1 /* libunwind - a platform-independent unwind library 2 Copyright (C) 2010 Konstantin Belousov <kib (at) freebsd.org> 3 4 This file is part of libunwind. 5 6 Permission is hereby granted, free of charge, to any person obtaining 7 a copy of this software and associated documentation files (the 8 "Software"), to deal in the Software without restriction, including 9 without limitation the rights to use, copy, modify, merge, publish, 10 distribute, sublicense, and/or sell copies of the Software, and to 11 permit persons to whom the Software is furnished to do so, subject to 12 the following conditions: 13 14 The above copyright notice and this permission notice shall be 15 included in all copies or substantial portions of the Software. 16 17 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 18 EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 19 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 20 NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE 21 LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION 22 OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION 23 WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ 24 25 #include "offsets.h" 26 27 .global _Ux86_getcontext 28 .type _Ux86_getcontext, @function 29 _Ux86_getcontext: 30 .cfi_startproc 31 pushl %eax 32 .cfi_adjust_cfa_offset 4 33 mov 8(%esp),%eax /* ucontext_t* */ 34 popl FREEBSD_UC_MCONTEXT_EAX_OFF(%eax) 35 .cfi_adjust_cfa_offset 4 36 movl %ebx, FREEBSD_UC_MCONTEXT_EBX_OFF(%eax) 37 movl %ecx, FREEBSD_UC_MCONTEXT_ECX_OFF(%eax) 38 movl %edx, FREEBSD_UC_MCONTEXT_EDX_OFF(%eax) 39 movl %edi, FREEBSD_UC_MCONTEXT_EDI_OFF(%eax) 40 movl %esi, FREEBSD_UC_MCONTEXT_ESI_OFF(%eax) 41 movl %ebp, FREEBSD_UC_MCONTEXT_EBP_OFF(%eax) 42 43 movl (%esp), %ecx 44 movl %ecx, FREEBSD_UC_MCONTEXT_EIP_OFF(%eax) 45 46 leal 4(%esp), %ecx /* Exclude the return address. */ 47 movl %ecx, FREEBSD_UC_MCONTEXT_ESP_OFF(%eax) 48 49 xorl %ecx, %ecx 50 movw %fs, %cx 51 movl %ecx, FREEBSD_UC_MCONTEXT_FS_OFF(%eax) 52 movw %gs, %cx 53 movl %ecx, FREEBSD_UC_MCONTEXT_GS_OFF(%eax) 54 movw %ds, %cx 55 movl %ecx, FREEBSD_UC_MCONTEXT_DS_OFF(%eax) 56 movw %es, %cx 57 movl %ecx, FREEBSD_UC_MCONTEXT_ES_OFF(%eax) 58 movw %ss, %cx 59 movl %ecx, FREEBSD_UC_MCONTEXT_SS_OFF(%eax) 60 movw %cs, %cx 61 movl %ecx, FREEBSD_UC_MCONTEXT_CS_OFF(%eax) 62 63 pushfl 64 .cfi_adjust_cfa_offset 4 65 popl FREEBSD_UC_MCONTEXT_EFLAGS_OFF(%eax) 66 .cfi_adjust_cfa_offset -4 67 68 movl $0, FREEBSD_UC_MCONTEXT_TRAPNO_OFF(%eax) 69 70 movl $FREEBSD_UC_MCONTEXT_FPOWNED_FPU,\ 71 FREEBSD_UC_MCONTEXT_OWNEDFP_OFF(%eax) 72 movl $FREEBSD_UC_MCONTEXT_FPFMT_XMM,\ 73 FREEBSD_UC_MCONTEXT_FPFORMAT_OFF(%eax) 74 75 /* 76 * Require CPU with fxsave implemented, and enabled by OS. 77 * 78 * If passed ucontext is not aligned to 16-byte boundary, 79 * save fpu context into temporary aligned location on stack 80 * and then copy. 81 */ 82 leal FREEBSD_UC_MCONTEXT_FPSTATE_OFF(%eax), %edx 83 testl $0xf, %edx 84 jne 2f 85 fxsave (%edx) /* fast path, passed ucontext save area was aligned */ 86 1: movl $FREEBSD_UC_MCONTEXT_MC_LEN_VAL,\ 87 FREEBSD_UC_MCONTEXT_MC_LEN_OFF(%eax) 88 89 xorl %eax, %eax 90 ret 91 92 2: movl %edx, %edi /* not aligned, do the dance */ 93 subl $512 + 16, %esp /* save area and 16 bytes for alignment */ 94 .cfi_adjust_cfa_offset 512 + 16 95 movl %esp, %edx 96 orl $0xf, %edx /* align *%edx to 16-byte up */ 97 incl %edx 98 fxsave (%edx) 99 movl %edx, %esi /* copy to the final destination */ 100 movl $512/4,%ecx 101 rep; movsl 102 addl $512 + 16, %esp /* restore the stack */ 103 .cfi_adjust_cfa_offset -512 - 16 104 movl FREEBSD_UC_MCONTEXT_ESI_OFF(%eax), %esi 105 movl FREEBSD_UC_MCONTEXT_EDI_OFF(%eax), %edi 106 jmp 1b 107 108 .cfi_endproc 109 .size _Ux86_getcontext, . - _Ux86_getcontext 110 111 /* We do not need executable stack. */ 112 .section .note.GNU-stack,"",@progbits 113
