1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * BPF Jit compiler for s390.
4  *
5  * Minimum build requirements:
6  *
7  *  - HAVE_MARCH_Z196_FEATURES: laal, laalg
8  *  - HAVE_MARCH_Z10_FEATURES: msfi, cgrj, clgrj
9  *  - HAVE_MARCH_Z9_109_FEATURES: alfi, llilf, clfi, oilf, nilf
10  *  - PACK_STACK
11  *  - 64BIT
12  *
13  * Copyright IBM Corp. 2012,2015
14  *
15  * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
16  *	      Michael Holzheu <holzheu@linux.vnet.ibm.com>
17  */
18 
19 #define KMSG_COMPONENT "bpf_jit"
20 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
21 
22 #include <linux/netdevice.h>
23 #include <linux/filter.h>
24 #include <linux/init.h>
25 #include <linux/bpf.h>
26 #include <linux/mm.h>
27 #include <linux/kernel.h>
28 #include <asm/cacheflush.h>
29 #include <asm/dis.h>
30 #include <asm/facility.h>
31 #include <asm/nospec-branch.h>
32 #include <asm/set_memory.h>
33 #include "bpf_jit.h"
34 
35 struct bpf_jit {
36 	u32 seen;		/* Flags to remember seen eBPF instructions */
37 	u32 seen_reg[16];	/* Array to remember which registers are used */
38 	u32 *addrs;		/* Array with relative instruction addresses */
39 	u8 *prg_buf;		/* Start of program */
40 	int size;		/* Size of program and literal pool */
41 	int size_prg;		/* Size of program */
42 	int prg;		/* Current position in program */
43 	int lit32_start;	/* Start of 32-bit literal pool */
44 	int lit32;		/* Current position in 32-bit literal pool */
45 	int lit64_start;	/* Start of 64-bit literal pool */
46 	int lit64;		/* Current position in 64-bit literal pool */
47 	int base_ip;		/* Base address for literal pool */
48 	int exit_ip;		/* Address of exit */
49 	int r1_thunk_ip;	/* Address of expoline thunk for 'br %r1' */
50 	int r14_thunk_ip;	/* Address of expoline thunk for 'br %r14' */
51 	int tail_call_start;	/* Tail call start offset */
52 	int excnt;		/* Number of exception table entries */
53 };
54 
55 #define SEEN_MEM	BIT(0)		/* use mem[] for temporary storage */
56 #define SEEN_LITERAL	BIT(1)		/* code uses literals */
57 #define SEEN_FUNC	BIT(2)		/* calls C functions */
58 #define SEEN_TAIL_CALL	BIT(3)		/* code uses tail calls */
59 #define SEEN_STACK	(SEEN_FUNC | SEEN_MEM)
60 
61 /*
62  * s390 registers
63  */
64 #define REG_W0		(MAX_BPF_JIT_REG + 0)	/* Work register 1 (even) */
65 #define REG_W1		(MAX_BPF_JIT_REG + 1)	/* Work register 2 (odd) */
66 #define REG_L		(MAX_BPF_JIT_REG + 2)	/* Literal pool register */
67 #define REG_15		(MAX_BPF_JIT_REG + 3)	/* Register 15 */
68 #define REG_0		REG_W0			/* Register 0 */
69 #define REG_1		REG_W1			/* Register 1 */
70 #define REG_2		BPF_REG_1		/* Register 2 */
71 #define REG_14		BPF_REG_0		/* Register 14 */
72 
73 /*
74  * Mapping of BPF registers to s390 registers
75  */
76 static const int reg2hex[] = {
77 	/* Return code */
78 	[BPF_REG_0]	= 14,
79 	/* Function parameters */
80 	[BPF_REG_1]	= 2,
81 	[BPF_REG_2]	= 3,
82 	[BPF_REG_3]	= 4,
83 	[BPF_REG_4]	= 5,
84 	[BPF_REG_5]	= 6,
85 	/* Call saved registers */
86 	[BPF_REG_6]	= 7,
87 	[BPF_REG_7]	= 8,
88 	[BPF_REG_8]	= 9,
89 	[BPF_REG_9]	= 10,
90 	/* BPF stack pointer */
91 	[BPF_REG_FP]	= 13,
92 	/* Register for blinding */
93 	[BPF_REG_AX]	= 12,
94 	/* Work registers for s390x backend */
95 	[REG_W0]	= 0,
96 	[REG_W1]	= 1,
97 	[REG_L]		= 11,
98 	[REG_15]	= 15,
99 };
100 
reg(u32 dst_reg,u32 src_reg)101 static inline u32 reg(u32 dst_reg, u32 src_reg)
102 {
103 	return reg2hex[dst_reg] << 4 | reg2hex[src_reg];
104 }
105 
reg_high(u32 reg)106 static inline u32 reg_high(u32 reg)
107 {
108 	return reg2hex[reg] << 4;
109 }
110 
reg_set_seen(struct bpf_jit * jit,u32 b1)111 static inline void reg_set_seen(struct bpf_jit *jit, u32 b1)
112 {
113 	u32 r1 = reg2hex[b1];
114 
115 	if (!jit->seen_reg[r1] && r1 >= 6 && r1 <= 15)
116 		jit->seen_reg[r1] = 1;
117 }
118 
119 #define REG_SET_SEEN(b1)					\
120 ({								\
121 	reg_set_seen(jit, b1);					\
122 })
123 
124 #define REG_SEEN(b1) jit->seen_reg[reg2hex[(b1)]]
125 
126 /*
127  * EMIT macros for code generation
128  */
129 
130 #define _EMIT2(op)						\
131 ({								\
132 	if (jit->prg_buf)					\
133 		*(u16 *) (jit->prg_buf + jit->prg) = (op);	\
134 	jit->prg += 2;						\
135 })
136 
137 #define EMIT2(op, b1, b2)					\
138 ({								\
139 	_EMIT2((op) | reg(b1, b2));				\
140 	REG_SET_SEEN(b1);					\
141 	REG_SET_SEEN(b2);					\
142 })
143 
144 #define _EMIT4(op)						\
145 ({								\
146 	if (jit->prg_buf)					\
147 		*(u32 *) (jit->prg_buf + jit->prg) = (op);	\
148 	jit->prg += 4;						\
149 })
150 
151 #define EMIT4(op, b1, b2)					\
152 ({								\
153 	_EMIT4((op) | reg(b1, b2));				\
154 	REG_SET_SEEN(b1);					\
155 	REG_SET_SEEN(b2);					\
156 })
157 
158 #define EMIT4_RRF(op, b1, b2, b3)				\
159 ({								\
160 	_EMIT4((op) | reg_high(b3) << 8 | reg(b1, b2));		\
161 	REG_SET_SEEN(b1);					\
162 	REG_SET_SEEN(b2);					\
163 	REG_SET_SEEN(b3);					\
164 })
165 
166 #define _EMIT4_DISP(op, disp)					\
167 ({								\
168 	unsigned int __disp = (disp) & 0xfff;			\
169 	_EMIT4((op) | __disp);					\
170 })
171 
172 #define EMIT4_DISP(op, b1, b2, disp)				\
173 ({								\
174 	_EMIT4_DISP((op) | reg_high(b1) << 16 |			\
175 		    reg_high(b2) << 8, (disp));			\
176 	REG_SET_SEEN(b1);					\
177 	REG_SET_SEEN(b2);					\
178 })
179 
180 #define EMIT4_IMM(op, b1, imm)					\
181 ({								\
182 	unsigned int __imm = (imm) & 0xffff;			\
183 	_EMIT4((op) | reg_high(b1) << 16 | __imm);		\
184 	REG_SET_SEEN(b1);					\
185 })
186 
187 #define EMIT4_PCREL(op, pcrel)					\
188 ({								\
189 	long __pcrel = ((pcrel) >> 1) & 0xffff;			\
190 	_EMIT4((op) | __pcrel);					\
191 })
192 
193 #define EMIT4_PCREL_RIC(op, mask, target)			\
194 ({								\
195 	int __rel = ((target) - jit->prg) / 2;			\
196 	_EMIT4((op) | (mask) << 20 | (__rel & 0xffff));		\
197 })
198 
199 #define _EMIT6(op1, op2)					\
200 ({								\
201 	if (jit->prg_buf) {					\
202 		*(u32 *) (jit->prg_buf + jit->prg) = (op1);	\
203 		*(u16 *) (jit->prg_buf + jit->prg + 4) = (op2);	\
204 	}							\
205 	jit->prg += 6;						\
206 })
207 
208 #define _EMIT6_DISP(op1, op2, disp)				\
209 ({								\
210 	unsigned int __disp = (disp) & 0xfff;			\
211 	_EMIT6((op1) | __disp, op2);				\
212 })
213 
214 #define _EMIT6_DISP_LH(op1, op2, disp)				\
215 ({								\
216 	u32 _disp = (u32) (disp);				\
217 	unsigned int __disp_h = _disp & 0xff000;		\
218 	unsigned int __disp_l = _disp & 0x00fff;		\
219 	_EMIT6((op1) | __disp_l, (op2) | __disp_h >> 4);	\
220 })
221 
222 #define EMIT6_DISP_LH(op1, op2, b1, b2, b3, disp)		\
223 ({								\
224 	_EMIT6_DISP_LH((op1) | reg(b1, b2) << 16 |		\
225 		       reg_high(b3) << 8, op2, disp);		\
226 	REG_SET_SEEN(b1);					\
227 	REG_SET_SEEN(b2);					\
228 	REG_SET_SEEN(b3);					\
229 })
230 
231 #define EMIT6_PCREL_RIEB(op1, op2, b1, b2, mask, target)	\
232 ({								\
233 	unsigned int rel = (int)((target) - jit->prg) / 2;	\
234 	_EMIT6((op1) | reg(b1, b2) << 16 | (rel & 0xffff),	\
235 	       (op2) | (mask) << 12);				\
236 	REG_SET_SEEN(b1);					\
237 	REG_SET_SEEN(b2);					\
238 })
239 
240 #define EMIT6_PCREL_RIEC(op1, op2, b1, imm, mask, target)	\
241 ({								\
242 	unsigned int rel = (int)((target) - jit->prg) / 2;	\
243 	_EMIT6((op1) | (reg_high(b1) | (mask)) << 16 |		\
244 		(rel & 0xffff), (op2) | ((imm) & 0xff) << 8);	\
245 	REG_SET_SEEN(b1);					\
246 	BUILD_BUG_ON(((unsigned long) (imm)) > 0xff);		\
247 })
248 
249 #define EMIT6_PCREL(op1, op2, b1, b2, i, off, mask)		\
250 ({								\
251 	/* Branch instruction needs 6 bytes */			\
252 	int rel = (addrs[(i) + (off) + 1] - (addrs[(i) + 1] - 6)) / 2;\
253 	_EMIT6((op1) | reg(b1, b2) << 16 | (rel & 0xffff), (op2) | (mask));\
254 	REG_SET_SEEN(b1);					\
255 	REG_SET_SEEN(b2);					\
256 })
257 
258 #define EMIT6_PCREL_RILB(op, b, target)				\
259 ({								\
260 	unsigned int rel = (int)((target) - jit->prg) / 2;	\
261 	_EMIT6((op) | reg_high(b) << 16 | rel >> 16, rel & 0xffff);\
262 	REG_SET_SEEN(b);					\
263 })
264 
265 #define EMIT6_PCREL_RIL(op, target)				\
266 ({								\
267 	unsigned int rel = (int)((target) - jit->prg) / 2;	\
268 	_EMIT6((op) | rel >> 16, rel & 0xffff);			\
269 })
270 
271 #define EMIT6_PCREL_RILC(op, mask, target)			\
272 ({								\
273 	EMIT6_PCREL_RIL((op) | (mask) << 20, (target));		\
274 })
275 
276 #define _EMIT6_IMM(op, imm)					\
277 ({								\
278 	unsigned int __imm = (imm);				\
279 	_EMIT6((op) | (__imm >> 16), __imm & 0xffff);		\
280 })
281 
282 #define EMIT6_IMM(op, b1, imm)					\
283 ({								\
284 	_EMIT6_IMM((op) | reg_high(b1) << 16, imm);		\
285 	REG_SET_SEEN(b1);					\
286 })
287 
288 #define _EMIT_CONST_U32(val)					\
289 ({								\
290 	unsigned int ret;					\
291 	ret = jit->lit32;					\
292 	if (jit->prg_buf)					\
293 		*(u32 *)(jit->prg_buf + jit->lit32) = (u32)(val);\
294 	jit->lit32 += 4;					\
295 	ret;							\
296 })
297 
298 #define EMIT_CONST_U32(val)					\
299 ({								\
300 	jit->seen |= SEEN_LITERAL;				\
301 	_EMIT_CONST_U32(val) - jit->base_ip;			\
302 })
303 
304 #define _EMIT_CONST_U64(val)					\
305 ({								\
306 	unsigned int ret;					\
307 	ret = jit->lit64;					\
308 	if (jit->prg_buf)					\
309 		*(u64 *)(jit->prg_buf + jit->lit64) = (u64)(val);\
310 	jit->lit64 += 8;					\
311 	ret;							\
312 })
313 
314 #define EMIT_CONST_U64(val)					\
315 ({								\
316 	jit->seen |= SEEN_LITERAL;				\
317 	_EMIT_CONST_U64(val) - jit->base_ip;			\
318 })
319 
320 #define EMIT_ZERO(b1)						\
321 ({								\
322 	if (!fp->aux->verifier_zext) {				\
323 		/* llgfr %dst,%dst (zero extend to 64 bit) */	\
324 		EMIT4(0xb9160000, b1, b1);			\
325 		REG_SET_SEEN(b1);				\
326 	}							\
327 })
328 
329 /*
330  * Return whether this is the first pass. The first pass is special, since we
331  * don't know any sizes yet, and thus must be conservative.
332  */
is_first_pass(struct bpf_jit * jit)333 static bool is_first_pass(struct bpf_jit *jit)
334 {
335 	return jit->size == 0;
336 }
337 
338 /*
339  * Return whether this is the code generation pass. The code generation pass is
340  * special, since we should change as little as possible.
341  */
is_codegen_pass(struct bpf_jit * jit)342 static bool is_codegen_pass(struct bpf_jit *jit)
343 {
344 	return jit->prg_buf;
345 }
346 
347 /*
348  * Return whether "rel" can be encoded as a short PC-relative offset
349  */
is_valid_rel(int rel)350 static bool is_valid_rel(int rel)
351 {
352 	return rel >= -65536 && rel <= 65534;
353 }
354 
355 /*
356  * Return whether "off" can be reached using a short PC-relative offset
357  */
can_use_rel(struct bpf_jit * jit,int off)358 static bool can_use_rel(struct bpf_jit *jit, int off)
359 {
360 	return is_valid_rel(off - jit->prg);
361 }
362 
363 /*
364  * Return whether given displacement can be encoded using
365  * Long-Displacement Facility
366  */
is_valid_ldisp(int disp)367 static bool is_valid_ldisp(int disp)
368 {
369 	return disp >= -524288 && disp <= 524287;
370 }
371 
372 /*
373  * Return whether the next 32-bit literal pool entry can be referenced using
374  * Long-Displacement Facility
375  */
can_use_ldisp_for_lit32(struct bpf_jit * jit)376 static bool can_use_ldisp_for_lit32(struct bpf_jit *jit)
377 {
378 	return is_valid_ldisp(jit->lit32 - jit->base_ip);
379 }
380 
381 /*
382  * Return whether the next 64-bit literal pool entry can be referenced using
383  * Long-Displacement Facility
384  */
can_use_ldisp_for_lit64(struct bpf_jit * jit)385 static bool can_use_ldisp_for_lit64(struct bpf_jit *jit)
386 {
387 	return is_valid_ldisp(jit->lit64 - jit->base_ip);
388 }
389 
390 /*
391  * Fill whole space with illegal instructions
392  */
jit_fill_hole(void * area,unsigned int size)393 static void jit_fill_hole(void *area, unsigned int size)
394 {
395 	memset(area, 0, size);
396 }
397 
398 /*
399  * Save registers from "rs" (register start) to "re" (register end) on stack
400  */
save_regs(struct bpf_jit * jit,u32 rs,u32 re)401 static void save_regs(struct bpf_jit *jit, u32 rs, u32 re)
402 {
403 	u32 off = STK_OFF_R6 + (rs - 6) * 8;
404 
405 	if (rs == re)
406 		/* stg %rs,off(%r15) */
407 		_EMIT6(0xe300f000 | rs << 20 | off, 0x0024);
408 	else
409 		/* stmg %rs,%re,off(%r15) */
410 		_EMIT6_DISP(0xeb00f000 | rs << 20 | re << 16, 0x0024, off);
411 }
412 
413 /*
414  * Restore registers from "rs" (register start) to "re" (register end) on stack
415  */
restore_regs(struct bpf_jit * jit,u32 rs,u32 re,u32 stack_depth)416 static void restore_regs(struct bpf_jit *jit, u32 rs, u32 re, u32 stack_depth)
417 {
418 	u32 off = STK_OFF_R6 + (rs - 6) * 8;
419 
420 	if (jit->seen & SEEN_STACK)
421 		off += STK_OFF + stack_depth;
422 
423 	if (rs == re)
424 		/* lg %rs,off(%r15) */
425 		_EMIT6(0xe300f000 | rs << 20 | off, 0x0004);
426 	else
427 		/* lmg %rs,%re,off(%r15) */
428 		_EMIT6_DISP(0xeb00f000 | rs << 20 | re << 16, 0x0004, off);
429 }
430 
431 /*
432  * Return first seen register (from start)
433  */
get_start(struct bpf_jit * jit,int start)434 static int get_start(struct bpf_jit *jit, int start)
435 {
436 	int i;
437 
438 	for (i = start; i <= 15; i++) {
439 		if (jit->seen_reg[i])
440 			return i;
441 	}
442 	return 0;
443 }
444 
445 /*
446  * Return last seen register (from start) (gap >= 2)
447  */
get_end(struct bpf_jit * jit,int start)448 static int get_end(struct bpf_jit *jit, int start)
449 {
450 	int i;
451 
452 	for (i = start; i < 15; i++) {
453 		if (!jit->seen_reg[i] && !jit->seen_reg[i + 1])
454 			return i - 1;
455 	}
456 	return jit->seen_reg[15] ? 15 : 14;
457 }
458 
459 #define REGS_SAVE	1
460 #define REGS_RESTORE	0
461 /*
462  * Save and restore clobbered registers (6-15) on stack.
463  * We save/restore registers in chunks with gap >= 2 registers.
464  */
save_restore_regs(struct bpf_jit * jit,int op,u32 stack_depth)465 static void save_restore_regs(struct bpf_jit *jit, int op, u32 stack_depth)
466 {
467 	const int last = 15, save_restore_size = 6;
468 	int re = 6, rs;
469 
470 	if (is_first_pass(jit)) {
471 		/*
472 		 * We don't know yet which registers are used. Reserve space
473 		 * conservatively.
474 		 */
475 		jit->prg += (last - re + 1) * save_restore_size;
476 		return;
477 	}
478 
479 	do {
480 		rs = get_start(jit, re);
481 		if (!rs)
482 			break;
483 		re = get_end(jit, rs + 1);
484 		if (op == REGS_SAVE)
485 			save_regs(jit, rs, re);
486 		else
487 			restore_regs(jit, rs, re, stack_depth);
488 		re++;
489 	} while (re <= last);
490 }
491 
bpf_skip(struct bpf_jit * jit,int size)492 static void bpf_skip(struct bpf_jit *jit, int size)
493 {
494 	if (size >= 6 && !is_valid_rel(size)) {
495 		/* brcl 0xf,size */
496 		EMIT6_PCREL_RIL(0xc0f4000000, size);
497 		size -= 6;
498 	} else if (size >= 4 && is_valid_rel(size)) {
499 		/* brc 0xf,size */
500 		EMIT4_PCREL(0xa7f40000, size);
501 		size -= 4;
502 	}
503 	while (size >= 2) {
504 		/* bcr 0,%0 */
505 		_EMIT2(0x0700);
506 		size -= 2;
507 	}
508 }
509 
510 /*
511  * Emit function prologue
512  *
513  * Save registers and create stack frame if necessary.
514  * See stack frame layout desription in "bpf_jit.h"!
515  */
bpf_jit_prologue(struct bpf_jit * jit,u32 stack_depth)516 static void bpf_jit_prologue(struct bpf_jit *jit, u32 stack_depth)
517 {
518 	if (jit->seen & SEEN_TAIL_CALL) {
519 		/* xc STK_OFF_TCCNT(4,%r15),STK_OFF_TCCNT(%r15) */
520 		_EMIT6(0xd703f000 | STK_OFF_TCCNT, 0xf000 | STK_OFF_TCCNT);
521 	} else {
522 		/*
523 		 * There are no tail calls. Insert nops in order to have
524 		 * tail_call_start at a predictable offset.
525 		 */
526 		bpf_skip(jit, 6);
527 	}
528 	/* Tail calls have to skip above initialization */
529 	jit->tail_call_start = jit->prg;
530 	/* Save registers */
531 	save_restore_regs(jit, REGS_SAVE, stack_depth);
532 	/* Setup literal pool */
533 	if (is_first_pass(jit) || (jit->seen & SEEN_LITERAL)) {
534 		if (!is_first_pass(jit) &&
535 		    is_valid_ldisp(jit->size - (jit->prg + 2))) {
536 			/* basr %l,0 */
537 			EMIT2(0x0d00, REG_L, REG_0);
538 			jit->base_ip = jit->prg;
539 		} else {
540 			/* larl %l,lit32_start */
541 			EMIT6_PCREL_RILB(0xc0000000, REG_L, jit->lit32_start);
542 			jit->base_ip = jit->lit32_start;
543 		}
544 	}
545 	/* Setup stack and backchain */
546 	if (is_first_pass(jit) || (jit->seen & SEEN_STACK)) {
547 		if (is_first_pass(jit) || (jit->seen & SEEN_FUNC))
548 			/* lgr %w1,%r15 (backchain) */
549 			EMIT4(0xb9040000, REG_W1, REG_15);
550 		/* la %bfp,STK_160_UNUSED(%r15) (BPF frame pointer) */
551 		EMIT4_DISP(0x41000000, BPF_REG_FP, REG_15, STK_160_UNUSED);
552 		/* aghi %r15,-STK_OFF */
553 		EMIT4_IMM(0xa70b0000, REG_15, -(STK_OFF + stack_depth));
554 		if (is_first_pass(jit) || (jit->seen & SEEN_FUNC))
555 			/* stg %w1,152(%r15) (backchain) */
556 			EMIT6_DISP_LH(0xe3000000, 0x0024, REG_W1, REG_0,
557 				      REG_15, 152);
558 	}
559 }
560 
561 /*
562  * Function epilogue
563  */
bpf_jit_epilogue(struct bpf_jit * jit,u32 stack_depth)564 static void bpf_jit_epilogue(struct bpf_jit *jit, u32 stack_depth)
565 {
566 	jit->exit_ip = jit->prg;
567 	/* Load exit code: lgr %r2,%b0 */
568 	EMIT4(0xb9040000, REG_2, BPF_REG_0);
569 	/* Restore registers */
570 	save_restore_regs(jit, REGS_RESTORE, stack_depth);
571 	if (__is_defined(CC_USING_EXPOLINE) && !nospec_disable) {
572 		jit->r14_thunk_ip = jit->prg;
573 		/* Generate __s390_indirect_jump_r14 thunk */
574 		if (test_facility(35)) {
575 			/* exrl %r0,.+10 */
576 			EMIT6_PCREL_RIL(0xc6000000, jit->prg + 10);
577 		} else {
578 			/* larl %r1,.+14 */
579 			EMIT6_PCREL_RILB(0xc0000000, REG_1, jit->prg + 14);
580 			/* ex 0,0(%r1) */
581 			EMIT4_DISP(0x44000000, REG_0, REG_1, 0);
582 		}
583 		/* j . */
584 		EMIT4_PCREL(0xa7f40000, 0);
585 	}
586 	/* br %r14 */
587 	_EMIT2(0x07fe);
588 
589 	if (__is_defined(CC_USING_EXPOLINE) && !nospec_disable &&
590 	    (is_first_pass(jit) || (jit->seen & SEEN_FUNC))) {
591 		jit->r1_thunk_ip = jit->prg;
592 		/* Generate __s390_indirect_jump_r1 thunk */
593 		if (test_facility(35)) {
594 			/* exrl %r0,.+10 */
595 			EMIT6_PCREL_RIL(0xc6000000, jit->prg + 10);
596 			/* j . */
597 			EMIT4_PCREL(0xa7f40000, 0);
598 			/* br %r1 */
599 			_EMIT2(0x07f1);
600 		} else {
601 			/* ex 0,S390_lowcore.br_r1_tampoline */
602 			EMIT4_DISP(0x44000000, REG_0, REG_0,
603 				   offsetof(struct lowcore, br_r1_trampoline));
604 			/* j . */
605 			EMIT4_PCREL(0xa7f40000, 0);
606 		}
607 	}
608 }
609 
get_probe_mem_regno(const u8 * insn)610 static int get_probe_mem_regno(const u8 *insn)
611 {
612 	/*
613 	 * insn must point to llgc, llgh, llgf or lg, which have destination
614 	 * register at the same position.
615 	 */
616 	if (insn[0] != 0xe3) /* common llgc, llgh, llgf and lg prefix */
617 		return -1;
618 	if (insn[5] != 0x90 && /* llgc */
619 	    insn[5] != 0x91 && /* llgh */
620 	    insn[5] != 0x16 && /* llgf */
621 	    insn[5] != 0x04) /* lg */
622 		return -1;
623 	return insn[1] >> 4;
624 }
625 
ex_handler_bpf(const struct exception_table_entry * x,struct pt_regs * regs)626 static bool ex_handler_bpf(const struct exception_table_entry *x,
627 			   struct pt_regs *regs)
628 {
629 	int regno;
630 	u8 *insn;
631 
632 	regs->psw.addr = extable_fixup(x);
633 	insn = (u8 *)__rewind_psw(regs->psw, regs->int_code >> 16);
634 	regno = get_probe_mem_regno(insn);
635 	if (WARN_ON_ONCE(regno < 0))
636 		/* JIT bug - unexpected instruction. */
637 		return false;
638 	regs->gprs[regno] = 0;
639 	return true;
640 }
641 
bpf_jit_probe_mem(struct bpf_jit * jit,struct bpf_prog * fp,int probe_prg,int nop_prg)642 static int bpf_jit_probe_mem(struct bpf_jit *jit, struct bpf_prog *fp,
643 			     int probe_prg, int nop_prg)
644 {
645 	struct exception_table_entry *ex;
646 	s64 delta;
647 	u8 *insn;
648 	int prg;
649 	int i;
650 
651 	if (!fp->aux->extable)
652 		/* Do nothing during early JIT passes. */
653 		return 0;
654 	insn = jit->prg_buf + probe_prg;
655 	if (WARN_ON_ONCE(get_probe_mem_regno(insn) < 0))
656 		/* JIT bug - unexpected probe instruction. */
657 		return -1;
658 	if (WARN_ON_ONCE(probe_prg + insn_length(*insn) != nop_prg))
659 		/* JIT bug - gap between probe and nop instructions. */
660 		return -1;
661 	for (i = 0; i < 2; i++) {
662 		if (WARN_ON_ONCE(jit->excnt >= fp->aux->num_exentries))
663 			/* Verifier bug - not enough entries. */
664 			return -1;
665 		ex = &fp->aux->extable[jit->excnt];
666 		/* Add extable entries for probe and nop instructions. */
667 		prg = i == 0 ? probe_prg : nop_prg;
668 		delta = jit->prg_buf + prg - (u8 *)&ex->insn;
669 		if (WARN_ON_ONCE(delta < INT_MIN || delta > INT_MAX))
670 			/* JIT bug - code and extable must be close. */
671 			return -1;
672 		ex->insn = delta;
673 		/*
674 		 * Always land on the nop. Note that extable infrastructure
675 		 * ignores fixup field, it is handled by ex_handler_bpf().
676 		 */
677 		delta = jit->prg_buf + nop_prg - (u8 *)&ex->fixup;
678 		if (WARN_ON_ONCE(delta < INT_MIN || delta > INT_MAX))
679 			/* JIT bug - landing pad and extable must be close. */
680 			return -1;
681 		ex->fixup = delta;
682 		ex->handler = (u8 *)ex_handler_bpf - (u8 *)&ex->handler;
683 		jit->excnt++;
684 	}
685 	return 0;
686 }
687 
688 /*
689  * Compile one eBPF instruction into s390x code
690  *
691  * NOTE: Use noinline because for gcov (-fprofile-arcs) gcc allocates a lot of
692  * stack space for the large switch statement.
693  */
bpf_jit_insn(struct bpf_jit * jit,struct bpf_prog * fp,int i,bool extra_pass,u32 stack_depth)694 static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp,
695 				 int i, bool extra_pass, u32 stack_depth)
696 {
697 	struct bpf_insn *insn = &fp->insnsi[i];
698 	u32 dst_reg = insn->dst_reg;
699 	u32 src_reg = insn->src_reg;
700 	int last, insn_count = 1;
701 	u32 *addrs = jit->addrs;
702 	s32 imm = insn->imm;
703 	s16 off = insn->off;
704 	int probe_prg = -1;
705 	unsigned int mask;
706 	int nop_prg;
707 	int err;
708 
709 	if (BPF_CLASS(insn->code) == BPF_LDX &&
710 	    BPF_MODE(insn->code) == BPF_PROBE_MEM)
711 		probe_prg = jit->prg;
712 
713 	switch (insn->code) {
714 	/*
715 	 * BPF_MOV
716 	 */
717 	case BPF_ALU | BPF_MOV | BPF_X: /* dst = (u32) src */
718 		/* llgfr %dst,%src */
719 		EMIT4(0xb9160000, dst_reg, src_reg);
720 		if (insn_is_zext(&insn[1]))
721 			insn_count = 2;
722 		break;
723 	case BPF_ALU64 | BPF_MOV | BPF_X: /* dst = src */
724 		/* lgr %dst,%src */
725 		EMIT4(0xb9040000, dst_reg, src_reg);
726 		break;
727 	case BPF_ALU | BPF_MOV | BPF_K: /* dst = (u32) imm */
728 		/* llilf %dst,imm */
729 		EMIT6_IMM(0xc00f0000, dst_reg, imm);
730 		if (insn_is_zext(&insn[1]))
731 			insn_count = 2;
732 		break;
733 	case BPF_ALU64 | BPF_MOV | BPF_K: /* dst = imm */
734 		/* lgfi %dst,imm */
735 		EMIT6_IMM(0xc0010000, dst_reg, imm);
736 		break;
737 	/*
738 	 * BPF_LD 64
739 	 */
740 	case BPF_LD | BPF_IMM | BPF_DW: /* dst = (u64) imm */
741 	{
742 		/* 16 byte instruction that uses two 'struct bpf_insn' */
743 		u64 imm64;
744 
745 		imm64 = (u64)(u32) insn[0].imm | ((u64)(u32) insn[1].imm) << 32;
746 		/* lgrl %dst,imm */
747 		EMIT6_PCREL_RILB(0xc4080000, dst_reg, _EMIT_CONST_U64(imm64));
748 		insn_count = 2;
749 		break;
750 	}
751 	/*
752 	 * BPF_ADD
753 	 */
754 	case BPF_ALU | BPF_ADD | BPF_X: /* dst = (u32) dst + (u32) src */
755 		/* ar %dst,%src */
756 		EMIT2(0x1a00, dst_reg, src_reg);
757 		EMIT_ZERO(dst_reg);
758 		break;
759 	case BPF_ALU64 | BPF_ADD | BPF_X: /* dst = dst + src */
760 		/* agr %dst,%src */
761 		EMIT4(0xb9080000, dst_reg, src_reg);
762 		break;
763 	case BPF_ALU | BPF_ADD | BPF_K: /* dst = (u32) dst + (u32) imm */
764 		if (!imm)
765 			break;
766 		/* alfi %dst,imm */
767 		EMIT6_IMM(0xc20b0000, dst_reg, imm);
768 		EMIT_ZERO(dst_reg);
769 		break;
770 	case BPF_ALU64 | BPF_ADD | BPF_K: /* dst = dst + imm */
771 		if (!imm)
772 			break;
773 		/* agfi %dst,imm */
774 		EMIT6_IMM(0xc2080000, dst_reg, imm);
775 		break;
776 	/*
777 	 * BPF_SUB
778 	 */
779 	case BPF_ALU | BPF_SUB | BPF_X: /* dst = (u32) dst - (u32) src */
780 		/* sr %dst,%src */
781 		EMIT2(0x1b00, dst_reg, src_reg);
782 		EMIT_ZERO(dst_reg);
783 		break;
784 	case BPF_ALU64 | BPF_SUB | BPF_X: /* dst = dst - src */
785 		/* sgr %dst,%src */
786 		EMIT4(0xb9090000, dst_reg, src_reg);
787 		break;
788 	case BPF_ALU | BPF_SUB | BPF_K: /* dst = (u32) dst - (u32) imm */
789 		if (!imm)
790 			break;
791 		/* alfi %dst,-imm */
792 		EMIT6_IMM(0xc20b0000, dst_reg, -imm);
793 		EMIT_ZERO(dst_reg);
794 		break;
795 	case BPF_ALU64 | BPF_SUB | BPF_K: /* dst = dst - imm */
796 		if (!imm)
797 			break;
798 		/* agfi %dst,-imm */
799 		EMIT6_IMM(0xc2080000, dst_reg, -imm);
800 		break;
801 	/*
802 	 * BPF_MUL
803 	 */
804 	case BPF_ALU | BPF_MUL | BPF_X: /* dst = (u32) dst * (u32) src */
805 		/* msr %dst,%src */
806 		EMIT4(0xb2520000, dst_reg, src_reg);
807 		EMIT_ZERO(dst_reg);
808 		break;
809 	case BPF_ALU64 | BPF_MUL | BPF_X: /* dst = dst * src */
810 		/* msgr %dst,%src */
811 		EMIT4(0xb90c0000, dst_reg, src_reg);
812 		break;
813 	case BPF_ALU | BPF_MUL | BPF_K: /* dst = (u32) dst * (u32) imm */
814 		if (imm == 1)
815 			break;
816 		/* msfi %r5,imm */
817 		EMIT6_IMM(0xc2010000, dst_reg, imm);
818 		EMIT_ZERO(dst_reg);
819 		break;
820 	case BPF_ALU64 | BPF_MUL | BPF_K: /* dst = dst * imm */
821 		if (imm == 1)
822 			break;
823 		/* msgfi %dst,imm */
824 		EMIT6_IMM(0xc2000000, dst_reg, imm);
825 		break;
826 	/*
827 	 * BPF_DIV / BPF_MOD
828 	 */
829 	case BPF_ALU | BPF_DIV | BPF_X: /* dst = (u32) dst / (u32) src */
830 	case BPF_ALU | BPF_MOD | BPF_X: /* dst = (u32) dst % (u32) src */
831 	{
832 		int rc_reg = BPF_OP(insn->code) == BPF_DIV ? REG_W1 : REG_W0;
833 
834 		/* lhi %w0,0 */
835 		EMIT4_IMM(0xa7080000, REG_W0, 0);
836 		/* lr %w1,%dst */
837 		EMIT2(0x1800, REG_W1, dst_reg);
838 		/* dlr %w0,%src */
839 		EMIT4(0xb9970000, REG_W0, src_reg);
840 		/* llgfr %dst,%rc */
841 		EMIT4(0xb9160000, dst_reg, rc_reg);
842 		if (insn_is_zext(&insn[1]))
843 			insn_count = 2;
844 		break;
845 	}
846 	case BPF_ALU64 | BPF_DIV | BPF_X: /* dst = dst / src */
847 	case BPF_ALU64 | BPF_MOD | BPF_X: /* dst = dst % src */
848 	{
849 		int rc_reg = BPF_OP(insn->code) == BPF_DIV ? REG_W1 : REG_W0;
850 
851 		/* lghi %w0,0 */
852 		EMIT4_IMM(0xa7090000, REG_W0, 0);
853 		/* lgr %w1,%dst */
854 		EMIT4(0xb9040000, REG_W1, dst_reg);
855 		/* dlgr %w0,%dst */
856 		EMIT4(0xb9870000, REG_W0, src_reg);
857 		/* lgr %dst,%rc */
858 		EMIT4(0xb9040000, dst_reg, rc_reg);
859 		break;
860 	}
861 	case BPF_ALU | BPF_DIV | BPF_K: /* dst = (u32) dst / (u32) imm */
862 	case BPF_ALU | BPF_MOD | BPF_K: /* dst = (u32) dst % (u32) imm */
863 	{
864 		int rc_reg = BPF_OP(insn->code) == BPF_DIV ? REG_W1 : REG_W0;
865 
866 		if (imm == 1) {
867 			if (BPF_OP(insn->code) == BPF_MOD)
868 				/* lhgi %dst,0 */
869 				EMIT4_IMM(0xa7090000, dst_reg, 0);
870 			break;
871 		}
872 		/* lhi %w0,0 */
873 		EMIT4_IMM(0xa7080000, REG_W0, 0);
874 		/* lr %w1,%dst */
875 		EMIT2(0x1800, REG_W1, dst_reg);
876 		if (!is_first_pass(jit) && can_use_ldisp_for_lit32(jit)) {
877 			/* dl %w0,<d(imm)>(%l) */
878 			EMIT6_DISP_LH(0xe3000000, 0x0097, REG_W0, REG_0, REG_L,
879 				      EMIT_CONST_U32(imm));
880 		} else {
881 			/* lgfrl %dst,imm */
882 			EMIT6_PCREL_RILB(0xc40c0000, dst_reg,
883 					 _EMIT_CONST_U32(imm));
884 			jit->seen |= SEEN_LITERAL;
885 			/* dlr %w0,%dst */
886 			EMIT4(0xb9970000, REG_W0, dst_reg);
887 		}
888 		/* llgfr %dst,%rc */
889 		EMIT4(0xb9160000, dst_reg, rc_reg);
890 		if (insn_is_zext(&insn[1]))
891 			insn_count = 2;
892 		break;
893 	}
894 	case BPF_ALU64 | BPF_DIV | BPF_K: /* dst = dst / imm */
895 	case BPF_ALU64 | BPF_MOD | BPF_K: /* dst = dst % imm */
896 	{
897 		int rc_reg = BPF_OP(insn->code) == BPF_DIV ? REG_W1 : REG_W0;
898 
899 		if (imm == 1) {
900 			if (BPF_OP(insn->code) == BPF_MOD)
901 				/* lhgi %dst,0 */
902 				EMIT4_IMM(0xa7090000, dst_reg, 0);
903 			break;
904 		}
905 		/* lghi %w0,0 */
906 		EMIT4_IMM(0xa7090000, REG_W0, 0);
907 		/* lgr %w1,%dst */
908 		EMIT4(0xb9040000, REG_W1, dst_reg);
909 		if (!is_first_pass(jit) && can_use_ldisp_for_lit64(jit)) {
910 			/* dlg %w0,<d(imm)>(%l) */
911 			EMIT6_DISP_LH(0xe3000000, 0x0087, REG_W0, REG_0, REG_L,
912 				      EMIT_CONST_U64(imm));
913 		} else {
914 			/* lgrl %dst,imm */
915 			EMIT6_PCREL_RILB(0xc4080000, dst_reg,
916 					 _EMIT_CONST_U64(imm));
917 			jit->seen |= SEEN_LITERAL;
918 			/* dlgr %w0,%dst */
919 			EMIT4(0xb9870000, REG_W0, dst_reg);
920 		}
921 		/* lgr %dst,%rc */
922 		EMIT4(0xb9040000, dst_reg, rc_reg);
923 		break;
924 	}
925 	/*
926 	 * BPF_AND
927 	 */
928 	case BPF_ALU | BPF_AND | BPF_X: /* dst = (u32) dst & (u32) src */
929 		/* nr %dst,%src */
930 		EMIT2(0x1400, dst_reg, src_reg);
931 		EMIT_ZERO(dst_reg);
932 		break;
933 	case BPF_ALU64 | BPF_AND | BPF_X: /* dst = dst & src */
934 		/* ngr %dst,%src */
935 		EMIT4(0xb9800000, dst_reg, src_reg);
936 		break;
937 	case BPF_ALU | BPF_AND | BPF_K: /* dst = (u32) dst & (u32) imm */
938 		/* nilf %dst,imm */
939 		EMIT6_IMM(0xc00b0000, dst_reg, imm);
940 		EMIT_ZERO(dst_reg);
941 		break;
942 	case BPF_ALU64 | BPF_AND | BPF_K: /* dst = dst & imm */
943 		if (!is_first_pass(jit) && can_use_ldisp_for_lit64(jit)) {
944 			/* ng %dst,<d(imm)>(%l) */
945 			EMIT6_DISP_LH(0xe3000000, 0x0080,
946 				      dst_reg, REG_0, REG_L,
947 				      EMIT_CONST_U64(imm));
948 		} else {
949 			/* lgrl %w0,imm */
950 			EMIT6_PCREL_RILB(0xc4080000, REG_W0,
951 					 _EMIT_CONST_U64(imm));
952 			jit->seen |= SEEN_LITERAL;
953 			/* ngr %dst,%w0 */
954 			EMIT4(0xb9800000, dst_reg, REG_W0);
955 		}
956 		break;
957 	/*
958 	 * BPF_OR
959 	 */
960 	case BPF_ALU | BPF_OR | BPF_X: /* dst = (u32) dst | (u32) src */
961 		/* or %dst,%src */
962 		EMIT2(0x1600, dst_reg, src_reg);
963 		EMIT_ZERO(dst_reg);
964 		break;
965 	case BPF_ALU64 | BPF_OR | BPF_X: /* dst = dst | src */
966 		/* ogr %dst,%src */
967 		EMIT4(0xb9810000, dst_reg, src_reg);
968 		break;
969 	case BPF_ALU | BPF_OR | BPF_K: /* dst = (u32) dst | (u32) imm */
970 		/* oilf %dst,imm */
971 		EMIT6_IMM(0xc00d0000, dst_reg, imm);
972 		EMIT_ZERO(dst_reg);
973 		break;
974 	case BPF_ALU64 | BPF_OR | BPF_K: /* dst = dst | imm */
975 		if (!is_first_pass(jit) && can_use_ldisp_for_lit64(jit)) {
976 			/* og %dst,<d(imm)>(%l) */
977 			EMIT6_DISP_LH(0xe3000000, 0x0081,
978 				      dst_reg, REG_0, REG_L,
979 				      EMIT_CONST_U64(imm));
980 		} else {
981 			/* lgrl %w0,imm */
982 			EMIT6_PCREL_RILB(0xc4080000, REG_W0,
983 					 _EMIT_CONST_U64(imm));
984 			jit->seen |= SEEN_LITERAL;
985 			/* ogr %dst,%w0 */
986 			EMIT4(0xb9810000, dst_reg, REG_W0);
987 		}
988 		break;
989 	/*
990 	 * BPF_XOR
991 	 */
992 	case BPF_ALU | BPF_XOR | BPF_X: /* dst = (u32) dst ^ (u32) src */
993 		/* xr %dst,%src */
994 		EMIT2(0x1700, dst_reg, src_reg);
995 		EMIT_ZERO(dst_reg);
996 		break;
997 	case BPF_ALU64 | BPF_XOR | BPF_X: /* dst = dst ^ src */
998 		/* xgr %dst,%src */
999 		EMIT4(0xb9820000, dst_reg, src_reg);
1000 		break;
1001 	case BPF_ALU | BPF_XOR | BPF_K: /* dst = (u32) dst ^ (u32) imm */
1002 		if (!imm)
1003 			break;
1004 		/* xilf %dst,imm */
1005 		EMIT6_IMM(0xc0070000, dst_reg, imm);
1006 		EMIT_ZERO(dst_reg);
1007 		break;
1008 	case BPF_ALU64 | BPF_XOR | BPF_K: /* dst = dst ^ imm */
1009 		if (!is_first_pass(jit) && can_use_ldisp_for_lit64(jit)) {
1010 			/* xg %dst,<d(imm)>(%l) */
1011 			EMIT6_DISP_LH(0xe3000000, 0x0082,
1012 				      dst_reg, REG_0, REG_L,
1013 				      EMIT_CONST_U64(imm));
1014 		} else {
1015 			/* lgrl %w0,imm */
1016 			EMIT6_PCREL_RILB(0xc4080000, REG_W0,
1017 					 _EMIT_CONST_U64(imm));
1018 			jit->seen |= SEEN_LITERAL;
1019 			/* xgr %dst,%w0 */
1020 			EMIT4(0xb9820000, dst_reg, REG_W0);
1021 		}
1022 		break;
1023 	/*
1024 	 * BPF_LSH
1025 	 */
1026 	case BPF_ALU | BPF_LSH | BPF_X: /* dst = (u32) dst << (u32) src */
1027 		/* sll %dst,0(%src) */
1028 		EMIT4_DISP(0x89000000, dst_reg, src_reg, 0);
1029 		EMIT_ZERO(dst_reg);
1030 		break;
1031 	case BPF_ALU64 | BPF_LSH | BPF_X: /* dst = dst << src */
1032 		/* sllg %dst,%dst,0(%src) */
1033 		EMIT6_DISP_LH(0xeb000000, 0x000d, dst_reg, dst_reg, src_reg, 0);
1034 		break;
1035 	case BPF_ALU | BPF_LSH | BPF_K: /* dst = (u32) dst << (u32) imm */
1036 		if (imm == 0)
1037 			break;
1038 		/* sll %dst,imm(%r0) */
1039 		EMIT4_DISP(0x89000000, dst_reg, REG_0, imm);
1040 		EMIT_ZERO(dst_reg);
1041 		break;
1042 	case BPF_ALU64 | BPF_LSH | BPF_K: /* dst = dst << imm */
1043 		if (imm == 0)
1044 			break;
1045 		/* sllg %dst,%dst,imm(%r0) */
1046 		EMIT6_DISP_LH(0xeb000000, 0x000d, dst_reg, dst_reg, REG_0, imm);
1047 		break;
1048 	/*
1049 	 * BPF_RSH
1050 	 */
1051 	case BPF_ALU | BPF_RSH | BPF_X: /* dst = (u32) dst >> (u32) src */
1052 		/* srl %dst,0(%src) */
1053 		EMIT4_DISP(0x88000000, dst_reg, src_reg, 0);
1054 		EMIT_ZERO(dst_reg);
1055 		break;
1056 	case BPF_ALU64 | BPF_RSH | BPF_X: /* dst = dst >> src */
1057 		/* srlg %dst,%dst,0(%src) */
1058 		EMIT6_DISP_LH(0xeb000000, 0x000c, dst_reg, dst_reg, src_reg, 0);
1059 		break;
1060 	case BPF_ALU | BPF_RSH | BPF_K: /* dst = (u32) dst >> (u32) imm */
1061 		if (imm == 0)
1062 			break;
1063 		/* srl %dst,imm(%r0) */
1064 		EMIT4_DISP(0x88000000, dst_reg, REG_0, imm);
1065 		EMIT_ZERO(dst_reg);
1066 		break;
1067 	case BPF_ALU64 | BPF_RSH | BPF_K: /* dst = dst >> imm */
1068 		if (imm == 0)
1069 			break;
1070 		/* srlg %dst,%dst,imm(%r0) */
1071 		EMIT6_DISP_LH(0xeb000000, 0x000c, dst_reg, dst_reg, REG_0, imm);
1072 		break;
1073 	/*
1074 	 * BPF_ARSH
1075 	 */
1076 	case BPF_ALU | BPF_ARSH | BPF_X: /* ((s32) dst) >>= src */
1077 		/* sra %dst,%dst,0(%src) */
1078 		EMIT4_DISP(0x8a000000, dst_reg, src_reg, 0);
1079 		EMIT_ZERO(dst_reg);
1080 		break;
1081 	case BPF_ALU64 | BPF_ARSH | BPF_X: /* ((s64) dst) >>= src */
1082 		/* srag %dst,%dst,0(%src) */
1083 		EMIT6_DISP_LH(0xeb000000, 0x000a, dst_reg, dst_reg, src_reg, 0);
1084 		break;
1085 	case BPF_ALU | BPF_ARSH | BPF_K: /* ((s32) dst >> imm */
1086 		if (imm == 0)
1087 			break;
1088 		/* sra %dst,imm(%r0) */
1089 		EMIT4_DISP(0x8a000000, dst_reg, REG_0, imm);
1090 		EMIT_ZERO(dst_reg);
1091 		break;
1092 	case BPF_ALU64 | BPF_ARSH | BPF_K: /* ((s64) dst) >>= imm */
1093 		if (imm == 0)
1094 			break;
1095 		/* srag %dst,%dst,imm(%r0) */
1096 		EMIT6_DISP_LH(0xeb000000, 0x000a, dst_reg, dst_reg, REG_0, imm);
1097 		break;
1098 	/*
1099 	 * BPF_NEG
1100 	 */
1101 	case BPF_ALU | BPF_NEG: /* dst = (u32) -dst */
1102 		/* lcr %dst,%dst */
1103 		EMIT2(0x1300, dst_reg, dst_reg);
1104 		EMIT_ZERO(dst_reg);
1105 		break;
1106 	case BPF_ALU64 | BPF_NEG: /* dst = -dst */
1107 		/* lcgr %dst,%dst */
1108 		EMIT4(0xb9030000, dst_reg, dst_reg);
1109 		break;
1110 	/*
1111 	 * BPF_FROM_BE/LE
1112 	 */
1113 	case BPF_ALU | BPF_END | BPF_FROM_BE:
1114 		/* s390 is big endian, therefore only clear high order bytes */
1115 		switch (imm) {
1116 		case 16: /* dst = (u16) cpu_to_be16(dst) */
1117 			/* llghr %dst,%dst */
1118 			EMIT4(0xb9850000, dst_reg, dst_reg);
1119 			if (insn_is_zext(&insn[1]))
1120 				insn_count = 2;
1121 			break;
1122 		case 32: /* dst = (u32) cpu_to_be32(dst) */
1123 			if (!fp->aux->verifier_zext)
1124 				/* llgfr %dst,%dst */
1125 				EMIT4(0xb9160000, dst_reg, dst_reg);
1126 			break;
1127 		case 64: /* dst = (u64) cpu_to_be64(dst) */
1128 			break;
1129 		}
1130 		break;
1131 	case BPF_ALU | BPF_END | BPF_FROM_LE:
1132 		switch (imm) {
1133 		case 16: /* dst = (u16) cpu_to_le16(dst) */
1134 			/* lrvr %dst,%dst */
1135 			EMIT4(0xb91f0000, dst_reg, dst_reg);
1136 			/* srl %dst,16(%r0) */
1137 			EMIT4_DISP(0x88000000, dst_reg, REG_0, 16);
1138 			/* llghr %dst,%dst */
1139 			EMIT4(0xb9850000, dst_reg, dst_reg);
1140 			if (insn_is_zext(&insn[1]))
1141 				insn_count = 2;
1142 			break;
1143 		case 32: /* dst = (u32) cpu_to_le32(dst) */
1144 			/* lrvr %dst,%dst */
1145 			EMIT4(0xb91f0000, dst_reg, dst_reg);
1146 			if (!fp->aux->verifier_zext)
1147 				/* llgfr %dst,%dst */
1148 				EMIT4(0xb9160000, dst_reg, dst_reg);
1149 			break;
1150 		case 64: /* dst = (u64) cpu_to_le64(dst) */
1151 			/* lrvgr %dst,%dst */
1152 			EMIT4(0xb90f0000, dst_reg, dst_reg);
1153 			break;
1154 		}
1155 		break;
1156 	/*
1157 	 * BPF_ST(X)
1158 	 */
1159 	case BPF_STX | BPF_MEM | BPF_B: /* *(u8 *)(dst + off) = src_reg */
1160 		/* stcy %src,off(%dst) */
1161 		EMIT6_DISP_LH(0xe3000000, 0x0072, src_reg, dst_reg, REG_0, off);
1162 		jit->seen |= SEEN_MEM;
1163 		break;
1164 	case BPF_STX | BPF_MEM | BPF_H: /* (u16 *)(dst + off) = src */
1165 		/* sthy %src,off(%dst) */
1166 		EMIT6_DISP_LH(0xe3000000, 0x0070, src_reg, dst_reg, REG_0, off);
1167 		jit->seen |= SEEN_MEM;
1168 		break;
1169 	case BPF_STX | BPF_MEM | BPF_W: /* *(u32 *)(dst + off) = src */
1170 		/* sty %src,off(%dst) */
1171 		EMIT6_DISP_LH(0xe3000000, 0x0050, src_reg, dst_reg, REG_0, off);
1172 		jit->seen |= SEEN_MEM;
1173 		break;
1174 	case BPF_STX | BPF_MEM | BPF_DW: /* (u64 *)(dst + off) = src */
1175 		/* stg %src,off(%dst) */
1176 		EMIT6_DISP_LH(0xe3000000, 0x0024, src_reg, dst_reg, REG_0, off);
1177 		jit->seen |= SEEN_MEM;
1178 		break;
1179 	case BPF_ST | BPF_MEM | BPF_B: /* *(u8 *)(dst + off) = imm */
1180 		/* lhi %w0,imm */
1181 		EMIT4_IMM(0xa7080000, REG_W0, (u8) imm);
1182 		/* stcy %w0,off(dst) */
1183 		EMIT6_DISP_LH(0xe3000000, 0x0072, REG_W0, dst_reg, REG_0, off);
1184 		jit->seen |= SEEN_MEM;
1185 		break;
1186 	case BPF_ST | BPF_MEM | BPF_H: /* (u16 *)(dst + off) = imm */
1187 		/* lhi %w0,imm */
1188 		EMIT4_IMM(0xa7080000, REG_W0, (u16) imm);
1189 		/* sthy %w0,off(dst) */
1190 		EMIT6_DISP_LH(0xe3000000, 0x0070, REG_W0, dst_reg, REG_0, off);
1191 		jit->seen |= SEEN_MEM;
1192 		break;
1193 	case BPF_ST | BPF_MEM | BPF_W: /* *(u32 *)(dst + off) = imm */
1194 		/* llilf %w0,imm  */
1195 		EMIT6_IMM(0xc00f0000, REG_W0, (u32) imm);
1196 		/* sty %w0,off(%dst) */
1197 		EMIT6_DISP_LH(0xe3000000, 0x0050, REG_W0, dst_reg, REG_0, off);
1198 		jit->seen |= SEEN_MEM;
1199 		break;
1200 	case BPF_ST | BPF_MEM | BPF_DW: /* *(u64 *)(dst + off) = imm */
1201 		/* lgfi %w0,imm */
1202 		EMIT6_IMM(0xc0010000, REG_W0, imm);
1203 		/* stg %w0,off(%dst) */
1204 		EMIT6_DISP_LH(0xe3000000, 0x0024, REG_W0, dst_reg, REG_0, off);
1205 		jit->seen |= SEEN_MEM;
1206 		break;
1207 	/*
1208 	 * BPF_ATOMIC
1209 	 */
1210 	case BPF_STX | BPF_ATOMIC | BPF_DW:
1211 	case BPF_STX | BPF_ATOMIC | BPF_W:
1212 	{
1213 		bool is32 = BPF_SIZE(insn->code) == BPF_W;
1214 
1215 		switch (insn->imm) {
1216 /* {op32|op64} {%w0|%src},%src,off(%dst) */
1217 #define EMIT_ATOMIC(op32, op64) do {					\
1218 	EMIT6_DISP_LH(0xeb000000, is32 ? (op32) : (op64),		\
1219 		      (insn->imm & BPF_FETCH) ? src_reg : REG_W0,	\
1220 		      src_reg, dst_reg, off);				\
1221 	if (is32 && (insn->imm & BPF_FETCH))				\
1222 		EMIT_ZERO(src_reg);					\
1223 } while (0)
1224 		case BPF_ADD:
1225 		case BPF_ADD | BPF_FETCH:
1226 			/* {laal|laalg} */
1227 			EMIT_ATOMIC(0x00fa, 0x00ea);
1228 			break;
1229 		case BPF_AND:
1230 		case BPF_AND | BPF_FETCH:
1231 			/* {lan|lang} */
1232 			EMIT_ATOMIC(0x00f4, 0x00e4);
1233 			break;
1234 		case BPF_OR:
1235 		case BPF_OR | BPF_FETCH:
1236 			/* {lao|laog} */
1237 			EMIT_ATOMIC(0x00f6, 0x00e6);
1238 			break;
1239 		case BPF_XOR:
1240 		case BPF_XOR | BPF_FETCH:
1241 			/* {lax|laxg} */
1242 			EMIT_ATOMIC(0x00f7, 0x00e7);
1243 			break;
1244 #undef EMIT_ATOMIC
1245 		case BPF_XCHG:
1246 			/* {ly|lg} %w0,off(%dst) */
1247 			EMIT6_DISP_LH(0xe3000000,
1248 				      is32 ? 0x0058 : 0x0004, REG_W0, REG_0,
1249 				      dst_reg, off);
1250 			/* 0: {csy|csg} %w0,%src,off(%dst) */
1251 			EMIT6_DISP_LH(0xeb000000, is32 ? 0x0014 : 0x0030,
1252 				      REG_W0, src_reg, dst_reg, off);
1253 			/* brc 4,0b */
1254 			EMIT4_PCREL_RIC(0xa7040000, 4, jit->prg - 6);
1255 			/* {llgfr|lgr} %src,%w0 */
1256 			EMIT4(is32 ? 0xb9160000 : 0xb9040000, src_reg, REG_W0);
1257 			if (is32 && insn_is_zext(&insn[1]))
1258 				insn_count = 2;
1259 			break;
1260 		case BPF_CMPXCHG:
1261 			/* 0: {csy|csg} %b0,%src,off(%dst) */
1262 			EMIT6_DISP_LH(0xeb000000, is32 ? 0x0014 : 0x0030,
1263 				      BPF_REG_0, src_reg, dst_reg, off);
1264 			break;
1265 		default:
1266 			pr_err("Unknown atomic operation %02x\n", insn->imm);
1267 			return -1;
1268 		}
1269 
1270 		jit->seen |= SEEN_MEM;
1271 		break;
1272 	}
1273 	/*
1274 	 * BPF_LDX
1275 	 */
1276 	case BPF_LDX | BPF_MEM | BPF_B: /* dst = *(u8 *)(ul) (src + off) */
1277 	case BPF_LDX | BPF_PROBE_MEM | BPF_B:
1278 		/* llgc %dst,0(off,%src) */
1279 		EMIT6_DISP_LH(0xe3000000, 0x0090, dst_reg, src_reg, REG_0, off);
1280 		jit->seen |= SEEN_MEM;
1281 		if (insn_is_zext(&insn[1]))
1282 			insn_count = 2;
1283 		break;
1284 	case BPF_LDX | BPF_MEM | BPF_H: /* dst = *(u16 *)(ul) (src + off) */
1285 	case BPF_LDX | BPF_PROBE_MEM | BPF_H:
1286 		/* llgh %dst,0(off,%src) */
1287 		EMIT6_DISP_LH(0xe3000000, 0x0091, dst_reg, src_reg, REG_0, off);
1288 		jit->seen |= SEEN_MEM;
1289 		if (insn_is_zext(&insn[1]))
1290 			insn_count = 2;
1291 		break;
1292 	case BPF_LDX | BPF_MEM | BPF_W: /* dst = *(u32 *)(ul) (src + off) */
1293 	case BPF_LDX | BPF_PROBE_MEM | BPF_W:
1294 		/* llgf %dst,off(%src) */
1295 		jit->seen |= SEEN_MEM;
1296 		EMIT6_DISP_LH(0xe3000000, 0x0016, dst_reg, src_reg, REG_0, off);
1297 		if (insn_is_zext(&insn[1]))
1298 			insn_count = 2;
1299 		break;
1300 	case BPF_LDX | BPF_MEM | BPF_DW: /* dst = *(u64 *)(ul) (src + off) */
1301 	case BPF_LDX | BPF_PROBE_MEM | BPF_DW:
1302 		/* lg %dst,0(off,%src) */
1303 		jit->seen |= SEEN_MEM;
1304 		EMIT6_DISP_LH(0xe3000000, 0x0004, dst_reg, src_reg, REG_0, off);
1305 		break;
1306 	/*
1307 	 * BPF_JMP / CALL
1308 	 */
1309 	case BPF_JMP | BPF_CALL:
1310 	{
1311 		u64 func;
1312 		bool func_addr_fixed;
1313 		int ret;
1314 
1315 		ret = bpf_jit_get_func_addr(fp, insn, extra_pass,
1316 					    &func, &func_addr_fixed);
1317 		if (ret < 0)
1318 			return -1;
1319 
1320 		REG_SET_SEEN(BPF_REG_5);
1321 		jit->seen |= SEEN_FUNC;
1322 		/* lgrl %w1,func */
1323 		EMIT6_PCREL_RILB(0xc4080000, REG_W1, _EMIT_CONST_U64(func));
1324 		if (__is_defined(CC_USING_EXPOLINE) && !nospec_disable) {
1325 			/* brasl %r14,__s390_indirect_jump_r1 */
1326 			EMIT6_PCREL_RILB(0xc0050000, REG_14, jit->r1_thunk_ip);
1327 		} else {
1328 			/* basr %r14,%w1 */
1329 			EMIT2(0x0d00, REG_14, REG_W1);
1330 		}
1331 		/* lgr %b0,%r2: load return value into %b0 */
1332 		EMIT4(0xb9040000, BPF_REG_0, REG_2);
1333 		break;
1334 	}
1335 	case BPF_JMP | BPF_TAIL_CALL: {
1336 		int patch_1_clrj, patch_2_clij, patch_3_brc;
1337 
1338 		/*
1339 		 * Implicit input:
1340 		 *  B1: pointer to ctx
1341 		 *  B2: pointer to bpf_array
1342 		 *  B3: index in bpf_array
1343 		 */
1344 		jit->seen |= SEEN_TAIL_CALL;
1345 
1346 		/*
1347 		 * if (index >= array->map.max_entries)
1348 		 *         goto out;
1349 		 */
1350 
1351 		/* llgf %w1,map.max_entries(%b2) */
1352 		EMIT6_DISP_LH(0xe3000000, 0x0016, REG_W1, REG_0, BPF_REG_2,
1353 			      offsetof(struct bpf_array, map.max_entries));
1354 		/* if ((u32)%b3 >= (u32)%w1) goto out; */
1355 		/* clrj %b3,%w1,0xa,out */
1356 		patch_1_clrj = jit->prg;
1357 		EMIT6_PCREL_RIEB(0xec000000, 0x0077, BPF_REG_3, REG_W1, 0xa,
1358 				 jit->prg);
1359 
1360 		/*
1361 		 * if (tail_call_cnt++ > MAX_TAIL_CALL_CNT)
1362 		 *         goto out;
1363 		 */
1364 
1365 		if (jit->seen & SEEN_STACK)
1366 			off = STK_OFF_TCCNT + STK_OFF + stack_depth;
1367 		else
1368 			off = STK_OFF_TCCNT;
1369 		/* lhi %w0,1 */
1370 		EMIT4_IMM(0xa7080000, REG_W0, 1);
1371 		/* laal %w1,%w0,off(%r15) */
1372 		EMIT6_DISP_LH(0xeb000000, 0x00fa, REG_W1, REG_W0, REG_15, off);
1373 		/* clij %w1,MAX_TAIL_CALL_CNT,0x2,out */
1374 		patch_2_clij = jit->prg;
1375 		EMIT6_PCREL_RIEC(0xec000000, 0x007f, REG_W1, MAX_TAIL_CALL_CNT,
1376 				 2, jit->prg);
1377 
1378 		/*
1379 		 * prog = array->ptrs[index];
1380 		 * if (prog == NULL)
1381 		 *         goto out;
1382 		 */
1383 
1384 		/* llgfr %r1,%b3: %r1 = (u32) index */
1385 		EMIT4(0xb9160000, REG_1, BPF_REG_3);
1386 		/* sllg %r1,%r1,3: %r1 *= 8 */
1387 		EMIT6_DISP_LH(0xeb000000, 0x000d, REG_1, REG_1, REG_0, 3);
1388 		/* ltg %r1,prog(%b2,%r1) */
1389 		EMIT6_DISP_LH(0xe3000000, 0x0002, REG_1, BPF_REG_2,
1390 			      REG_1, offsetof(struct bpf_array, ptrs));
1391 		/* brc 0x8,out */
1392 		patch_3_brc = jit->prg;
1393 		EMIT4_PCREL_RIC(0xa7040000, 8, jit->prg);
1394 
1395 		/*
1396 		 * Restore registers before calling function
1397 		 */
1398 		save_restore_regs(jit, REGS_RESTORE, stack_depth);
1399 
1400 		/*
1401 		 * goto *(prog->bpf_func + tail_call_start);
1402 		 */
1403 
1404 		/* lg %r1,bpf_func(%r1) */
1405 		EMIT6_DISP_LH(0xe3000000, 0x0004, REG_1, REG_1, REG_0,
1406 			      offsetof(struct bpf_prog, bpf_func));
1407 		/* bc 0xf,tail_call_start(%r1) */
1408 		_EMIT4(0x47f01000 + jit->tail_call_start);
1409 		/* out: */
1410 		if (jit->prg_buf) {
1411 			*(u16 *)(jit->prg_buf + patch_1_clrj + 2) =
1412 				(jit->prg - patch_1_clrj) >> 1;
1413 			*(u16 *)(jit->prg_buf + patch_2_clij + 2) =
1414 				(jit->prg - patch_2_clij) >> 1;
1415 			*(u16 *)(jit->prg_buf + patch_3_brc + 2) =
1416 				(jit->prg - patch_3_brc) >> 1;
1417 		}
1418 		break;
1419 	}
1420 	case BPF_JMP | BPF_EXIT: /* return b0 */
1421 		last = (i == fp->len - 1) ? 1 : 0;
1422 		if (last)
1423 			break;
1424 		if (!is_first_pass(jit) && can_use_rel(jit, jit->exit_ip))
1425 			/* brc 0xf, <exit> */
1426 			EMIT4_PCREL_RIC(0xa7040000, 0xf, jit->exit_ip);
1427 		else
1428 			/* brcl 0xf, <exit> */
1429 			EMIT6_PCREL_RILC(0xc0040000, 0xf, jit->exit_ip);
1430 		break;
1431 	/*
1432 	 * Branch relative (number of skipped instructions) to offset on
1433 	 * condition.
1434 	 *
1435 	 * Condition code to mask mapping:
1436 	 *
1437 	 * CC | Description	   | Mask
1438 	 * ------------------------------
1439 	 * 0  | Operands equal	   |	8
1440 	 * 1  | First operand low  |	4
1441 	 * 2  | First operand high |	2
1442 	 * 3  | Unused		   |	1
1443 	 *
1444 	 * For s390x relative branches: ip = ip + off_bytes
1445 	 * For BPF relative branches:	insn = insn + off_insns + 1
1446 	 *
1447 	 * For example for s390x with offset 0 we jump to the branch
1448 	 * instruction itself (loop) and for BPF with offset 0 we
1449 	 * branch to the instruction behind the branch.
1450 	 */
1451 	case BPF_JMP | BPF_JA: /* if (true) */
1452 		mask = 0xf000; /* j */
1453 		goto branch_oc;
1454 	case BPF_JMP | BPF_JSGT | BPF_K: /* ((s64) dst > (s64) imm) */
1455 	case BPF_JMP32 | BPF_JSGT | BPF_K: /* ((s32) dst > (s32) imm) */
1456 		mask = 0x2000; /* jh */
1457 		goto branch_ks;
1458 	case BPF_JMP | BPF_JSLT | BPF_K: /* ((s64) dst < (s64) imm) */
1459 	case BPF_JMP32 | BPF_JSLT | BPF_K: /* ((s32) dst < (s32) imm) */
1460 		mask = 0x4000; /* jl */
1461 		goto branch_ks;
1462 	case BPF_JMP | BPF_JSGE | BPF_K: /* ((s64) dst >= (s64) imm) */
1463 	case BPF_JMP32 | BPF_JSGE | BPF_K: /* ((s32) dst >= (s32) imm) */
1464 		mask = 0xa000; /* jhe */
1465 		goto branch_ks;
1466 	case BPF_JMP | BPF_JSLE | BPF_K: /* ((s64) dst <= (s64) imm) */
1467 	case BPF_JMP32 | BPF_JSLE | BPF_K: /* ((s32) dst <= (s32) imm) */
1468 		mask = 0xc000; /* jle */
1469 		goto branch_ks;
1470 	case BPF_JMP | BPF_JGT | BPF_K: /* (dst_reg > imm) */
1471 	case BPF_JMP32 | BPF_JGT | BPF_K: /* ((u32) dst_reg > (u32) imm) */
1472 		mask = 0x2000; /* jh */
1473 		goto branch_ku;
1474 	case BPF_JMP | BPF_JLT | BPF_K: /* (dst_reg < imm) */
1475 	case BPF_JMP32 | BPF_JLT | BPF_K: /* ((u32) dst_reg < (u32) imm) */
1476 		mask = 0x4000; /* jl */
1477 		goto branch_ku;
1478 	case BPF_JMP | BPF_JGE | BPF_K: /* (dst_reg >= imm) */
1479 	case BPF_JMP32 | BPF_JGE | BPF_K: /* ((u32) dst_reg >= (u32) imm) */
1480 		mask = 0xa000; /* jhe */
1481 		goto branch_ku;
1482 	case BPF_JMP | BPF_JLE | BPF_K: /* (dst_reg <= imm) */
1483 	case BPF_JMP32 | BPF_JLE | BPF_K: /* ((u32) dst_reg <= (u32) imm) */
1484 		mask = 0xc000; /* jle */
1485 		goto branch_ku;
1486 	case BPF_JMP | BPF_JNE | BPF_K: /* (dst_reg != imm) */
1487 	case BPF_JMP32 | BPF_JNE | BPF_K: /* ((u32) dst_reg != (u32) imm) */
1488 		mask = 0x7000; /* jne */
1489 		goto branch_ku;
1490 	case BPF_JMP | BPF_JEQ | BPF_K: /* (dst_reg == imm) */
1491 	case BPF_JMP32 | BPF_JEQ | BPF_K: /* ((u32) dst_reg == (u32) imm) */
1492 		mask = 0x8000; /* je */
1493 		goto branch_ku;
1494 	case BPF_JMP | BPF_JSET | BPF_K: /* (dst_reg & imm) */
1495 	case BPF_JMP32 | BPF_JSET | BPF_K: /* ((u32) dst_reg & (u32) imm) */
1496 		mask = 0x7000; /* jnz */
1497 		if (BPF_CLASS(insn->code) == BPF_JMP32) {
1498 			/* llilf %w1,imm (load zero extend imm) */
1499 			EMIT6_IMM(0xc00f0000, REG_W1, imm);
1500 			/* nr %w1,%dst */
1501 			EMIT2(0x1400, REG_W1, dst_reg);
1502 		} else {
1503 			/* lgfi %w1,imm (load sign extend imm) */
1504 			EMIT6_IMM(0xc0010000, REG_W1, imm);
1505 			/* ngr %w1,%dst */
1506 			EMIT4(0xb9800000, REG_W1, dst_reg);
1507 		}
1508 		goto branch_oc;
1509 
1510 	case BPF_JMP | BPF_JSGT | BPF_X: /* ((s64) dst > (s64) src) */
1511 	case BPF_JMP32 | BPF_JSGT | BPF_X: /* ((s32) dst > (s32) src) */
1512 		mask = 0x2000; /* jh */
1513 		goto branch_xs;
1514 	case BPF_JMP | BPF_JSLT | BPF_X: /* ((s64) dst < (s64) src) */
1515 	case BPF_JMP32 | BPF_JSLT | BPF_X: /* ((s32) dst < (s32) src) */
1516 		mask = 0x4000; /* jl */
1517 		goto branch_xs;
1518 	case BPF_JMP | BPF_JSGE | BPF_X: /* ((s64) dst >= (s64) src) */
1519 	case BPF_JMP32 | BPF_JSGE | BPF_X: /* ((s32) dst >= (s32) src) */
1520 		mask = 0xa000; /* jhe */
1521 		goto branch_xs;
1522 	case BPF_JMP | BPF_JSLE | BPF_X: /* ((s64) dst <= (s64) src) */
1523 	case BPF_JMP32 | BPF_JSLE | BPF_X: /* ((s32) dst <= (s32) src) */
1524 		mask = 0xc000; /* jle */
1525 		goto branch_xs;
1526 	case BPF_JMP | BPF_JGT | BPF_X: /* (dst > src) */
1527 	case BPF_JMP32 | BPF_JGT | BPF_X: /* ((u32) dst > (u32) src) */
1528 		mask = 0x2000; /* jh */
1529 		goto branch_xu;
1530 	case BPF_JMP | BPF_JLT | BPF_X: /* (dst < src) */
1531 	case BPF_JMP32 | BPF_JLT | BPF_X: /* ((u32) dst < (u32) src) */
1532 		mask = 0x4000; /* jl */
1533 		goto branch_xu;
1534 	case BPF_JMP | BPF_JGE | BPF_X: /* (dst >= src) */
1535 	case BPF_JMP32 | BPF_JGE | BPF_X: /* ((u32) dst >= (u32) src) */
1536 		mask = 0xa000; /* jhe */
1537 		goto branch_xu;
1538 	case BPF_JMP | BPF_JLE | BPF_X: /* (dst <= src) */
1539 	case BPF_JMP32 | BPF_JLE | BPF_X: /* ((u32) dst <= (u32) src) */
1540 		mask = 0xc000; /* jle */
1541 		goto branch_xu;
1542 	case BPF_JMP | BPF_JNE | BPF_X: /* (dst != src) */
1543 	case BPF_JMP32 | BPF_JNE | BPF_X: /* ((u32) dst != (u32) src) */
1544 		mask = 0x7000; /* jne */
1545 		goto branch_xu;
1546 	case BPF_JMP | BPF_JEQ | BPF_X: /* (dst == src) */
1547 	case BPF_JMP32 | BPF_JEQ | BPF_X: /* ((u32) dst == (u32) src) */
1548 		mask = 0x8000; /* je */
1549 		goto branch_xu;
1550 	case BPF_JMP | BPF_JSET | BPF_X: /* (dst & src) */
1551 	case BPF_JMP32 | BPF_JSET | BPF_X: /* ((u32) dst & (u32) src) */
1552 	{
1553 		bool is_jmp32 = BPF_CLASS(insn->code) == BPF_JMP32;
1554 
1555 		mask = 0x7000; /* jnz */
1556 		/* nrk or ngrk %w1,%dst,%src */
1557 		EMIT4_RRF((is_jmp32 ? 0xb9f40000 : 0xb9e40000),
1558 			  REG_W1, dst_reg, src_reg);
1559 		goto branch_oc;
1560 branch_ks:
1561 		is_jmp32 = BPF_CLASS(insn->code) == BPF_JMP32;
1562 		/* cfi or cgfi %dst,imm */
1563 		EMIT6_IMM(is_jmp32 ? 0xc20d0000 : 0xc20c0000,
1564 			  dst_reg, imm);
1565 		if (!is_first_pass(jit) &&
1566 		    can_use_rel(jit, addrs[i + off + 1])) {
1567 			/* brc mask,off */
1568 			EMIT4_PCREL_RIC(0xa7040000,
1569 					mask >> 12, addrs[i + off + 1]);
1570 		} else {
1571 			/* brcl mask,off */
1572 			EMIT6_PCREL_RILC(0xc0040000,
1573 					 mask >> 12, addrs[i + off + 1]);
1574 		}
1575 		break;
1576 branch_ku:
1577 		/* lgfi %w1,imm (load sign extend imm) */
1578 		src_reg = REG_1;
1579 		EMIT6_IMM(0xc0010000, src_reg, imm);
1580 		goto branch_xu;
1581 branch_xs:
1582 		is_jmp32 = BPF_CLASS(insn->code) == BPF_JMP32;
1583 		if (!is_first_pass(jit) &&
1584 		    can_use_rel(jit, addrs[i + off + 1])) {
1585 			/* crj or cgrj %dst,%src,mask,off */
1586 			EMIT6_PCREL(0xec000000, (is_jmp32 ? 0x0076 : 0x0064),
1587 				    dst_reg, src_reg, i, off, mask);
1588 		} else {
1589 			/* cr or cgr %dst,%src */
1590 			if (is_jmp32)
1591 				EMIT2(0x1900, dst_reg, src_reg);
1592 			else
1593 				EMIT4(0xb9200000, dst_reg, src_reg);
1594 			/* brcl mask,off */
1595 			EMIT6_PCREL_RILC(0xc0040000,
1596 					 mask >> 12, addrs[i + off + 1]);
1597 		}
1598 		break;
1599 branch_xu:
1600 		is_jmp32 = BPF_CLASS(insn->code) == BPF_JMP32;
1601 		if (!is_first_pass(jit) &&
1602 		    can_use_rel(jit, addrs[i + off + 1])) {
1603 			/* clrj or clgrj %dst,%src,mask,off */
1604 			EMIT6_PCREL(0xec000000, (is_jmp32 ? 0x0077 : 0x0065),
1605 				    dst_reg, src_reg, i, off, mask);
1606 		} else {
1607 			/* clr or clgr %dst,%src */
1608 			if (is_jmp32)
1609 				EMIT2(0x1500, dst_reg, src_reg);
1610 			else
1611 				EMIT4(0xb9210000, dst_reg, src_reg);
1612 			/* brcl mask,off */
1613 			EMIT6_PCREL_RILC(0xc0040000,
1614 					 mask >> 12, addrs[i + off + 1]);
1615 		}
1616 		break;
1617 branch_oc:
1618 		if (!is_first_pass(jit) &&
1619 		    can_use_rel(jit, addrs[i + off + 1])) {
1620 			/* brc mask,off */
1621 			EMIT4_PCREL_RIC(0xa7040000,
1622 					mask >> 12, addrs[i + off + 1]);
1623 		} else {
1624 			/* brcl mask,off */
1625 			EMIT6_PCREL_RILC(0xc0040000,
1626 					 mask >> 12, addrs[i + off + 1]);
1627 		}
1628 		break;
1629 	}
1630 	default: /* too complex, give up */
1631 		pr_err("Unknown opcode %02x\n", insn->code);
1632 		return -1;
1633 	}
1634 
1635 	if (probe_prg != -1) {
1636 		/*
1637 		 * Handlers of certain exceptions leave psw.addr pointing to
1638 		 * the instruction directly after the failing one. Therefore,
1639 		 * create two exception table entries and also add a nop in
1640 		 * case two probing instructions come directly after each
1641 		 * other.
1642 		 */
1643 		nop_prg = jit->prg;
1644 		/* bcr 0,%0 */
1645 		_EMIT2(0x0700);
1646 		err = bpf_jit_probe_mem(jit, fp, probe_prg, nop_prg);
1647 		if (err < 0)
1648 			return err;
1649 	}
1650 
1651 	return insn_count;
1652 }
1653 
1654 /*
1655  * Return whether new i-th instruction address does not violate any invariant
1656  */
bpf_is_new_addr_sane(struct bpf_jit * jit,int i)1657 static bool bpf_is_new_addr_sane(struct bpf_jit *jit, int i)
1658 {
1659 	/* On the first pass anything goes */
1660 	if (is_first_pass(jit))
1661 		return true;
1662 
1663 	/* The codegen pass must not change anything */
1664 	if (is_codegen_pass(jit))
1665 		return jit->addrs[i] == jit->prg;
1666 
1667 	/* Passes in between must not increase code size */
1668 	return jit->addrs[i] >= jit->prg;
1669 }
1670 
1671 /*
1672  * Update the address of i-th instruction
1673  */
bpf_set_addr(struct bpf_jit * jit,int i)1674 static int bpf_set_addr(struct bpf_jit *jit, int i)
1675 {
1676 	int delta;
1677 
1678 	if (is_codegen_pass(jit)) {
1679 		delta = jit->prg - jit->addrs[i];
1680 		if (delta < 0)
1681 			bpf_skip(jit, -delta);
1682 	}
1683 	if (WARN_ON_ONCE(!bpf_is_new_addr_sane(jit, i)))
1684 		return -1;
1685 	jit->addrs[i] = jit->prg;
1686 	return 0;
1687 }
1688 
1689 /*
1690  * Compile eBPF program into s390x code
1691  */
bpf_jit_prog(struct bpf_jit * jit,struct bpf_prog * fp,bool extra_pass,u32 stack_depth)1692 static int bpf_jit_prog(struct bpf_jit *jit, struct bpf_prog *fp,
1693 			bool extra_pass, u32 stack_depth)
1694 {
1695 	int i, insn_count, lit32_size, lit64_size;
1696 
1697 	jit->lit32 = jit->lit32_start;
1698 	jit->lit64 = jit->lit64_start;
1699 	jit->prg = 0;
1700 	jit->excnt = 0;
1701 
1702 	bpf_jit_prologue(jit, stack_depth);
1703 	if (bpf_set_addr(jit, 0) < 0)
1704 		return -1;
1705 	for (i = 0; i < fp->len; i += insn_count) {
1706 		insn_count = bpf_jit_insn(jit, fp, i, extra_pass, stack_depth);
1707 		if (insn_count < 0)
1708 			return -1;
1709 		/* Next instruction address */
1710 		if (bpf_set_addr(jit, i + insn_count) < 0)
1711 			return -1;
1712 	}
1713 	bpf_jit_epilogue(jit, stack_depth);
1714 
1715 	lit32_size = jit->lit32 - jit->lit32_start;
1716 	lit64_size = jit->lit64 - jit->lit64_start;
1717 	jit->lit32_start = jit->prg;
1718 	if (lit32_size)
1719 		jit->lit32_start = ALIGN(jit->lit32_start, 4);
1720 	jit->lit64_start = jit->lit32_start + lit32_size;
1721 	if (lit64_size)
1722 		jit->lit64_start = ALIGN(jit->lit64_start, 8);
1723 	jit->size = jit->lit64_start + lit64_size;
1724 	jit->size_prg = jit->prg;
1725 
1726 	if (WARN_ON_ONCE(fp->aux->extable &&
1727 			 jit->excnt != fp->aux->num_exentries))
1728 		/* Verifier bug - too many entries. */
1729 		return -1;
1730 
1731 	return 0;
1732 }
1733 
bpf_jit_needs_zext(void)1734 bool bpf_jit_needs_zext(void)
1735 {
1736 	return true;
1737 }
1738 
1739 struct s390_jit_data {
1740 	struct bpf_binary_header *header;
1741 	struct bpf_jit ctx;
1742 	int pass;
1743 };
1744 
bpf_jit_alloc(struct bpf_jit * jit,struct bpf_prog * fp)1745 static struct bpf_binary_header *bpf_jit_alloc(struct bpf_jit *jit,
1746 					       struct bpf_prog *fp)
1747 {
1748 	struct bpf_binary_header *header;
1749 	u32 extable_size;
1750 	u32 code_size;
1751 
1752 	/* We need two entries per insn. */
1753 	fp->aux->num_exentries *= 2;
1754 
1755 	code_size = roundup(jit->size,
1756 			    __alignof__(struct exception_table_entry));
1757 	extable_size = fp->aux->num_exentries *
1758 		sizeof(struct exception_table_entry);
1759 	header = bpf_jit_binary_alloc(code_size + extable_size, &jit->prg_buf,
1760 				      8, jit_fill_hole);
1761 	if (!header)
1762 		return NULL;
1763 	fp->aux->extable = (struct exception_table_entry *)
1764 		(jit->prg_buf + code_size);
1765 	return header;
1766 }
1767 
1768 /*
1769  * Compile eBPF program "fp"
1770  */
bpf_int_jit_compile(struct bpf_prog * fp)1771 struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp)
1772 {
1773 	u32 stack_depth = round_up(fp->aux->stack_depth, 8);
1774 	struct bpf_prog *tmp, *orig_fp = fp;
1775 	struct bpf_binary_header *header;
1776 	struct s390_jit_data *jit_data;
1777 	bool tmp_blinded = false;
1778 	bool extra_pass = false;
1779 	struct bpf_jit jit;
1780 	int pass;
1781 
1782 	if (!fp->jit_requested)
1783 		return orig_fp;
1784 
1785 	tmp = bpf_jit_blind_constants(fp);
1786 	/*
1787 	 * If blinding was requested and we failed during blinding,
1788 	 * we must fall back to the interpreter.
1789 	 */
1790 	if (IS_ERR(tmp))
1791 		return orig_fp;
1792 	if (tmp != fp) {
1793 		tmp_blinded = true;
1794 		fp = tmp;
1795 	}
1796 
1797 	jit_data = fp->aux->jit_data;
1798 	if (!jit_data) {
1799 		jit_data = kzalloc(sizeof(*jit_data), GFP_KERNEL);
1800 		if (!jit_data) {
1801 			fp = orig_fp;
1802 			goto out;
1803 		}
1804 		fp->aux->jit_data = jit_data;
1805 	}
1806 	if (jit_data->ctx.addrs) {
1807 		jit = jit_data->ctx;
1808 		header = jit_data->header;
1809 		extra_pass = true;
1810 		pass = jit_data->pass + 1;
1811 		goto skip_init_ctx;
1812 	}
1813 
1814 	memset(&jit, 0, sizeof(jit));
1815 	jit.addrs = kvcalloc(fp->len + 1, sizeof(*jit.addrs), GFP_KERNEL);
1816 	if (jit.addrs == NULL) {
1817 		fp = orig_fp;
1818 		goto out;
1819 	}
1820 	/*
1821 	 * Three initial passes:
1822 	 *   - 1/2: Determine clobbered registers
1823 	 *   - 3:   Calculate program size and addrs arrray
1824 	 */
1825 	for (pass = 1; pass <= 3; pass++) {
1826 		if (bpf_jit_prog(&jit, fp, extra_pass, stack_depth)) {
1827 			fp = orig_fp;
1828 			goto free_addrs;
1829 		}
1830 	}
1831 	/*
1832 	 * Final pass: Allocate and generate program
1833 	 */
1834 	header = bpf_jit_alloc(&jit, fp);
1835 	if (!header) {
1836 		fp = orig_fp;
1837 		goto free_addrs;
1838 	}
1839 skip_init_ctx:
1840 	if (bpf_jit_prog(&jit, fp, extra_pass, stack_depth)) {
1841 		bpf_jit_binary_free(header);
1842 		fp = orig_fp;
1843 		goto free_addrs;
1844 	}
1845 	if (bpf_jit_enable > 1) {
1846 		bpf_jit_dump(fp->len, jit.size, pass, jit.prg_buf);
1847 		print_fn_code(jit.prg_buf, jit.size_prg);
1848 	}
1849 	if (!fp->is_func || extra_pass) {
1850 		bpf_jit_binary_lock_ro(header);
1851 	} else {
1852 		jit_data->header = header;
1853 		jit_data->ctx = jit;
1854 		jit_data->pass = pass;
1855 	}
1856 	fp->bpf_func = (void *) jit.prg_buf;
1857 	fp->jited = 1;
1858 	fp->jited_len = jit.size;
1859 
1860 	if (!fp->is_func || extra_pass) {
1861 		bpf_prog_fill_jited_linfo(fp, jit.addrs + 1);
1862 free_addrs:
1863 		kvfree(jit.addrs);
1864 		kfree(jit_data);
1865 		fp->aux->jit_data = NULL;
1866 	}
1867 out:
1868 	if (tmp_blinded)
1869 		bpf_jit_prog_release_other(fp, fp == orig_fp ?
1870 					   tmp : orig_fp);
1871 	return fp;
1872 }
1873