1 /* SPDX-License-Identifier: GPL-2.0+ */
2 /*
3 * Security related feature bit definitions.
4 *
5 * Copyright 2018, Michael Ellerman, IBM Corporation.
6 */
7
8 #ifndef _ASM_POWERPC_SECURITY_FEATURES_H
9 #define _ASM_POWERPC_SECURITY_FEATURES_H
10
11
12 extern unsigned long powerpc_security_features;
13 extern bool rfi_flush;
14
15 /* These are bit flags */
16 enum stf_barrier_type {
17 STF_BARRIER_NONE = 0x1,
18 STF_BARRIER_FALLBACK = 0x2,
19 STF_BARRIER_EIEIO = 0x4,
20 STF_BARRIER_SYNC_ORI = 0x8,
21 };
22
23 void setup_stf_barrier(void);
24 void do_stf_barrier_fixups(enum stf_barrier_type types);
25 void setup_count_cache_flush(void);
26
security_ftr_set(unsigned long feature)27 static inline void security_ftr_set(unsigned long feature)
28 {
29 powerpc_security_features |= feature;
30 }
31
security_ftr_clear(unsigned long feature)32 static inline void security_ftr_clear(unsigned long feature)
33 {
34 powerpc_security_features &= ~feature;
35 }
36
security_ftr_enabled(unsigned long feature)37 static inline bool security_ftr_enabled(unsigned long feature)
38 {
39 return !!(powerpc_security_features & feature);
40 }
41
42
43 // Features indicating support for Spectre/Meltdown mitigations
44
45 // The L1-D cache can be flushed with ori r30,r30,0
46 #define SEC_FTR_L1D_FLUSH_ORI30 0x0000000000000001ull
47
48 // The L1-D cache can be flushed with mtspr 882,r0 (aka SPRN_TRIG2)
49 #define SEC_FTR_L1D_FLUSH_TRIG2 0x0000000000000002ull
50
51 // ori r31,r31,0 acts as a speculation barrier
52 #define SEC_FTR_SPEC_BAR_ORI31 0x0000000000000004ull
53
54 // Speculation past bctr is disabled
55 #define SEC_FTR_BCCTRL_SERIALISED 0x0000000000000008ull
56
57 // Entries in L1-D are private to a SMT thread
58 #define SEC_FTR_L1D_THREAD_PRIV 0x0000000000000010ull
59
60 // Indirect branch prediction cache disabled
61 #define SEC_FTR_COUNT_CACHE_DISABLED 0x0000000000000020ull
62
63 // bcctr 2,0,0 triggers a hardware assisted count cache flush
64 #define SEC_FTR_BCCTR_FLUSH_ASSIST 0x0000000000000800ull
65
66
67 // Features indicating need for Spectre/Meltdown mitigations
68
69 // The L1-D cache should be flushed on MSR[HV] 1->0 transition (hypervisor to guest)
70 #define SEC_FTR_L1D_FLUSH_HV 0x0000000000000040ull
71
72 // The L1-D cache should be flushed on MSR[PR] 0->1 transition (kernel to userspace)
73 #define SEC_FTR_L1D_FLUSH_PR 0x0000000000000080ull
74
75 // A speculation barrier should be used for bounds checks (Spectre variant 1)
76 #define SEC_FTR_BNDS_CHK_SPEC_BAR 0x0000000000000100ull
77
78 // Firmware configuration indicates user favours security over performance
79 #define SEC_FTR_FAVOUR_SECURITY 0x0000000000000200ull
80
81 // Software required to flush count cache on context switch
82 #define SEC_FTR_FLUSH_COUNT_CACHE 0x0000000000000400ull
83
84
85 // Features enabled by default
86 #define SEC_FTR_DEFAULT \
87 (SEC_FTR_L1D_FLUSH_HV | \
88 SEC_FTR_L1D_FLUSH_PR | \
89 SEC_FTR_BNDS_CHK_SPEC_BAR | \
90 SEC_FTR_FAVOUR_SECURITY)
91
92 #endif /* _ASM_POWERPC_SECURITY_FEATURES_H */
93
