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bb12df9732
s/addrees/address/ Signed-off-by: Paul Menzel <paulepanter@users.sourceforge.net> Acked-by: Ward Vandewege <ward@gnu.org> git-svn-id: svn://coreboot.org/repository/coreboot-v3@777 f3766cd6-281f-0410-b1cd-43a5c92072e9
60 lines
2 KiB
Bash
Executable file
60 lines
2 KiB
Bash
Executable file
#!/bin/bash
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#
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# This file is part of the coreboot project.
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#
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# Copyright (C) 2008 Carl-Daniel Hailfinger
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; version 2 of the License.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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#
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#
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# This program creates wrappers to be able to call non-PIC code from PIC code
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# for the x86 instruction architecture. The wrappers are needed because of the
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# ABI mismatch between PIC and non-PIC.
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# Other architectures may need similar wrappers.
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echo -e "\
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# These wrappers must fulfill the following conditions:
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# - They must not clobber the stuff already on the stack
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# - They must not clobber any register
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# - The jump/call must be absolute
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# - Neither caller nor callee shall have to be modified
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# - The parameters on the stack shall not be touched
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# - Referencing fixed memory locations is a no-go for PIC
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#
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# That rules out the following instructions:
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# - All relative jumps
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# - All jumps with address given in register/fixed memory
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# - All call instructions
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#
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# The only jump instructions left are far jumps, but hardcoding the code
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# segment in advance is ugly/bad/unworkable.
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#
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# The trick is to push the destination address on the stack with an immediate
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# instruction (no register/memory references), then return to that address.
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# This emulates the nonexisting "Jump near, absolute, address in operand"
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# instruction in the x86 instruction set.
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#
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.text
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"
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while read a; do
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echo -e "\
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.globl $a
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.type $a, @function
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$a:
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pushl \$stage0_$a
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ret
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"
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done
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