linux/arch/arm/kernel/head-inflate-data.c
Arnd Bergmann c9a1d4f672 ARM: 9310/1: xip-kernel: add __inflate_kernel_data prototype
The kernel .data decompression is called from assembler, so it does
not need a prototype, but adding one avoids this W=1 warning:

arch/arm/kernel/head-inflate-data.c:35:12: error: no previous prototype for '__inflate_kernel_data' [-Werror=missing-prototypes]

The same file contains a few extern declarations for assembler
symbols, move those into the header as well for consistency.

Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
2023-06-19 09:35:56 +01:00

57 lines
1.8 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* XIP kernel .data segment decompressor
*
* Created by: Nicolas Pitre, August 2017
* Copyright: (C) 2017 Linaro Limited
*/
#include <linux/init.h>
#include <linux/zutil.h>
#include "head.h"
/* for struct inflate_state */
#include "../../../lib/zlib_inflate/inftrees.h"
#include "../../../lib/zlib_inflate/inflate.h"
#include "../../../lib/zlib_inflate/infutil.h"
/*
* This code is called very early during the boot process to decompress
* the .data segment stored compressed in ROM. Therefore none of the global
* variables are valid yet, hence no kernel services such as memory
* allocation is available. Everything must be allocated on the stack and
* we must avoid any global data access. We use a temporary stack located
* in the .bss area. The linker script makes sure the .bss is big enough
* to hold our stack frame plus some room for called functions.
*
* We mimic the code in lib/decompress_inflate.c to use the smallest work
* area possible. And because everything is statically allocated on the
* stack then there is no need to clean up before returning.
*/
int __init __inflate_kernel_data(void)
{
struct z_stream_s stream, *strm = &stream;
struct inflate_state state;
char *in = __data_loc;
int rc;
/* Check and skip gzip header (assume no filename) */
if (in[0] != 0x1f || in[1] != 0x8b || in[2] != 0x08 || in[3] & ~3)
return -1;
in += 10;
strm->workspace = &state;
strm->next_in = in;
strm->avail_in = _edata_loc - __data_loc; /* upper bound */
strm->next_out = _sdata;
strm->avail_out = _edata_loc - __data_loc;
zlib_inflateInit2(strm, -MAX_WBITS);
WS(strm)->inflate_state.wsize = 0;
WS(strm)->inflate_state.window = NULL;
rc = zlib_inflate(strm, Z_FINISH);
if (rc == Z_OK || rc == Z_STREAM_END)
rc = strm->avail_out; /* should be 0 */
return rc;
}