1 .section ".text","ax" 2 3#define SIGTRAP 5 4 5#define SIZEOF_I386_REGS 32 6#define SIZEOF_I386_FLAGS 4 7 8/* When invoked, the stack contains: eflags, cs, eip, signo. */ 9#define IH_OFFSET_GDB_REGS ( 0 ) 10#define IH_OFFSET_GDB_EIP ( IH_OFFSET_GDB_REGS + SIZEOF_I386_REGS ) 11#define IH_OFFSET_GDB_EFLAGS ( IH_OFFSET_GDB_EIP + 4 ) 12#define IH_OFFSET_GDB_SEG_REGS ( IH_OFFSET_GDB_EFLAGS + SIZEOF_I386_FLAGS ) 13#define IH_OFFSET_GDB_END ( IH_OFFSET_GDB_SEG_REGS + 6 * 4 ) 14#define IH_OFFSET_OLD_EIP ( IH_OFFSET_GDB_END ) 15#define IH_OFFSET_OLD_CS ( IH_OFFSET_OLD_EIP + 4 ) 16#define IH_OFFSET_OLD_EFLAGS ( IH_OFFSET_OLD_CS + 4 ) 17#define IH_OFFSET_END ( IH_OFFSET_OLD_EFLAGS + 4 ) 18 19/* We also access the stack whilst still storing or restoring 20 * the register snapshot. Since ESP is in flux, we need 21 * special offsets. 22 */ 23#define IH_OFFSET_FLUX_OLD_CS ( IH_OFFSET_OLD_CS - 44 ) 24#define IH_OFFSET_FLUX_OLD_EFLAGS ( IH_OFFSET_OLD_EFLAGS - 40 ) 25#define IH_OFFSET_FLUX_OLD_EIP ( IH_OFFSET_OLD_EIP - 36 ) 26#define IH_OFFSET_FLUX_END ( IH_OFFSET_END - 20 ) 27 28 .global int_handler 29int_handler: 30 /* Store CPU state in GDB register snapshot */ 31 pushw $0 32 pushw %gs 33 pushw $0 34 pushw %fs 35 pushw $0 36 pushw %es 37 pushw $0 38 pushw %ds 39 pushw $0 40 pushw %ss 41 pushw $0 42 pushw IH_OFFSET_FLUX_OLD_CS + 2(%esp) 43 pushl IH_OFFSET_FLUX_OLD_EFLAGS(%esp) 44 pushl IH_OFFSET_FLUX_OLD_EIP(%esp) 45 pushl %edi 46 pushl %esi 47 pushl %ebp 48 leal IH_OFFSET_FLUX_END(%esp), %edi 49 pushl %edi /* old ESP */ 50 pushl %ebx 51 pushl %edx 52 pushl %ecx 53 pushl %eax 54 55 /* Call GDB stub exception handler */ 56 movl $SIGTRAP, %eax 57 movl %esp, %edx 58 call gdbstub_handler 59 60 /* Restore CPU state from GDB register snapshot */ 61 popl %eax 62 popl %ecx 63 popl %edx 64 popl %ebx 65 addl $4, %esp /* Changing ESP currently not supported */ 66 popl %ebp 67 popl %esi 68 popl %edi 69 popl IH_OFFSET_FLUX_OLD_EIP(%esp) 70 popl IH_OFFSET_FLUX_OLD_EFLAGS(%esp) 71 popl IH_OFFSET_FLUX_OLD_CS(%esp) 72 popl %ss 73 popl %ds 74 popl %es 75 popl %fs 76 popl %gs 77 iret 78