arch/powerpc/net/bpf_jit.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * bpf_jit.h: BPF JIT compiler for PPC
   4  *
   5  * Copyright 2011 Matt Evans <matt@ozlabs.org>, IBM Corporation
   6  *           2016 Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
   7  */
   8 #ifndef _BPF_JIT_H
   9 #define _BPF_JIT_H
  10
  11 #ifndef __ASSEMBLY__
  12
  13 #include <asm/types.h>
  14 #include <asm/ppc-opcode.h>
  15 #include <asm/code-patching.h>
  16
  17 #ifdef PPC64_ELF_ABI_v1
  18 #define FUNCTION_DESCR_SIZE     24
  19 #else
  20 #define FUNCTION_DESCR_SIZE     0
  21 #endif
  22
  23 #define PLANT_INSTR(d, idx, instr)                                            \
  24         do { if (d) { (d)[idx] = instr; } idx++; } while (0)
  25 #define EMIT(instr)             PLANT_INSTR(image, ctx->idx, instr)
  26
  27 /* Long jump; (unconditional 'branch') */
  28 #define PPC_JMP(dest)                                                         \
  29         do {                                                                  \
  30                 long offset = (long)(dest) - (ctx->idx * 4);                  \
  31                 if (!is_offset_in_branch_range(offset)) {                     \
  32                         pr_err_ratelimited("Branch offset 0x%lx (@%u) out of range\n", offset, ctx->idx);                       \
  33                         return -ERANGE;                                       \
  34                 }                                                             \
  35                 EMIT(PPC_INST_BRANCH | (offset & 0x03fffffc));                \
  36         } while (0)
  37 /* "cond" here covers BO:BI fields. */
  38 #define PPC_BCC_SHORT(cond, dest)                                             \
  39         do {                                                                  \
  40                 long offset = (long)(dest) - (ctx->idx * 4);                  \
  41                 if (!is_offset_in_cond_branch_range(offset)) {                \
  42                         pr_err_ratelimited("Conditional branch offset 0x%lx (@%u) out of range\n", offset, ctx->idx);           \
  43                         return -ERANGE;                                       \
  44                 }                                                             \
  45                 EMIT(PPC_INST_BRANCH_COND | (((cond) & 0x3ff) << 16) | (offset & 0xfffc));                                      \
  46         } while (0)
  47
  48 /* Sign-extended 32-bit immediate load */
  49 #define PPC_LI32(d, i)          do {                                          \
  50                 if ((int)(uintptr_t)(i) >= -32768 &&                          \
  51                                 (int)(uintptr_t)(i) < 32768)                  \
  52                         EMIT(PPC_RAW_LI(d, i));                               \
  53                 else {                                                        \
  54                         EMIT(PPC_RAW_LIS(d, IMM_H(i)));                       \
  55                         if (IMM_L(i))                                         \
  56                                 EMIT(PPC_RAW_ORI(d, d, IMM_L(i)));            \
  57                 } } while(0)
  58
  59 #define PPC_LI64(d, i)          do {                                          \
  60                 if ((long)(i) >= -2147483648 &&                               \
  61                                 (long)(i) < 2147483648)                       \
  62                         PPC_LI32(d, i);                                       \
  63                 else {                                                        \
  64                         if (!((uintptr_t)(i) & 0xffff800000000000ULL))        \
  65                                 EMIT(PPC_RAW_LI(d, ((uintptr_t)(i) >> 32) &   \
  66                                                 0xffff));                     \
  67                         else {                                                \
  68                                 EMIT(PPC_RAW_LIS(d, ((uintptr_t)(i) >> 48))); \
  69                                 if ((uintptr_t)(i) & 0x0000ffff00000000ULL)   \
  70                                         EMIT(PPC_RAW_ORI(d, d,                \
  71                                           ((uintptr_t)(i) >> 32) & 0xffff));  \
  72                         }                                                     \
  73                         EMIT(PPC_RAW_SLDI(d, d, 32));                         \
  74                         if ((uintptr_t)(i) & 0x00000000ffff0000ULL)           \
  75                                 EMIT(PPC_RAW_ORIS(d, d,                       \
  76                                          ((uintptr_t)(i) >> 16) & 0xffff));   \
  77                         if ((uintptr_t)(i) & 0x000000000000ffffULL)           \
  78                                 EMIT(PPC_RAW_ORI(d, d, (uintptr_t)(i) &       \
  79                                                         0xffff));             \
  80                 } } while (0)
  81
  82 #ifdef CONFIG_PPC64
  83 #define PPC_FUNC_ADDR(d,i) do { PPC_LI64(d, i); } while(0)
  84 #else
  85 #define PPC_FUNC_ADDR(d,i) do { PPC_LI32(d, i); } while(0)
  86 #endif
  87
  88 /*
  89  * The fly in the ointment of code size changing from pass to pass is
  90  * avoided by padding the short branch case with a NOP.  If code size differs
  91  * with different branch reaches we will have the issue of code moving from
  92  * one pass to the next and will need a few passes to converge on a stable
  93  * state.
  94  */
  95 #define PPC_BCC(cond, dest)     do {                                          \
  96                 if (is_offset_in_cond_branch_range((long)(dest) - (ctx->idx * 4))) {    \
  97                         PPC_BCC_SHORT(cond, dest);                            \
  98                         EMIT(PPC_RAW_NOP());                                  \
  99                 } else {                                                      \
 100                         /* Flip the 'T or F' bit to invert comparison */      \
 101                         PPC_BCC_SHORT(cond ^ COND_CMP_TRUE, (ctx->idx+2)*4);  \
 102                         PPC_JMP(dest);                                        \
 103                 } } while(0)
 104
 105 /* To create a branch condition, select a bit of cr0... */
 106 #define CR0_LT          0
 107 #define CR0_GT          1
 108 #define CR0_EQ          2
 109 /* ...and modify BO[3] */
 110 #define COND_CMP_TRUE   0x100
 111 #define COND_CMP_FALSE  0x000
 112 /* Together, they make all required comparisons: */
 113 #define COND_GT         (CR0_GT | COND_CMP_TRUE)
 114 #define COND_GE         (CR0_LT | COND_CMP_FALSE)
 115 #define COND_EQ         (CR0_EQ | COND_CMP_TRUE)
 116 #define COND_NE         (CR0_EQ | COND_CMP_FALSE)
 117 #define COND_LT         (CR0_LT | COND_CMP_TRUE)
 118 #define COND_LE         (CR0_GT | COND_CMP_FALSE)
 119
 120 #endif
 121
 122 #endif