~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/arch/arm64/net/bpf_jit_comp.c

Version: ~ [ linux-4.17-rc6 ] ~ [ linux-4.16.10 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.42 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.101 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.132 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.51 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.109 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.56 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.101 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.39.4 ] ~ [ linux-2.6.38.8 ] ~ [ linux-2.6.37.6 ] ~ [ linux-2.6.36.4 ] ~ [ linux-2.6.35.14 ] ~ [ linux-2.6.34.15 ] ~ [ linux-2.6.33.20 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.27.62 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 /*
  2  * BPF JIT compiler for ARM64
  3  *
  4  * Copyright (C) 2014-2016 Zi Shen Lim <zlim.lnx@gmail.com>
  5  *
  6  * This program is free software; you can redistribute it and/or modify
  7  * it under the terms of the GNU General Public License version 2 as
  8  * published by the Free Software Foundation.
  9  *
 10  * This program is distributed in the hope that it will be useful,
 11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 13  * GNU General Public License for more details.
 14  *
 15  * You should have received a copy of the GNU General Public License
 16  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 17  */
 18 
 19 #define pr_fmt(fmt) "bpf_jit: " fmt
 20 
 21 #include <linux/bpf.h>
 22 #include <linux/filter.h>
 23 #include <linux/printk.h>
 24 #include <linux/skbuff.h>
 25 #include <linux/slab.h>
 26 
 27 #include <asm/byteorder.h>
 28 #include <asm/cacheflush.h>
 29 #include <asm/debug-monitors.h>
 30 #include <asm/set_memory.h>
 31 
 32 #include "bpf_jit.h"
 33 
 34 #define TMP_REG_1 (MAX_BPF_JIT_REG + 0)
 35 #define TMP_REG_2 (MAX_BPF_JIT_REG + 1)
 36 #define TCALL_CNT (MAX_BPF_JIT_REG + 2)
 37 #define TMP_REG_3 (MAX_BPF_JIT_REG + 3)
 38 
 39 /* Map BPF registers to A64 registers */
 40 static const int bpf2a64[] = {
 41         /* return value from in-kernel function, and exit value from eBPF */
 42         [BPF_REG_0] = A64_R(7),
 43         /* arguments from eBPF program to in-kernel function */
 44         [BPF_REG_1] = A64_R(0),
 45         [BPF_REG_2] = A64_R(1),
 46         [BPF_REG_3] = A64_R(2),
 47         [BPF_REG_4] = A64_R(3),
 48         [BPF_REG_5] = A64_R(4),
 49         /* callee saved registers that in-kernel function will preserve */
 50         [BPF_REG_6] = A64_R(19),
 51         [BPF_REG_7] = A64_R(20),
 52         [BPF_REG_8] = A64_R(21),
 53         [BPF_REG_9] = A64_R(22),
 54         /* read-only frame pointer to access stack */
 55         [BPF_REG_FP] = A64_R(25),
 56         /* temporary registers for internal BPF JIT */
 57         [TMP_REG_1] = A64_R(10),
 58         [TMP_REG_2] = A64_R(11),
 59         [TMP_REG_3] = A64_R(12),
 60         /* tail_call_cnt */
 61         [TCALL_CNT] = A64_R(26),
 62         /* temporary register for blinding constants */
 63         [BPF_REG_AX] = A64_R(9),
 64 };
 65 
 66 struct jit_ctx {
 67         const struct bpf_prog *prog;
 68         int idx;
 69         int epilogue_offset;
 70         int *offset;
 71         __le32 *image;
 72         u32 stack_size;
 73 };
 74 
 75 static inline void emit(const u32 insn, struct jit_ctx *ctx)
 76 {
 77         if (ctx->image != NULL)
 78                 ctx->image[ctx->idx] = cpu_to_le32(insn);
 79 
 80         ctx->idx++;
 81 }
 82 
 83 static inline void emit_a64_mov_i64(const int reg, const u64 val,
 84                                     struct jit_ctx *ctx)
 85 {
 86         u64 tmp = val;
 87         int shift = 0;
 88 
 89         emit(A64_MOVZ(1, reg, tmp & 0xffff, shift), ctx);
 90         tmp >>= 16;
 91         shift += 16;
 92         while (tmp) {
 93                 if (tmp & 0xffff)
 94                         emit(A64_MOVK(1, reg, tmp & 0xffff, shift), ctx);
 95                 tmp >>= 16;
 96                 shift += 16;
 97         }
 98 }
 99 
100 static inline void emit_addr_mov_i64(const int reg, const u64 val,
101                                      struct jit_ctx *ctx)
102 {
103         u64 tmp = val;
104         int shift = 0;
105 
106         emit(A64_MOVZ(1, reg, tmp & 0xffff, shift), ctx);
107         for (;shift < 48;) {
108                 tmp >>= 16;
109                 shift += 16;
110                 emit(A64_MOVK(1, reg, tmp & 0xffff, shift), ctx);
111         }
112 }
113 
114 static inline void emit_a64_mov_i(const int is64, const int reg,
115                                   const s32 val, struct jit_ctx *ctx)
116 {
117         u16 hi = val >> 16;
118         u16 lo = val & 0xffff;
119 
120         if (hi & 0x8000) {
121                 if (hi == 0xffff) {
122                         emit(A64_MOVN(is64, reg, (u16)~lo, 0), ctx);
123                 } else {
124                         emit(A64_MOVN(is64, reg, (u16)~hi, 16), ctx);
125                         emit(A64_MOVK(is64, reg, lo, 0), ctx);
126                 }
127         } else {
128                 emit(A64_MOVZ(is64, reg, lo, 0), ctx);
129                 if (hi)
130                         emit(A64_MOVK(is64, reg, hi, 16), ctx);
131         }
132 }
133 
134 static inline int bpf2a64_offset(int bpf_to, int bpf_from,
135                                  const struct jit_ctx *ctx)
136 {
137         int to = ctx->offset[bpf_to];
138         /* -1 to account for the Branch instruction */
139         int from = ctx->offset[bpf_from] - 1;
140 
141         return to - from;
142 }
143 
144 static void jit_fill_hole(void *area, unsigned int size)
145 {
146         __le32 *ptr;
147         /* We are guaranteed to have aligned memory. */
148         for (ptr = area; size >= sizeof(u32); size -= sizeof(u32))
149                 *ptr++ = cpu_to_le32(AARCH64_BREAK_FAULT);
150 }
151 
152 static inline int epilogue_offset(const struct jit_ctx *ctx)
153 {
154         int to = ctx->epilogue_offset;
155         int from = ctx->idx;
156 
157         return to - from;
158 }
159 
160 /* Stack must be multiples of 16B */
161 #define STACK_ALIGN(sz) (((sz) + 15) & ~15)
162 
163 /* Tail call offset to jump into */
164 #define PROLOGUE_OFFSET 7
165 
166 static int build_prologue(struct jit_ctx *ctx)
167 {
168         const struct bpf_prog *prog = ctx->prog;
169         const u8 r6 = bpf2a64[BPF_REG_6];
170         const u8 r7 = bpf2a64[BPF_REG_7];
171         const u8 r8 = bpf2a64[BPF_REG_8];
172         const u8 r9 = bpf2a64[BPF_REG_9];
173         const u8 fp = bpf2a64[BPF_REG_FP];
174         const u8 tcc = bpf2a64[TCALL_CNT];
175         const int idx0 = ctx->idx;
176         int cur_offset;
177 
178         /*
179          * BPF prog stack layout
180          *
181          *                         high
182          * original A64_SP =>   0:+-----+ BPF prologue
183          *                        |FP/LR|
184          * current A64_FP =>  -16:+-----+
185          *                        | ... | callee saved registers
186          * BPF fp register => -64:+-----+ <= (BPF_FP)
187          *                        |     |
188          *                        | ... | BPF prog stack
189          *                        |     |
190          *                        +-----+ <= (BPF_FP - prog->aux->stack_depth)
191          *                        |RSVD | JIT scratchpad
192          * current A64_SP =>      +-----+ <= (BPF_FP - ctx->stack_size)
193          *                        |     |
194          *                        | ... | Function call stack
195          *                        |     |
196          *                        +-----+
197          *                          low
198          *
199          */
200 
201         /* Save FP and LR registers to stay align with ARM64 AAPCS */
202         emit(A64_PUSH(A64_FP, A64_LR, A64_SP), ctx);
203         emit(A64_MOV(1, A64_FP, A64_SP), ctx);
204 
205         /* Save callee-saved registers */
206         emit(A64_PUSH(r6, r7, A64_SP), ctx);
207         emit(A64_PUSH(r8, r9, A64_SP), ctx);
208         emit(A64_PUSH(fp, tcc, A64_SP), ctx);
209 
210         /* Set up BPF prog stack base register */
211         emit(A64_MOV(1, fp, A64_SP), ctx);
212 
213         /* Initialize tail_call_cnt */
214         emit(A64_MOVZ(1, tcc, 0, 0), ctx);
215 
216         cur_offset = ctx->idx - idx0;
217         if (cur_offset != PROLOGUE_OFFSET) {
218                 pr_err_once("PROLOGUE_OFFSET = %d, expected %d!\n",
219                             cur_offset, PROLOGUE_OFFSET);
220                 return -1;
221         }
222 
223         /* 4 byte extra for skb_copy_bits buffer */
224         ctx->stack_size = prog->aux->stack_depth + 4;
225         ctx->stack_size = STACK_ALIGN(ctx->stack_size);
226 
227         /* Set up function call stack */
228         emit(A64_SUB_I(1, A64_SP, A64_SP, ctx->stack_size), ctx);
229         return 0;
230 }
231 
232 static int out_offset = -1; /* initialized on the first pass of build_body() */
233 static int emit_bpf_tail_call(struct jit_ctx *ctx)
234 {
235         /* bpf_tail_call(void *prog_ctx, struct bpf_array *array, u64 index) */
236         const u8 r2 = bpf2a64[BPF_REG_2];
237         const u8 r3 = bpf2a64[BPF_REG_3];
238 
239         const u8 tmp = bpf2a64[TMP_REG_1];
240         const u8 prg = bpf2a64[TMP_REG_2];
241         const u8 tcc = bpf2a64[TCALL_CNT];
242         const int idx0 = ctx->idx;
243 #define cur_offset (ctx->idx - idx0)
244 #define jmp_offset (out_offset - (cur_offset))
245         size_t off;
246 
247         /* if (index >= array->map.max_entries)
248          *     goto out;
249          */
250         off = offsetof(struct bpf_array, map.max_entries);
251         emit_a64_mov_i64(tmp, off, ctx);
252         emit(A64_LDR32(tmp, r2, tmp), ctx);
253         emit(A64_MOV(0, r3, r3), ctx);
254         emit(A64_CMP(0, r3, tmp), ctx);
255         emit(A64_B_(A64_COND_CS, jmp_offset), ctx);
256 
257         /* if (tail_call_cnt > MAX_TAIL_CALL_CNT)
258          *     goto out;
259          * tail_call_cnt++;
260          */
261         emit_a64_mov_i64(tmp, MAX_TAIL_CALL_CNT, ctx);
262         emit(A64_CMP(1, tcc, tmp), ctx);
263         emit(A64_B_(A64_COND_HI, jmp_offset), ctx);
264         emit(A64_ADD_I(1, tcc, tcc, 1), ctx);
265 
266         /* prog = array->ptrs[index];
267          * if (prog == NULL)
268          *     goto out;
269          */
270         off = offsetof(struct bpf_array, ptrs);
271         emit_a64_mov_i64(tmp, off, ctx);
272         emit(A64_ADD(1, tmp, r2, tmp), ctx);
273         emit(A64_LSL(1, prg, r3, 3), ctx);
274         emit(A64_LDR64(prg, tmp, prg), ctx);
275         emit(A64_CBZ(1, prg, jmp_offset), ctx);
276 
277         /* goto *(prog->bpf_func + prologue_offset); */
278         off = offsetof(struct bpf_prog, bpf_func);
279         emit_a64_mov_i64(tmp, off, ctx);
280         emit(A64_LDR64(tmp, prg, tmp), ctx);
281         emit(A64_ADD_I(1, tmp, tmp, sizeof(u32) * PROLOGUE_OFFSET), ctx);
282         emit(A64_ADD_I(1, A64_SP, A64_SP, ctx->stack_size), ctx);
283         emit(A64_BR(tmp), ctx);
284 
285         /* out: */
286         if (out_offset == -1)
287                 out_offset = cur_offset;
288         if (cur_offset != out_offset) {
289                 pr_err_once("tail_call out_offset = %d, expected %d!\n",
290                             cur_offset, out_offset);
291                 return -1;
292         }
293         return 0;
294 #undef cur_offset
295 #undef jmp_offset
296 }
297 
298 static void build_epilogue(struct jit_ctx *ctx)
299 {
300         const u8 r0 = bpf2a64[BPF_REG_0];
301         const u8 r6 = bpf2a64[BPF_REG_6];
302         const u8 r7 = bpf2a64[BPF_REG_7];
303         const u8 r8 = bpf2a64[BPF_REG_8];
304         const u8 r9 = bpf2a64[BPF_REG_9];
305         const u8 fp = bpf2a64[BPF_REG_FP];
306 
307         /* We're done with BPF stack */
308         emit(A64_ADD_I(1, A64_SP, A64_SP, ctx->stack_size), ctx);
309 
310         /* Restore fs (x25) and x26 */
311         emit(A64_POP(fp, A64_R(26), A64_SP), ctx);
312 
313         /* Restore callee-saved register */
314         emit(A64_POP(r8, r9, A64_SP), ctx);
315         emit(A64_POP(r6, r7, A64_SP), ctx);
316 
317         /* Restore FP/LR registers */
318         emit(A64_POP(A64_FP, A64_LR, A64_SP), ctx);
319 
320         /* Set return value */
321         emit(A64_MOV(1, A64_R(0), r0), ctx);
322 
323         emit(A64_RET(A64_LR), ctx);
324 }
325 
326 /* JITs an eBPF instruction.
327  * Returns:
328  * 0  - successfully JITed an 8-byte eBPF instruction.
329  * >0 - successfully JITed a 16-byte eBPF instruction.
330  * <0 - failed to JIT.
331  */
332 static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx)
333 {
334         const u8 code = insn->code;
335         const u8 dst = bpf2a64[insn->dst_reg];
336         const u8 src = bpf2a64[insn->src_reg];
337         const u8 tmp = bpf2a64[TMP_REG_1];
338         const u8 tmp2 = bpf2a64[TMP_REG_2];
339         const u8 tmp3 = bpf2a64[TMP_REG_3];
340         const s16 off = insn->off;
341         const s32 imm = insn->imm;
342         const int i = insn - ctx->prog->insnsi;
343         const bool is64 = BPF_CLASS(code) == BPF_ALU64;
344         const bool isdw = BPF_SIZE(code) == BPF_DW;
345         u8 jmp_cond;
346         s32 jmp_offset;
347 
348 #define check_imm(bits, imm) do {                               \
349         if ((((imm) > 0) && ((imm) >> (bits))) ||               \
350             (((imm) < 0) && (~(imm) >> (bits)))) {              \
351                 pr_info("[%2d] imm=%d(0x%x) out of range\n",    \
352                         i, imm, imm);                           \
353                 return -EINVAL;                                 \
354         }                                                       \
355 } while (0)
356 #define check_imm19(imm) check_imm(19, imm)
357 #define check_imm26(imm) check_imm(26, imm)
358 
359         switch (code) {
360         /* dst = src */
361         case BPF_ALU | BPF_MOV | BPF_X:
362         case BPF_ALU64 | BPF_MOV | BPF_X:
363                 emit(A64_MOV(is64, dst, src), ctx);
364                 break;
365         /* dst = dst OP src */
366         case BPF_ALU | BPF_ADD | BPF_X:
367         case BPF_ALU64 | BPF_ADD | BPF_X:
368                 emit(A64_ADD(is64, dst, dst, src), ctx);
369                 break;
370         case BPF_ALU | BPF_SUB | BPF_X:
371         case BPF_ALU64 | BPF_SUB | BPF_X:
372                 emit(A64_SUB(is64, dst, dst, src), ctx);
373                 break;
374         case BPF_ALU | BPF_AND | BPF_X:
375         case BPF_ALU64 | BPF_AND | BPF_X:
376                 emit(A64_AND(is64, dst, dst, src), ctx);
377                 break;
378         case BPF_ALU | BPF_OR | BPF_X:
379         case BPF_ALU64 | BPF_OR | BPF_X:
380                 emit(A64_ORR(is64, dst, dst, src), ctx);
381                 break;
382         case BPF_ALU | BPF_XOR | BPF_X:
383         case BPF_ALU64 | BPF_XOR | BPF_X:
384                 emit(A64_EOR(is64, dst, dst, src), ctx);
385                 break;
386         case BPF_ALU | BPF_MUL | BPF_X:
387         case BPF_ALU64 | BPF_MUL | BPF_X:
388                 emit(A64_MUL(is64, dst, dst, src), ctx);
389                 break;
390         case BPF_ALU | BPF_DIV | BPF_X:
391         case BPF_ALU64 | BPF_DIV | BPF_X:
392         case BPF_ALU | BPF_MOD | BPF_X:
393         case BPF_ALU64 | BPF_MOD | BPF_X:
394                 switch (BPF_OP(code)) {
395                 case BPF_DIV:
396                         emit(A64_UDIV(is64, dst, dst, src), ctx);
397                         break;
398                 case BPF_MOD:
399                         emit(A64_UDIV(is64, tmp, dst, src), ctx);
400                         emit(A64_MUL(is64, tmp, tmp, src), ctx);
401                         emit(A64_SUB(is64, dst, dst, tmp), ctx);
402                         break;
403                 }
404                 break;
405         case BPF_ALU | BPF_LSH | BPF_X:
406         case BPF_ALU64 | BPF_LSH | BPF_X:
407                 emit(A64_LSLV(is64, dst, dst, src), ctx);
408                 break;
409         case BPF_ALU | BPF_RSH | BPF_X:
410         case BPF_ALU64 | BPF_RSH | BPF_X:
411                 emit(A64_LSRV(is64, dst, dst, src), ctx);
412                 break;
413         case BPF_ALU | BPF_ARSH | BPF_X:
414         case BPF_ALU64 | BPF_ARSH | BPF_X:
415                 emit(A64_ASRV(is64, dst, dst, src), ctx);
416                 break;
417         /* dst = -dst */
418         case BPF_ALU | BPF_NEG:
419         case BPF_ALU64 | BPF_NEG:
420                 emit(A64_NEG(is64, dst, dst), ctx);
421                 break;
422         /* dst = BSWAP##imm(dst) */
423         case BPF_ALU | BPF_END | BPF_FROM_LE:
424         case BPF_ALU | BPF_END | BPF_FROM_BE:
425 #ifdef CONFIG_CPU_BIG_ENDIAN
426                 if (BPF_SRC(code) == BPF_FROM_BE)
427                         goto emit_bswap_uxt;
428 #else /* !CONFIG_CPU_BIG_ENDIAN */
429                 if (BPF_SRC(code) == BPF_FROM_LE)
430                         goto emit_bswap_uxt;
431 #endif
432                 switch (imm) {
433                 case 16:
434                         emit(A64_REV16(is64, dst, dst), ctx);
435                         /* zero-extend 16 bits into 64 bits */
436                         emit(A64_UXTH(is64, dst, dst), ctx);
437                         break;
438                 case 32:
439                         emit(A64_REV32(is64, dst, dst), ctx);
440                         /* upper 32 bits already cleared */
441                         break;
442                 case 64:
443                         emit(A64_REV64(dst, dst), ctx);
444                         break;
445                 }
446                 break;
447 emit_bswap_uxt:
448                 switch (imm) {
449                 case 16:
450                         /* zero-extend 16 bits into 64 bits */
451                         emit(A64_UXTH(is64, dst, dst), ctx);
452                         break;
453                 case 32:
454                         /* zero-extend 32 bits into 64 bits */
455                         emit(A64_UXTW(is64, dst, dst), ctx);
456                         break;
457                 case 64:
458                         /* nop */
459                         break;
460                 }
461                 break;
462         /* dst = imm */
463         case BPF_ALU | BPF_MOV | BPF_K:
464         case BPF_ALU64 | BPF_MOV | BPF_K:
465                 emit_a64_mov_i(is64, dst, imm, ctx);
466                 break;
467         /* dst = dst OP imm */
468         case BPF_ALU | BPF_ADD | BPF_K:
469         case BPF_ALU64 | BPF_ADD | BPF_K:
470                 emit_a64_mov_i(is64, tmp, imm, ctx);
471                 emit(A64_ADD(is64, dst, dst, tmp), ctx);
472                 break;
473         case BPF_ALU | BPF_SUB | BPF_K:
474         case BPF_ALU64 | BPF_SUB | BPF_K:
475                 emit_a64_mov_i(is64, tmp, imm, ctx);
476                 emit(A64_SUB(is64, dst, dst, tmp), ctx);
477                 break;
478         case BPF_ALU | BPF_AND | BPF_K:
479         case BPF_ALU64 | BPF_AND | BPF_K:
480                 emit_a64_mov_i(is64, tmp, imm, ctx);
481                 emit(A64_AND(is64, dst, dst, tmp), ctx);
482                 break;
483         case BPF_ALU | BPF_OR | BPF_K:
484         case BPF_ALU64 | BPF_OR | BPF_K:
485                 emit_a64_mov_i(is64, tmp, imm, ctx);
486                 emit(A64_ORR(is64, dst, dst, tmp), ctx);
487                 break;
488         case BPF_ALU | BPF_XOR | BPF_K:
489         case BPF_ALU64 | BPF_XOR | BPF_K:
490                 emit_a64_mov_i(is64, tmp, imm, ctx);
491                 emit(A64_EOR(is64, dst, dst, tmp), ctx);
492                 break;
493         case BPF_ALU | BPF_MUL | BPF_K:
494         case BPF_ALU64 | BPF_MUL | BPF_K:
495                 emit_a64_mov_i(is64, tmp, imm, ctx);
496                 emit(A64_MUL(is64, dst, dst, tmp), ctx);
497                 break;
498         case BPF_ALU | BPF_DIV | BPF_K:
499         case BPF_ALU64 | BPF_DIV | BPF_K:
500                 emit_a64_mov_i(is64, tmp, imm, ctx);
501                 emit(A64_UDIV(is64, dst, dst, tmp), ctx);
502                 break;
503         case BPF_ALU | BPF_MOD | BPF_K:
504         case BPF_ALU64 | BPF_MOD | BPF_K:
505                 emit_a64_mov_i(is64, tmp2, imm, ctx);
506                 emit(A64_UDIV(is64, tmp, dst, tmp2), ctx);
507                 emit(A64_MUL(is64, tmp, tmp, tmp2), ctx);
508                 emit(A64_SUB(is64, dst, dst, tmp), ctx);
509                 break;
510         case BPF_ALU | BPF_LSH | BPF_K:
511         case BPF_ALU64 | BPF_LSH | BPF_K:
512                 emit(A64_LSL(is64, dst, dst, imm), ctx);
513                 break;
514         case BPF_ALU | BPF_RSH | BPF_K:
515         case BPF_ALU64 | BPF_RSH | BPF_K:
516                 emit(A64_LSR(is64, dst, dst, imm), ctx);
517                 break;
518         case BPF_ALU | BPF_ARSH | BPF_K:
519         case BPF_ALU64 | BPF_ARSH | BPF_K:
520                 emit(A64_ASR(is64, dst, dst, imm), ctx);
521                 break;
522 
523         /* JUMP off */
524         case BPF_JMP | BPF_JA:
525                 jmp_offset = bpf2a64_offset(i + off, i, ctx);
526                 check_imm26(jmp_offset);
527                 emit(A64_B(jmp_offset), ctx);
528                 break;
529         /* IF (dst COND src) JUMP off */
530         case BPF_JMP | BPF_JEQ | BPF_X:
531         case BPF_JMP | BPF_JGT | BPF_X:
532         case BPF_JMP | BPF_JLT | BPF_X:
533         case BPF_JMP | BPF_JGE | BPF_X:
534         case BPF_JMP | BPF_JLE | BPF_X:
535         case BPF_JMP | BPF_JNE | BPF_X:
536         case BPF_JMP | BPF_JSGT | BPF_X:
537         case BPF_JMP | BPF_JSLT | BPF_X:
538         case BPF_JMP | BPF_JSGE | BPF_X:
539         case BPF_JMP | BPF_JSLE | BPF_X:
540                 emit(A64_CMP(1, dst, src), ctx);
541 emit_cond_jmp:
542                 jmp_offset = bpf2a64_offset(i + off, i, ctx);
543                 check_imm19(jmp_offset);
544                 switch (BPF_OP(code)) {
545                 case BPF_JEQ:
546                         jmp_cond = A64_COND_EQ;
547                         break;
548                 case BPF_JGT:
549                         jmp_cond = A64_COND_HI;
550                         break;
551                 case BPF_JLT:
552                         jmp_cond = A64_COND_CC;
553                         break;
554                 case BPF_JGE:
555                         jmp_cond = A64_COND_CS;
556                         break;
557                 case BPF_JLE:
558                         jmp_cond = A64_COND_LS;
559                         break;
560                 case BPF_JSET:
561                 case BPF_JNE:
562                         jmp_cond = A64_COND_NE;
563                         break;
564                 case BPF_JSGT:
565                         jmp_cond = A64_COND_GT;
566                         break;
567                 case BPF_JSLT:
568                         jmp_cond = A64_COND_LT;
569                         break;
570                 case BPF_JSGE:
571                         jmp_cond = A64_COND_GE;
572                         break;
573                 case BPF_JSLE:
574                         jmp_cond = A64_COND_LE;
575                         break;
576                 default:
577                         return -EFAULT;
578                 }
579                 emit(A64_B_(jmp_cond, jmp_offset), ctx);
580                 break;
581         case BPF_JMP | BPF_JSET | BPF_X:
582                 emit(A64_TST(1, dst, src), ctx);
583                 goto emit_cond_jmp;
584         /* IF (dst COND imm) JUMP off */
585         case BPF_JMP | BPF_JEQ | BPF_K:
586         case BPF_JMP | BPF_JGT | BPF_K:
587         case BPF_JMP | BPF_JLT | BPF_K:
588         case BPF_JMP | BPF_JGE | BPF_K:
589         case BPF_JMP | BPF_JLE | BPF_K:
590         case BPF_JMP | BPF_JNE | BPF_K:
591         case BPF_JMP | BPF_JSGT | BPF_K:
592         case BPF_JMP | BPF_JSLT | BPF_K:
593         case BPF_JMP | BPF_JSGE | BPF_K:
594         case BPF_JMP | BPF_JSLE | BPF_K:
595                 emit_a64_mov_i(1, tmp, imm, ctx);
596                 emit(A64_CMP(1, dst, tmp), ctx);
597                 goto emit_cond_jmp;
598         case BPF_JMP | BPF_JSET | BPF_K:
599                 emit_a64_mov_i(1, tmp, imm, ctx);
600                 emit(A64_TST(1, dst, tmp), ctx);
601                 goto emit_cond_jmp;
602         /* function call */
603         case BPF_JMP | BPF_CALL:
604         {
605                 const u8 r0 = bpf2a64[BPF_REG_0];
606                 const u64 func = (u64)__bpf_call_base + imm;
607 
608                 if (ctx->prog->is_func)
609                         emit_addr_mov_i64(tmp, func, ctx);
610                 else
611                         emit_a64_mov_i64(tmp, func, ctx);
612                 emit(A64_BLR(tmp), ctx);
613                 emit(A64_MOV(1, r0, A64_R(0)), ctx);
614                 break;
615         }
616         /* tail call */
617         case BPF_JMP | BPF_TAIL_CALL:
618                 if (emit_bpf_tail_call(ctx))
619                         return -EFAULT;
620                 break;
621         /* function return */
622         case BPF_JMP | BPF_EXIT:
623                 /* Optimization: when last instruction is EXIT,
624                    simply fallthrough to epilogue. */
625                 if (i == ctx->prog->len - 1)
626                         break;
627                 jmp_offset = epilogue_offset(ctx);
628                 check_imm26(jmp_offset);
629                 emit(A64_B(jmp_offset), ctx);
630                 break;
631 
632         /* dst = imm64 */
633         case BPF_LD | BPF_IMM | BPF_DW:
634         {
635                 const struct bpf_insn insn1 = insn[1];
636                 u64 imm64;
637 
638                 imm64 = (u64)insn1.imm << 32 | (u32)imm;
639                 emit_a64_mov_i64(dst, imm64, ctx);
640 
641                 return 1;
642         }
643 
644         /* LDX: dst = *(size *)(src + off) */
645         case BPF_LDX | BPF_MEM | BPF_W:
646         case BPF_LDX | BPF_MEM | BPF_H:
647         case BPF_LDX | BPF_MEM | BPF_B:
648         case BPF_LDX | BPF_MEM | BPF_DW:
649                 emit_a64_mov_i(1, tmp, off, ctx);
650                 switch (BPF_SIZE(code)) {
651                 case BPF_W:
652                         emit(A64_LDR32(dst, src, tmp), ctx);
653                         break;
654                 case BPF_H:
655                         emit(A64_LDRH(dst, src, tmp), ctx);
656                         break;
657                 case BPF_B:
658                         emit(A64_LDRB(dst, src, tmp), ctx);
659                         break;
660                 case BPF_DW:
661                         emit(A64_LDR64(dst, src, tmp), ctx);
662                         break;
663                 }
664                 break;
665 
666         /* ST: *(size *)(dst + off) = imm */
667         case BPF_ST | BPF_MEM | BPF_W:
668         case BPF_ST | BPF_MEM | BPF_H:
669         case BPF_ST | BPF_MEM | BPF_B:
670         case BPF_ST | BPF_MEM | BPF_DW:
671                 /* Load imm to a register then store it */
672                 emit_a64_mov_i(1, tmp2, off, ctx);
673                 emit_a64_mov_i(1, tmp, imm, ctx);
674                 switch (BPF_SIZE(code)) {
675                 case BPF_W:
676                         emit(A64_STR32(tmp, dst, tmp2), ctx);
677                         break;
678                 case BPF_H:
679                         emit(A64_STRH(tmp, dst, tmp2), ctx);
680                         break;
681                 case BPF_B:
682                         emit(A64_STRB(tmp, dst, tmp2), ctx);
683                         break;
684                 case BPF_DW:
685                         emit(A64_STR64(tmp, dst, tmp2), ctx);
686                         break;
687                 }
688                 break;
689 
690         /* STX: *(size *)(dst + off) = src */
691         case BPF_STX | BPF_MEM | BPF_W:
692         case BPF_STX | BPF_MEM | BPF_H:
693         case BPF_STX | BPF_MEM | BPF_B:
694         case BPF_STX | BPF_MEM | BPF_DW:
695                 emit_a64_mov_i(1, tmp, off, ctx);
696                 switch (BPF_SIZE(code)) {
697                 case BPF_W:
698                         emit(A64_STR32(src, dst, tmp), ctx);
699                         break;
700                 case BPF_H:
701                         emit(A64_STRH(src, dst, tmp), ctx);
702                         break;
703                 case BPF_B:
704                         emit(A64_STRB(src, dst, tmp), ctx);
705                         break;
706                 case BPF_DW:
707                         emit(A64_STR64(src, dst, tmp), ctx);
708                         break;
709                 }
710                 break;
711         /* STX XADD: lock *(u32 *)(dst + off) += src */
712         case BPF_STX | BPF_XADD | BPF_W:
713         /* STX XADD: lock *(u64 *)(dst + off) += src */
714         case BPF_STX | BPF_XADD | BPF_DW:
715                 emit_a64_mov_i(1, tmp, off, ctx);
716                 emit(A64_ADD(1, tmp, tmp, dst), ctx);
717                 emit(A64_PRFM(tmp, PST, L1, STRM), ctx);
718                 emit(A64_LDXR(isdw, tmp2, tmp), ctx);
719                 emit(A64_ADD(isdw, tmp2, tmp2, src), ctx);
720                 emit(A64_STXR(isdw, tmp2, tmp, tmp3), ctx);
721                 jmp_offset = -3;
722                 check_imm19(jmp_offset);
723                 emit(A64_CBNZ(0, tmp3, jmp_offset), ctx);
724                 break;
725 
726         /* R0 = ntohx(*(size *)(((struct sk_buff *)R6)->data + imm)) */
727         case BPF_LD | BPF_ABS | BPF_W:
728         case BPF_LD | BPF_ABS | BPF_H:
729         case BPF_LD | BPF_ABS | BPF_B:
730         /* R0 = ntohx(*(size *)(((struct sk_buff *)R6)->data + src + imm)) */
731         case BPF_LD | BPF_IND | BPF_W:
732         case BPF_LD | BPF_IND | BPF_H:
733         case BPF_LD | BPF_IND | BPF_B:
734         {
735                 const u8 r0 = bpf2a64[BPF_REG_0]; /* r0 = return value */
736                 const u8 r6 = bpf2a64[BPF_REG_6]; /* r6 = pointer to sk_buff */
737                 const u8 fp = bpf2a64[BPF_REG_FP];
738                 const u8 r1 = bpf2a64[BPF_REG_1]; /* r1: struct sk_buff *skb */
739                 const u8 r2 = bpf2a64[BPF_REG_2]; /* r2: int k */
740                 const u8 r3 = bpf2a64[BPF_REG_3]; /* r3: unsigned int size */
741                 const u8 r4 = bpf2a64[BPF_REG_4]; /* r4: void *buffer */
742                 const u8 r5 = bpf2a64[BPF_REG_5]; /* r5: void *(*func)(...) */
743                 int size;
744 
745                 emit(A64_MOV(1, r1, r6), ctx);
746                 emit_a64_mov_i(0, r2, imm, ctx);
747                 if (BPF_MODE(code) == BPF_IND)
748                         emit(A64_ADD(0, r2, r2, src), ctx);
749                 switch (BPF_SIZE(code)) {
750                 case BPF_W:
751                         size = 4;
752                         break;
753                 case BPF_H:
754                         size = 2;
755                         break;
756                 case BPF_B:
757                         size = 1;
758                         break;
759                 default:
760                         return -EINVAL;
761                 }
762                 emit_a64_mov_i64(r3, size, ctx);
763                 emit(A64_SUB_I(1, r4, fp, ctx->stack_size), ctx);
764                 emit_a64_mov_i64(r5, (unsigned long)bpf_load_pointer, ctx);
765                 emit(A64_BLR(r5), ctx);
766                 emit(A64_MOV(1, r0, A64_R(0)), ctx);
767 
768                 jmp_offset = epilogue_offset(ctx);
769                 check_imm19(jmp_offset);
770                 emit(A64_CBZ(1, r0, jmp_offset), ctx);
771                 emit(A64_MOV(1, r5, r0), ctx);
772                 switch (BPF_SIZE(code)) {
773                 case BPF_W:
774                         emit(A64_LDR32(r0, r5, A64_ZR), ctx);
775 #ifndef CONFIG_CPU_BIG_ENDIAN
776                         emit(A64_REV32(0, r0, r0), ctx);
777 #endif
778                         break;
779                 case BPF_H:
780                         emit(A64_LDRH(r0, r5, A64_ZR), ctx);
781 #ifndef CONFIG_CPU_BIG_ENDIAN
782                         emit(A64_REV16(0, r0, r0), ctx);
783 #endif
784                         break;
785                 case BPF_B:
786                         emit(A64_LDRB(r0, r5, A64_ZR), ctx);
787                         break;
788                 }
789                 break;
790         }
791         default:
792                 pr_err_once("unknown opcode %02x\n", code);
793                 return -EINVAL;
794         }
795 
796         return 0;
797 }
798 
799 static int build_body(struct jit_ctx *ctx)
800 {
801         const struct bpf_prog *prog = ctx->prog;
802         int i;
803 
804         for (i = 0; i < prog->len; i++) {
805                 const struct bpf_insn *insn = &prog->insnsi[i];
806                 int ret;
807 
808                 ret = build_insn(insn, ctx);
809                 if (ret > 0) {
810                         i++;
811                         if (ctx->image == NULL)
812                                 ctx->offset[i] = ctx->idx;
813                         continue;
814                 }
815                 if (ctx->image == NULL)
816                         ctx->offset[i] = ctx->idx;
817                 if (ret)
818                         return ret;
819         }
820 
821         return 0;
822 }
823 
824 static int validate_code(struct jit_ctx *ctx)
825 {
826         int i;
827 
828         for (i = 0; i < ctx->idx; i++) {
829                 u32 a64_insn = le32_to_cpu(ctx->image[i]);
830 
831                 if (a64_insn == AARCH64_BREAK_FAULT)
832                         return -1;
833         }
834 
835         return 0;
836 }
837 
838 static inline void bpf_flush_icache(void *start, void *end)
839 {
840         flush_icache_range((unsigned long)start, (unsigned long)end);
841 }
842 
843 struct arm64_jit_data {
844         struct bpf_binary_header *header;
845         u8 *image;
846         struct jit_ctx ctx;
847 };
848 
849 struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
850 {
851         struct bpf_prog *tmp, *orig_prog = prog;
852         struct bpf_binary_header *header;
853         struct arm64_jit_data *jit_data;
854         bool tmp_blinded = false;
855         bool extra_pass = false;
856         struct jit_ctx ctx;
857         int image_size;
858         u8 *image_ptr;
859 
860         if (!prog->jit_requested)
861                 return orig_prog;
862 
863         tmp = bpf_jit_blind_constants(prog);
864         /* If blinding was requested and we failed during blinding,
865          * we must fall back to the interpreter.
866          */
867         if (IS_ERR(tmp))
868                 return orig_prog;
869         if (tmp != prog) {
870                 tmp_blinded = true;
871                 prog = tmp;
872         }
873 
874         jit_data = prog->aux->jit_data;
875         if (!jit_data) {
876                 jit_data = kzalloc(sizeof(*jit_data), GFP_KERNEL);
877                 if (!jit_data) {
878                         prog = orig_prog;
879                         goto out;
880                 }
881                 prog->aux->jit_data = jit_data;
882         }
883         if (jit_data->ctx.offset) {
884                 ctx = jit_data->ctx;
885                 image_ptr = jit_data->image;
886                 header = jit_data->header;
887                 extra_pass = true;
888                 image_size = sizeof(u32) * ctx.idx;
889                 goto skip_init_ctx;
890         }
891         memset(&ctx, 0, sizeof(ctx));
892         ctx.prog = prog;
893 
894         ctx.offset = kcalloc(prog->len, sizeof(int), GFP_KERNEL);
895         if (ctx.offset == NULL) {
896                 prog = orig_prog;
897                 goto out_off;
898         }
899 
900         /* 1. Initial fake pass to compute ctx->idx. */
901 
902         /* Fake pass to fill in ctx->offset. */
903         if (build_body(&ctx)) {
904                 prog = orig_prog;
905                 goto out_off;
906         }
907 
908         if (build_prologue(&ctx)) {
909                 prog = orig_prog;
910                 goto out_off;
911         }
912 
913         ctx.epilogue_offset = ctx.idx;
914         build_epilogue(&ctx);
915 
916         /* Now we know the actual image size. */
917         image_size = sizeof(u32) * ctx.idx;
918         header = bpf_jit_binary_alloc(image_size, &image_ptr,
919                                       sizeof(u32), jit_fill_hole);
920         if (header == NULL) {
921                 prog = orig_prog;
922                 goto out_off;
923         }
924 
925         /* 2. Now, the actual pass. */
926 
927         ctx.image = (__le32 *)image_ptr;
928 skip_init_ctx:
929         ctx.idx = 0;
930 
931         build_prologue(&ctx);
932 
933         if (build_body(&ctx)) {
934                 bpf_jit_binary_free(header);
935                 prog = orig_prog;
936                 goto out_off;
937         }
938 
939         build_epilogue(&ctx);
940 
941         /* 3. Extra pass to validate JITed code. */
942         if (validate_code(&ctx)) {
943                 bpf_jit_binary_free(header);
944                 prog = orig_prog;
945                 goto out_off;
946         }
947 
948         /* And we're done. */
949         if (bpf_jit_enable > 1)
950                 bpf_jit_dump(prog->len, image_size, 2, ctx.image);
951 
952         bpf_flush_icache(header, ctx.image + ctx.idx);
953 
954         if (!prog->is_func || extra_pass) {
955                 if (extra_pass && ctx.idx != jit_data->ctx.idx) {
956                         pr_err_once("multi-func JIT bug %d != %d\n",
957                                     ctx.idx, jit_data->ctx.idx);
958                         bpf_jit_binary_free(header);
959                         prog->bpf_func = NULL;
960                         prog->jited = 0;
961                         goto out_off;
962                 }
963                 bpf_jit_binary_lock_ro(header);
964         } else {
965                 jit_data->ctx = ctx;
966                 jit_data->image = image_ptr;
967                 jit_data->header = header;
968         }
969         prog->bpf_func = (void *)ctx.image;
970         prog->jited = 1;
971         prog->jited_len = image_size;
972 
973         if (!prog->is_func || extra_pass) {
974 out_off:
975                 kfree(ctx.offset);
976                 kfree(jit_data);
977                 prog->aux->jit_data = NULL;
978         }
979 out:
980         if (tmp_blinded)
981                 bpf_jit_prog_release_other(prog, prog == orig_prog ?
982                                            tmp : orig_prog);
983         return prog;
984 }
985 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp