1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * The actual FRED entry points.
4 */
5
6 #include <linux/export.h>
7
8 #include <asm/asm.h>
9 #include <asm/fred.h>
10 #include <asm/segment.h>
11
12 #include "calling.h"
13
14 .code64
15 .section .noinstr.text, "ax"
16
17 .macro FRED_ENTER
18 UNWIND_HINT_END_OF_STACK
19 ENDBR
20 PUSH_AND_CLEAR_REGS
21 movq %rsp, %rdi /* %rdi -> pt_
22 .endm
23
24 .macro FRED_EXIT
25 UNWIND_HINT_REGS
26 POP_REGS
27 .endm
28
29 /*
30 * The new RIP value that FRED event delivery
31 * IA32_FRED_CONFIG & ~FFFH for events that oc
32 * Thus the FRED ring 3 entry point must be 4K
33 */
34 .align 4096
35
36 SYM_CODE_START_NOALIGN(asm_fred_entrypoint_use
37 FRED_ENTER
38 call fred_entry_from_user
39 SYM_INNER_LABEL(asm_fred_exit_user, SYM_L_GLOB
40 FRED_EXIT
41 1: ERETU
42
43 _ASM_EXTABLE_TYPE(1b, asm_fred_entrypo
44 SYM_CODE_END(asm_fred_entrypoint_user)
45
46 /*
47 * The new RIP value that FRED event delivery
48 * (IA32_FRED_CONFIG & ~FFFH) + 256 for events
49 * ring 0, i.e., asm_fred_entrypoint_user + 25
50 */
51 .org asm_fred_entrypoint_user + 256, 0
52 SYM_CODE_START_NOALIGN(asm_fred_entrypoint_ker
53 FRED_ENTER
54 call fred_entry_from_kernel
55 FRED_EXIT
56 ERETS
57 SYM_CODE_END(asm_fred_entrypoint_kernel)
58
59 #if IS_ENABLED(CONFIG_KVM_INTEL)
60 SYM_FUNC_START(asm_fred_entry_from_kvm)
61 push %rbp
62 mov %rsp, %rbp
63
64 UNWIND_HINT_SAVE
65
66 /*
67 * Both IRQ and NMI from VMX can be ha
68 * because there is no need to protect
69 * stack leading to this helper is eff
70 * (relatively speaking). Do the same
71 * need to check current stack level f
72 *
73 * Emulate the FRED-defined redzone an
74 */
75 sub $(FRED_CONFIG_REDZONE_AMOUNT << 6)
76 and $FRED_STACK_FRAME_RSP_MASK, %rsp
77
78 /*
79 * Start to push a FRED stack frame, w
80 *
81 * +--------+-----------------+
82 * | Bytes | Usage |
83 * +--------+-----------------+
84 * | 63:56 | Reserved |
85 * | 55:48 | Event Data |
86 * | 47:40 | SS + Event Info |
87 * | 39:32 | RSP |
88 * | 31:24 | RFLAGS |
89 * | 23:16 | CS + Aux Info |
90 * | 15:8 | RIP |
91 * | 7:0 | Error Code |
92 * +--------+-----------------+
93 */
94 push $0 /* Res
95 push $0 /* Eve
96 push %rdi /* fre
97 push %rbp
98 pushf
99 mov $__KERNEL_CS, %rax
100 push %rax
101
102 /*
103 * Unlike the IDT event delivery, FRED
104 * after pushing the return RIP, thus
105 * used here to push the return RIP, o
106 * push an error code before invoking
107 *
108 * Use LEA to get the return RIP and p
109 */
110 lea 1f(%rip), %rax
111 push %rax
112 push $0
113
114 PUSH_AND_CLEAR_REGS clear_bp=0 unwind_
115 movq %rsp, %rdi
116 call __fred_entry_from_kvm
117 POP_REGS
118 ERETS
119 1:
120 /*
121 * Objtool doesn't understand what ERE
122 * yes, we'll reach here and with what
123 * isn't strictly needed, but it's the
124 */
125 UNWIND_HINT_RESTORE
126 pop %rbp
127 RET
128
129 SYM_FUNC_END(asm_fred_entry_from_kvm)
130 EXPORT_SYMBOL_GPL(asm_fred_entry_from_kvm);
131 #endif
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