xref: /freebsd/sys/cddl/dev/kinst/amd64/kinst_isa.h (revision 7ee6b0f125a092ed99d327bb8d608dd2ff77b7aa)
1 /*
2  * SPDX-License-Identifier: CDDL 1.0
3  *
4  * Copyright 2022 Christos Margiolis <christos@FreeBSD.org>
5  * Copyright 2022 Mark Johnston <markj@FreeBSD.org>
6  */
7 
8 #ifndef _KINST_ISA_H_
9 #define _KINST_ISA_H_
10 
11 #include <sys/types.h>
12 
13 #define KINST_PATCHVAL		0xcc
14 
15 /*
16  * Each trampoline is 32 bytes long and contains [instruction, jmp]. Since we
17  * have 2 instructions stored in the trampoline, and each of them can take up
18  * to 16 bytes, 32 bytes is enough to cover even the worst case scenario.
19  */
20 #define	KINST_TRAMP_SIZE		32
21 #define	KINST_TRAMPCHUNK_SIZE		PAGE_SIZE
22 #define KINST_TRAMP_FILL_PATTERN	((uint8_t []){KINST_PATCHVAL})
23 #define KINST_TRAMP_FILL_SIZE		sizeof(uint8_t)
24 
25 typedef uint8_t kinst_patchval_t;
26 
27 struct kinst_probe_md {
28 	int			flags;
29 	int			instlen;	/* original instr len */
30 	int			tinstlen;	/* trampoline instr len */
31 	uint8_t			template[16];	/* copied into thread tramps */
32 	int			dispoff;	/* offset of rip displacement */
33 
34 	/* operands to "call" instruction branch target */
35 	int			reg1;
36 	int			reg2;
37 	int			scale;
38 	int64_t			disp;
39 };
40 
41 #endif /* _KINST_ISA_H_ */
42