1 /* Bounded-pointer definitions for x86 assembler. 2 Copyright (C) 2000 Free Software Foundation, Inc. 3 Contributed by Greg McGary <greg@mcgary.org> 4 This file is part of the GNU C Library. Its master source is NOT part of 5 the C library, however. The master source lives in the GNU MP Library. 6 7 The GNU C Library is free software; you can redistribute it and/or 8 modify it under the terms of the GNU Lesser General Public 9 License as published by the Free Software Foundation; either 10 version 2.1 of the License, or (at your option) any later version. 11 12 The GNU C Library is distributed in the hope that it will be useful, 13 but WITHOUT ANY WARRANTY; without even the implied warranty of 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15 Lesser General Public License for more details. 16 17 You should have received a copy of the GNU Lesser General Public 18 License along with the GNU C Library; if not, write to the Free 19 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 20 02111-1307 USA. */ 21 22 #ifndef _bp_asm_h_ 23 # define _bp_asm_h_ 1 24 25 # if __ASSEMBLER__ 26 27 # if __BOUNDED_POINTERS__ 28 29 /* Bounded pointers occupy three words. */ 30 # define PTR_SIZE 12 31 /* Bounded pointer return values are passed back through a hidden 32 argument that points to caller-allocate space. The hidden arg 33 occupies one word on the stack. */ 34 # define RTN_SIZE 4 35 /* Although the caller pushes the hidden arg, the callee is 36 responsible for popping it. */ 37 # define RET_PTR ret $RTN_SIZE 38 /* Maintain frame pointer chain in leaf assembler functions for the benefit 39 of debugging stack traces when bounds violations occur. */ 40 # define ENTER pushl %ebp; movl %esp, %ebp 41 # define LEAVE movl %ebp, %esp; popl %ebp 42 /* Stack space overhead of procedure-call linkage: return address and 43 frame pointer. */ 44 # define LINKAGE 8 45 /* Stack offset of return address after calling ENTER. */ 46 # define PCOFF 4 47 48 /* Int 5 is the "bound range" exception also raised by the "bound" 49 instruction. */ 50 # define BOUNDS_VIOLATED int $5 51 52 # define CHECK_BOUNDS_LOW(VAL_REG, BP_MEM) \ 53 cmpl 4+BP_MEM, VAL_REG; \ 54 jae 0f; /* continue if value >= low */ \ 55 BOUNDS_VIOLATED; \ 56 0: 57 58 # define CHECK_BOUNDS_HIGH(VAL_REG, BP_MEM, Jcc) \ 59 cmpl 8+BP_MEM, VAL_REG; \ 60 Jcc 0f; /* continue if value < high */ \ 61 BOUNDS_VIOLATED; \ 62 0: 63 64 # define CHECK_BOUNDS_BOTH(VAL_REG, BP_MEM) \ 65 cmpl 4+BP_MEM, VAL_REG; \ 66 jb 1f; /* die if value < low */ \ 67 cmpl 8+BP_MEM, VAL_REG; \ 68 jb 0f; /* continue if value < high */ \ 69 1: BOUNDS_VIOLATED; \ 70 0: 71 72 # define CHECK_BOUNDS_BOTH_WIDE(VAL_REG, BP_MEM, LENGTH) \ 73 CHECK_BOUNDS_LOW(VAL_REG, BP_MEM); \ 74 addl LENGTH, VAL_REG; \ 75 cmpl 8+BP_MEM, VAL_REG; \ 76 jbe 0f; /* continue if value <= high */ \ 77 BOUNDS_VIOLATED; \ 78 0: subl LENGTH, VAL_REG /* restore value */ 79 80 /* Take bounds from BP_MEM and affix them to the pointer 81 value in %eax, stuffing all into memory at RTN(%esp). 82 Use %edx as a scratch register. */ 83 84 # define RETURN_BOUNDED_POINTER(BP_MEM) \ 85 movl RTN(%esp), %edx; \ 86 movl %eax, 0(%edx); \ 87 movl 4+BP_MEM, %eax; \ 88 movl %eax, 4(%edx); \ 89 movl 8+BP_MEM, %eax; \ 90 movl %eax, 8(%edx) 91 92 # define RETURN_NULL_BOUNDED_POINTER \ 93 movl RTN(%esp), %edx; \ 94 movl %eax, 0(%edx); \ 95 movl %eax, 4(%edx); \ 96 movl %eax, 8(%edx) 97 98 /* The caller of __errno_location is responsible for allocating space 99 for the three-word BP return-value and passing pushing its address 100 as an implicit first argument. */ 101 # define PUSH_ERRNO_LOCATION_RETURN \ 102 subl $8, %esp; \ 103 subl $4, %esp; \ 104 pushl %esp 105 106 /* __errno_location is responsible for popping the implicit first 107 argument, but we must pop the space for the BP itself. We also 108 dereference the return value in order to dig out the pointer value. */ 109 # define POP_ERRNO_LOCATION_RETURN \ 110 popl %eax; \ 111 addl $8, %esp 112 113 # else /* !__BOUNDED_POINTERS__ */ 114 115 /* Unbounded pointers occupy one word. */ 116 # define PTR_SIZE 4 117 /* Unbounded pointer return values are passed back in the register %eax. */ 118 # define RTN_SIZE 0 119 /* Use simple return instruction for unbounded pointer values. */ 120 # define RET_PTR ret 121 /* Don't maintain frame pointer chain for leaf assembler functions. */ 122 # define ENTER 123 # define LEAVE 124 /* Stack space overhead of procedure-call linkage: return address only. */ 125 # define LINKAGE 4 126 /* Stack offset of return address after calling ENTER. */ 127 # define PCOFF 0 128 129 # define CHECK_BOUNDS_LOW(VAL_REG, BP_MEM) 130 # define CHECK_BOUNDS_HIGH(VAL_REG, BP_MEM, Jcc) 131 # define CHECK_BOUNDS_BOTH(VAL_REG, BP_MEM) 132 # define CHECK_BOUNDS_BOTH_WIDE(VAL_REG, BP_MEM, LENGTH) 133 # define RETURN_BOUNDED_POINTER(BP_MEM) 134 135 # define RETURN_NULL_BOUNDED_POINTER 136 137 # define PUSH_ERRNO_LOCATION_RETURN 138 # define POP_ERRNO_LOCATION_RETURN 139 140 # endif /* !__BOUNDED_POINTERS__ */ 141 142 # endif /* __ASSEMBLER__ */ 143 144 #endif /* _bp_asm_h_ */ 145