We tried the following patch (2.1.131) and it worked just fine.
--- include/asm-i386/system.h.orig Mon Dec 7 14:21:45 1998
+++ include/asm-i386/system.h Mon Dec 7 14:22:30 1998
@@ -15,10 +15,7 @@
*/
#define switch_to(prev,next) do { \
unsigned long eax, edx, ecx; \
- asm volatile("pushl %%ebx\n\t" \
- "pushl %%esi\n\t" \
- "pushl %%edi\n\t" \
- "pushl %%ebp\n\t" \
+ asm volatile("pushl %%ebp\n\t" \
"movl %%esp,%0\n\t" /* save ESP */ \
"movl %5,%%esp\n\t" /* restore ESP */ \
"movl $1f,%1\n\t" /* save EIP */ \
@@ -26,9 +23,6 @@
"jmp __switch_to\n" \
"1:\t" \
"popl %%ebp\n\t" \
- "popl %%edi\n\t" \
- "popl %%esi\n\t" \
- "popl %%ebx" \
:"=m" (prev->tss.esp),"=m" (prev->tss.eip), \
"=a" (eax), "=d" (edx), "=c" (ecx) \
:"m" (next->tss.esp),"m" (next->tss.eip), \
By the way, why inserting the following code in the __switch_to() function?
As far as I know, the debug registers can only be accessed in Kernel Mode
and (as far as I could see) Linux doesn't provide any support to change their
values stored in TSSs.
/*
* Now maybe reload the debug registers
*/
if (next->tss.debugreg[7]){
loaddebug(next,0);
loaddebug(next,1);
loaddebug(next,2);
loaddebug(next,3);
loaddebug(next,6);
loaddebug(next,7);
}
Marco Cesati
+---------------------------------------------------------------+
| Computer Engineering - Project BRAVO |
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| University of Rome "Tor Vergata" |
| Dept. of Computer Science, Systems and Industrial Engineering |
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| e-mail: bravo@russell.ce.uniroma2.it |
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