int
pmc_save_kernel_callchain(uintptr_t *cc, int maxsamples,
struct trapframe *tf)
{
uintptr_t pc, r, stackstart, stackend, fp;
struct thread *td;
int count;
KASSERT(TRAPF_USERMODE(tf) == 0,("[arm,%d] not a kernel backtrace",
__LINE__));
pc = PMC_TRAPFRAME_TO_PC(tf);
*cc++ = pc;
if ((td = curthread) == NULL)
return (1);
if (maxsamples <= 1)
return (1);
stackstart = (uintptr_t) td->td_kstack;
stackend = (uintptr_t) td->td_kstack + td->td_kstack_pages * PAGE_SIZE;
fp = PMC_TRAPFRAME_TO_FP(tf);
if (!PMC_IN_KERNEL(pc) ||
!PMC_IN_KERNEL_STACK(fp, stackstart, stackend))
return (1);
for (count = 1; count < maxsamples; count++) {
/* Use saved lr as pc. */
r = fp - sizeof(uintptr_t);
if (!PMC_IN_KERNEL_STACK(r, stackstart, stackend))
break;
pc = *(uintptr_t *)r;
if (!PMC_IN_KERNEL(pc))
break;
*cc++ = pc;
/* Switch to next frame up */
r = fp - 3 * sizeof(uintptr_t);
if (!PMC_IN_KERNEL_STACK(r, stackstart, stackend))
break;
fp = *(uintptr_t *)r;
if (!PMC_IN_KERNEL_STACK(fp, stackstart, stackend))
break;
}
return (count);
}
int
pmc_save_kernel_callchain(uintptr_t *cc, int nframes, struct trapframe *tf)
{
int n;
uint32_t instr;
uintptr_t fp, pc, r, sp, stackstart, stackend;
struct thread *td;
KASSERT(TRAPF_USERMODE(tf) == 0,("[x86,%d] not a kernel backtrace",
__LINE__));
td = curthread;
pc = PMC_TRAPFRAME_TO_PC(tf);
fp = PMC_TRAPFRAME_TO_FP(tf);
sp = PMC_TRAPFRAME_TO_KERNEL_SP(tf);
*cc++ = pc;
r = fp + sizeof(uintptr_t); /* points to return address */
if (nframes <= 1)
return (1);
stackstart = (uintptr_t) td->td_kstack;
stackend = (uintptr_t) td->td_kstack + td->td_kstack_pages * PAGE_SIZE;
if (PMC_IN_TRAP_HANDLER(pc) ||
!PMC_IN_KERNEL(pc) ||
!PMC_IN_KERNEL_STACK(r, stackstart, stackend) ||
!PMC_IN_KERNEL_STACK(sp, stackstart, stackend) ||
!PMC_IN_KERNEL_STACK(fp, stackstart, stackend))
return (1);
instr = *(uint32_t *) pc;
/*
* Determine whether the interrupted function was in the
* processing of either laying down its stack frame or taking
* it off.
*
* If we haven't started laying down a stack frame, or are
* just about to return, then our caller's address is at
* *sp, and we don't have a frame to unwind.
*/
if (PMC_AT_FUNCTION_PROLOGUE_PUSH_BP(instr) ||
PMC_AT_FUNCTION_EPILOGUE_RET(instr))
pc = *(uintptr_t *) sp;
else if (PMC_AT_FUNCTION_PROLOGUE_MOV_SP_BP(instr)) {
/*
* The code was midway through laying down a frame.
* At this point sp[0] has a frame back pointer,
* and the caller's address is therefore at sp[1].
*/
sp += sizeof(uintptr_t);
if (!PMC_IN_KERNEL_STACK(sp, stackstart, stackend))
return (1);
pc = *(uintptr_t *) sp;
} else {
/*
* Not in the function prologue or epilogue.
*/
pc = *(uintptr_t *) r;
fp = *(uintptr_t *) fp;
}
for (n = 1; n < nframes; n++) {
*cc++ = pc;
if (PMC_IN_TRAP_HANDLER(pc))
break;
r = fp + sizeof(uintptr_t);
if (!PMC_IN_KERNEL_STACK(fp, stackstart, stackend) ||
!PMC_IN_KERNEL_STACK(r, stackstart, stackend))
break;
pc = *(uintptr_t *) r;
fp = *(uintptr_t *) fp;
}
return (n);
}
