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