Hi Keith,
I was getting pretty desperate yesterday and even considered writing
the whole setjmp over in assembler;-) Finally I realized that the
stack is pretty consistent. If setjmp is compiled to save a frame
pointer it will always be the first thing pushed on the stack after
the return address. So I don't need the __builtin_frame_address().
Here is a new version of the patch. I like this better than
defeating the leaf optimization.
Jim Houston - Concurrent Computer Corp.
--
diff -urN -X dontdiff 2.4.18-ccur1.orig/arch/i386/kdb/kdbasupport.c
2.4.18-ccur1/arch/i386/kdb/kdbasupport.c
--- 2.4.18-ccur1.orig/arch/i386/kdb/kdbasupport.c Wed Jun 12 09:44:32 2002
+++ 2.4.18-ccur1/arch/i386/kdb/kdbasupport.c Thu Aug 1 19:48:29 2002
@@ -1041,56 +1041,37 @@
int
kdba_setjmp(kdb_jmp_buf *jb)
{
-#if defined(CONFIG_FRAME_POINTER)
- __asm__ ("movl 8(%esp), %eax\n\t"
- "movl %ebx, 0(%eax)\n\t"
- "movl %esi, 4(%eax)\n\t"
- "movl %edi, 8(%eax)\n\t"
- "movl (%esp), %ecx\n\t"
- "movl %ecx, 12(%eax)\n\t"
- "leal 8(%esp), %ecx\n\t"
- "movl %ecx, 16(%eax)\n\t"
- "movl 4(%esp), %ecx\n\t"
- "movl %ecx, 20(%eax)\n\t");
-#else /* CONFIG_FRAME_POINTER */
- __asm__ ("movl 4(%esp), %eax\n\t"
- "movl %ebx, 0(%eax)\n\t"
- "movl %esi, 4(%eax)\n\t"
- "movl %edi, 8(%eax)\n\t"
- "movl %ebp, 12(%eax)\n\t"
- "leal 4(%esp), %ecx\n\t"
- "movl %ecx, 16(%eax)\n\t"
- "movl 0(%esp), %ecx\n\t"
- "movl %ecx, 20(%eax)\n\t");
-#endif /* CONFIG_FRAME_POINTER */
+ register kdb_jmp_buf *eax asm("eax") = jb;
+ register long *ebp;
+
+ /* save the callee save registers. */
+ __asm__("movl %%ebx,0(%0)\n\t"
+ "movl %%esi,4(%0)\n\t"
+ "movl %%edi,8(%0)\n\t" : : "a" (eax));
+ /* check if we saved bp on our stack */
+ __asm__("movl %%ebp,%0" : "=r" (ebp) : );
+ if (ebp == ((long *)&jb)-2)
+ ebp = (long *)(*ebp);
+ eax->regs[3] = (unsigned long)ebp;
+ eax->regs[4] = (unsigned long)&jb;
+ eax->regs[5] = (unsigned long)__builtin_return_address(0);
KDB_STATE_SET(LONGJMP);
return 0;
}
void
kdba_longjmp(kdb_jmp_buf *jb, int reason)
-{
-#if defined(CONFIG_FRAME_POINTER)
- __asm__("movl 8(%esp), %ecx\n\t"
- "movl 12(%esp), %eax\n\t"
- "movl 20(%ecx), %edx\n\t"
- "movl 0(%ecx), %ebx\n\t"
- "movl 4(%ecx), %esi\n\t"
- "movl 8(%ecx), %edi\n\t"
- "movl 12(%ecx), %ebp\n\t"
- "movl 16(%ecx), %esp\n\t"
- "jmp *%edx\n");
-#else /* CONFIG_FRAME_POINTER */
- __asm__("movl 4(%esp), %ecx\n\t"
- "movl 8(%esp), %eax\n\t"
- "movl 20(%ecx), %edx\n\t"
- "movl 0(%ecx), %ebx\n\t"
- "movl 4(%ecx), %esi\n\t"
- "movl 8(%ecx), %edi\n\t"
- "movl 12(%ecx), %ebp\n\t"
- "movl 16(%ecx), %esp\n\t"
- "jmp *%edx\n");
-#endif /* CONFIG_FRAME_POINTER */
+{
+ __asm__(
+ "movl 20(%0), %%edx\n\t"
+ "movl 0(%0), %%ebx\n\t"
+ "movl 4(%0), %%esi\n\t"
+ "movl 8(%0), %%edi\n\t"
+ "movl 12(%0), %%ebp\n\t"
+ "movl 16(%0), %%esp\n\t"
+ "jmp *%%edx\n" : :
+ "c" (jb),
+ "a" (reason));
}
#endif /* KDB_HAVE_LONGJMP */
