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144 lines
4.8 KiB
C
144 lines
4.8 KiB
C
/* Bounded-pointer definitions for x86 assembler.
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Copyright (C) 2000 Free Software Foundation, Inc.
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Contributed by Greg McGary <greg@mcgary.org>
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This file is part of the GNU C Library. Its master source is NOT part of
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the C library, however. The master source lives in the GNU MP Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library 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 GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#ifndef _bp_asm_h_
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# define _bp_asm_h_ 1
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# if __ASSEMBLER__
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# if __BOUNDED_POINTERS__
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/* Bounded pointers occupy three words. */
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# define PTR_SIZE 12
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/* Bounded pointer return values are passed back through a hidden
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argument that points to caller-allocate space. The hidden arg
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occupies one word on the stack. */
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# define RTN_SIZE 4
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/* Although the caller pushes the hidden arg, the callee is
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responsible for popping it. */
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# define RET_PTR ret $RTN_SIZE
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/* Maintain frame pointer chain in leaf assembler functions for the benefit
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of debugging stack traces when bounds violations occur. */
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# define ENTER pushl %ebp; movl %esp, %ebp
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# define LEAVE movl %ebp, %esp; popl %ebp
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/* Stack space overhead of procedure-call linkage: return address and
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frame pointer. */
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# define LINKAGE 8
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/* Stack offset of return address after calling ENTER. */
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# define PCOFF 4
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/* Int 5 is the "bound range" exception also raised by the "bound"
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instruction. */
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# define BOUNDS_VIOLATED int $5
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# define CHECK_BOUNDS_LOW(VAL_REG, BP_MEM) \
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cmpl 4+BP_MEM, VAL_REG; \
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jae 0f; /* continue if value >= low */ \
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BOUNDS_VIOLATED; \
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0:
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# define CHECK_BOUNDS_HIGH(VAL_REG, BP_MEM, Jcc) \
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cmpl 8+BP_MEM, VAL_REG; \
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Jcc 0f; /* continue if value < high */ \
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BOUNDS_VIOLATED; \
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0:
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# define CHECK_BOUNDS_BOTH(VAL_REG, BP_MEM) \
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cmpl 4+BP_MEM, VAL_REG; \
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jb 1f; /* die if value < low */ \
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cmpl 8+BP_MEM, VAL_REG; \
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jb 0f; /* continue if value < high */ \
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1: BOUNDS_VIOLATED; \
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0:
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# define CHECK_BOUNDS_BOTH_WIDE(VAL_REG, BP_MEM, LENGTH) \
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CHECK_BOUNDS_LOW(VAL_REG, BP_MEM); \
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addl LENGTH, VAL_REG; \
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cmpl 8+BP_MEM, VAL_REG; \
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jbe 0f; /* continue if value <= high */ \
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BOUNDS_VIOLATED; \
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0: subl LENGTH, VAL_REG /* restore value */
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/* Take bounds from BP_MEM and affix them to the pointer
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value in %eax, stuffing all into memory at RTN(%esp).
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Use %edx as a scratch register. */
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# define RETURN_BOUNDED_POINTER(BP_MEM) \
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movl RTN(%esp), %edx; \
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movl %eax, 0(%edx); \
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movl 4+BP_MEM, %eax; \
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movl %eax, 4(%edx); \
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movl 8+BP_MEM, %eax; \
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movl %eax, 8(%edx)
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# define RETURN_NULL_BOUNDED_POINTER \
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movl RTN(%esp), %edx; \
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movl %eax, 0(%edx); \
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movl %eax, 4(%edx); \
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movl %eax, 8(%edx)
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/* The caller of __errno_location is responsible for allocating space
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for the three-word BP return-value and passing pushing its address
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as an implicit first argument. */
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# define PUSH_ERRNO_LOCATION_RETURN \
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subl $8, %esp; \
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subl $4, %esp; \
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pushl %esp
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/* __errno_location is responsible for popping the implicit first
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argument, but we must pop the space for the BP itself. We also
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dereference the return value in order to dig out the pointer value. */
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# define POP_ERRNO_LOCATION_RETURN \
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popl %eax; \
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addl $8, %esp
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# else /* !__BOUNDED_POINTERS__ */
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/* Unbounded pointers occupy one word. */
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# define PTR_SIZE 4
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/* Unbounded pointer return values are passed back in the register %eax. */
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# define RTN_SIZE 0
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/* Use simple return instruction for unbounded pointer values. */
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# define RET_PTR ret
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/* Don't maintain frame pointer chain for leaf assembler functions. */
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# define ENTER
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# define LEAVE
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/* Stack space overhead of procedure-call linkage: return address only. */
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# define LINKAGE 4
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/* Stack offset of return address after calling ENTER. */
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# define PCOFF 0
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# define CHECK_BOUNDS_LOW(VAL_REG, BP_MEM)
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# define CHECK_BOUNDS_HIGH(VAL_REG, BP_MEM, Jcc)
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# define CHECK_BOUNDS_BOTH(VAL_REG, BP_MEM)
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# define CHECK_BOUNDS_BOTH_WIDE(VAL_REG, BP_MEM, LENGTH)
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# define RETURN_BOUNDED_POINTER(BP_MEM)
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# define RETURN_NULL_BOUNDED_POINTER
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# define PUSH_ERRNO_LOCATION_RETURN
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# define POP_ERRNO_LOCATION_RETURN
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# endif /* !__BOUNDED_POINTERS__ */
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# endif /* __ASSEMBLER__ */
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#endif /* _bp_asm_h_ */
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