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45e576b1 MS |
1 | /* |
2 | * arch/s390/mm/page-states.c | |
3 | * | |
4 | * Copyright IBM Corp. 2008 | |
5 | * | |
6 | * Guest page hinting for unused pages. | |
7 | * | |
8 | * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com> | |
9 | */ | |
10 | ||
11 | #include <linux/kernel.h> | |
12 | #include <linux/errno.h> | |
13 | #include <linux/types.h> | |
14 | #include <linux/mm.h> | |
15 | #include <linux/init.h> | |
16 | ||
17 | #define ESSA_SET_STABLE 1 | |
18 | #define ESSA_SET_UNUSED 2 | |
19 | ||
20 | static int cmma_flag; | |
21 | ||
22 | static int __init cmma(char *str) | |
23 | { | |
24 | char *parm; | |
25 | parm = strstrip(str); | |
26 | if (strcmp(parm, "yes") == 0 || strcmp(parm, "on") == 0) { | |
27 | cmma_flag = 1; | |
28 | return 1; | |
29 | } | |
30 | cmma_flag = 0; | |
31 | if (strcmp(parm, "no") == 0 || strcmp(parm, "off") == 0) | |
32 | return 1; | |
33 | return 0; | |
34 | } | |
35 | ||
36 | __setup("cmma=", cmma); | |
37 | ||
38 | void __init cmma_init(void) | |
39 | { | |
40 | register unsigned long tmp asm("0") = 0; | |
41 | register int rc asm("1") = -EOPNOTSUPP; | |
42 | ||
43 | if (!cmma_flag) | |
44 | return; | |
45 | asm volatile( | |
46 | " .insn rrf,0xb9ab0000,%1,%1,0,0\n" | |
47 | "0: la %0,0\n" | |
48 | "1:\n" | |
49 | EX_TABLE(0b,1b) | |
50 | : "+&d" (rc), "+&d" (tmp)); | |
51 | if (rc) | |
52 | cmma_flag = 0; | |
53 | } | |
54 | ||
55 | void arch_free_page(struct page *page, int order) | |
56 | { | |
57 | int i, rc; | |
58 | ||
59 | if (!cmma_flag) | |
60 | return; | |
61 | for (i = 0; i < (1 << order); i++) | |
62 | asm volatile(".insn rrf,0xb9ab0000,%0,%1,%2,0" | |
63 | : "=&d" (rc) | |
64 | : "a" ((page_to_pfn(page) + i) << PAGE_SHIFT), | |
65 | "i" (ESSA_SET_UNUSED)); | |
66 | } | |
67 | ||
68 | void arch_alloc_page(struct page *page, int order) | |
69 | { | |
70 | int i, rc; | |
71 | ||
72 | if (!cmma_flag) | |
73 | return; | |
74 | for (i = 0; i < (1 << order); i++) | |
75 | asm volatile(".insn rrf,0xb9ab0000,%0,%1,%2,0" | |
76 | : "=&d" (rc) | |
77 | : "a" ((page_to_pfn(page) + i) << PAGE_SHIFT), | |
78 | "i" (ESSA_SET_STABLE)); | |
79 | } |