xref: /openbmc/linux/tools/lib/bpf/bpf_tracing.h (revision 2cf1c348)
1 /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
2 #ifndef __BPF_TRACING_H__
3 #define __BPF_TRACING_H__
4 
5 /* Scan the ARCH passed in from ARCH env variable (see Makefile) */
6 #if defined(__TARGET_ARCH_x86)
7 	#define bpf_target_x86
8 	#define bpf_target_defined
9 #elif defined(__TARGET_ARCH_s390)
10 	#define bpf_target_s390
11 	#define bpf_target_defined
12 #elif defined(__TARGET_ARCH_arm)
13 	#define bpf_target_arm
14 	#define bpf_target_defined
15 #elif defined(__TARGET_ARCH_arm64)
16 	#define bpf_target_arm64
17 	#define bpf_target_defined
18 #elif defined(__TARGET_ARCH_mips)
19 	#define bpf_target_mips
20 	#define bpf_target_defined
21 #elif defined(__TARGET_ARCH_powerpc)
22 	#define bpf_target_powerpc
23 	#define bpf_target_defined
24 #elif defined(__TARGET_ARCH_sparc)
25 	#define bpf_target_sparc
26 	#define bpf_target_defined
27 #elif defined(__TARGET_ARCH_riscv)
28 	#define bpf_target_riscv
29 	#define bpf_target_defined
30 #else
31 
32 /* Fall back to what the compiler says */
33 #if defined(__x86_64__)
34 	#define bpf_target_x86
35 	#define bpf_target_defined
36 #elif defined(__s390__)
37 	#define bpf_target_s390
38 	#define bpf_target_defined
39 #elif defined(__arm__)
40 	#define bpf_target_arm
41 	#define bpf_target_defined
42 #elif defined(__aarch64__)
43 	#define bpf_target_arm64
44 	#define bpf_target_defined
45 #elif defined(__mips__)
46 	#define bpf_target_mips
47 	#define bpf_target_defined
48 #elif defined(__powerpc__)
49 	#define bpf_target_powerpc
50 	#define bpf_target_defined
51 #elif defined(__sparc__)
52 	#define bpf_target_sparc
53 	#define bpf_target_defined
54 #elif defined(__riscv) && __riscv_xlen == 64
55 	#define bpf_target_riscv
56 	#define bpf_target_defined
57 #endif /* no compiler target */
58 
59 #endif
60 
61 #ifndef __BPF_TARGET_MISSING
62 #define __BPF_TARGET_MISSING "GCC error \"Must specify a BPF target arch via __TARGET_ARCH_xxx\""
63 #endif
64 
65 #if defined(bpf_target_x86)
66 
67 #if defined(__KERNEL__) || defined(__VMLINUX_H__)
68 
69 #define __PT_PARM1_REG di
70 #define __PT_PARM2_REG si
71 #define __PT_PARM3_REG dx
72 #define __PT_PARM4_REG cx
73 #define __PT_PARM5_REG r8
74 #define __PT_RET_REG sp
75 #define __PT_FP_REG bp
76 #define __PT_RC_REG ax
77 #define __PT_SP_REG sp
78 #define __PT_IP_REG ip
79 
80 #else
81 
82 #ifdef __i386__
83 
84 #define __PT_PARM1_REG eax
85 #define __PT_PARM2_REG edx
86 #define __PT_PARM3_REG ecx
87 /* i386 kernel is built with -mregparm=3 */
88 #define __PT_PARM4_REG __unsupported__
89 #define __PT_PARM5_REG __unsupported__
90 #define __PT_RET_REG esp
91 #define __PT_FP_REG ebp
92 #define __PT_RC_REG eax
93 #define __PT_SP_REG esp
94 #define __PT_IP_REG eip
95 
96 #else /* __i386__ */
97 
98 #define __PT_PARM1_REG rdi
99 #define __PT_PARM2_REG rsi
100 #define __PT_PARM3_REG rdx
101 #define __PT_PARM4_REG rcx
102 #define __PT_PARM5_REG r8
103 #define __PT_RET_REG rsp
104 #define __PT_FP_REG rbp
105 #define __PT_RC_REG rax
106 #define __PT_SP_REG rsp
107 #define __PT_IP_REG rip
108 
109 #endif /* __i386__ */
110 
111 #endif /* __KERNEL__ || __VMLINUX_H__ */
112 
113 #elif defined(bpf_target_s390)
114 
115 /* s390 provides user_pt_regs instead of struct pt_regs to userspace */
116 #define __PT_REGS_CAST(x) ((const user_pt_regs *)(x))
117 #define __PT_PARM1_REG gprs[2]
118 #define __PT_PARM2_REG gprs[3]
119 #define __PT_PARM3_REG gprs[4]
120 #define __PT_PARM4_REG gprs[5]
121 #define __PT_PARM5_REG gprs[6]
122 #define __PT_RET_REG grps[14]
123 #define __PT_FP_REG gprs[11]	/* Works only with CONFIG_FRAME_POINTER */
124 #define __PT_RC_REG gprs[2]
125 #define __PT_SP_REG gprs[15]
126 #define __PT_IP_REG psw.addr
127 
128 #elif defined(bpf_target_arm)
129 
130 #define __PT_PARM1_REG uregs[0]
131 #define __PT_PARM2_REG uregs[1]
132 #define __PT_PARM3_REG uregs[2]
133 #define __PT_PARM4_REG uregs[3]
134 #define __PT_PARM5_REG uregs[4]
135 #define __PT_RET_REG uregs[14]
136 #define __PT_FP_REG uregs[11]	/* Works only with CONFIG_FRAME_POINTER */
137 #define __PT_RC_REG uregs[0]
138 #define __PT_SP_REG uregs[13]
139 #define __PT_IP_REG uregs[12]
140 
141 #elif defined(bpf_target_arm64)
142 
143 /* arm64 provides struct user_pt_regs instead of struct pt_regs to userspace */
144 #define __PT_REGS_CAST(x) ((const struct user_pt_regs *)(x))
145 #define __PT_PARM1_REG regs[0]
146 #define __PT_PARM2_REG regs[1]
147 #define __PT_PARM3_REG regs[2]
148 #define __PT_PARM4_REG regs[3]
149 #define __PT_PARM5_REG regs[4]
150 #define __PT_RET_REG regs[30]
151 #define __PT_FP_REG regs[29]	/* Works only with CONFIG_FRAME_POINTER */
152 #define __PT_RC_REG regs[0]
153 #define __PT_SP_REG sp
154 #define __PT_IP_REG pc
155 
156 #elif defined(bpf_target_mips)
157 
158 #define __PT_PARM1_REG regs[4]
159 #define __PT_PARM2_REG regs[5]
160 #define __PT_PARM3_REG regs[6]
161 #define __PT_PARM4_REG regs[7]
162 #define __PT_PARM5_REG regs[8]
163 #define __PT_RET_REG regs[31]
164 #define __PT_FP_REG regs[30]	/* Works only with CONFIG_FRAME_POINTER */
165 #define __PT_RC_REG regs[2]
166 #define __PT_SP_REG regs[29]
167 #define __PT_IP_REG cp0_epc
168 
169 #elif defined(bpf_target_powerpc)
170 
171 #define __PT_PARM1_REG gpr[3]
172 #define __PT_PARM2_REG gpr[4]
173 #define __PT_PARM3_REG gpr[5]
174 #define __PT_PARM4_REG gpr[6]
175 #define __PT_PARM5_REG gpr[7]
176 #define __PT_RET_REG regs[31]
177 #define __PT_FP_REG __unsupported__
178 #define __PT_RC_REG gpr[3]
179 #define __PT_SP_REG sp
180 #define __PT_IP_REG nip
181 
182 #elif defined(bpf_target_sparc)
183 
184 #define __PT_PARM1_REG u_regs[UREG_I0]
185 #define __PT_PARM2_REG u_regs[UREG_I1]
186 #define __PT_PARM3_REG u_regs[UREG_I2]
187 #define __PT_PARM4_REG u_regs[UREG_I3]
188 #define __PT_PARM5_REG u_regs[UREG_I4]
189 #define __PT_RET_REG u_regs[UREG_I7]
190 #define __PT_FP_REG __unsupported__
191 #define __PT_RC_REG u_regs[UREG_I0]
192 #define __PT_SP_REG u_regs[UREG_FP]
193 /* Should this also be a bpf_target check for the sparc case? */
194 #if defined(__arch64__)
195 #define __PT_IP_REG tpc
196 #else
197 #define __PT_IP_REG pc
198 #endif
199 
200 #elif defined(bpf_target_riscv)
201 
202 #define __PT_REGS_CAST(x) ((const struct user_regs_struct *)(x))
203 #define __PT_PARM1_REG a0
204 #define __PT_PARM2_REG a1
205 #define __PT_PARM3_REG a2
206 #define __PT_PARM4_REG a3
207 #define __PT_PARM5_REG a4
208 #define __PT_RET_REG ra
209 #define __PT_FP_REG fp
210 #define __PT_RC_REG a5
211 #define __PT_SP_REG sp
212 #define __PT_IP_REG epc
213 
214 #endif
215 
216 #if defined(bpf_target_defined)
217 
218 struct pt_regs;
219 
220 /* allow some architecutres to override `struct pt_regs` */
221 #ifndef __PT_REGS_CAST
222 #define __PT_REGS_CAST(x) (x)
223 #endif
224 
225 #define PT_REGS_PARM1(x) (__PT_REGS_CAST(x)->__PT_PARM1_REG)
226 #define PT_REGS_PARM2(x) (__PT_REGS_CAST(x)->__PT_PARM2_REG)
227 #define PT_REGS_PARM3(x) (__PT_REGS_CAST(x)->__PT_PARM3_REG)
228 #define PT_REGS_PARM4(x) (__PT_REGS_CAST(x)->__PT_PARM4_REG)
229 #define PT_REGS_PARM5(x) (__PT_REGS_CAST(x)->__PT_PARM5_REG)
230 #define PT_REGS_RET(x) (__PT_REGS_CAST(x)->__PT_RET_REG)
231 #define PT_REGS_FP(x) (__PT_REGS_CAST(x)->__PT_FP_REG)
232 #define PT_REGS_RC(x) (__PT_REGS_CAST(x)->__PT_RC_REG)
233 #define PT_REGS_SP(x) (__PT_REGS_CAST(x)->__PT_SP_REG)
234 #define PT_REGS_IP(x) (__PT_REGS_CAST(x)->__PT_IP_REG)
235 
236 #define PT_REGS_PARM1_CORE(x) BPF_CORE_READ(__PT_REGS_CAST(x), __PT_PARM1_REG)
237 #define PT_REGS_PARM2_CORE(x) BPF_CORE_READ(__PT_REGS_CAST(x), __PT_PARM2_REG)
238 #define PT_REGS_PARM3_CORE(x) BPF_CORE_READ(__PT_REGS_CAST(x), __PT_PARM3_REG)
239 #define PT_REGS_PARM4_CORE(x) BPF_CORE_READ(__PT_REGS_CAST(x), __PT_PARM4_REG)
240 #define PT_REGS_PARM5_CORE(x) BPF_CORE_READ(__PT_REGS_CAST(x), __PT_PARM5_REG)
241 #define PT_REGS_RET_CORE(x) BPF_CORE_READ(__PT_REGS_CAST(x), __PT_RET_REG)
242 #define PT_REGS_FP_CORE(x) BPF_CORE_READ(__PT_REGS_CAST(x), __PT_FP_REG)
243 #define PT_REGS_RC_CORE(x) BPF_CORE_READ(__PT_REGS_CAST(x), __PT_RC_REG)
244 #define PT_REGS_SP_CORE(x) BPF_CORE_READ(__PT_REGS_CAST(x), __PT_SP_REG)
245 #define PT_REGS_IP_CORE(x) BPF_CORE_READ(__PT_REGS_CAST(x), __PT_IP_REG)
246 
247 #if defined(bpf_target_powerpc)
248 
249 #define BPF_KPROBE_READ_RET_IP(ip, ctx)		({ (ip) = (ctx)->link; })
250 #define BPF_KRETPROBE_READ_RET_IP		BPF_KPROBE_READ_RET_IP
251 
252 #elif defined(bpf_target_sparc)
253 
254 #define BPF_KPROBE_READ_RET_IP(ip, ctx)		({ (ip) = PT_REGS_RET(ctx); })
255 #define BPF_KRETPROBE_READ_RET_IP		BPF_KPROBE_READ_RET_IP
256 
257 #else
258 
259 #define BPF_KPROBE_READ_RET_IP(ip, ctx)					    \
260 	({ bpf_probe_read_kernel(&(ip), sizeof(ip), (void *)PT_REGS_RET(ctx)); })
261 #define BPF_KRETPROBE_READ_RET_IP(ip, ctx)				    \
262 	({ bpf_probe_read_kernel(&(ip), sizeof(ip), (void *)(PT_REGS_FP(ctx) + sizeof(ip))); })
263 
264 #endif
265 
266 #else /* defined(bpf_target_defined) */
267 
268 #define PT_REGS_PARM1(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
269 #define PT_REGS_PARM2(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
270 #define PT_REGS_PARM3(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
271 #define PT_REGS_PARM4(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
272 #define PT_REGS_PARM5(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
273 #define PT_REGS_RET(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
274 #define PT_REGS_FP(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
275 #define PT_REGS_RC(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
276 #define PT_REGS_SP(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
277 #define PT_REGS_IP(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
278 
279 #define PT_REGS_PARM1_CORE(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
280 #define PT_REGS_PARM2_CORE(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
281 #define PT_REGS_PARM3_CORE(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
282 #define PT_REGS_PARM4_CORE(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
283 #define PT_REGS_PARM5_CORE(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
284 #define PT_REGS_RET_CORE(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
285 #define PT_REGS_FP_CORE(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
286 #define PT_REGS_RC_CORE(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
287 #define PT_REGS_SP_CORE(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
288 #define PT_REGS_IP_CORE(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
289 
290 #define BPF_KPROBE_READ_RET_IP(ip, ctx) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
291 #define BPF_KRETPROBE_READ_RET_IP(ip, ctx) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
292 
293 #endif /* defined(bpf_target_defined) */
294 
295 #ifndef ___bpf_concat
296 #define ___bpf_concat(a, b) a ## b
297 #endif
298 #ifndef ___bpf_apply
299 #define ___bpf_apply(fn, n) ___bpf_concat(fn, n)
300 #endif
301 #ifndef ___bpf_nth
302 #define ___bpf_nth(_, _1, _2, _3, _4, _5, _6, _7, _8, _9, _a, _b, _c, N, ...) N
303 #endif
304 #ifndef ___bpf_narg
305 #define ___bpf_narg(...) ___bpf_nth(_, ##__VA_ARGS__, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0)
306 #endif
307 
308 #define ___bpf_ctx_cast0()            ctx
309 #define ___bpf_ctx_cast1(x)           ___bpf_ctx_cast0(), (void *)ctx[0]
310 #define ___bpf_ctx_cast2(x, args...)  ___bpf_ctx_cast1(args), (void *)ctx[1]
311 #define ___bpf_ctx_cast3(x, args...)  ___bpf_ctx_cast2(args), (void *)ctx[2]
312 #define ___bpf_ctx_cast4(x, args...)  ___bpf_ctx_cast3(args), (void *)ctx[3]
313 #define ___bpf_ctx_cast5(x, args...)  ___bpf_ctx_cast4(args), (void *)ctx[4]
314 #define ___bpf_ctx_cast6(x, args...)  ___bpf_ctx_cast5(args), (void *)ctx[5]
315 #define ___bpf_ctx_cast7(x, args...)  ___bpf_ctx_cast6(args), (void *)ctx[6]
316 #define ___bpf_ctx_cast8(x, args...)  ___bpf_ctx_cast7(args), (void *)ctx[7]
317 #define ___bpf_ctx_cast9(x, args...)  ___bpf_ctx_cast8(args), (void *)ctx[8]
318 #define ___bpf_ctx_cast10(x, args...) ___bpf_ctx_cast9(args), (void *)ctx[9]
319 #define ___bpf_ctx_cast11(x, args...) ___bpf_ctx_cast10(args), (void *)ctx[10]
320 #define ___bpf_ctx_cast12(x, args...) ___bpf_ctx_cast11(args), (void *)ctx[11]
321 #define ___bpf_ctx_cast(args...)      ___bpf_apply(___bpf_ctx_cast, ___bpf_narg(args))(args)
322 
323 /*
324  * BPF_PROG is a convenience wrapper for generic tp_btf/fentry/fexit and
325  * similar kinds of BPF programs, that accept input arguments as a single
326  * pointer to untyped u64 array, where each u64 can actually be a typed
327  * pointer or integer of different size. Instead of requring user to write
328  * manual casts and work with array elements by index, BPF_PROG macro
329  * allows user to declare a list of named and typed input arguments in the
330  * same syntax as for normal C function. All the casting is hidden and
331  * performed transparently, while user code can just assume working with
332  * function arguments of specified type and name.
333  *
334  * Original raw context argument is preserved as well as 'ctx' argument.
335  * This is useful when using BPF helpers that expect original context
336  * as one of the parameters (e.g., for bpf_perf_event_output()).
337  */
338 #define BPF_PROG(name, args...)						    \
339 name(unsigned long long *ctx);						    \
340 static __attribute__((always_inline)) typeof(name(0))			    \
341 ____##name(unsigned long long *ctx, ##args);				    \
342 typeof(name(0)) name(unsigned long long *ctx)				    \
343 {									    \
344 	_Pragma("GCC diagnostic push")					    \
345 	_Pragma("GCC diagnostic ignored \"-Wint-conversion\"")		    \
346 	return ____##name(___bpf_ctx_cast(args));			    \
347 	_Pragma("GCC diagnostic pop")					    \
348 }									    \
349 static __attribute__((always_inline)) typeof(name(0))			    \
350 ____##name(unsigned long long *ctx, ##args)
351 
352 struct pt_regs;
353 
354 #define ___bpf_kprobe_args0()           ctx
355 #define ___bpf_kprobe_args1(x)          ___bpf_kprobe_args0(), (void *)PT_REGS_PARM1(ctx)
356 #define ___bpf_kprobe_args2(x, args...) ___bpf_kprobe_args1(args), (void *)PT_REGS_PARM2(ctx)
357 #define ___bpf_kprobe_args3(x, args...) ___bpf_kprobe_args2(args), (void *)PT_REGS_PARM3(ctx)
358 #define ___bpf_kprobe_args4(x, args...) ___bpf_kprobe_args3(args), (void *)PT_REGS_PARM4(ctx)
359 #define ___bpf_kprobe_args5(x, args...) ___bpf_kprobe_args4(args), (void *)PT_REGS_PARM5(ctx)
360 #define ___bpf_kprobe_args(args...)     ___bpf_apply(___bpf_kprobe_args, ___bpf_narg(args))(args)
361 
362 /*
363  * BPF_KPROBE serves the same purpose for kprobes as BPF_PROG for
364  * tp_btf/fentry/fexit BPF programs. It hides the underlying platform-specific
365  * low-level way of getting kprobe input arguments from struct pt_regs, and
366  * provides a familiar typed and named function arguments syntax and
367  * semantics of accessing kprobe input paremeters.
368  *
369  * Original struct pt_regs* context is preserved as 'ctx' argument. This might
370  * be necessary when using BPF helpers like bpf_perf_event_output().
371  */
372 #define BPF_KPROBE(name, args...)					    \
373 name(struct pt_regs *ctx);						    \
374 static __attribute__((always_inline)) typeof(name(0))			    \
375 ____##name(struct pt_regs *ctx, ##args);				    \
376 typeof(name(0)) name(struct pt_regs *ctx)				    \
377 {									    \
378 	_Pragma("GCC diagnostic push")					    \
379 	_Pragma("GCC diagnostic ignored \"-Wint-conversion\"")		    \
380 	return ____##name(___bpf_kprobe_args(args));			    \
381 	_Pragma("GCC diagnostic pop")					    \
382 }									    \
383 static __attribute__((always_inline)) typeof(name(0))			    \
384 ____##name(struct pt_regs *ctx, ##args)
385 
386 #define ___bpf_kretprobe_args0()       ctx
387 #define ___bpf_kretprobe_args1(x)      ___bpf_kretprobe_args0(), (void *)PT_REGS_RC(ctx)
388 #define ___bpf_kretprobe_args(args...) ___bpf_apply(___bpf_kretprobe_args, ___bpf_narg(args))(args)
389 
390 /*
391  * BPF_KRETPROBE is similar to BPF_KPROBE, except, it only provides optional
392  * return value (in addition to `struct pt_regs *ctx`), but no input
393  * arguments, because they will be clobbered by the time probed function
394  * returns.
395  */
396 #define BPF_KRETPROBE(name, args...)					    \
397 name(struct pt_regs *ctx);						    \
398 static __attribute__((always_inline)) typeof(name(0))			    \
399 ____##name(struct pt_regs *ctx, ##args);				    \
400 typeof(name(0)) name(struct pt_regs *ctx)				    \
401 {									    \
402 	_Pragma("GCC diagnostic push")					    \
403 	_Pragma("GCC diagnostic ignored \"-Wint-conversion\"")		    \
404 	return ____##name(___bpf_kretprobe_args(args));			    \
405 	_Pragma("GCC diagnostic pop")					    \
406 }									    \
407 static __always_inline typeof(name(0)) ____##name(struct pt_regs *ctx, ##args)
408 
409 #endif
410