summaryrefslogtreecommitdiff
path: root/arch/powerpc/net/bpf_jit.h
blob: d767e39d564598598a0089a41fd470089ef04a4a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * bpf_jit.h: BPF JIT compiler for PPC
 *
 * Copyright 2011 Matt Evans <matt@ozlabs.org>, IBM Corporation
 * 	     2016 Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
 */
#ifndef _BPF_JIT_H
#define _BPF_JIT_H

#ifndef __ASSEMBLY__

#include <asm/types.h>
#include <asm/ppc-opcode.h>

#ifdef CONFIG_PPC64_ELF_ABI_V1
#define FUNCTION_DESCR_SIZE	24
#else
#define FUNCTION_DESCR_SIZE	0
#endif

#define PLANT_INSTR(d, idx, instr)					      \
	do { if (d) { (d)[idx] = instr; } idx++; } while (0)
#define EMIT(instr)		PLANT_INSTR(image, ctx->idx, instr)

/* Long jump; (unconditional 'branch') */
#define PPC_JMP(dest)							      \
	do {								      \
		long offset = (long)(dest) - (ctx->idx * 4);		      \
		if ((dest) != 0 && !is_offset_in_branch_range(offset)) {		      \
			pr_err_ratelimited("Branch offset 0x%lx (@%u) out of range\n", offset, ctx->idx);			\
			return -ERANGE;					      \
		}							      \
		EMIT(PPC_RAW_BRANCH(offset));				      \
	} while (0)

/* bl (unconditional 'branch' with link) */
#define PPC_BL(dest)	EMIT(PPC_RAW_BL((dest) - (unsigned long)(image + ctx->idx)))

/* "cond" here covers BO:BI fields. */
#define PPC_BCC_SHORT(cond, dest)					      \
	do {								      \
		long offset = (long)(dest) - (ctx->idx * 4);		      \
		if ((dest) != 0 && !is_offset_in_cond_branch_range(offset)) {		      \
			pr_err_ratelimited("Conditional branch offset 0x%lx (@%u) out of range\n", offset, ctx->idx);		\
			return -ERANGE;					      \
		}							      \
		EMIT(PPC_INST_BRANCH_COND | (((cond) & 0x3ff) << 16) | (offset & 0xfffc));					\
	} while (0)

/* Sign-extended 32-bit immediate load */
#define PPC_LI32(d, i)		do {					      \
		if ((int)(uintptr_t)(i) >= -32768 &&			      \
				(int)(uintptr_t)(i) < 32768)		      \
			EMIT(PPC_RAW_LI(d, i));				      \
		else {							      \
			EMIT(PPC_RAW_LIS(d, IMM_H(i)));			      \
			if (IMM_L(i))					      \
				EMIT(PPC_RAW_ORI(d, d, IMM_L(i)));	      \
		} } while(0)

#ifdef CONFIG_PPC64
#define PPC_LI64(d, i)		do {					      \
		if ((long)(i) >= -2147483648 &&				      \
				(long)(i) < 2147483648)			      \
			PPC_LI32(d, i);					      \
		else {							      \
			if (!((uintptr_t)(i) & 0xffff800000000000ULL))	      \
				EMIT(PPC_RAW_LI(d, ((uintptr_t)(i) >> 32) &   \
						0xffff));		      \
			else {						      \
				EMIT(PPC_RAW_LIS(d, ((uintptr_t)(i) >> 48))); \
				if ((uintptr_t)(i) & 0x0000ffff00000000ULL)   \
					EMIT(PPC_RAW_ORI(d, d,		      \
					  ((uintptr_t)(i) >> 32) & 0xffff));  \
			}						      \
			EMIT(PPC_RAW_SLDI(d, d, 32));			      \
			if ((uintptr_t)(i) & 0x00000000ffff0000ULL)	      \
				EMIT(PPC_RAW_ORIS(d, d,			      \
					 ((uintptr_t)(i) >> 16) & 0xffff));   \
			if ((uintptr_t)(i) & 0x000000000000ffffULL)	      \
				EMIT(PPC_RAW_ORI(d, d, (uintptr_t)(i) &       \
							0xffff));             \
		} } while (0)
#endif

/*
 * The fly in the ointment of code size changing from pass to pass is
 * avoided by padding the short branch case with a NOP.	 If code size differs
 * with different branch reaches we will have the issue of code moving from
 * one pass to the next and will need a few passes to converge on a stable
 * state.
 */
#define PPC_BCC(cond, dest)	do {					      \
		if (is_offset_in_cond_branch_range((long)(dest) - (ctx->idx * 4))) {	\
			PPC_BCC_SHORT(cond, dest);			      \
			EMIT(PPC_RAW_NOP());				      \
		} else {						      \
			/* Flip the 'T or F' bit to invert comparison */      \
			PPC_BCC_SHORT(cond ^ COND_CMP_TRUE, (ctx->idx+2)*4);  \
			PPC_JMP(dest);					      \
		} } while(0)

/* To create a branch condition, select a bit of cr0... */
#define CR0_LT		0
#define CR0_GT		1
#define CR0_EQ		2
/* ...and modify BO[3] */
#define COND_CMP_TRUE	0x100
#define COND_CMP_FALSE	0x000
/* Together, they make all required comparisons: */
#define COND_GT		(CR0_GT | COND_CMP_TRUE)
#define COND_GE		(CR0_LT | COND_CMP_FALSE)
#define COND_EQ		(CR0_EQ | COND_CMP_TRUE)
#define COND_NE		(CR0_EQ | COND_CMP_FALSE)
#define COND_LT		(CR0_LT | COND_CMP_TRUE)
#define COND_LE		(CR0_GT | COND_CMP_FALSE)

#define SEEN_FUNC	0x20000000 /* might call external helpers */
#define SEEN_TAILCALL	0x40000000 /* uses tail calls */

struct codegen_context {
	/*
	 * This is used to track register usage as well
	 * as calls to external helpers.
	 * - register usage is tracked with corresponding
	 *   bits (r3-r31)
	 * - rest of the bits can be used to track other
	 *   things -- for now, we use bits 0 to 2
	 *   encoded in SEEN_* macros above
	 */
	unsigned int seen;
	unsigned int idx;
	unsigned int stack_size;
	int b2p[MAX_BPF_JIT_REG + 2];
	unsigned int exentry_idx;
	unsigned int alt_exit_addr;
};

#define bpf_to_ppc(r)	(ctx->b2p[r])

#ifdef CONFIG_PPC32
#define BPF_FIXUP_LEN	3 /* Three instructions => 12 bytes */
#else
#define BPF_FIXUP_LEN	2 /* Two instructions => 8 bytes */
#endif

static inline void bpf_flush_icache(void *start, void *end)
{
	smp_wmb();	/* smp write barrier */
	flush_icache_range((unsigned long)start, (unsigned long)end);
}

static inline bool bpf_is_seen_register(struct codegen_context *ctx, int i)
{
	return ctx->seen & (1 << (31 - i));
}

static inline void bpf_set_seen_register(struct codegen_context *ctx, int i)
{
	ctx->seen |= 1 << (31 - i);
}

static inline void bpf_clear_seen_register(struct codegen_context *ctx, int i)
{
	ctx->seen &= ~(1 << (31 - i));
}

void bpf_jit_init_reg_mapping(struct codegen_context *ctx);
int bpf_jit_emit_func_call_rel(u32 *image, struct codegen_context *ctx, u64 func);
int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context *ctx,
		       u32 *addrs, int pass, bool extra_pass);
void bpf_jit_build_prologue(u32 *image, struct codegen_context *ctx);
void bpf_jit_build_epilogue(u32 *image, struct codegen_context *ctx);
void bpf_jit_realloc_regs(struct codegen_context *ctx);
int bpf_jit_emit_exit_insn(u32 *image, struct codegen_context *ctx, int tmp_reg, long exit_addr);

int bpf_add_extable_entry(struct bpf_prog *fp, u32 *image, int pass, struct codegen_context *ctx,
			  int insn_idx, int jmp_off, int dst_reg);

#endif

#endif