lib/zlib_dfltcc/dfltcc_util.h

   1 // SPDX-License-Identifier: Zlib
   2 #ifndef DFLTCC_UTIL_H
   3 #define DFLTCC_UTIL_H
   4
   5 #include "dfltcc.h"
   6 #include <linux/kmsan-checks.h>
   7 #include <linux/zutil.h>
   8
   9 /*
  10  * C wrapper for the DEFLATE CONVERSION CALL instruction.
  11  */
  12 typedef enum {
  13     DFLTCC_CC_OK = 0,
  14     DFLTCC_CC_OP1_TOO_SHORT = 1,
  15     DFLTCC_CC_OP2_TOO_SHORT = 2,
  16     DFLTCC_CC_OP2_CORRUPT = 2,
  17     DFLTCC_CC_AGAIN = 3,
  18 } dfltcc_cc;
  19
  20 #define DFLTCC_QAF 0
  21 #define DFLTCC_GDHT 1
  22 #define DFLTCC_CMPR 2
  23 #define DFLTCC_XPND 4
  24 #define HBT_CIRCULAR (1 << 7)
  25 #define DFLTCC_FN_MASK ((1 << 7) - 1)
  26 #define HB_BITS 15
  27 #define HB_SIZE (1 << HB_BITS)
  28
  29 static inline dfltcc_cc dfltcc(
  30     int fn,
  31     void *param,
  32     Byte **op1,
  33     size_t *len1,
  34     const Byte **op2,
  35     size_t *len2,
  36     void *hist
  37 )
  38 {
  39     Byte *t2 = op1 ? *op1 : NULL;
  40     unsigned char *orig_t2 = t2;
  41     size_t t3 = len1 ? *len1 : 0;
  42     const Byte *t4 = op2 ? *op2 : NULL;
  43     size_t t5 = len2 ? *len2 : 0;
  44     register int r0 __asm__("r0") = fn;
  45     register void *r1 __asm__("r1") = param;
  46     register Byte *r2 __asm__("r2") = t2;
  47     register size_t r3 __asm__("r3") = t3;
  48     register const Byte *r4 __asm__("r4") = t4;
  49     register size_t r5 __asm__("r5") = t5;
  50     int cc;
  51
  52     __asm__ volatile(
  53                      ".insn rrf,0xb9390000,%[r2],%[r4],%[hist],0\n"
  54                      "ipm %[cc]\n"
  55                      : [r2] "+r" (r2)
  56                      , [r3] "+r" (r3)
  57                      , [r4] "+r" (r4)
  58                      , [r5] "+r" (r5)
  59                      , [cc] "=r" (cc)
  60                      : [r0] "r" (r0)
  61                      , [r1] "r" (r1)
  62                      , [hist] "r" (hist)
  63                      : "cc", "memory");
  64     t2 = r2; t3 = r3; t4 = r4; t5 = r5;
  65
  66     /*
  67      * Unpoison the parameter block and the output buffer.
  68      * This is a no-op in non-KMSAN builds.
  69      */
  70     switch (fn & DFLTCC_FN_MASK) {
  71     case DFLTCC_QAF:
  72         kmsan_unpoison_memory(param, sizeof(struct dfltcc_qaf_param));
  73         break;
  74     case DFLTCC_GDHT:
  75         kmsan_unpoison_memory(param, offsetof(struct dfltcc_param_v0, csb));
  76         break;
  77     case DFLTCC_CMPR:
  78         kmsan_unpoison_memory(param, sizeof(struct dfltcc_param_v0));
  79         kmsan_unpoison_memory(
  80                 orig_t2,
  81                 t2 - orig_t2 +
  82                     (((struct dfltcc_param_v0 *)param)->sbb == 0 ? 0 : 1));
  83         break;
  84     case DFLTCC_XPND:
  85         kmsan_unpoison_memory(param, sizeof(struct dfltcc_param_v0));
  86         kmsan_unpoison_memory(orig_t2, t2 - orig_t2);
  87         break;
  88     }
  89
  90     if (op1)
  91         *op1 = t2;
  92     if (len1)
  93         *len1 = t3;
  94     if (op2)
  95         *op2 = t4;
  96     if (len2)
  97         *len2 = t5;
  98     return (cc >> 28) & 3;
  99 }
 100
 101 static inline int is_bit_set(
 102     const char *bits,
 103     int n
 104 )
 105 {
 106     return bits[n / 8] & (1 << (7 - (n % 8)));
 107 }
 108
 109 static inline void turn_bit_off(
 110     char *bits,
 111     int n
 112 )
 113 {
 114     bits[n / 8] &= ~(1 << (7 - (n % 8)));
 115 }
 116
 117 static inline int dfltcc_are_params_ok(
 118     int level,
 119     uInt window_bits,
 120     int strategy,
 121     uLong level_mask
 122 )
 123 {
 124     return (level_mask & (1 << level)) != 0 &&
 125         (window_bits == HB_BITS) &&
 126         (strategy == Z_DEFAULT_STRATEGY);
 127 }
 128
 129 char *oesc_msg(char *buf, int oesc);
 130
 131 #endif /* DFLTCC_UTIL_H */