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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
43struct 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 */
50struct fred_frame {
51 struct pt_regs regs;
52 struct fred_info info;
53};
54
55static __always_inline struct fred_info *fred_info(struct pt_regs *regs)
56{
57 return &container_of(regs, struct fred_frame, regs)->info;
58}
59
60static __always_inline unsigned long fred_event_data(struct pt_regs *regs)
61{
62 return fred_info(regs)->edata;
63}
64
65void asm_fred_entrypoint_user(void);
66void asm_fred_entrypoint_kernel(void);
67void 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 */
74static __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
87void cpu_init_fred_exceptions(void);
88void cpu_init_fred_rsps(void);
89void fred_complete_exception_setup(void);
90
91DECLARE_PER_CPU(unsigned long, fred_rsp0);
92
93static __always_inline void fred_sync_rsp0(unsigned long rsp0)
94{
95 __this_cpu_write(fred_rsp0, rsp0);
96}
97
98static __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 */
108static __always_inline unsigned long fred_event_data(struct pt_regs *regs) { return 0; }
109static inline void cpu_init_fred_exceptions(void) { }
110static inline void cpu_init_fred_rsps(void) { }
111static inline void fred_complete_exception_setup(void) { }
112static inline void fred_entry_from_kvm(unsigned int type, unsigned int vector) { }
113static inline void fred_sync_rsp0(unsigned long rsp0) { }
114static inline void fred_update_rsp0(void) { }
115#endif /* CONFIG_X86_FRED */
116#endif /* !__ASSEMBLY__ */
117
118#endif /* ASM_X86_FRED_H */