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vmlinuz/386 fix for physical_start not at bzimage_offset

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This commit is contained in:
John Reiser 2006-10-16 17:18:19 -07:00
parent 4442a282e1
commit de3e9f2809
2 changed files with 20 additions and 10 deletions
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29
src/p_vmlinz.cpp
View File

@ -38,7 +38,6 @@
static const
#include "stub/i386-linux.kernel.vmlinuz.h"
static const unsigned kernel_entry = 0x100000;
static const unsigned stack_offset_during_uncompression = 0x9000;
// add to "real mode pointer" in %esi; total 0x99000 is typical
@ -52,7 +51,7 @@ static const unsigned bzimage_offset = 0x100000;
**************************************************************************/
PackVmlinuzI386::PackVmlinuzI386(InputFile *f) :
super(f)
super(f), physical_start(0x100000)
{
COMPILE_TIME_ASSERT(sizeof(boot_sect_t) == 0x218);
}
@ -133,6 +132,16 @@ int PackVmlinuzI386::decompressKernel()
fi->seek(0, SEEK_SET);
fi->readx(obuf, file_size);
// Find "ljmp $__BOOT_CS,$__PHYSICAL_START" if any.
// See startup_32: in linux/arch/i386/boot/compressed/head.S
char const *p = (char const *)&obuf[setup_size];
for (int j= 0; j < 0x200; ++j, ++p)
if (0==strncmp("\xEA\x00\x00", p, 3) && 0==(0xf & p[3]) && 0==p[4]) {
/* whole megabyte < 16MB */
physical_start = get_le32(1+ p);
break;
}
checkAlreadyPacked(obuf + setup_size, UPX_MIN(file_size - setup_size, 1024));
for (int gzoff = setup_size; gzoff < file_size; gzoff++)
@ -295,7 +304,7 @@ void PackVmlinuzI386::pack(OutputFile *fo)
// prepare filter
Filter ft(ph.level);
ft.buf_len = ph.u_len;
ft.addvalue = kernel_entry; // saves 4 bytes in unfilter code
ft.addvalue = physical_start; // saves 4 bytes in unfilter code
// compress
upx_compress_config_t cconf; cconf.reset();
@ -308,7 +317,7 @@ void PackVmlinuzI386::pack(OutputFile *fo)
defineFilterSymbols(linker, &ft);
defineDecompressorSymbols();
linker->defineSymbol("src_for_decompressor", zimage_offset + lsize);
linker->defineSymbol("original_entry", kernel_entry);
linker->defineSymbol("original_entry", physical_start);
linker->defineSymbol("stack_offset", stack_offset_during_uncompression);
linker->relocate();
@ -383,7 +392,7 @@ void PackBvmlinuzI386::pack(OutputFile *fo)
// prepare filter
Filter ft(ph.level);
ft.buf_len = ph.u_len;
ft.addvalue = kernel_entry; // saves 4 bytes in unfilter code
ft.addvalue = physical_start; // saves 4 bytes in unfilter code
upx_compress_config_t cconf; cconf.reset();
// limit stack size needed for runtime decompression
@ -420,10 +429,10 @@ void PackBvmlinuzI386::pack(OutputFile *fo)
const unsigned edi = decompr_pos + d_len4 - 4; // copy to
const unsigned esi = ALIGN_UP(c_len + lsize, 4) - 4; // copy from
linker->defineSymbol("decompressor", decompr_pos);
linker->defineSymbol("src_for_decompressor", bzimage_offset + decompr_pos - c_len);
linker->defineSymbol("decompressor", decompr_pos - bzimage_offset + physical_start);
linker->defineSymbol("src_for_decompressor", physical_start + decompr_pos - c_len);
linker->defineSymbol("words_to_copy", copy_size / 4);
linker->defineSymbol("copy_dest", bzimage_offset + edi);
linker->defineSymbol("copy_dest", physical_start + edi);
linker->defineSymbol("copy_source", bzimage_offset + esi);
defineFilterSymbols(linker, &ft);
@ -431,7 +440,7 @@ void PackBvmlinuzI386::pack(OutputFile *fo)
linker->defineSymbol("filter_length", ph.u_len); // redefine
}
defineDecompressorSymbols();
linker->defineSymbol("original_entry", kernel_entry);
linker->defineSymbol("original_entry", physical_start);
linker->defineSymbol("stack_offset", stack_offset_during_uncompression);
linker->relocate();
@ -493,7 +502,7 @@ void PackVmlinuzI386::unpack(OutputFile *fo)
// unfilter
Filter ft(ph.level);
ft.init(ph.filter, kernel_entry);
ft.init(ph.filter, physical_start);
ft.cto = (unsigned char) ph.filter_cto;
ft.unfilter(obuf, ph.u_len);

1
src/p_vmlinz.h
View File

@ -86,6 +86,7 @@ protected:
MemBuffer setup_buf;
int setup_size;
unsigned physical_start;
};