1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | |
3 | #include <linux/types.h> |
4 | #include <linux/slab.h> |
5 | #include <linux/syscore_ops.h> |
6 | #include <asm/cpufeature.h> |
7 | #include <asm/mtrr.h> |
8 | #include <asm/processor.h> |
9 | #include "mtrr.h" |
10 | |
11 | void mtrr_set_if(void) |
12 | { |
13 | switch (boot_cpu_data.x86_vendor) { |
14 | case X86_VENDOR_AMD: |
15 | /* Pre-Athlon (K6) AMD CPU MTRRs */ |
16 | if (cpu_feature_enabled(X86_FEATURE_K6_MTRR)) |
17 | mtrr_if = &amd_mtrr_ops; |
18 | break; |
19 | case X86_VENDOR_CENTAUR: |
20 | if (cpu_feature_enabled(X86_FEATURE_CENTAUR_MCR)) |
21 | mtrr_if = ¢aur_mtrr_ops; |
22 | break; |
23 | case X86_VENDOR_CYRIX: |
24 | if (cpu_feature_enabled(X86_FEATURE_CYRIX_ARR)) |
25 | mtrr_if = &cyrix_mtrr_ops; |
26 | break; |
27 | default: |
28 | break; |
29 | } |
30 | } |
31 | |
32 | /* |
33 | * The suspend/resume methods are only for CPUs without MTRR. CPUs using generic |
34 | * MTRR driver don't require this. |
35 | */ |
36 | struct mtrr_value { |
37 | mtrr_type ltype; |
38 | unsigned long lbase; |
39 | unsigned long lsize; |
40 | }; |
41 | |
42 | static struct mtrr_value *mtrr_value; |
43 | |
44 | static int mtrr_save(void) |
45 | { |
46 | int i; |
47 | |
48 | if (!mtrr_value) |
49 | return -ENOMEM; |
50 | |
51 | for (i = 0; i < num_var_ranges; i++) { |
52 | mtrr_if->get(i, &mtrr_value[i].lbase, |
53 | &mtrr_value[i].lsize, |
54 | &mtrr_value[i].ltype); |
55 | } |
56 | return 0; |
57 | } |
58 | |
59 | static void mtrr_restore(void) |
60 | { |
61 | int i; |
62 | |
63 | for (i = 0; i < num_var_ranges; i++) { |
64 | if (mtrr_value[i].lsize) { |
65 | mtrr_if->set(i, mtrr_value[i].lbase, |
66 | mtrr_value[i].lsize, |
67 | mtrr_value[i].ltype); |
68 | } |
69 | } |
70 | } |
71 | |
72 | static struct syscore_ops mtrr_syscore_ops = { |
73 | .suspend = mtrr_save, |
74 | .resume = mtrr_restore, |
75 | }; |
76 | |
77 | void mtrr_register_syscore(void) |
78 | { |
79 | mtrr_value = kcalloc(n: num_var_ranges, size: sizeof(*mtrr_value), GFP_KERNEL); |
80 | |
81 | /* |
82 | * The CPU has no MTRR and seems to not support SMP. They have |
83 | * specific drivers, we use a tricky method to support |
84 | * suspend/resume for them. |
85 | * |
86 | * TBD: is there any system with such CPU which supports |
87 | * suspend/resume? If no, we should remove the code. |
88 | */ |
89 | register_syscore_ops(ops: &mtrr_syscore_ops); |
90 | } |
91 | |