bpf_jit_comp.c 32 KB

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  1. /*
  2. * BPF Jit compiler for s390.
  3. *
  4. * Minimum build requirements:
  5. *
  6. * - HAVE_MARCH_Z196_FEATURES: laal, laalg
  7. * - HAVE_MARCH_Z10_FEATURES: msfi, cgrj, clgrj
  8. * - HAVE_MARCH_Z9_109_FEATURES: alfi, llilf, clfi, oilf, nilf
  9. * - PACK_STACK
  10. * - 64BIT
  11. *
  12. * Copyright IBM Corp. 2012,2015
  13. *
  14. * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
  15. * Michael Holzheu <holzheu@linux.vnet.ibm.com>
  16. */
  17. #define KMSG_COMPONENT "bpf_jit"
  18. #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  19. #include <linux/netdevice.h>
  20. #include <linux/filter.h>
  21. #include <linux/init.h>
  22. #include <asm/cacheflush.h>
  23. #include <asm/dis.h>
  24. #include "bpf_jit.h"
  25. int bpf_jit_enable __read_mostly;
  26. struct bpf_jit {
  27. u32 seen; /* Flags to remember seen eBPF instructions */
  28. u32 seen_reg[16]; /* Array to remember which registers are used */
  29. u32 *addrs; /* Array with relative instruction addresses */
  30. u8 *prg_buf; /* Start of program */
  31. int size; /* Size of program and literal pool */
  32. int size_prg; /* Size of program */
  33. int prg; /* Current position in program */
  34. int lit_start; /* Start of literal pool */
  35. int lit; /* Current position in literal pool */
  36. int base_ip; /* Base address for literal pool */
  37. int ret0_ip; /* Address of return 0 */
  38. int exit_ip; /* Address of exit */
  39. };
  40. #define BPF_SIZE_MAX 4096 /* Max size for program */
  41. #define SEEN_SKB 1 /* skb access */
  42. #define SEEN_MEM 2 /* use mem[] for temporary storage */
  43. #define SEEN_RET0 4 /* ret0_ip points to a valid return 0 */
  44. #define SEEN_LITERAL 8 /* code uses literals */
  45. #define SEEN_FUNC 16 /* calls C functions */
  46. #define SEEN_STACK (SEEN_FUNC | SEEN_MEM | SEEN_SKB)
  47. /*
  48. * s390 registers
  49. */
  50. #define REG_W0 (__MAX_BPF_REG+0) /* Work register 1 (even) */
  51. #define REG_W1 (__MAX_BPF_REG+1) /* Work register 2 (odd) */
  52. #define REG_SKB_DATA (__MAX_BPF_REG+2) /* SKB data register */
  53. #define REG_L (__MAX_BPF_REG+3) /* Literal pool register */
  54. #define REG_15 (__MAX_BPF_REG+4) /* Register 15 */
  55. #define REG_0 REG_W0 /* Register 0 */
  56. #define REG_2 BPF_REG_1 /* Register 2 */
  57. #define REG_14 BPF_REG_0 /* Register 14 */
  58. /*
  59. * Mapping of BPF registers to s390 registers
  60. */
  61. static const int reg2hex[] = {
  62. /* Return code */
  63. [BPF_REG_0] = 14,
  64. /* Function parameters */
  65. [BPF_REG_1] = 2,
  66. [BPF_REG_2] = 3,
  67. [BPF_REG_3] = 4,
  68. [BPF_REG_4] = 5,
  69. [BPF_REG_5] = 6,
  70. /* Call saved registers */
  71. [BPF_REG_6] = 7,
  72. [BPF_REG_7] = 8,
  73. [BPF_REG_8] = 9,
  74. [BPF_REG_9] = 10,
  75. /* BPF stack pointer */
  76. [BPF_REG_FP] = 13,
  77. /* SKB data pointer */
  78. [REG_SKB_DATA] = 12,
  79. /* Work registers for s390x backend */
  80. [REG_W0] = 0,
  81. [REG_W1] = 1,
  82. [REG_L] = 11,
  83. [REG_15] = 15,
  84. };
  85. static inline u32 reg(u32 dst_reg, u32 src_reg)
  86. {
  87. return reg2hex[dst_reg] << 4 | reg2hex[src_reg];
  88. }
  89. static inline u32 reg_high(u32 reg)
  90. {
  91. return reg2hex[reg] << 4;
  92. }
  93. static inline void reg_set_seen(struct bpf_jit *jit, u32 b1)
  94. {
  95. u32 r1 = reg2hex[b1];
  96. if (!jit->seen_reg[r1] && r1 >= 6 && r1 <= 15)
  97. jit->seen_reg[r1] = 1;
  98. }
  99. #define REG_SET_SEEN(b1) \
  100. ({ \
  101. reg_set_seen(jit, b1); \
  102. })
  103. #define REG_SEEN(b1) jit->seen_reg[reg2hex[(b1)]]
  104. /*
  105. * EMIT macros for code generation
  106. */
  107. #define _EMIT2(op) \
  108. ({ \
  109. if (jit->prg_buf) \
  110. *(u16 *) (jit->prg_buf + jit->prg) = op; \
  111. jit->prg += 2; \
  112. })
  113. #define EMIT2(op, b1, b2) \
  114. ({ \
  115. _EMIT2(op | reg(b1, b2)); \
  116. REG_SET_SEEN(b1); \
  117. REG_SET_SEEN(b2); \
  118. })
  119. #define _EMIT4(op) \
  120. ({ \
  121. if (jit->prg_buf) \
  122. *(u32 *) (jit->prg_buf + jit->prg) = op; \
  123. jit->prg += 4; \
  124. })
  125. #define EMIT4(op, b1, b2) \
  126. ({ \
  127. _EMIT4(op | reg(b1, b2)); \
  128. REG_SET_SEEN(b1); \
  129. REG_SET_SEEN(b2); \
  130. })
  131. #define EMIT4_RRF(op, b1, b2, b3) \
  132. ({ \
  133. _EMIT4(op | reg_high(b3) << 8 | reg(b1, b2)); \
  134. REG_SET_SEEN(b1); \
  135. REG_SET_SEEN(b2); \
  136. REG_SET_SEEN(b3); \
  137. })
  138. #define _EMIT4_DISP(op, disp) \
  139. ({ \
  140. unsigned int __disp = (disp) & 0xfff; \
  141. _EMIT4(op | __disp); \
  142. })
  143. #define EMIT4_DISP(op, b1, b2, disp) \
  144. ({ \
  145. _EMIT4_DISP(op | reg_high(b1) << 16 | \
  146. reg_high(b2) << 8, disp); \
  147. REG_SET_SEEN(b1); \
  148. REG_SET_SEEN(b2); \
  149. })
  150. #define EMIT4_IMM(op, b1, imm) \
  151. ({ \
  152. unsigned int __imm = (imm) & 0xffff; \
  153. _EMIT4(op | reg_high(b1) << 16 | __imm); \
  154. REG_SET_SEEN(b1); \
  155. })
  156. #define EMIT4_PCREL(op, pcrel) \
  157. ({ \
  158. long __pcrel = ((pcrel) >> 1) & 0xffff; \
  159. _EMIT4(op | __pcrel); \
  160. })
  161. #define _EMIT6(op1, op2) \
  162. ({ \
  163. if (jit->prg_buf) { \
  164. *(u32 *) (jit->prg_buf + jit->prg) = op1; \
  165. *(u16 *) (jit->prg_buf + jit->prg + 4) = op2; \
  166. } \
  167. jit->prg += 6; \
  168. })
  169. #define _EMIT6_DISP(op1, op2, disp) \
  170. ({ \
  171. unsigned int __disp = (disp) & 0xfff; \
  172. _EMIT6(op1 | __disp, op2); \
  173. })
  174. #define EMIT6_DISP(op1, op2, b1, b2, b3, disp) \
  175. ({ \
  176. _EMIT6_DISP(op1 | reg(b1, b2) << 16 | \
  177. reg_high(b3) << 8, op2, disp); \
  178. REG_SET_SEEN(b1); \
  179. REG_SET_SEEN(b2); \
  180. REG_SET_SEEN(b3); \
  181. })
  182. #define _EMIT6_DISP_LH(op1, op2, disp) \
  183. ({ \
  184. unsigned int __disp_h = ((u32)disp) & 0xff000; \
  185. unsigned int __disp_l = ((u32)disp) & 0x00fff; \
  186. _EMIT6(op1 | __disp_l, op2 | __disp_h >> 4); \
  187. })
  188. #define EMIT6_DISP_LH(op1, op2, b1, b2, b3, disp) \
  189. ({ \
  190. _EMIT6_DISP_LH(op1 | reg(b1, b2) << 16 | \
  191. reg_high(b3) << 8, op2, disp); \
  192. REG_SET_SEEN(b1); \
  193. REG_SET_SEEN(b2); \
  194. REG_SET_SEEN(b3); \
  195. })
  196. #define EMIT6_PCREL(op1, op2, b1, b2, i, off, mask) \
  197. ({ \
  198. /* Branch instruction needs 6 bytes */ \
  199. int rel = (addrs[i + off + 1] - (addrs[i + 1] - 6)) / 2;\
  200. _EMIT6(op1 | reg(b1, b2) << 16 | rel, op2 | mask); \
  201. REG_SET_SEEN(b1); \
  202. REG_SET_SEEN(b2); \
  203. })
  204. #define _EMIT6_IMM(op, imm) \
  205. ({ \
  206. unsigned int __imm = (imm); \
  207. _EMIT6(op | (__imm >> 16), __imm & 0xffff); \
  208. })
  209. #define EMIT6_IMM(op, b1, imm) \
  210. ({ \
  211. _EMIT6_IMM(op | reg_high(b1) << 16, imm); \
  212. REG_SET_SEEN(b1); \
  213. })
  214. #define EMIT_CONST_U32(val) \
  215. ({ \
  216. unsigned int ret; \
  217. ret = jit->lit - jit->base_ip; \
  218. jit->seen |= SEEN_LITERAL; \
  219. if (jit->prg_buf) \
  220. *(u32 *) (jit->prg_buf + jit->lit) = (u32) val; \
  221. jit->lit += 4; \
  222. ret; \
  223. })
  224. #define EMIT_CONST_U64(val) \
  225. ({ \
  226. unsigned int ret; \
  227. ret = jit->lit - jit->base_ip; \
  228. jit->seen |= SEEN_LITERAL; \
  229. if (jit->prg_buf) \
  230. *(u64 *) (jit->prg_buf + jit->lit) = (u64) val; \
  231. jit->lit += 8; \
  232. ret; \
  233. })
  234. #define EMIT_ZERO(b1) \
  235. ({ \
  236. /* llgfr %dst,%dst (zero extend to 64 bit) */ \
  237. EMIT4(0xb9160000, b1, b1); \
  238. REG_SET_SEEN(b1); \
  239. })
  240. /*
  241. * Fill whole space with illegal instructions
  242. */
  243. static void jit_fill_hole(void *area, unsigned int size)
  244. {
  245. memset(area, 0, size);
  246. }
  247. /*
  248. * Save registers from "rs" (register start) to "re" (register end) on stack
  249. */
  250. static void save_regs(struct bpf_jit *jit, u32 rs, u32 re)
  251. {
  252. u32 off = 72 + (rs - 6) * 8;
  253. if (rs == re)
  254. /* stg %rs,off(%r15) */
  255. _EMIT6(0xe300f000 | rs << 20 | off, 0x0024);
  256. else
  257. /* stmg %rs,%re,off(%r15) */
  258. _EMIT6_DISP(0xeb00f000 | rs << 20 | re << 16, 0x0024, off);
  259. }
  260. /*
  261. * Restore registers from "rs" (register start) to "re" (register end) on stack
  262. */
  263. static void restore_regs(struct bpf_jit *jit, u32 rs, u32 re)
  264. {
  265. u32 off = 72 + (rs - 6) * 8;
  266. if (jit->seen & SEEN_STACK)
  267. off += STK_OFF;
  268. if (rs == re)
  269. /* lg %rs,off(%r15) */
  270. _EMIT6(0xe300f000 | rs << 20 | off, 0x0004);
  271. else
  272. /* lmg %rs,%re,off(%r15) */
  273. _EMIT6_DISP(0xeb00f000 | rs << 20 | re << 16, 0x0004, off);
  274. }
  275. /*
  276. * Return first seen register (from start)
  277. */
  278. static int get_start(struct bpf_jit *jit, int start)
  279. {
  280. int i;
  281. for (i = start; i <= 15; i++) {
  282. if (jit->seen_reg[i])
  283. return i;
  284. }
  285. return 0;
  286. }
  287. /*
  288. * Return last seen register (from start) (gap >= 2)
  289. */
  290. static int get_end(struct bpf_jit *jit, int start)
  291. {
  292. int i;
  293. for (i = start; i < 15; i++) {
  294. if (!jit->seen_reg[i] && !jit->seen_reg[i + 1])
  295. return i - 1;
  296. }
  297. return jit->seen_reg[15] ? 15 : 14;
  298. }
  299. #define REGS_SAVE 1
  300. #define REGS_RESTORE 0
  301. /*
  302. * Save and restore clobbered registers (6-15) on stack.
  303. * We save/restore registers in chunks with gap >= 2 registers.
  304. */
  305. static void save_restore_regs(struct bpf_jit *jit, int op)
  306. {
  307. int re = 6, rs;
  308. do {
  309. rs = get_start(jit, re);
  310. if (!rs)
  311. break;
  312. re = get_end(jit, rs + 1);
  313. if (op == REGS_SAVE)
  314. save_regs(jit, rs, re);
  315. else
  316. restore_regs(jit, rs, re);
  317. re++;
  318. } while (re <= 15);
  319. }
  320. /*
  321. * Emit function prologue
  322. *
  323. * Save registers and create stack frame if necessary.
  324. * See stack frame layout desription in "bpf_jit.h"!
  325. */
  326. static void bpf_jit_prologue(struct bpf_jit *jit)
  327. {
  328. /* Save registers */
  329. save_restore_regs(jit, REGS_SAVE);
  330. /* Setup literal pool */
  331. if (jit->seen & SEEN_LITERAL) {
  332. /* basr %r13,0 */
  333. EMIT2(0x0d00, REG_L, REG_0);
  334. jit->base_ip = jit->prg;
  335. }
  336. /* Setup stack and backchain */
  337. if (jit->seen & SEEN_STACK) {
  338. /* lgr %bfp,%r15 (BPF frame pointer) */
  339. EMIT4(0xb9040000, BPF_REG_FP, REG_15);
  340. /* aghi %r15,-STK_OFF */
  341. EMIT4_IMM(0xa70b0000, REG_15, -STK_OFF);
  342. if (jit->seen & SEEN_FUNC)
  343. /* stg %bfp,152(%r15) (backchain) */
  344. EMIT6_DISP_LH(0xe3000000, 0x0024, BPF_REG_FP, REG_0,
  345. REG_15, 152);
  346. }
  347. /*
  348. * For SKB access %b1 contains the SKB pointer. For "bpf_jit.S"
  349. * we store the SKB header length on the stack and the SKB data
  350. * pointer in REG_SKB_DATA.
  351. */
  352. if (jit->seen & SEEN_SKB) {
  353. /* Header length: llgf %w1,<len>(%b1) */
  354. EMIT6_DISP_LH(0xe3000000, 0x0016, REG_W1, REG_0, BPF_REG_1,
  355. offsetof(struct sk_buff, len));
  356. /* s %w1,<data_len>(%b1) */
  357. EMIT4_DISP(0x5b000000, REG_W1, BPF_REG_1,
  358. offsetof(struct sk_buff, data_len));
  359. /* stg %w1,ST_OFF_HLEN(%r0,%r15) */
  360. EMIT6_DISP_LH(0xe3000000, 0x0024, REG_W1, REG_0, REG_15,
  361. STK_OFF_HLEN);
  362. /* lg %skb_data,data_off(%b1) */
  363. EMIT6_DISP_LH(0xe3000000, 0x0004, REG_SKB_DATA, REG_0,
  364. BPF_REG_1, offsetof(struct sk_buff, data));
  365. }
  366. /* BPF compatibility: clear A (%b7) and X (%b8) registers */
  367. if (REG_SEEN(BPF_REG_7))
  368. /* lghi %b7,0 */
  369. EMIT4_IMM(0xa7090000, BPF_REG_7, 0);
  370. if (REG_SEEN(BPF_REG_8))
  371. /* lghi %b8,0 */
  372. EMIT4_IMM(0xa7090000, BPF_REG_8, 0);
  373. }
  374. /*
  375. * Function epilogue
  376. */
  377. static void bpf_jit_epilogue(struct bpf_jit *jit)
  378. {
  379. /* Return 0 */
  380. if (jit->seen & SEEN_RET0) {
  381. jit->ret0_ip = jit->prg;
  382. /* lghi %b0,0 */
  383. EMIT4_IMM(0xa7090000, BPF_REG_0, 0);
  384. }
  385. jit->exit_ip = jit->prg;
  386. /* Load exit code: lgr %r2,%b0 */
  387. EMIT4(0xb9040000, REG_2, BPF_REG_0);
  388. /* Restore registers */
  389. save_restore_regs(jit, REGS_RESTORE);
  390. /* br %r14 */
  391. _EMIT2(0x07fe);
  392. }
  393. /*
  394. * Compile one eBPF instruction into s390x code
  395. *
  396. * NOTE: Use noinline because for gcov (-fprofile-arcs) gcc allocates a lot of
  397. * stack space for the large switch statement.
  398. */
  399. static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, int i)
  400. {
  401. struct bpf_insn *insn = &fp->insnsi[i];
  402. int jmp_off, last, insn_count = 1;
  403. unsigned int func_addr, mask;
  404. u32 dst_reg = insn->dst_reg;
  405. u32 src_reg = insn->src_reg;
  406. u32 *addrs = jit->addrs;
  407. s32 imm = insn->imm;
  408. s16 off = insn->off;
  409. switch (insn->code) {
  410. /*
  411. * BPF_MOV
  412. */
  413. case BPF_ALU | BPF_MOV | BPF_X: /* dst = (u32) src */
  414. /* llgfr %dst,%src */
  415. EMIT4(0xb9160000, dst_reg, src_reg);
  416. break;
  417. case BPF_ALU64 | BPF_MOV | BPF_X: /* dst = src */
  418. /* lgr %dst,%src */
  419. EMIT4(0xb9040000, dst_reg, src_reg);
  420. break;
  421. case BPF_ALU | BPF_MOV | BPF_K: /* dst = (u32) imm */
  422. /* llilf %dst,imm */
  423. EMIT6_IMM(0xc00f0000, dst_reg, imm);
  424. break;
  425. case BPF_ALU64 | BPF_MOV | BPF_K: /* dst = imm */
  426. /* lgfi %dst,imm */
  427. EMIT6_IMM(0xc0010000, dst_reg, imm);
  428. break;
  429. /*
  430. * BPF_LD 64
  431. */
  432. case BPF_LD | BPF_IMM | BPF_DW: /* dst = (u64) imm */
  433. {
  434. /* 16 byte instruction that uses two 'struct bpf_insn' */
  435. u64 imm64;
  436. imm64 = (u64)(u32) insn[0].imm | ((u64)(u32) insn[1].imm) << 32;
  437. /* lg %dst,<d(imm)>(%l) */
  438. EMIT6_DISP_LH(0xe3000000, 0x0004, dst_reg, REG_0, REG_L,
  439. EMIT_CONST_U64(imm64));
  440. insn_count = 2;
  441. break;
  442. }
  443. /*
  444. * BPF_ADD
  445. */
  446. case BPF_ALU | BPF_ADD | BPF_X: /* dst = (u32) dst + (u32) src */
  447. /* ar %dst,%src */
  448. EMIT2(0x1a00, dst_reg, src_reg);
  449. EMIT_ZERO(dst_reg);
  450. break;
  451. case BPF_ALU64 | BPF_ADD | BPF_X: /* dst = dst + src */
  452. /* agr %dst,%src */
  453. EMIT4(0xb9080000, dst_reg, src_reg);
  454. break;
  455. case BPF_ALU | BPF_ADD | BPF_K: /* dst = (u32) dst + (u32) imm */
  456. if (!imm)
  457. break;
  458. /* alfi %dst,imm */
  459. EMIT6_IMM(0xc20b0000, dst_reg, imm);
  460. EMIT_ZERO(dst_reg);
  461. break;
  462. case BPF_ALU64 | BPF_ADD | BPF_K: /* dst = dst + imm */
  463. if (!imm)
  464. break;
  465. /* agfi %dst,imm */
  466. EMIT6_IMM(0xc2080000, dst_reg, imm);
  467. break;
  468. /*
  469. * BPF_SUB
  470. */
  471. case BPF_ALU | BPF_SUB | BPF_X: /* dst = (u32) dst - (u32) src */
  472. /* sr %dst,%src */
  473. EMIT2(0x1b00, dst_reg, src_reg);
  474. EMIT_ZERO(dst_reg);
  475. break;
  476. case BPF_ALU64 | BPF_SUB | BPF_X: /* dst = dst - src */
  477. /* sgr %dst,%src */
  478. EMIT4(0xb9090000, dst_reg, src_reg);
  479. break;
  480. case BPF_ALU | BPF_SUB | BPF_K: /* dst = (u32) dst - (u32) imm */
  481. if (!imm)
  482. break;
  483. /* alfi %dst,-imm */
  484. EMIT6_IMM(0xc20b0000, dst_reg, -imm);
  485. EMIT_ZERO(dst_reg);
  486. break;
  487. case BPF_ALU64 | BPF_SUB | BPF_K: /* dst = dst - imm */
  488. if (!imm)
  489. break;
  490. /* agfi %dst,-imm */
  491. EMIT6_IMM(0xc2080000, dst_reg, -imm);
  492. break;
  493. /*
  494. * BPF_MUL
  495. */
  496. case BPF_ALU | BPF_MUL | BPF_X: /* dst = (u32) dst * (u32) src */
  497. /* msr %dst,%src */
  498. EMIT4(0xb2520000, dst_reg, src_reg);
  499. EMIT_ZERO(dst_reg);
  500. break;
  501. case BPF_ALU64 | BPF_MUL | BPF_X: /* dst = dst * src */
  502. /* msgr %dst,%src */
  503. EMIT4(0xb90c0000, dst_reg, src_reg);
  504. break;
  505. case BPF_ALU | BPF_MUL | BPF_K: /* dst = (u32) dst * (u32) imm */
  506. if (imm == 1)
  507. break;
  508. /* msfi %r5,imm */
  509. EMIT6_IMM(0xc2010000, dst_reg, imm);
  510. EMIT_ZERO(dst_reg);
  511. break;
  512. case BPF_ALU64 | BPF_MUL | BPF_K: /* dst = dst * imm */
  513. if (imm == 1)
  514. break;
  515. /* msgfi %dst,imm */
  516. EMIT6_IMM(0xc2000000, dst_reg, imm);
  517. break;
  518. /*
  519. * BPF_DIV / BPF_MOD
  520. */
  521. case BPF_ALU | BPF_DIV | BPF_X: /* dst = (u32) dst / (u32) src */
  522. case BPF_ALU | BPF_MOD | BPF_X: /* dst = (u32) dst % (u32) src */
  523. {
  524. int rc_reg = BPF_OP(insn->code) == BPF_DIV ? REG_W1 : REG_W0;
  525. jit->seen |= SEEN_RET0;
  526. /* ltr %src,%src (if src == 0 goto fail) */
  527. EMIT2(0x1200, src_reg, src_reg);
  528. /* jz <ret0> */
  529. EMIT4_PCREL(0xa7840000, jit->ret0_ip - jit->prg);
  530. /* lhi %w0,0 */
  531. EMIT4_IMM(0xa7080000, REG_W0, 0);
  532. /* lr %w1,%dst */
  533. EMIT2(0x1800, REG_W1, dst_reg);
  534. /* dlr %w0,%src */
  535. EMIT4(0xb9970000, REG_W0, src_reg);
  536. /* llgfr %dst,%rc */
  537. EMIT4(0xb9160000, dst_reg, rc_reg);
  538. break;
  539. }
  540. case BPF_ALU64 | BPF_DIV | BPF_X: /* dst = dst / src */
  541. case BPF_ALU64 | BPF_MOD | BPF_X: /* dst = dst % src */
  542. {
  543. int rc_reg = BPF_OP(insn->code) == BPF_DIV ? REG_W1 : REG_W0;
  544. jit->seen |= SEEN_RET0;
  545. /* ltgr %src,%src (if src == 0 goto fail) */
  546. EMIT4(0xb9020000, src_reg, src_reg);
  547. /* jz <ret0> */
  548. EMIT4_PCREL(0xa7840000, jit->ret0_ip - jit->prg);
  549. /* lghi %w0,0 */
  550. EMIT4_IMM(0xa7090000, REG_W0, 0);
  551. /* lgr %w1,%dst */
  552. EMIT4(0xb9040000, REG_W1, dst_reg);
  553. /* dlgr %w0,%dst */
  554. EMIT4(0xb9870000, REG_W0, src_reg);
  555. /* lgr %dst,%rc */
  556. EMIT4(0xb9040000, dst_reg, rc_reg);
  557. break;
  558. }
  559. case BPF_ALU | BPF_DIV | BPF_K: /* dst = (u32) dst / (u32) imm */
  560. case BPF_ALU | BPF_MOD | BPF_K: /* dst = (u32) dst % (u32) imm */
  561. {
  562. int rc_reg = BPF_OP(insn->code) == BPF_DIV ? REG_W1 : REG_W0;
  563. if (imm == 1) {
  564. if (BPF_OP(insn->code) == BPF_MOD)
  565. /* lhgi %dst,0 */
  566. EMIT4_IMM(0xa7090000, dst_reg, 0);
  567. break;
  568. }
  569. /* lhi %w0,0 */
  570. EMIT4_IMM(0xa7080000, REG_W0, 0);
  571. /* lr %w1,%dst */
  572. EMIT2(0x1800, REG_W1, dst_reg);
  573. /* dl %w0,<d(imm)>(%l) */
  574. EMIT6_DISP_LH(0xe3000000, 0x0097, REG_W0, REG_0, REG_L,
  575. EMIT_CONST_U32(imm));
  576. /* llgfr %dst,%rc */
  577. EMIT4(0xb9160000, dst_reg, rc_reg);
  578. break;
  579. }
  580. case BPF_ALU64 | BPF_DIV | BPF_K: /* dst = dst / imm */
  581. case BPF_ALU64 | BPF_MOD | BPF_K: /* dst = dst % imm */
  582. {
  583. int rc_reg = BPF_OP(insn->code) == BPF_DIV ? REG_W1 : REG_W0;
  584. if (imm == 1) {
  585. if (BPF_OP(insn->code) == BPF_MOD)
  586. /* lhgi %dst,0 */
  587. EMIT4_IMM(0xa7090000, dst_reg, 0);
  588. break;
  589. }
  590. /* lghi %w0,0 */
  591. EMIT4_IMM(0xa7090000, REG_W0, 0);
  592. /* lgr %w1,%dst */
  593. EMIT4(0xb9040000, REG_W1, dst_reg);
  594. /* dlg %w0,<d(imm)>(%l) */
  595. EMIT6_DISP_LH(0xe3000000, 0x0087, REG_W0, REG_0, REG_L,
  596. EMIT_CONST_U64(imm));
  597. /* lgr %dst,%rc */
  598. EMIT4(0xb9040000, dst_reg, rc_reg);
  599. break;
  600. }
  601. /*
  602. * BPF_AND
  603. */
  604. case BPF_ALU | BPF_AND | BPF_X: /* dst = (u32) dst & (u32) src */
  605. /* nr %dst,%src */
  606. EMIT2(0x1400, dst_reg, src_reg);
  607. EMIT_ZERO(dst_reg);
  608. break;
  609. case BPF_ALU64 | BPF_AND | BPF_X: /* dst = dst & src */
  610. /* ngr %dst,%src */
  611. EMIT4(0xb9800000, dst_reg, src_reg);
  612. break;
  613. case BPF_ALU | BPF_AND | BPF_K: /* dst = (u32) dst & (u32) imm */
  614. /* nilf %dst,imm */
  615. EMIT6_IMM(0xc00b0000, dst_reg, imm);
  616. EMIT_ZERO(dst_reg);
  617. break;
  618. case BPF_ALU64 | BPF_AND | BPF_K: /* dst = dst & imm */
  619. /* ng %dst,<d(imm)>(%l) */
  620. EMIT6_DISP_LH(0xe3000000, 0x0080, dst_reg, REG_0, REG_L,
  621. EMIT_CONST_U64(imm));
  622. break;
  623. /*
  624. * BPF_OR
  625. */
  626. case BPF_ALU | BPF_OR | BPF_X: /* dst = (u32) dst | (u32) src */
  627. /* or %dst,%src */
  628. EMIT2(0x1600, dst_reg, src_reg);
  629. EMIT_ZERO(dst_reg);
  630. break;
  631. case BPF_ALU64 | BPF_OR | BPF_X: /* dst = dst | src */
  632. /* ogr %dst,%src */
  633. EMIT4(0xb9810000, dst_reg, src_reg);
  634. break;
  635. case BPF_ALU | BPF_OR | BPF_K: /* dst = (u32) dst | (u32) imm */
  636. /* oilf %dst,imm */
  637. EMIT6_IMM(0xc00d0000, dst_reg, imm);
  638. EMIT_ZERO(dst_reg);
  639. break;
  640. case BPF_ALU64 | BPF_OR | BPF_K: /* dst = dst | imm */
  641. /* og %dst,<d(imm)>(%l) */
  642. EMIT6_DISP_LH(0xe3000000, 0x0081, dst_reg, REG_0, REG_L,
  643. EMIT_CONST_U64(imm));
  644. break;
  645. /*
  646. * BPF_XOR
  647. */
  648. case BPF_ALU | BPF_XOR | BPF_X: /* dst = (u32) dst ^ (u32) src */
  649. /* xr %dst,%src */
  650. EMIT2(0x1700, dst_reg, src_reg);
  651. EMIT_ZERO(dst_reg);
  652. break;
  653. case BPF_ALU64 | BPF_XOR | BPF_X: /* dst = dst ^ src */
  654. /* xgr %dst,%src */
  655. EMIT4(0xb9820000, dst_reg, src_reg);
  656. break;
  657. case BPF_ALU | BPF_XOR | BPF_K: /* dst = (u32) dst ^ (u32) imm */
  658. if (!imm)
  659. break;
  660. /* xilf %dst,imm */
  661. EMIT6_IMM(0xc0070000, dst_reg, imm);
  662. EMIT_ZERO(dst_reg);
  663. break;
  664. case BPF_ALU64 | BPF_XOR | BPF_K: /* dst = dst ^ imm */
  665. /* xg %dst,<d(imm)>(%l) */
  666. EMIT6_DISP_LH(0xe3000000, 0x0082, dst_reg, REG_0, REG_L,
  667. EMIT_CONST_U64(imm));
  668. break;
  669. /*
  670. * BPF_LSH
  671. */
  672. case BPF_ALU | BPF_LSH | BPF_X: /* dst = (u32) dst << (u32) src */
  673. /* sll %dst,0(%src) */
  674. EMIT4_DISP(0x89000000, dst_reg, src_reg, 0);
  675. EMIT_ZERO(dst_reg);
  676. break;
  677. case BPF_ALU64 | BPF_LSH | BPF_X: /* dst = dst << src */
  678. /* sllg %dst,%dst,0(%src) */
  679. EMIT6_DISP_LH(0xeb000000, 0x000d, dst_reg, dst_reg, src_reg, 0);
  680. break;
  681. case BPF_ALU | BPF_LSH | BPF_K: /* dst = (u32) dst << (u32) imm */
  682. if (imm == 0)
  683. break;
  684. /* sll %dst,imm(%r0) */
  685. EMIT4_DISP(0x89000000, dst_reg, REG_0, imm);
  686. EMIT_ZERO(dst_reg);
  687. break;
  688. case BPF_ALU64 | BPF_LSH | BPF_K: /* dst = dst << imm */
  689. if (imm == 0)
  690. break;
  691. /* sllg %dst,%dst,imm(%r0) */
  692. EMIT6_DISP_LH(0xeb000000, 0x000d, dst_reg, dst_reg, REG_0, imm);
  693. break;
  694. /*
  695. * BPF_RSH
  696. */
  697. case BPF_ALU | BPF_RSH | BPF_X: /* dst = (u32) dst >> (u32) src */
  698. /* srl %dst,0(%src) */
  699. EMIT4_DISP(0x88000000, dst_reg, src_reg, 0);
  700. EMIT_ZERO(dst_reg);
  701. break;
  702. case BPF_ALU64 | BPF_RSH | BPF_X: /* dst = dst >> src */
  703. /* srlg %dst,%dst,0(%src) */
  704. EMIT6_DISP_LH(0xeb000000, 0x000c, dst_reg, dst_reg, src_reg, 0);
  705. break;
  706. case BPF_ALU | BPF_RSH | BPF_K: /* dst = (u32) dst >> (u32) imm */
  707. if (imm == 0)
  708. break;
  709. /* srl %dst,imm(%r0) */
  710. EMIT4_DISP(0x88000000, dst_reg, REG_0, imm);
  711. EMIT_ZERO(dst_reg);
  712. break;
  713. case BPF_ALU64 | BPF_RSH | BPF_K: /* dst = dst >> imm */
  714. if (imm == 0)
  715. break;
  716. /* srlg %dst,%dst,imm(%r0) */
  717. EMIT6_DISP_LH(0xeb000000, 0x000c, dst_reg, dst_reg, REG_0, imm);
  718. break;
  719. /*
  720. * BPF_ARSH
  721. */
  722. case BPF_ALU64 | BPF_ARSH | BPF_X: /* ((s64) dst) >>= src */
  723. /* srag %dst,%dst,0(%src) */
  724. EMIT6_DISP_LH(0xeb000000, 0x000a, dst_reg, dst_reg, src_reg, 0);
  725. break;
  726. case BPF_ALU64 | BPF_ARSH | BPF_K: /* ((s64) dst) >>= imm */
  727. if (imm == 0)
  728. break;
  729. /* srag %dst,%dst,imm(%r0) */
  730. EMIT6_DISP_LH(0xeb000000, 0x000a, dst_reg, dst_reg, REG_0, imm);
  731. break;
  732. /*
  733. * BPF_NEG
  734. */
  735. case BPF_ALU | BPF_NEG: /* dst = (u32) -dst */
  736. /* lcr %dst,%dst */
  737. EMIT2(0x1300, dst_reg, dst_reg);
  738. EMIT_ZERO(dst_reg);
  739. break;
  740. case BPF_ALU64 | BPF_NEG: /* dst = -dst */
  741. /* lcgr %dst,%dst */
  742. EMIT4(0xb9130000, dst_reg, dst_reg);
  743. break;
  744. /*
  745. * BPF_FROM_BE/LE
  746. */
  747. case BPF_ALU | BPF_END | BPF_FROM_BE:
  748. /* s390 is big endian, therefore only clear high order bytes */
  749. switch (imm) {
  750. case 16: /* dst = (u16) cpu_to_be16(dst) */
  751. /* llghr %dst,%dst */
  752. EMIT4(0xb9850000, dst_reg, dst_reg);
  753. break;
  754. case 32: /* dst = (u32) cpu_to_be32(dst) */
  755. /* llgfr %dst,%dst */
  756. EMIT4(0xb9160000, dst_reg, dst_reg);
  757. break;
  758. case 64: /* dst = (u64) cpu_to_be64(dst) */
  759. break;
  760. }
  761. break;
  762. case BPF_ALU | BPF_END | BPF_FROM_LE:
  763. switch (imm) {
  764. case 16: /* dst = (u16) cpu_to_le16(dst) */
  765. /* lrvr %dst,%dst */
  766. EMIT4(0xb91f0000, dst_reg, dst_reg);
  767. /* srl %dst,16(%r0) */
  768. EMIT4_DISP(0x88000000, dst_reg, REG_0, 16);
  769. /* llghr %dst,%dst */
  770. EMIT4(0xb9850000, dst_reg, dst_reg);
  771. break;
  772. case 32: /* dst = (u32) cpu_to_le32(dst) */
  773. /* lrvr %dst,%dst */
  774. EMIT4(0xb91f0000, dst_reg, dst_reg);
  775. /* llgfr %dst,%dst */
  776. EMIT4(0xb9160000, dst_reg, dst_reg);
  777. break;
  778. case 64: /* dst = (u64) cpu_to_le64(dst) */
  779. /* lrvgr %dst,%dst */
  780. EMIT4(0xb90f0000, dst_reg, dst_reg);
  781. break;
  782. }
  783. break;
  784. /*
  785. * BPF_ST(X)
  786. */
  787. case BPF_STX | BPF_MEM | BPF_B: /* *(u8 *)(dst + off) = src_reg */
  788. /* stcy %src,off(%dst) */
  789. EMIT6_DISP_LH(0xe3000000, 0x0072, src_reg, dst_reg, REG_0, off);
  790. jit->seen |= SEEN_MEM;
  791. break;
  792. case BPF_STX | BPF_MEM | BPF_H: /* (u16 *)(dst + off) = src */
  793. /* sthy %src,off(%dst) */
  794. EMIT6_DISP_LH(0xe3000000, 0x0070, src_reg, dst_reg, REG_0, off);
  795. jit->seen |= SEEN_MEM;
  796. break;
  797. case BPF_STX | BPF_MEM | BPF_W: /* *(u32 *)(dst + off) = src */
  798. /* sty %src,off(%dst) */
  799. EMIT6_DISP_LH(0xe3000000, 0x0050, src_reg, dst_reg, REG_0, off);
  800. jit->seen |= SEEN_MEM;
  801. break;
  802. case BPF_STX | BPF_MEM | BPF_DW: /* (u64 *)(dst + off) = src */
  803. /* stg %src,off(%dst) */
  804. EMIT6_DISP_LH(0xe3000000, 0x0024, src_reg, dst_reg, REG_0, off);
  805. jit->seen |= SEEN_MEM;
  806. break;
  807. case BPF_ST | BPF_MEM | BPF_B: /* *(u8 *)(dst + off) = imm */
  808. /* lhi %w0,imm */
  809. EMIT4_IMM(0xa7080000, REG_W0, (u8) imm);
  810. /* stcy %w0,off(dst) */
  811. EMIT6_DISP_LH(0xe3000000, 0x0072, REG_W0, dst_reg, REG_0, off);
  812. jit->seen |= SEEN_MEM;
  813. break;
  814. case BPF_ST | BPF_MEM | BPF_H: /* (u16 *)(dst + off) = imm */
  815. /* lhi %w0,imm */
  816. EMIT4_IMM(0xa7080000, REG_W0, (u16) imm);
  817. /* sthy %w0,off(dst) */
  818. EMIT6_DISP_LH(0xe3000000, 0x0070, REG_W0, dst_reg, REG_0, off);
  819. jit->seen |= SEEN_MEM;
  820. break;
  821. case BPF_ST | BPF_MEM | BPF_W: /* *(u32 *)(dst + off) = imm */
  822. /* llilf %w0,imm */
  823. EMIT6_IMM(0xc00f0000, REG_W0, (u32) imm);
  824. /* sty %w0,off(%dst) */
  825. EMIT6_DISP_LH(0xe3000000, 0x0050, REG_W0, dst_reg, REG_0, off);
  826. jit->seen |= SEEN_MEM;
  827. break;
  828. case BPF_ST | BPF_MEM | BPF_DW: /* *(u64 *)(dst + off) = imm */
  829. /* lgfi %w0,imm */
  830. EMIT6_IMM(0xc0010000, REG_W0, imm);
  831. /* stg %w0,off(%dst) */
  832. EMIT6_DISP_LH(0xe3000000, 0x0024, REG_W0, dst_reg, REG_0, off);
  833. jit->seen |= SEEN_MEM;
  834. break;
  835. /*
  836. * BPF_STX XADD (atomic_add)
  837. */
  838. case BPF_STX | BPF_XADD | BPF_W: /* *(u32 *)(dst + off) += src */
  839. /* laal %w0,%src,off(%dst) */
  840. EMIT6_DISP_LH(0xeb000000, 0x00fa, REG_W0, src_reg,
  841. dst_reg, off);
  842. jit->seen |= SEEN_MEM;
  843. break;
  844. case BPF_STX | BPF_XADD | BPF_DW: /* *(u64 *)(dst + off) += src */
  845. /* laalg %w0,%src,off(%dst) */
  846. EMIT6_DISP_LH(0xeb000000, 0x00ea, REG_W0, src_reg,
  847. dst_reg, off);
  848. jit->seen |= SEEN_MEM;
  849. break;
  850. /*
  851. * BPF_LDX
  852. */
  853. case BPF_LDX | BPF_MEM | BPF_B: /* dst = *(u8 *)(ul) (src + off) */
  854. /* llgc %dst,0(off,%src) */
  855. EMIT6_DISP_LH(0xe3000000, 0x0090, dst_reg, src_reg, REG_0, off);
  856. jit->seen |= SEEN_MEM;
  857. break;
  858. case BPF_LDX | BPF_MEM | BPF_H: /* dst = *(u16 *)(ul) (src + off) */
  859. /* llgh %dst,0(off,%src) */
  860. EMIT6_DISP_LH(0xe3000000, 0x0091, dst_reg, src_reg, REG_0, off);
  861. jit->seen |= SEEN_MEM;
  862. break;
  863. case BPF_LDX | BPF_MEM | BPF_W: /* dst = *(u32 *)(ul) (src + off) */
  864. /* llgf %dst,off(%src) */
  865. jit->seen |= SEEN_MEM;
  866. EMIT6_DISP_LH(0xe3000000, 0x0016, dst_reg, src_reg, REG_0, off);
  867. break;
  868. case BPF_LDX | BPF_MEM | BPF_DW: /* dst = *(u64 *)(ul) (src + off) */
  869. /* lg %dst,0(off,%src) */
  870. jit->seen |= SEEN_MEM;
  871. EMIT6_DISP_LH(0xe3000000, 0x0004, dst_reg, src_reg, REG_0, off);
  872. break;
  873. /*
  874. * BPF_JMP / CALL
  875. */
  876. case BPF_JMP | BPF_CALL:
  877. {
  878. /*
  879. * b0 = (__bpf_call_base + imm)(b1, b2, b3, b4, b5)
  880. */
  881. const u64 func = (u64)__bpf_call_base + imm;
  882. REG_SET_SEEN(BPF_REG_5);
  883. jit->seen |= SEEN_FUNC;
  884. /* lg %w1,<d(imm)>(%l) */
  885. EMIT6_DISP(0xe3000000, 0x0004, REG_W1, REG_0, REG_L,
  886. EMIT_CONST_U64(func));
  887. /* basr %r14,%w1 */
  888. EMIT2(0x0d00, REG_14, REG_W1);
  889. /* lgr %b0,%r2: load return value into %b0 */
  890. EMIT4(0xb9040000, BPF_REG_0, REG_2);
  891. break;
  892. }
  893. case BPF_JMP | BPF_EXIT: /* return b0 */
  894. last = (i == fp->len - 1) ? 1 : 0;
  895. if (last && !(jit->seen & SEEN_RET0))
  896. break;
  897. /* j <exit> */
  898. EMIT4_PCREL(0xa7f40000, jit->exit_ip - jit->prg);
  899. break;
  900. /*
  901. * Branch relative (number of skipped instructions) to offset on
  902. * condition.
  903. *
  904. * Condition code to mask mapping:
  905. *
  906. * CC | Description | Mask
  907. * ------------------------------
  908. * 0 | Operands equal | 8
  909. * 1 | First operand low | 4
  910. * 2 | First operand high | 2
  911. * 3 | Unused | 1
  912. *
  913. * For s390x relative branches: ip = ip + off_bytes
  914. * For BPF relative branches: insn = insn + off_insns + 1
  915. *
  916. * For example for s390x with offset 0 we jump to the branch
  917. * instruction itself (loop) and for BPF with offset 0 we
  918. * branch to the instruction behind the branch.
  919. */
  920. case BPF_JMP | BPF_JA: /* if (true) */
  921. mask = 0xf000; /* j */
  922. goto branch_oc;
  923. case BPF_JMP | BPF_JSGT | BPF_K: /* ((s64) dst > (s64) imm) */
  924. mask = 0x2000; /* jh */
  925. goto branch_ks;
  926. case BPF_JMP | BPF_JSGE | BPF_K: /* ((s64) dst >= (s64) imm) */
  927. mask = 0xa000; /* jhe */
  928. goto branch_ks;
  929. case BPF_JMP | BPF_JGT | BPF_K: /* (dst_reg > imm) */
  930. mask = 0x2000; /* jh */
  931. goto branch_ku;
  932. case BPF_JMP | BPF_JGE | BPF_K: /* (dst_reg >= imm) */
  933. mask = 0xa000; /* jhe */
  934. goto branch_ku;
  935. case BPF_JMP | BPF_JNE | BPF_K: /* (dst_reg != imm) */
  936. mask = 0x7000; /* jne */
  937. goto branch_ku;
  938. case BPF_JMP | BPF_JEQ | BPF_K: /* (dst_reg == imm) */
  939. mask = 0x8000; /* je */
  940. goto branch_ku;
  941. case BPF_JMP | BPF_JSET | BPF_K: /* (dst_reg & imm) */
  942. mask = 0x7000; /* jnz */
  943. /* lgfi %w1,imm (load sign extend imm) */
  944. EMIT6_IMM(0xc0010000, REG_W1, imm);
  945. /* ngr %w1,%dst */
  946. EMIT4(0xb9800000, REG_W1, dst_reg);
  947. goto branch_oc;
  948. case BPF_JMP | BPF_JSGT | BPF_X: /* ((s64) dst > (s64) src) */
  949. mask = 0x2000; /* jh */
  950. goto branch_xs;
  951. case BPF_JMP | BPF_JSGE | BPF_X: /* ((s64) dst >= (s64) src) */
  952. mask = 0xa000; /* jhe */
  953. goto branch_xs;
  954. case BPF_JMP | BPF_JGT | BPF_X: /* (dst > src) */
  955. mask = 0x2000; /* jh */
  956. goto branch_xu;
  957. case BPF_JMP | BPF_JGE | BPF_X: /* (dst >= src) */
  958. mask = 0xa000; /* jhe */
  959. goto branch_xu;
  960. case BPF_JMP | BPF_JNE | BPF_X: /* (dst != src) */
  961. mask = 0x7000; /* jne */
  962. goto branch_xu;
  963. case BPF_JMP | BPF_JEQ | BPF_X: /* (dst == src) */
  964. mask = 0x8000; /* je */
  965. goto branch_xu;
  966. case BPF_JMP | BPF_JSET | BPF_X: /* (dst & src) */
  967. mask = 0x7000; /* jnz */
  968. /* ngrk %w1,%dst,%src */
  969. EMIT4_RRF(0xb9e40000, REG_W1, dst_reg, src_reg);
  970. goto branch_oc;
  971. branch_ks:
  972. /* lgfi %w1,imm (load sign extend imm) */
  973. EMIT6_IMM(0xc0010000, REG_W1, imm);
  974. /* cgrj %dst,%w1,mask,off */
  975. EMIT6_PCREL(0xec000000, 0x0064, dst_reg, REG_W1, i, off, mask);
  976. break;
  977. branch_ku:
  978. /* lgfi %w1,imm (load sign extend imm) */
  979. EMIT6_IMM(0xc0010000, REG_W1, imm);
  980. /* clgrj %dst,%w1,mask,off */
  981. EMIT6_PCREL(0xec000000, 0x0065, dst_reg, REG_W1, i, off, mask);
  982. break;
  983. branch_xs:
  984. /* cgrj %dst,%src,mask,off */
  985. EMIT6_PCREL(0xec000000, 0x0064, dst_reg, src_reg, i, off, mask);
  986. break;
  987. branch_xu:
  988. /* clgrj %dst,%src,mask,off */
  989. EMIT6_PCREL(0xec000000, 0x0065, dst_reg, src_reg, i, off, mask);
  990. break;
  991. branch_oc:
  992. /* brc mask,jmp_off (branch instruction needs 4 bytes) */
  993. jmp_off = addrs[i + off + 1] - (addrs[i + 1] - 4);
  994. EMIT4_PCREL(0xa7040000 | mask << 8, jmp_off);
  995. break;
  996. /*
  997. * BPF_LD
  998. */
  999. case BPF_LD | BPF_ABS | BPF_B: /* b0 = *(u8 *) (skb->data+imm) */
  1000. case BPF_LD | BPF_IND | BPF_B: /* b0 = *(u8 *) (skb->data+imm+src) */
  1001. if ((BPF_MODE(insn->code) == BPF_ABS) && (imm >= 0))
  1002. func_addr = __pa(sk_load_byte_pos);
  1003. else
  1004. func_addr = __pa(sk_load_byte);
  1005. goto call_fn;
  1006. case BPF_LD | BPF_ABS | BPF_H: /* b0 = *(u16 *) (skb->data+imm) */
  1007. case BPF_LD | BPF_IND | BPF_H: /* b0 = *(u16 *) (skb->data+imm+src) */
  1008. if ((BPF_MODE(insn->code) == BPF_ABS) && (imm >= 0))
  1009. func_addr = __pa(sk_load_half_pos);
  1010. else
  1011. func_addr = __pa(sk_load_half);
  1012. goto call_fn;
  1013. case BPF_LD | BPF_ABS | BPF_W: /* b0 = *(u32 *) (skb->data+imm) */
  1014. case BPF_LD | BPF_IND | BPF_W: /* b0 = *(u32 *) (skb->data+imm+src) */
  1015. if ((BPF_MODE(insn->code) == BPF_ABS) && (imm >= 0))
  1016. func_addr = __pa(sk_load_word_pos);
  1017. else
  1018. func_addr = __pa(sk_load_word);
  1019. goto call_fn;
  1020. call_fn:
  1021. jit->seen |= SEEN_SKB | SEEN_RET0 | SEEN_FUNC;
  1022. REG_SET_SEEN(REG_14); /* Return address of possible func call */
  1023. /*
  1024. * Implicit input:
  1025. * BPF_REG_6 (R7) : skb pointer
  1026. * REG_SKB_DATA (R12): skb data pointer
  1027. *
  1028. * Calculated input:
  1029. * BPF_REG_2 (R3) : offset of byte(s) to fetch in skb
  1030. * BPF_REG_5 (R6) : return address
  1031. *
  1032. * Output:
  1033. * BPF_REG_0 (R14): data read from skb
  1034. *
  1035. * Scratch registers (BPF_REG_1-5)
  1036. */
  1037. /* Call function: llilf %w1,func_addr */
  1038. EMIT6_IMM(0xc00f0000, REG_W1, func_addr);
  1039. /* Offset: lgfi %b2,imm */
  1040. EMIT6_IMM(0xc0010000, BPF_REG_2, imm);
  1041. if (BPF_MODE(insn->code) == BPF_IND)
  1042. /* agfr %b2,%src (%src is s32 here) */
  1043. EMIT4(0xb9180000, BPF_REG_2, src_reg);
  1044. /* basr %b5,%w1 (%b5 is call saved) */
  1045. EMIT2(0x0d00, BPF_REG_5, REG_W1);
  1046. /*
  1047. * Note: For fast access we jump directly after the
  1048. * jnz instruction from bpf_jit.S
  1049. */
  1050. /* jnz <ret0> */
  1051. EMIT4_PCREL(0xa7740000, jit->ret0_ip - jit->prg);
  1052. break;
  1053. default: /* too complex, give up */
  1054. pr_err("Unknown opcode %02x\n", insn->code);
  1055. return -1;
  1056. }
  1057. return insn_count;
  1058. }
  1059. /*
  1060. * Compile eBPF program into s390x code
  1061. */
  1062. static int bpf_jit_prog(struct bpf_jit *jit, struct bpf_prog *fp)
  1063. {
  1064. int i, insn_count;
  1065. jit->lit = jit->lit_start;
  1066. jit->prg = 0;
  1067. bpf_jit_prologue(jit);
  1068. for (i = 0; i < fp->len; i += insn_count) {
  1069. insn_count = bpf_jit_insn(jit, fp, i);
  1070. if (insn_count < 0)
  1071. return -1;
  1072. jit->addrs[i + 1] = jit->prg; /* Next instruction address */
  1073. }
  1074. bpf_jit_epilogue(jit);
  1075. jit->lit_start = jit->prg;
  1076. jit->size = jit->lit;
  1077. jit->size_prg = jit->prg;
  1078. return 0;
  1079. }
  1080. /*
  1081. * Classic BPF function stub. BPF programs will be converted into
  1082. * eBPF and then bpf_int_jit_compile() will be called.
  1083. */
  1084. void bpf_jit_compile(struct bpf_prog *fp)
  1085. {
  1086. }
  1087. /*
  1088. * Compile eBPF program "fp"
  1089. */
  1090. void bpf_int_jit_compile(struct bpf_prog *fp)
  1091. {
  1092. struct bpf_binary_header *header;
  1093. struct bpf_jit jit;
  1094. int pass;
  1095. if (!bpf_jit_enable)
  1096. return;
  1097. memset(&jit, 0, sizeof(jit));
  1098. jit.addrs = kcalloc(fp->len + 1, sizeof(*jit.addrs), GFP_KERNEL);
  1099. if (jit.addrs == NULL)
  1100. return;
  1101. /*
  1102. * Three initial passes:
  1103. * - 1/2: Determine clobbered registers
  1104. * - 3: Calculate program size and addrs arrray
  1105. */
  1106. for (pass = 1; pass <= 3; pass++) {
  1107. if (bpf_jit_prog(&jit, fp))
  1108. goto free_addrs;
  1109. }
  1110. /*
  1111. * Final pass: Allocate and generate program
  1112. */
  1113. if (jit.size >= BPF_SIZE_MAX)
  1114. goto free_addrs;
  1115. header = bpf_jit_binary_alloc(jit.size, &jit.prg_buf, 2, jit_fill_hole);
  1116. if (!header)
  1117. goto free_addrs;
  1118. if (bpf_jit_prog(&jit, fp))
  1119. goto free_addrs;
  1120. if (bpf_jit_enable > 1) {
  1121. bpf_jit_dump(fp->len, jit.size, pass, jit.prg_buf);
  1122. if (jit.prg_buf)
  1123. print_fn_code(jit.prg_buf, jit.size_prg);
  1124. }
  1125. if (jit.prg_buf) {
  1126. set_memory_ro((unsigned long)header, header->pages);
  1127. fp->bpf_func = (void *) jit.prg_buf;
  1128. fp->jited = true;
  1129. }
  1130. free_addrs:
  1131. kfree(jit.addrs);
  1132. }
  1133. /*
  1134. * Free eBPF program
  1135. */
  1136. void bpf_jit_free(struct bpf_prog *fp)
  1137. {
  1138. unsigned long addr = (unsigned long)fp->bpf_func & PAGE_MASK;
  1139. struct bpf_binary_header *header = (void *)addr;
  1140. if (!fp->jited)
  1141. goto free_filter;
  1142. set_memory_rw(addr, header->pages);
  1143. bpf_jit_binary_free(header);
  1144. free_filter:
  1145. bpf_prog_unlock_free(fp);
  1146. }