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kernel: restore stacktraces

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When processes have entered the kernel with one of the new
trap modes, %ebp is not valid, used for stacktraces, so we
need an alternative way to retrieve it to make the stacktraces
valid again.
This commit is contained in:
Ben Gras 2013-01-04 18:26:10 +00:00
parent c0c581a635
commit 9ee8c2c75f
2 changed files with 42 additions and 1 deletions
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37
kernel/arch/i386/exception.c
View file

@ -312,8 +312,43 @@ static void proc_stacktrace_execute(struct proc *whichproc, reg_t v_bp, reg_t pc
*===========================================================================*/
void proc_stacktrace(struct proc *whichproc)
{
u32_t use_bp;
if(whichproc->p_seg.p_kern_trap_style == KTS_NONE) {
printf("WARNING: stacktrace of running proecss\n");
}
switch(whichproc->p_seg.p_kern_trap_style) {
case KTS_SYSENTER:
case KTS_SYSCALL:
{
u32_t sp = whichproc->p_reg.sp;
/* Full context is not available in the p_reg
* struct. Obtain it from the user's stack.
* The use stack pointer is always available.
* The fact that it's there, and the 16 byte offset,
* is a dependency on the trap code in
* kernel/arch/i386/usermapped_glo_ipc.S.
*/
if(data_copy(whichproc->p_endpoint, sp+16,
KERNEL, (vir_bytes) &use_bp,
sizeof(use_bp)) != OK) {
printf("stacktrace: aborting, copy failed\n");
return;
}
break;
}
default:
/* Full context is available; use the stored ebp */
use_bp = whichproc->p_reg.fp;
break;
}
#if USE_SYSDEBUG
proc_stacktrace_execute(whichproc, whichproc->p_reg.fp, whichproc->p_reg.pc);
proc_stacktrace_execute(whichproc, use_bp, whichproc->p_reg.pc);
#endif /* USE_SYSDEBUG */
}

6
kernel/arch/i386/usermapped_glo_ipc.S
View file

@ -29,6 +29,9 @@ ENTRY(usermapped_ ## name ## _sysenter) ;\
movl %esp, %esi /* kernel uses %esi for restored %esp */;\
movl $0f, %edx /* kernel uses %edx for restored %eip */;\
movl $VEC, %edi /* %edi to distinguish ipc/kerncall */ ;\
/* !!! There is a dependency of proc_stacktrace() ;\
* on this stack layout; it needs to find %ebp on it. ;\
*/ ;\
SETARGS /* call-specific register setup */ ;\
sysenter /* disappear into kernel */ ;\
0: ;\
@ -50,6 +53,9 @@ ENTRY(usermapped_ ## name ## _syscall) ;\
push %esi ;\
push %edi ;\
movl $VEC, %edi /* %edi to distinguish ipc/kerncall */ ;\
/* !!! There is a dependency of proc_stacktrace() ;\
* on this stack layout; it needs to find %ebp on it. ;\
*/ ;\
SETARGS /* call-specific register setup */ ;\
movl %ecx, %edx /* %ecx is clobbered by SYSCALL */ ;\
syscall /* disappear into kernel */ ;\