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 */
132
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