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 */
 12typedef 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
 29static 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
101static 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
109static inline void turn_bit_off(
110    char *bits,
111    int n
112)
113{
114    bits[n / 8] &= ~(1 << (7 - (n % 8)));
115}
116
117static 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
129char *oesc_msg(char *buf, int oesc);
130
131#endif /* DFLTCC_UTIL_H */