_3;
123 	unsigned long psize, tsize, shift;
124 	unsigned long flags;
125 	struct mm_struct *mm;
126 	int index;
127 
128 	if (unlikely(is_kernel_addr(ea)))
129 		return;
130 
131 	mm = vma->vm_mm;
132 
133 	psize = vma_mmu_pagesize(vma);
134 	shift = __ilog2(psize);
135 	tsize = shift - 10;
136 	/*
137 	 * We can't be interrupted while we're setting up the MAS
138 	 * registers or after we've confirmed that no tlb exists.
139 	 */
140 	local_irq_save(flags);
141 
142 	book3e_tlb_lock();
143 
144 	if (unlikely(book3e_tlb_exists(ea, mm->context.id))) {
145 		book3e_tlb_unlock();
146 		local_irq_restore(flags);
147 		return;
148 	}
149 
150 	/* We have to use the CAM(TLB1) on FSL parts for hugepages */
151 	index = tlb1_next();
152 	mtspr(SPRN_MAS0, MAS0_ESEL(index) | MAS0_TLBSEL(1));
153 
154 	mas1 = MAS1_VALID | MAS1_TID(mm->context.id) | MAS1_TSIZE(tsize);
155 	mas2 = ea & ~((1UL << shift) - 1);
156 	mas2 |= (pte_val(pte) >> PTE_WIMGE_SHIFT) & MAS2_WIMGE_MASK;
157 	mas7_3 = (u64)pte_pfn(pte) << PAGE_SHIFT;
158 	mas7_3 |= (pte_val(pte) >> PTE_BAP_SHIFT) & MAS3_BAP_MASK;
159 	if (!pte_dirty(pte))
160 		mas7_3 &= ~(MAS3_SW|MAS3_UW);
161 
162 	mtspr(SPRN_MAS1, mas1);
163 	mtspr(SPRN_MAS2, mas2);
164 
165 	if (mmu_has_feature(MMU_FTR_BIG_PHYS))
166 		mtspr(SPRN_MAS7, upper_32_bits(mas7_3));
167 	mtspr(SPRN_MAS3, lower_32_bits(mas7_3));
168 
169 	asm volatile ("tlbwe");
170 
171 	book3e_tlb_unlock();
172 	local_irq_restore(flags);
173 }
174 
175 /*
176  * This is called at the end of handling a user page fault, when the
177  * fault has been handled by updating a PTE in the linux page tables.
178  *
179  * This must always be called with the pte lock held.
180  */
181 void update_mmu_cache_range(struct vm_fault *vmf, struct vm_area_struct *vma,
182 		unsigned long address, pte_t *ptep, unsigned int nr)
183 {
184 	if (is_vm_hugetlb_page(vma))
185 		book3e_hugetlb_preload(vma, address, *ptep);
186 }
187 
188 void flush_hugetlb_page(struct vm_area_struct *vma, unsigned long vmaddr)
189 {
190 	struct hstate *hstate = hstate_file(vma->vm_file);
191 	unsigned long tsize = huge_page_shift(hstate) - 10;
192 
193 	__flush_tlb_page(vma->vm_mm, vmaddr, tsize, 0);
194 }
195