1 // SPDX-License-Identifier: Zlib
2
3 #include "../zlib_inflate/inflate.h"
4 #include "dfltcc_util.h"
5 #include "dfltcc.h"
6 #include <asm/setup.h>
7 #include <linux/export.h>
8 #include <linux/zutil.h>
9
10 /*
11 * Expand.
12 */
dfltcc_can_inflate(z_streamp strm)13 int dfltcc_can_inflate(
14 z_streamp strm
15 )
16 {
17 struct inflate_state *state = (struct inflate_state *)strm->state;
18 struct dfltcc_state *dfltcc_state = GET_DFLTCC_STATE(state);
19
20 /* Check for kernel dfltcc command line parameter */
21 if (zlib_dfltcc_support == ZLIB_DFLTCC_DISABLED ||
22 zlib_dfltcc_support == ZLIB_DFLTCC_DEFLATE_ONLY)
23 return 0;
24
25 /* Unsupported compression settings */
26 if (state->wbits != HB_BITS)
27 return 0;
28
29 /* Unsupported hardware */
30 return is_bit_set(dfltcc_state->af.fns, DFLTCC_XPND) &&
31 is_bit_set(dfltcc_state->af.fmts, DFLTCC_FMT0);
32 }
33 EXPORT_SYMBOL(dfltcc_can_inflate);
34
dfltcc_was_inflate_used(z_streamp strm)35 static int dfltcc_was_inflate_used(
36 z_streamp strm
37 )
38 {
39 struct inflate_state *state = (struct inflate_state *)strm->state;
40 struct dfltcc_param_v0 *param = &GET_DFLTCC_STATE(state)->param;
41
42 return !param->nt;
43 }
44
dfltcc_inflate_disable(z_streamp strm)45 static int dfltcc_inflate_disable(
46 z_streamp strm
47 )
48 {
49 struct inflate_state *state = (struct inflate_state *)strm->state;
50 struct dfltcc_state *dfltcc_state = GET_DFLTCC_STATE(state);
51
52 if (!dfltcc_can_inflate(strm))
53 return 0;
54 if (dfltcc_was_inflate_used(strm))
55 /* DFLTCC has already decompressed some data. Since there is not
56 * enough information to resume decompression in software, the call
57 * must fail.
58 */
59 return 1;
60 /* DFLTCC was not used yet - decompress in software */
61 memset(&dfltcc_state->af, 0, sizeof(dfltcc_state->af));
62 return 0;
63 }
64
dfltcc_xpnd(z_streamp strm)65 static dfltcc_cc dfltcc_xpnd(
66 z_streamp strm
67 )
68 {
69 struct inflate_state *state = (struct inflate_state *)strm->state;
70 struct dfltcc_param_v0 *param = &GET_DFLTCC_STATE(state)->param;
71 size_t avail_in = strm->avail_in;
72 size_t avail_out = strm->avail_out;
73 dfltcc_cc cc;
74
75 cc = dfltcc(DFLTCC_XPND | HBT_CIRCULAR,
76 param, &strm->next_out, &avail_out,
77 &strm->next_in, &avail_in, state->window);
78 strm->avail_in = avail_in;
79 strm->avail_out = avail_out;
80 return cc;
81 }
82
dfltcc_inflate(z_streamp strm,int flush,int * ret)83 dfltcc_inflate_action dfltcc_inflate(
84 z_streamp strm,
85 int flush,
86 int *ret
87 )
88 {
89 struct inflate_state *state = (struct inflate_state *)strm->state;
90 struct dfltcc_state *dfltcc_state = GET_DFLTCC_STATE(state);
91 struct dfltcc_param_v0 *param = &dfltcc_state->param;
92 dfltcc_cc cc;
93
94 if (flush == Z_BLOCK) {
95 /* DFLTCC does not support stopping on block boundaries */
96 if (dfltcc_inflate_disable(strm)) {
97 *ret = Z_STREAM_ERROR;
98 return DFLTCC_INFLATE_BREAK;
99 } else
100 return DFLTCC_INFLATE_SOFTWARE;
101 }
102
103 if (state->last) {
104 if (state->bits != 0) {
105 strm->next_in++;
106 strm->avail_in--;
107 state->bits = 0;
108 }
109 state->mode = CHECK;
110 return DFLTCC_INFLATE_CONTINUE;
111 }
112
113 if (strm->avail_in == 0 && !param->cf)
114 return DFLTCC_INFLATE_BREAK;
115
116 if (!state->window || state->wsize == 0) {
117 state->mode = MEM;
118 return DFLTCC_INFLATE_CONTINUE;
119 }
120
121 /* Translate stream to parameter block */
122 param->cvt = CVT_ADLER32;
123 param->sbb = state->bits;
124 param->hl = state->whave; /* Software and hardware history formats match */
125 param->ho = (state->write - state->whave) & ((1 << HB_BITS) - 1);
126 if (param->hl)
127 param->nt = 0; /* Honor history for the first block */
128 param->cv = state->check;
129
130 /* Inflate */
131 do {
132 cc = dfltcc_xpnd(strm);
133 } while (cc == DFLTCC_CC_AGAIN);
134
135 /* Translate parameter block to stream */
136 strm->msg = oesc_msg(dfltcc_state->msg, param->oesc);
137 state->last = cc == DFLTCC_CC_OK;
138 state->bits = param->sbb;
139 state->whave = param->hl;
140 state->write = (param->ho + param->hl) & ((1 << HB_BITS) - 1);
141 state->check = param->cv;
142 if (cc == DFLTCC_CC_OP2_CORRUPT && param->oesc != 0) {
143 /* Report an error if stream is corrupted */
144 state->mode = BAD;
145 return DFLTCC_INFLATE_CONTINUE;
146 }
147 state->mode = TYPEDO;
148 /* Break if operands are exhausted, otherwise continue looping */
149 return (cc == DFLTCC_CC_OP1_TOO_SHORT || cc == DFLTCC_CC_OP2_TOO_SHORT) ?
150 DFLTCC_INFLATE_BREAK : DFLTCC_INFLATE_CONTINUE;
151 }
152 EXPORT_SYMBOL(dfltcc_inflate);
153