reactos/lib/rtl/i386/except.s

   1 /*
   2  * COPYRIGHT:       See COPYING in the top level directory
   3  * PROJECT:         ReactOS NT Library
   4  * FILE:            lib/rtl/i386/except.S
   5  * PURPOSE:         User-mode exception support for IA-32
   6  * PROGRAMMERS:     Alex Ionescu (alex@relsoft.net)
   7  *                  Casper S. Hornstrup (chorns@users.sourceforge.net)
   8  */
   9
  10 /* INCLUDES ******************************************************************/
  11
  12 #include <ndk/asm.h>
  13 #include <ndk/i386/segment.h>
  14 .intel_syntax noprefix
  15
  16 #define EXCEPTION_UNWINDING         2
  17 #define EXCEPTION_EXIT_UNWIND       4
  18 #define EXCEPTION_UNWIND            (EXCEPTION_UNWINDING | EXCEPTION_EXIT_UNWIND)
  19
  20 #define ExceptionContinueExecution  0
  21 #define ExceptionContinueSearch     1
  22 #define ExceptionNestedException    2
  23 #define ExceptionCollidedUnwind     3
  24
  25 /* FUNCTIONS ****************************************************************/
  26
  27 .globl _RtlpGetExceptionList@0
  28 _RtlpGetExceptionList@0:
  29
  30     /* Return the exception list */
  31     mov eax, [fs:TEB_EXCEPTION_LIST]
  32     ret
  33
  34 .globl _RtlpSetExceptionList@4
  35 _RtlpSetExceptionList@4:
  36
  37     /* Get the new list */
  38     mov ecx, [esp+4]
  39     mov ecx, [ecx]
  40
  41     /* Write it */
  42     mov [fs:TEB_EXCEPTION_LIST], ecx
  43
  44     /* Return */
  45     ret 4
  46
  47 .globl _RtlpGetExceptionAddress@0
  48 _RtlpGetExceptionAddress@0:
  49
  50     /* Return the address from the stack */
  51     mov eax, [ebp+4]
  52
  53     /* Return */
  54     ret
  55
  56 .globl _RtlCaptureContext@4
  57 _RtlCaptureContext@4:
  58
  59     /* Preserve EBX and put the context in it */
  60     push ebx
  61     mov ebx, [esp+8]
  62
  63     /* Save the basic register context */
  64     mov [ebx+CONTEXT_EAX], eax
  65     mov [ebx+CONTEXT_ECX], ecx
  66     mov [ebx+CONTEXT_EDX], edx
  67     mov eax, [esp]              /* We pushed EBX, remember? ;) */
  68     mov [ebx+CONTEXT_EBX], eax
  69     mov [ebx+CONTEXT_ESI], esi
  70     mov [ebx+CONTEXT_EDI], edi
  71
  72     /* Capture the other regs */
  73     jmp CaptureRest
  74
  75 .globl _RtlpCaptureContext@4
  76 _RtlpCaptureContext@4:
  77
  78     /* Preserve EBX and put the context in it */
  79     push ebx
  80     mov ebx, [esp+8]
  81
  82     /* Clear the basic register context */
  83     mov dword ptr [ebx+CONTEXT_EAX], 0
  84     mov dword ptr [ebx+CONTEXT_ECX], 0
  85     mov dword ptr [ebx+CONTEXT_EDX], 0
  86     mov dword ptr [ebx+CONTEXT_EBX], 0
  87     mov dword ptr [ebx+CONTEXT_ESI], 0
  88     mov dword ptr [ebx+CONTEXT_EDI], 0
  89
  90 CaptureRest:
  91     /* Capture the segment registers */
  92     mov [ebx+CONTEXT_SEGCS], cs
  93     mov [ebx+CONTEXT_SEGDS], ds
  94     mov [ebx+CONTEXT_SEGES], es
  95     mov [ebx+CONTEXT_SEGFS], fs
  96     mov [ebx+CONTEXT_SEGGS], gs
  97     mov [ebx+CONTEXT_SEGSS], ss
  98
  99     /* Capture flags */
 100     pushfd
 101     pop [ebx+CONTEXT_EFLAGS]
 102
 103     /* The return address should be in [ebp+4] */
 104     mov eax, [ebp+4]
 105     mov [ebx+CONTEXT_EIP], eax
 106
 107     /* Get EBP */
 108     mov eax, [esp]
 109     mov [ebx+CONTEXT_EBP], eax
 110
 111     /* And get ESP */
 112     mov eax, [ebp+8]
 113     mov [ebx+CONTEXT_ESP], eax
 114
 115     /* Return to the caller */
 116     pop ebx
 117     ret 4
 118
 119 .globl _RtlpExecuteHandlerForException@20
 120 _RtlpExecuteHandlerForException@20:
 121
 122     /* Copy the routine in EDX */
 123     mov edx, offset _RtlpExceptionProtector
 124
 125     /* Jump to common routine */
 126     jmp _RtlpExecuteHandler@20
 127
 128 .globl _RtlpExecuteHandlerForUnwind@20
 129 _RtlpExecuteHandlerForUnwind@20:
 130
 131     /* Copy the routine in EDX */
 132     mov edx, offset _RtlpExceptionProtector
 133
 134     /* Run the common routine */
 135 _RtlpExecuteHandler@20:
 136
 137     /* Save non-volatile */
 138     push ebx
 139     push esi
 140     push edi
 141
 142     /* Clear registers */
 143     xor eax, eax
 144     xor ebx, ebx
 145     xor esi, esi
 146     xor edi, edi
 147
 148     /* Call the 2nd-stage executer */
 149     push [esp+0x20]
 150     push [esp+0x20]
 151     push [esp+0x20]
 152     push [esp+0x20]
 153     push [esp+0x20]
 154     call _RtlpExecuteHandler2@20
 155
 156     /* Restore non-volatile */
 157     pop edi
 158     pop esi
 159     pop ebx
 160     ret 0x14
 161
 162 .globl _RtlpExecuteHandler2@20
 163 _RtlpExecuteHandler2@20:
 164
 165     /* Set up stack frame */
 166     push ebp
 167     mov ebp, esp
 168
 169     /* Save the Frame */
 170     push [ebp+0xC]
 171
 172     /* Push handler address */
 173     push edx
 174
 175     /* Push the exception list */
 176     push [fs:TEB_EXCEPTION_LIST]
 177
 178     /* Link us to it */
 179     mov [fs:TEB_EXCEPTION_LIST], esp
 180
 181     /* Call the handler */
 182     push [ebp+0x14]
 183     push [ebp+0x10]
 184     push [ebp+0xC]
 185     push [ebp+8]
 186     mov ecx, [ebp+0x18]
 187     call ecx
 188
 189     /* Unlink us */
 190     mov esp, [fs:TEB_EXCEPTION_LIST]
 191
 192     /* Restore it */
 193     pop [fs:TEB_EXCEPTION_LIST]
 194
 195     /* Undo stack frame and return */
 196     mov esp, ebp
 197     pop ebp
 198     ret 0x14
 199
 200 _RtlpExceptionProtector:
 201
 202     /* Assume we'll continue */
 203     mov eax, ExceptionContinueSearch
 204
 205     /* Put the exception record in ECX and check the Flags */
 206     mov ecx, [esp+4]
 207     test dword ptr [ecx+EXCEPTION_RECORD_EXCEPTION_FLAGS], EXCEPTION_UNWIND
 208     jnz return
 209
 210     /* Save the frame in ECX and Context in EDX */
 211     mov ecx, [esp+8]
 212     mov edx, [esp+16]
 213
 214     /* Get the nested frame */
 215     mov eax, [ecx+8]
 216
 217     /* Set it as the dispatcher context */
 218     mov [edx], eax
 219
 220     /* Return nested exception */
 221     mov eax, ExceptionNestedException
 222
 223 return:
 224     ret 16
 225
 226 _RtlpUnwindProtector:
 227     /* Assume we'll continue */
 228     mov eax, ExceptionContinueSearch
 229
 230     /* Put the exception record in ECX and check the Flags */
 231     mov ecx, [esp+4]
 232     test dword ptr [ecx+EXCEPTION_RECORD_EXCEPTION_FLAGS], EXCEPTION_UNWIND
 233     jnz .return
 234
 235     /* Save the frame in ECX and Context in EDX */
 236     mov ecx, [esp+8]
 237     mov edx, [esp+16]
 238
 239     /* Get the nested frame */
 240     mov eax, [ecx+8]
 241
 242     /* Set it as the dispatcher context */
 243     mov [edx], eax
 244
 245     /* Return collided unwind */
 246     mov eax, ExceptionCollidedUnwind
 247
 248 .return:
 249     ret 16
 250