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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright IBM Corp. 2008
4 *
5 * Guest page hinting for unused pages.
6 *
7 * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
8 */
9
10#include <linux/kernel.h>
11#include <linux/errno.h>
12#include <linux/types.h>
13#include <linux/mm.h>
14#include <linux/memblock.h>
15#include <linux/gfp.h>
16#include <linux/init.h>
17#include <asm/asm-extable.h>
18#include <asm/facility.h>
19#include <asm/page-states.h>
20
21static int cmma_flag = 1;
22
23static int __init cmma(char *str)
24{
25 bool enabled;
26
27 if (!kstrtobool(str, &enabled))
28 cmma_flag = enabled;
29 return 1;
30}
31__setup("cmma=", cmma);
32
33static inline int cmma_test_essa(void)
34{
35 unsigned long tmp = 0;
36 int rc = -EOPNOTSUPP;
37
38 /* test ESSA_GET_STATE */
39 asm volatile(
40 " .insn rrf,0xb9ab0000,%[tmp],%[tmp],%[cmd],0\n"
41 "0: la %[rc],0\n"
42 "1:\n"
43 EX_TABLE(0b,1b)
44 : [rc] "+&d" (rc), [tmp] "+&d" (tmp)
45 : [cmd] "i" (ESSA_GET_STATE));
46 return rc;
47}
48
49void __init cmma_init(void)
50{
51 if (!cmma_flag)
52 return;
53 if (cmma_test_essa()) {
54 cmma_flag = 0;
55 return;
56 }
57 if (test_facility(147))
58 cmma_flag = 2;
59}
60
61static inline void set_page_unused(struct page *page, int order)
62{
63 int i, rc;
64
65 for (i = 0; i < (1 << order); i++)
66 asm volatile(".insn rrf,0xb9ab0000,%0,%1,%2,0"
67 : "=&d" (rc)
68 : "a" (page_to_phys(page + i)),
69 "i" (ESSA_SET_UNUSED));
70}
71
72static inline void set_page_stable_dat(struct page *page, int order)
73{
74 int i, rc;
75
76 for (i = 0; i < (1 << order); i++)
77 asm volatile(".insn rrf,0xb9ab0000,%0,%1,%2,0"
78 : "=&d" (rc)
79 : "a" (page_to_phys(page + i)),
80 "i" (ESSA_SET_STABLE));
81}
82
83static inline void set_page_stable_nodat(struct page *page, int order)
84{
85 int i, rc;
86
87 for (i = 0; i < (1 << order); i++)
88 asm volatile(".insn rrf,0xb9ab0000,%0,%1,%2,0"
89 : "=&d" (rc)
90 : "a" (page_to_phys(page + i)),
91 "i" (ESSA_SET_STABLE_NODAT));
92}
93
94static void mark_kernel_pmd(pud_t *pud, unsigned long addr, unsigned long end)
95{
96 unsigned long next;
97 struct page *page;
98 pmd_t *pmd;
99
100 pmd = pmd_offset(pud, addr);
101 do {
102 next = pmd_addr_end(addr, end);
103 if (pmd_none(*pmd) || pmd_large(*pmd))
104 continue;
105 page = phys_to_page(pmd_val(*pmd));
106 set_bit(PG_arch_1, &page->flags);
107 } while (pmd++, addr = next, addr != end);
108}
109
110static void mark_kernel_pud(p4d_t *p4d, unsigned long addr, unsigned long end)
111{
112 unsigned long next;
113 struct page *page;
114 pud_t *pud;
115 int i;
116
117 pud = pud_offset(p4d, addr);
118 do {
119 next = pud_addr_end(addr, end);
120 if (pud_none(*pud) || pud_large(*pud))
121 continue;
122 if (!pud_folded(*pud)) {
123 page = phys_to_page(pud_val(*pud));
124 for (i = 0; i < 3; i++)
125 set_bit(PG_arch_1, &page[i].flags);
126 }
127 mark_kernel_pmd(pud, addr, next);
128 } while (pud++, addr = next, addr != end);
129}
130
131static void mark_kernel_p4d(pgd_t *pgd, unsigned long addr, unsigned long end)
132{
133 unsigned long next;
134 struct page *page;
135 p4d_t *p4d;
136 int i;
137
138 p4d = p4d_offset(pgd, addr);
139 do {
140 next = p4d_addr_end(addr, end);
141 if (p4d_none(*p4d))
142 continue;
143 if (!p4d_folded(*p4d)) {
144 page = phys_to_page(p4d_val(*p4d));
145 for (i = 0; i < 3; i++)
146 set_bit(PG_arch_1, &page[i].flags);
147 }
148 mark_kernel_pud(p4d, addr, next);
149 } while (p4d++, addr = next, addr != end);
150}
151
152static void mark_kernel_pgd(void)
153{
154 unsigned long addr, next;
155 struct page *page;
156 pgd_t *pgd;
157 int i;
158
159 addr = 0;
160 pgd = pgd_offset_k(addr);
161 do {
162 next = pgd_addr_end(addr, MODULES_END);
163 if (pgd_none(*pgd))
164 continue;
165 if (!pgd_folded(*pgd)) {
166 page = phys_to_page(pgd_val(*pgd));
167 for (i = 0; i < 3; i++)
168 set_bit(PG_arch_1, &page[i].flags);
169 }
170 mark_kernel_p4d(pgd, addr, next);
171 } while (pgd++, addr = next, addr != MODULES_END);
172}
173
174void __init cmma_init_nodat(void)
175{
176 struct page *page;
177 unsigned long start, end, ix;
178 int i;
179
180 if (cmma_flag < 2)
181 return;
182 /* Mark pages used in kernel page tables */
183 mark_kernel_pgd();
184
185 /* Set all kernel pages not used for page tables to stable/no-dat */
186 for_each_mem_pfn_range(i, MAX_NUMNODES, &start, &end, NULL) {
187 page = pfn_to_page(start);
188 for (ix = start; ix < end; ix++, page++) {
189 if (__test_and_clear_bit(PG_arch_1, &page->flags))
190 continue; /* skip page table pages */
191 if (!list_empty(&page->lru))
192 continue; /* skip free pages */
193 set_page_stable_nodat(page, 0);
194 }
195 }
196}
197
198void arch_free_page(struct page *page, int order)
199{
200 if (!cmma_flag)
201 return;
202 set_page_unused(page, order);
203}
204
205void arch_alloc_page(struct page *page, int order)
206{
207 if (!cmma_flag)
208 return;
209 if (cmma_flag < 2)
210 set_page_stable_dat(page, order);
211 else
212 set_page_stable_nodat(page, order);
213}
214
215void arch_set_page_dat(struct page *page, int order)
216{
217 if (!cmma_flag)
218 return;
219 set_page_stable_dat(page, order);
220}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright IBM Corp. 2008
4 *
5 * Guest page hinting for unused pages.
6 *
7 * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
8 */
9
10#include <linux/mm.h>
11#include <asm/page-states.h>
12#include <asm/sections.h>
13#include <asm/page.h>
14
15int __bootdata_preserved(cmma_flag);
16
17void arch_free_page(struct page *page, int order)
18{
19 if (!cmma_flag)
20 return;
21 __set_page_unused(page_to_virt(page), 1UL << order);
22}
23
24void arch_alloc_page(struct page *page, int order)
25{
26 if (!cmma_flag)
27 return;
28 if (cmma_flag < 2)
29 __set_page_stable_dat(page_to_virt(page), 1UL << order);
30 else
31 __set_page_stable_nodat(page_to_virt(page), 1UL << order);
32}