1 /* Bounded-pointer definitions for x86-64 assembler. 2 Copyright (C) 2001 Free Software Foundation, Inc. 3 4 The GNU C Library is free software; you can redistribute it and/or 5 modify it under the terms of the GNU Lesser General Public 6 License as published by the Free Software Foundation; either 7 version 2.1 of the License, or (at your option) any later version. 8 9 The GNU C Library is distributed in the hope that it will be useful, 10 but WITHOUT ANY WARRANTY; without even the implied warranty of 11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 12 Lesser General Public License for more details. 13 14 You should have received a copy of the GNU Lesser General Public 15 License along with the GNU C Library; if not, write to the Free 16 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 17 02111-1307 USA. */ 18 19 #ifndef _bp_asm_h_ 20 # define _bp_asm_h_ 1 21 22 # if __ASSEMBLER__ 23 24 # if __BOUNDED_POINTERS__ 25 26 /* Bounded pointers occupy three words. */ 27 # define PTR_SIZE 24 28 /* Bounded pointer return values are passed back through a hidden 29 argument that points to caller-allocate space. The hidden arg 30 occupies one word on the stack. */ 31 # define RTN_SIZE 6 32 /* Although the caller pushes the hidden arg, the callee is 33 responsible for popping it. */ 34 # define RET_PTR ret $RTN_SIZE 35 /* Maintain frame pointer chain in leaf assembler functions for the benefit 36 of debugging stack traces when bounds violations occur. */ 37 # define ENTER pushq %rbp; movq %rsp, %rbp 38 # define LEAVE movq %rbp, %rsp; popq %rbp 39 /* Stack space overhead of procedure-call linkage: return address and 40 frame pointer. */ 41 # define LINKAGE 16 42 /* Stack offset of return address after calling ENTER. */ 43 # define PCOFF 8 44 45 /* Int 5 is the "bound range" exception also raised by the "bound" 46 instruction. */ 47 # define BOUNDS_VIOLATED int $5 48 49 # define CHECK_BOUNDS_LOW(VAL_REG, BP_MEM) \ 50 cmpq 8+BP_MEM, VAL_REG; \ 51 jae 0f; /* continue if value >= low */ \ 52 BOUNDS_VIOLATED; \ 53 0: 54 55 # define CHECK_BOUNDS_HIGH(VAL_REG, BP_MEM, Jcc) \ 56 cmpq 16+BP_MEM, VAL_REG; \ 57 Jcc 0f; /* continue if value < high */ \ 58 BOUNDS_VIOLATED; \ 59 0: 60 61 # define CHECK_BOUNDS_BOTH(VAL_REG, BP_MEM) \ 62 cmpq 8+BP_MEM, VAL_REG; \ 63 jb 1f; /* die if value < low */ \ 64 cmpq 16+BP_MEM, VAL_REG; \ 65 jb 0f; /* continue if value < high */ \ 66 1: BOUNDS_VIOLATED; \ 67 0: 68 69 # define CHECK_BOUNDS_BOTH_WIDE(VAL_REG, BP_MEM, LENGTH) \ 70 CHECK_BOUNDS_LOW(VAL_REG, BP_MEM); \ 71 addl LENGTH, VAL_REG; \ 72 cmpq 16+BP_MEM, VAL_REG; \ 73 jbe 0f; /* continue if value <= high */ \ 74 BOUNDS_VIOLATED; \ 75 0: subq LENGTH, VAL_REG /* restore value */ 76 77 /* Take bounds from BP_MEM and affix them to the pointer 78 value in %rax, stuffing all into memory at RTN(%esp). 79 Use %rdx as a scratch register. */ 80 81 # define RETURN_BOUNDED_POINTER(BP_MEM) \ 82 movq RTN(%rsp), %rdx; \ 83 movq %rax, 0(%rdx); \ 84 movq 8+BP_MEM, %rax; \ 85 movq %rax, 4(%rdx); \ 86 movq 16+BP_MEM, %rax; \ 87 movq %rax, 8(%rdx) 88 89 # define RETURN_NULL_BOUNDED_POINTER \ 90 movl RTN(%rsp), %rdx; \ 91 movl %rax, 0(%rdx); \ 92 movl %rax, 4(%rdx); \ 93 movl %rax, 8(%rdx) 94 95 /* The caller of __errno_location is responsible for allocating space 96 for the three-word BP return-value and passing pushing its address 97 as an implicit first argument. */ 98 # define PUSH_ERRNO_LOCATION_RETURN \ 99 subl $16, %esp; \ 100 subl $8, %esp; \ 101 pushq %rsp 102 103 /* __errno_location is responsible for popping the implicit first 104 argument, but we must pop the space for the BP itself. We also 105 dereference the return value in order to dig out the pointer value. */ 106 # define POP_ERRNO_LOCATION_RETURN \ 107 popq %rax; \ 108 addq $16, %rsp 109 110 # else /* !__BOUNDED_POINTERS__ */ 111 112 /* Unbounded pointers occupy one word. */ 113 # define PTR_SIZE 8 114 /* Unbounded pointer return values are passed back in the register %rax. */ 115 # define RTN_SIZE 0 116 /* Use simple return instruction for unbounded pointer values. */ 117 # define RET_PTR ret 118 /* Don't maintain frame pointer chain for leaf assembler functions. */ 119 # define ENTER 120 # define LEAVE 121 /* Stack space overhead of procedure-call linkage: return address only. */ 122 # define LINKAGE 8 123 /* Stack offset of return address after calling ENTER. */ 124 # define PCOFF 0 125 126 # define CHECK_BOUNDS_LOW(VAL_REG, BP_MEM) 127 # define CHECK_BOUNDS_HIGH(VAL_REG, BP_MEM, Jcc) 128 # define CHECK_BOUNDS_BOTH(VAL_REG, BP_MEM) 129 # define CHECK_BOUNDS_BOTH_WIDE(VAL_REG, BP_MEM, LENGTH) 130 # define RETURN_BOUNDED_POINTER(BP_MEM) 131 132 # define RETURN_NULL_BOUNDED_POINTER 133 134 # define PUSH_ERRNO_LOCATION_RETURN 135 # define POP_ERRNO_LOCATION_RETURN 136 137 # endif /* !__BOUNDED_POINTERS__ */ 138 139 # endif /* __ASSEMBLER__ */ 140 141 #endif /* _bp_asm_h_ */ 142