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 u64 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 
27 static inline void security_ftr_set(u64 feature)
28 {
29 	powerpc_security_features |= feature;
30 }
31 
32 static inline void security_ftr_clear(u64 feature)
33 {
34 	powerpc_security_features &= ~feature;
35 }
36 
37 static inline bool security_ftr_enabled(u64 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 // bcctr 2,0,0 triggers a hardware assisted link stack flush
67 #define SEC_FTR_BCCTR_LINK_FLUSH_ASSIST	0x0000000000002000ull
68 
69 // Features indicating need for Spectre/Meltdown mitigations
70 
71 // The L1-D cache should be flushed on MSR[HV] 1->0 transition (hypervisor to guest)
72 #define SEC_FTR_L1D_FLUSH_HV		0x0000000000000040ull
73 
74 // The L1-D cache should be flushed on MSR[PR] 0->1 transition (kernel to userspace)
75 #define SEC_FTR_L1D_FLUSH_PR		0x0000000000000080ull
76 
77 // A speculation barrier should be used for bounds checks (Spectre variant 1)
78 #define SEC_FTR_BNDS_CHK_SPEC_BAR	0x0000000000000100ull
79 
80 // Firmware configuration indicates user favours security over performance
81 #define SEC_FTR_FAVOUR_SECURITY		0x0000000000000200ull
82 
83 // Software required to flush count cache on context switch
84 #define SEC_FTR_FLUSH_COUNT_CACHE	0x0000000000000400ull
85 
86 // Software required to flush link stack on context switch
87 #define SEC_FTR_FLUSH_LINK_STACK	0x0000000000001000ull
88 
89 
90 // Features enabled by default
91 #define SEC_FTR_DEFAULT \
92 	(SEC_FTR_L1D_FLUSH_HV | \
93 	 SEC_FTR_L1D_FLUSH_PR | \
94 	 SEC_FTR_BNDS_CHK_SPEC_BAR | \
95 	 SEC_FTR_FAVOUR_SECURITY)
96 
97 #endif /* _ASM_POWERPC_SECURITY_FEATURES_H */
98