#endif
}
-
-static unsigned char __obscure_ccall_ret_code [] =
#if defined(i386_TARGET_ARCH)
-/* Now here's something obscure for you:
-
- When generating an adjustor thunk that uses the C calling
- convention, we have to make sure that the thunk kicks off
- the process of jumping into Haskell with a tail jump. Why?
- Because as a result of jumping in into Haskell we may end
- up freeing the very adjustor thunk we came from using
- freeHaskellFunctionPtr(). Hence, we better not return to
- the adjustor code on our way out, since it could by then
- point to junk.
-
- The fix is readily at hand, just include the opcodes
- for the C stack fixup code that we need to perform when
- returning in some static piece of memory and arrange
- to return to it before tail jumping from the adjustor thunk.
-
- For this to work we make the assumption that bytes in .data
- are considered executable.
-*/
- { 0x83, 0xc4, 0x04 /* addl $0x4, %esp */
- , 0xc3 /* ret */
- };
-#else
-/* No such mind-twisters on non-Intel platforms */
- { };
+static unsigned char *obscure_ccall_ret_code;
#endif
#if defined(alpha_TARGET_ARCH)
<c>: ff e0 jmp %eax # and jump to it.
# the callee cleans up the stack
*/
- if ((adjustor = stgMallocBytes(14, "createAdjustor")) != NULL) {
- unsigned char *const adj_code = (unsigned char *)adjustor;
- adj_code[0x00] = (unsigned char)0x58; /* popl %eax */
+ adjustor = stgMallocBytes(14, "createAdjustor");
+ unsigned char *const adj_code = (unsigned char *)adjustor;
+ adj_code[0x00] = (unsigned char)0x58; /* popl %eax */
- adj_code[0x01] = (unsigned char)0x68; /* pushl hptr (which is a dword immediate ) */
- *((StgStablePtr*)(adj_code + 0x02)) = (StgStablePtr)hptr;
+ adj_code[0x01] = (unsigned char)0x68; /* pushl hptr (which is a dword immediate ) */
+ *((StgStablePtr*)(adj_code + 0x02)) = (StgStablePtr)hptr;
- adj_code[0x06] = (unsigned char)0x50; /* pushl %eax */
+ adj_code[0x06] = (unsigned char)0x50; /* pushl %eax */
- adj_code[0x07] = (unsigned char)0xb8; /* movl $wptr, %eax */
- *((StgFunPtr*)(adj_code + 0x08)) = (StgFunPtr)wptr;
+ adj_code[0x07] = (unsigned char)0xb8; /* movl $wptr, %eax */
+ *((StgFunPtr*)(adj_code + 0x08)) = (StgFunPtr)wptr;
- adj_code[0x0c] = (unsigned char)0xff; /* jmp %eax */
- adj_code[0x0d] = (unsigned char)0xe0;
+ adj_code[0x0c] = (unsigned char)0xff; /* jmp %eax */
+ adj_code[0x0d] = (unsigned char)0xe0;
- execPage(adjustor, pageExecuteReadWrite);
- }
+ execPage(adjustor, pageExecuteReadWrite);
#endif
break;
<00>: 68 ef be ad de pushl $0xdeadbeef # constant is large enough to
# hold a StgStablePtr
<05>: b8 fa ef ff 00 movl $0x00ffeffa, %eax # load up wptr
- <0a>: 68 ef be ad de pushl $__obscure_ccall_ret_code # push the return address
+ <0a>: 68 ef be ad de pushl $obscure_ccall_ret_code # push the return address
<0f>: ff e0 jmp *%eax # jump to wptr
The ccall'ing version is a tad different, passing in the return
via the stable pointer.) (The auto-generated C stub is in on this
game, don't worry :-)
- See the comment next to __obscure_ccall_ret_code why we need to
+ See the comment next to obscure_ccall_ret_code why we need to
perform a tail jump instead of a call, followed by some C stack
fixup.
That's (thankfully) the case here with the restricted set of
return types that we support.
*/
- if ((adjustor = stgMallocBytes(17, "createAdjustor")) != NULL) {
- unsigned char *const adj_code = (unsigned char *)adjustor;
+ adjustor = stgMallocBytes(17, "createAdjustor");
+ unsigned char *const adj_code = (unsigned char *)adjustor;
- adj_code[0x00] = (unsigned char)0x68; /* pushl hptr (which is a dword immediate ) */
- *((StgStablePtr*)(adj_code+0x01)) = (StgStablePtr)hptr;
+ adj_code[0x00] = (unsigned char)0x68; /* pushl hptr (which is a dword immediate ) */
+ *((StgStablePtr*)(adj_code+0x01)) = (StgStablePtr)hptr;
- adj_code[0x05] = (unsigned char)0xb8; /* movl $wptr, %eax */
- *((StgFunPtr*)(adj_code + 0x06)) = (StgFunPtr)wptr;
+ adj_code[0x05] = (unsigned char)0xb8; /* movl $wptr, %eax */
+ *((StgFunPtr*)(adj_code + 0x06)) = (StgFunPtr)wptr;
- adj_code[0x0a] = (unsigned char)0x68; /* pushl __obscure_ccall_ret_code */
- *((StgFunPtr*)(adj_code + 0x0b)) = (StgFunPtr)__obscure_ccall_ret_code;
+ adj_code[0x0a] = (unsigned char)0x68; /* pushl obscure_ccall_ret_code */
+ *((StgFunPtr*)(adj_code + 0x0b)) = (StgFunPtr)obscure_ccall_ret_code;
- adj_code[0x0f] = (unsigned char)0xff; /* jmp *%eax */
- adj_code[0x10] = (unsigned char)0xe0;
+ adj_code[0x0f] = (unsigned char)0xff; /* jmp *%eax */
+ adj_code[0x10] = (unsigned char)0xe0;
- execPage(adjustor, pageExecuteReadWrite);
- }
+ execPage(adjustor, pageExecuteReadWrite);
#elif defined(sparc_TARGET_ARCH)
/* Magic constant computed by inspecting the code length of the following
assembly language snippet (offset and machine code prefixed):
similarly, and local variables should be accessed via %fp, not %sp. In a
nutshell: This should work! (Famous last words! :-)
*/
- if ((adjustor = stgMallocBytes(4*(11+1), "createAdjustor")) != NULL) {
- unsigned long *const adj_code = (unsigned long *)adjustor;
-
- adj_code[ 0] = 0x9C23A008UL; /* sub %sp, 8, %sp */
- adj_code[ 1] = 0xDA23A060UL; /* st %o5, [%sp + 96] */
- adj_code[ 2] = 0xD823A05CUL; /* st %o4, [%sp + 92] */
- adj_code[ 3] = 0x9A10000BUL; /* mov %o3, %o5 */
- adj_code[ 4] = 0x9810000AUL; /* mov %o2, %o4 */
- adj_code[ 5] = 0x96100009UL; /* mov %o1, %o3 */
- adj_code[ 6] = 0x94100008UL; /* mov %o0, %o2 */
- adj_code[ 7] = 0x13000000UL; /* sethi %hi(wptr), %o1 */
- adj_code[ 7] |= ((unsigned long)wptr) >> 10;
- adj_code[ 8] = 0x11000000UL; /* sethi %hi(hptr), %o0 */
- adj_code[ 8] |= ((unsigned long)hptr) >> 10;
- adj_code[ 9] = 0x81C26000UL; /* jmp %o1 + %lo(wptr) */
- adj_code[ 9] |= ((unsigned long)wptr) & 0x000003FFUL;
- adj_code[10] = 0x90122000UL; /* or %o0, %lo(hptr), %o0 */
- adj_code[10] |= ((unsigned long)hptr) & 0x000003FFUL;
-
- adj_code[11] = (unsigned long)hptr;
-
- /* flush cache */
- asm("flush %0" : : "r" (adj_code ));
- asm("flush %0" : : "r" (adj_code + 2));
- asm("flush %0" : : "r" (adj_code + 4));
- asm("flush %0" : : "r" (adj_code + 6));
- asm("flush %0" : : "r" (adj_code + 10));
-
- /* max. 5 instructions latency, and we need at >= 1 for returning */
- asm("nop");
- asm("nop");
- asm("nop");
- asm("nop");
- }
+ adjustor = stgMallocBytes(4*(11+1), "createAdjustor");
+ unsigned long *const adj_code = (unsigned long *)adjustor;
+
+ adj_code[ 0] = 0x9C23A008UL; /* sub %sp, 8, %sp */
+ adj_code[ 1] = 0xDA23A060UL; /* st %o5, [%sp + 96] */
+ adj_code[ 2] = 0xD823A05CUL; /* st %o4, [%sp + 92] */
+ adj_code[ 3] = 0x9A10000BUL; /* mov %o3, %o5 */
+ adj_code[ 4] = 0x9810000AUL; /* mov %o2, %o4 */
+ adj_code[ 5] = 0x96100009UL; /* mov %o1, %o3 */
+ adj_code[ 6] = 0x94100008UL; /* mov %o0, %o2 */
+ adj_code[ 7] = 0x13000000UL; /* sethi %hi(wptr), %o1 */
+ adj_code[ 7] |= ((unsigned long)wptr) >> 10;
+ adj_code[ 8] = 0x11000000UL; /* sethi %hi(hptr), %o0 */
+ adj_code[ 8] |= ((unsigned long)hptr) >> 10;
+ adj_code[ 9] = 0x81C26000UL; /* jmp %o1 + %lo(wptr) */
+ adj_code[ 9] |= ((unsigned long)wptr) & 0x000003FFUL;
+ adj_code[10] = 0x90122000UL; /* or %o0, %lo(hptr), %o0 */
+ adj_code[10] |= ((unsigned long)hptr) & 0x000003FFUL;
+
+ adj_code[11] = (unsigned long)hptr;
+
+ /* flush cache */
+ asm("flush %0" : : "r" (adj_code ));
+ asm("flush %0" : : "r" (adj_code + 2));
+ asm("flush %0" : : "r" (adj_code + 4));
+ asm("flush %0" : : "r" (adj_code + 6));
+ asm("flush %0" : : "r" (adj_code + 10));
+
+ /* max. 5 instructions latency, and we need at >= 1 for returning */
+ asm("nop");
+ asm("nop");
+ asm("nop");
+ asm("nop");
#elif defined(alpha_TARGET_ARCH)
/* Magic constant computed by inspecting the code length of
the following assembly language snippet
4 bytes (getting rid of the nop), hence saving memory. [ccshan]
*/
ASSERT(((StgWord64)wptr & 3) == 0);
- if ((adjustor = stgMallocBytes(48, "createAdjustor")) != NULL) {
- StgWord64 *const code = (StgWord64 *)adjustor;
+ adjustor = stgMallocBytes(48, "createAdjustor");
+ StgWord64 *const code = (StgWord64 *)adjustor;
- code[0] = 0x4610041246520414L;
- code[1] = 0x46730415a61b0020L;
- code[2] = 0x46310413a77b0028L;
- code[3] = 0x000000006bfb0000L
- | (((StgWord32*)(wptr) - (StgWord32*)(code) - 3) & 0x3fff);
+ code[0] = 0x4610041246520414L;
+ code[1] = 0x46730415a61b0020L;
+ code[2] = 0x46310413a77b0028L;
+ code[3] = 0x000000006bfb0000L
+ | (((StgWord32*)(wptr) - (StgWord32*)(code) - 3) & 0x3fff);
- code[4] = (StgWord64)hptr;
- code[5] = (StgWord64)wptr;
+ code[4] = (StgWord64)hptr;
+ code[5] = (StgWord64)wptr;
- /* Ensure that instruction cache is consistent with our new code */
- __asm__ volatile("call_pal %0" : : "i" (PAL_imb));
- }
+ /* Ensure that instruction cache is consistent with our new code */
+ __asm__ volatile("call_pal %0" : : "i" (PAL_imb));
#elif defined(powerpc_TARGET_ARCH)
/*
For PowerPC, the following code is used:
this code, it only works for up to 6 arguments (when floating point arguments
are involved, this may be more or less, depending on the exact situation).
*/
- if ((adjustor = stgMallocBytes(4*13, "createAdjustor")) != NULL) {
- unsigned long *const adj_code = (unsigned long *)adjustor;
-
- // make room for extra arguments
- adj_code[0] = 0x7d0a4378; //mr r10,r8
- adj_code[1] = 0x7ce93b78; //mr r9,r7
- adj_code[2] = 0x7cc83378; //mr r8,r6
- adj_code[3] = 0x7ca72b78; //mr r7,r5
- adj_code[4] = 0x7c862378; //mr r6,r4
- adj_code[5] = 0x7c651b78; //mr r5,r3
+ adjustor = stgMallocBytes(4*13, "createAdjustor");
+ unsigned long *const adj_code = (unsigned long *)adjustor;
+
+ // make room for extra arguments
+ adj_code[0] = 0x7d0a4378; //mr r10,r8
+ adj_code[1] = 0x7ce93b78; //mr r9,r7
+ adj_code[2] = 0x7cc83378; //mr r8,r6
+ adj_code[3] = 0x7ca72b78; //mr r7,r5
+ adj_code[4] = 0x7c862378; //mr r6,r4
+ adj_code[5] = 0x7c651b78; //mr r5,r3
- adj_code[6] = 0x3c000000; //lis r0,hi(wptr)
- adj_code[6] |= ((unsigned long)wptr) >> 16;
+ adj_code[6] = 0x3c000000; //lis r0,hi(wptr)
+ adj_code[6] |= ((unsigned long)wptr) >> 16;
- adj_code[7] = 0x3c600000; //lis r3,hi(hptr)
- adj_code[7] |= ((unsigned long)hptr) >> 16;
+ adj_code[7] = 0x3c600000; //lis r3,hi(hptr)
+ adj_code[7] |= ((unsigned long)hptr) >> 16;
- adj_code[8] = 0x60000000; //ori r0,r0,lo(wptr)
- adj_code[8] |= ((unsigned long)wptr) & 0xFFFF;
+ adj_code[8] = 0x60000000; //ori r0,r0,lo(wptr)
+ adj_code[8] |= ((unsigned long)wptr) & 0xFFFF;
- adj_code[9] = 0x60630000; //ori r3,r3,lo(hptr)
- adj_code[9] |= ((unsigned long)hptr) & 0xFFFF;
+ adj_code[9] = 0x60630000; //ori r3,r3,lo(hptr)
+ adj_code[9] |= ((unsigned long)hptr) & 0xFFFF;
- adj_code[10] = 0x7c0903a6; //mtctr r0
- adj_code[11] = 0x4e800420; //bctr
- adj_code[12] = (unsigned long)hptr;
+ adj_code[10] = 0x7c0903a6; //mtctr r0
+ adj_code[11] = 0x4e800420; //bctr
+ adj_code[12] = (unsigned long)hptr;
- // Flush the Instruction cache:
- // MakeDataExecutable(adjustor,4*13);
- /* This would require us to link with CoreServices.framework */
- { /* this should do the same: */
- int n = 13;
- unsigned long *p = adj_code;
- while(n--)
- {
- __asm__ volatile ("dcbf 0,%0\n\tsync\n\ticbi 0,%0"
- : : "r" (p));
- p++;
- }
- __asm__ volatile ("sync\n\tisync");
- }
- }
+ /* Flush the Instruction cache: */
+ /* MakeDataExecutable(adjustor,4*13); */
+ /* This would require us to link with CoreServices.framework */
+ { /* this should do the same: */
+ int n = 13;
+ unsigned long *p = adj_code;
+ while (n--) {
+ __asm__ volatile ("dcbf 0,%0\n\tsync\n\ticbi 0,%0" : : "r" (p));
+ p++;
+ }
+ __asm__ volatile ("sync\n\tisync");
+ }
#elif defined(ia64_TARGET_ARCH)
/*
Up to 8 inputs are passed in registers. We flush the last two inputs to
rtsBool
initAdjustor(void)
{
- return execPage(__obscure_ccall_ret_code, pageExecuteRead);
+#if defined(i386_TARGET_ARCH)
+ /* Now here's something obscure for you:
+
+ When generating an adjustor thunk that uses the C calling
+ convention, we have to make sure that the thunk kicks off
+ the process of jumping into Haskell with a tail jump. Why?
+ Because as a result of jumping in into Haskell we may end
+ up freeing the very adjustor thunk we came from using
+ freeHaskellFunctionPtr(). Hence, we better not return to
+ the adjustor code on our way out, since it could by then
+ point to junk.
+
+ The fix is readily at hand, just include the opcodes
+ for the C stack fixup code that we need to perform when
+ returning in some static piece of memory and arrange
+ to return to it before tail jumping from the adjustor thunk.
+ */
+
+ obscure_ccall_ret_code = stgMallocBytes(4, "initAdjustor");
+
+ obscure_ccall_ret_code[0x00] = (unsigned char)0x83; /* addl $0x4, %esp */
+ obscure_ccall_ret_code[0x01] = (unsigned char)0xc4;
+ obscure_ccall_ret_code[0x02] = (unsigned char)0x04;
+
+ obscure_ccall_ret_code[0x03] = (unsigned char)0xc3; /* ret */
+
+ execPage(obscure_ccall_ret_code, pageExecuteRead);
+#endif
+ return rtsTrue;
}