1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * misc.c
4  *
5  * This is a collection of several routines from gzip-1.0.3
6  * adapted for Linux.
7  *
8  * malloc by Hannu Savolainen 1993 and Matthias Urlichs 1994
9  *
10  * Modified for ARM Linux by Russell King
11  *
12  * Nicolas Pitre <nico@visuaide.com>  1999/04/14 :
13  *  For this code to run directly from Flash, all constant variables must
14  *  be marked with 'const' and all other variables initialized at run-time
15  *  only.  This way all non constant variables will end up in the bss segment,
16  *  which should point to addresses in RAM and cleared to 0 on start.
17  *  This allows for a much quicker boot time.
18  *
19  * Modified for Alpha, from the ARM version, by Jay Estabrook 2003.
20  */
21 
22 #include <linux/kernel.h>
23 #include <linux/slab.h>
24 
25 #include <linux/uaccess.h>
26 
27 #define memzero(s,n)	memset ((s),0,(n))
28 #define puts		srm_printk
29 extern long srm_printk(const char *, ...)
30      __attribute__ ((format (printf, 1, 2)));
31 
32 /*
33  * gzip declarations
34  */
35 #define OF(args)  args
36 #define STATIC static
37 
38 typedef unsigned char  uch;
39 typedef unsigned short ush;
40 typedef unsigned long  ulg;
41 
42 #define WSIZE 0x8000		/* Window size must be at least 32k, */
43 				/* and a power of two */
44 
45 static uch *inbuf;		/* input buffer */
46 static uch *window;		/* Sliding window buffer */
47 
48 static unsigned insize;		/* valid bytes in inbuf */
49 static unsigned inptr;		/* index of next byte to be processed in inbuf */
50 static unsigned outcnt;		/* bytes in output buffer */
51 
52 /* gzip flag byte */
53 #define ASCII_FLAG   0x01 /* bit 0 set: file probably ascii text */
54 #define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */
55 #define EXTRA_FIELD  0x04 /* bit 2 set: extra field present */
56 #define ORIG_NAME    0x08 /* bit 3 set: original file name present */
57 #define COMMENT      0x10 /* bit 4 set: file comment present */
58 #define ENCRYPTED    0x20 /* bit 5 set: file is encrypted */
59 #define RESERVED     0xC0 /* bit 6,7:   reserved */
60 
61 #define get_byte()  (inptr < insize ? inbuf[inptr++] : fill_inbuf())
62 
63 /* Diagnostic functions */
64 #ifdef DEBUG
65 #  define Assert(cond,msg) {if(!(cond)) error(msg);}
66 #  define Trace(x) fprintf x
67 #  define Tracev(x) {if (verbose) fprintf x ;}
68 #  define Tracevv(x) {if (verbose>1) fprintf x ;}
69 #  define Tracec(c,x) {if (verbose && (c)) fprintf x ;}
70 #  define Tracecv(c,x) {if (verbose>1 && (c)) fprintf x ;}
71 #else
72 #  define Assert(cond,msg)
73 #  define Trace(x)
74 #  define Tracev(x)
75 #  define Tracevv(x)
76 #  define Tracec(c,x)
77 #  define Tracecv(c,x)
78 #endif
79 
80 static int  fill_inbuf(void);
81 static void flush_window(void);
82 static void error(char *m);
83 
84 static char *input_data;
85 static int  input_data_size;
86 
87 static uch *output_data;
88 static ulg output_ptr;
89 static ulg bytes_out;
90 
91 static void error(char *m);
92 static void gzip_mark(void **);
93 static void gzip_release(void **);
94 
95 extern int end;
96 static ulg free_mem_ptr;
97 static ulg free_mem_end_ptr;
98 
99 #define HEAP_SIZE 0x3000
100 
101 #include "../../../lib/inflate.c"
102 
103 /* ===========================================================================
104  * Fill the input buffer. This is called only when the buffer is empty
105  * and at least one byte is really needed.
106  */
fill_inbuf(void)107 int fill_inbuf(void)
108 {
109 	if (insize != 0)
110 		error("ran out of input data");
111 
112 	inbuf = input_data;
113 	insize = input_data_size;
114 
115 	inptr = 1;
116 	return inbuf[0];
117 }
118 
119 /* ===========================================================================
120  * Write the output window window[0..outcnt-1] and update crc and bytes_out.
121  * (Used for the decompressed data only.)
122  */
flush_window(void)123 void flush_window(void)
124 {
125 	ulg c = crc;
126 	unsigned n;
127 	uch *in, *out, ch;
128 
129 	in = window;
130 	out = &output_data[output_ptr];
131 	for (n = 0; n < outcnt; n++) {
132 		ch = *out++ = *in++;
133 		c = crc_32_tab[((int)c ^ ch) & 0xff] ^ (c >> 8);
134 	}
135 	crc = c;
136 	bytes_out += (ulg)outcnt;
137 	output_ptr += (ulg)outcnt;
138 	outcnt = 0;
139 /*	puts("."); */
140 }
141 
error(char * x)142 static void error(char *x)
143 {
144 	puts("\n\n");
145 	puts(x);
146 	puts("\n\n -- System halted");
147 
148 	while(1);	/* Halt */
149 }
150 
151 unsigned int
decompress_kernel(void * output_start,void * input_start,size_t ksize,size_t kzsize)152 decompress_kernel(void *output_start,
153 		  void *input_start,
154 		  size_t ksize,
155 		  size_t kzsize)
156 {
157 	output_data		= (uch *)output_start;
158 	input_data		= (uch *)input_start;
159 	input_data_size		= kzsize; /* use compressed size */
160 
161 	/* FIXME FIXME FIXME */
162 	free_mem_ptr		= (ulg)output_start + ksize;
163 	free_mem_end_ptr	= (ulg)output_start + ksize + 0x200000;
164 	/* FIXME FIXME FIXME */
165 
166 	/* put in temp area to reduce initial footprint */
167 	window = malloc(WSIZE);
168 
169 	makecrc();
170 /*	puts("Uncompressing Linux..."); */
171 	gunzip();
172 /*	puts(" done, booting the kernel.\n"); */
173 	return output_ptr;
174 }
175