1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * Macros for Flexible Return and Event Delivery (FRED)
4 */
5
6 #ifndef ASM_X86_FRED_H
7 #define ASM_X86_FRED_H
8
9 #include <linux/const.h>
10
11 #include <asm/asm.h>
12 #include <asm/msr.h>
13 #include <asm/trapnr.h>
14
15 /*
16 * FRED event return instruction opcodes for ERET{S,U}; supported in
17 * binutils >= 2.41.
18 */
19 #define ERETS _ASM_BYTES(0xf2,0x0f,0x01,0xca)
20 #define ERETU _ASM_BYTES(0xf3,0x0f,0x01,0xca)
21
22 /*
23 * RSP is aligned to a 64-byte boundary before used to push a new stack frame
24 */
25 #define FRED_STACK_FRAME_RSP_MASK _AT(unsigned long, (~0x3f))
26
27 /*
28 * Used for the return address for call emulation during code patching,
29 * and measured in 64-byte cache lines.
30 */
31 #define FRED_CONFIG_REDZONE_AMOUNT 1
32 #define FRED_CONFIG_REDZONE (_AT(unsigned long, FRED_CONFIG_REDZONE_AMOUNT) << 6)
33 #define FRED_CONFIG_INT_STKLVL(l) (_AT(unsigned long, l) << 9)
34 #define FRED_CONFIG_ENTRYPOINT(p) _AT(unsigned long, (p))
35
36 #ifndef __ASSEMBLER__
37
38 #ifdef CONFIG_X86_FRED
39 #include <linux/kernel.h>
40 #include <linux/sched/task_stack.h>
41
42 #include <asm/ptrace.h>
43
44 struct fred_info {
45 /* Event data: CR2, DR6, ... */
46 unsigned long edata;
47 unsigned long resv;
48 };
49
50 /* Full format of the FRED stack frame */
51 struct fred_frame {
52 struct pt_regs regs;
53 struct fred_info info;
54 };
55
fred_info(struct pt_regs * regs)56 static __always_inline struct fred_info *fred_info(struct pt_regs *regs)
57 {
58 return &container_of(regs, struct fred_frame, regs)->info;
59 }
60
fred_event_data(struct pt_regs * regs)61 static __always_inline unsigned long fred_event_data(struct pt_regs *regs)
62 {
63 return fred_info(regs)->edata;
64 }
65
66 void asm_fred_entrypoint_user(void);
67 void asm_fred_entrypoint_kernel(void);
68 void asm_fred_entry_from_kvm(struct fred_ss);
69
70 __visible void fred_entry_from_user(struct pt_regs *regs);
71 __visible void fred_entry_from_kernel(struct pt_regs *regs);
72 __visible void __fred_entry_from_kvm(struct pt_regs *regs);
73
74 /* Can be called from noinstr code, thus __always_inline */
fred_entry_from_kvm(unsigned int type,unsigned int vector)75 static __always_inline void fred_entry_from_kvm(unsigned int type, unsigned int vector)
76 {
77 struct fred_ss ss = {
78 .ss =__KERNEL_DS,
79 .type = type,
80 .vector = vector,
81 .nmi = type == EVENT_TYPE_NMI,
82 .lm = 1,
83 };
84
85 asm_fred_entry_from_kvm(ss);
86 }
87
88 void cpu_init_fred_exceptions(void);
89 void cpu_init_fred_rsps(void);
90 void fred_complete_exception_setup(void);
91
92 DECLARE_PER_CPU(unsigned long, fred_rsp0);
93
fred_sync_rsp0(unsigned long rsp0)94 static __always_inline void fred_sync_rsp0(unsigned long rsp0)
95 {
96 __this_cpu_write(fred_rsp0, rsp0);
97 }
98
fred_update_rsp0(void)99 static __always_inline void fred_update_rsp0(void)
100 {
101 unsigned long rsp0 = (unsigned long) task_stack_page(current) + THREAD_SIZE;
102
103 if (cpu_feature_enabled(X86_FEATURE_FRED) && (__this_cpu_read(fred_rsp0) != rsp0)) {
104 wrmsrns(MSR_IA32_FRED_RSP0, rsp0);
105 __this_cpu_write(fred_rsp0, rsp0);
106 }
107 }
108 #else /* CONFIG_X86_FRED */
fred_event_data(struct pt_regs * regs)109 static __always_inline unsigned long fred_event_data(struct pt_regs *regs) { return 0; }
cpu_init_fred_exceptions(void)110 static inline void cpu_init_fred_exceptions(void) { }
cpu_init_fred_rsps(void)111 static inline void cpu_init_fred_rsps(void) { }
fred_complete_exception_setup(void)112 static inline void fred_complete_exception_setup(void) { }
fred_entry_from_kvm(unsigned int type,unsigned int vector)113 static inline void fred_entry_from_kvm(unsigned int type, unsigned int vector) { }
fred_sync_rsp0(unsigned long rsp0)114 static inline void fred_sync_rsp0(unsigned long rsp0) { }
fred_update_rsp0(void)115 static inline void fred_update_rsp0(void) { }
116 #endif /* CONFIG_X86_FRED */
117 #endif /* !__ASSEMBLER__ */
118
119 #endif /* ASM_X86_FRED_H */
120