1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3 * bpf_jit64.h: BPF JIT compiler for PPC64
4 *
5 * Copyright 2016 Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
6 * IBM Corporation
7 */
8 #ifndef _BPF_JIT64_H
9 #define _BPF_JIT64_H
10
11 #include "bpf_jit.h"
12
13 /*
14 * Stack layout:
15 * Ensure the top half (upto local_tmp_var) stays consistent
16 * with our redzone usage.
17 *
18 * [ prev sp ] <-------------
19 * [ nv gpr save area ] 6*8 |
20 * [ tail_call_cnt ] 8 |
21 * [ local_tmp_var ] 8 |
22 * fp (r31) --> [ ebpf stack space ] upto 512 |
23 * [ frame header ] 32/112 |
24 * sp (r1) ---> [ stack pointer ] --------------
25 */
26
27 /* for gpr non volatile registers BPG_REG_6 to 10 */
28 #define BPF_PPC_STACK_SAVE (6*8)
29 /* for bpf JIT code internal usage */
30 #define BPF_PPC_STACK_LOCALS 16
31 /* stack frame excluding BPF stack, ensure this is quadword aligned */
32 #define BPF_PPC_STACKFRAME (STACK_FRAME_MIN_SIZE + \
33 BPF_PPC_STACK_LOCALS + BPF_PPC_STACK_SAVE)
34
35 #ifndef __ASSEMBLY__
36
37 /* BPF register usage */
38 #define TMP_REG_1 (MAX_BPF_JIT_REG + 0)
39 #define TMP_REG_2 (MAX_BPF_JIT_REG + 1)
40
41 /* BPF to ppc register mappings */
42 static const int b2p[] = {
43 /* function return value */
44 [BPF_REG_0] = 8,
45 /* function arguments */
46 [BPF_REG_1] = 3,
47 [BPF_REG_2] = 4,
48 [BPF_REG_3] = 5,
49 [BPF_REG_4] = 6,
50 [BPF_REG_5] = 7,
51 /* non volatile registers */
52 [BPF_REG_6] = 27,
53 [BPF_REG_7] = 28,
54 [BPF_REG_8] = 29,
55 [BPF_REG_9] = 30,
56 /* frame pointer aka BPF_REG_10 */
57 [BPF_REG_FP] = 31,
58 /* eBPF jit internal registers */
59 [BPF_REG_AX] = 2,
60 [TMP_REG_1] = 9,
61 [TMP_REG_2] = 10
62 };
63
64 /* PPC NVR range -- update this if we ever use NVRs below r27 */
65 #define BPF_PPC_NVR_MIN 27
66
67 /*
68 * WARNING: These can use TMP_REG_2 if the offset is not at word boundary,
69 * so ensure that it isn't in use already.
70 */
71 #define PPC_BPF_LL(r, base, i) do { \
72 if ((i) % 4) { \
73 PPC_LI(b2p[TMP_REG_2], (i)); \
74 PPC_LDX(r, base, b2p[TMP_REG_2]); \
75 } else \
76 PPC_LD(r, base, i); \
77 } while(0)
78 #define PPC_BPF_STL(r, base, i) do { \
79 if ((i) % 4) { \
80 PPC_LI(b2p[TMP_REG_2], (i)); \
81 PPC_STDX(r, base, b2p[TMP_REG_2]); \
82 } else \
83 PPC_STD(r, base, i); \
84 } while(0)
85 #define PPC_BPF_STLU(r, base, i) do { PPC_STDU(r, base, i); } while(0)
86
87 #define SEEN_FUNC 0x1000 /* might call external helpers */
88 #define SEEN_STACK 0x2000 /* uses BPF stack */
89 #define SEEN_TAILCALL 0x4000 /* uses tail calls */
90
91 struct codegen_context {
92 /*
93 * This is used to track register usage as well
94 * as calls to external helpers.
95 * - register usage is tracked with corresponding
96 * bits (r3-r10 and r27-r31)
97 * - rest of the bits can be used to track other
98 * things -- for now, we use bits 16 to 23
99 * encoded in SEEN_* macros above
100 */
101 unsigned int seen;
102 unsigned int idx;
103 unsigned int stack_size;
104 };
105
106 #endif /* !__ASSEMBLY__ */
107
108 #endif