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dtrace/powerpc: "Fix" stack traces across trap frames

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In function boundary tracing the link register is not yet saved to the
save stack location, so the save point contains whatever the previous
'lr' save was, or even garbage, at the time the trap is taken.  Address
this by explicitly loading the link register from the trap frame instead
of the stack, and propagate that out.

Approved by:	re (cperciva)

(cherry picked from commit 3e1155ade1)
(cherry picked from commit e620e088cb)
(cherry picked from commit 0a21a6659e)
This commit is contained in:
Justin Hibbits 2023-03-11 11:30:00 -05:00
parent 5e49311e01
commit fcd94047f3
1 changed files with 14 additions and 6 deletions
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20
sys/cddl/dev/dtrace/powerpc/dtrace_isa.c
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@ -97,15 +97,18 @@ dtrace_sp_inkernel(uintptr_t sp)
}
static __inline void
dtrace_next_sp_pc(uintptr_t sp, uintptr_t *nsp, uintptr_t *pc)
dtrace_next_sp_pc(uintptr_t sp, uintptr_t *nsp, uintptr_t *pc, uintptr_t *lr)
{
vm_offset_t callpc;
struct trapframe *frame;
if (lr != 0 && *lr != 0)
callpc = *lr;
else
#ifdef __powerpc64__
callpc = *(vm_offset_t *)(sp + RETURN_OFFSET64);
callpc = *(vm_offset_t *)(sp + RETURN_OFFSET64);
#else
callpc = *(vm_offset_t *)(sp + RETURN_OFFSET);
callpc = *(vm_offset_t *)(sp + RETURN_OFFSET);
#endif
/*
@ -121,6 +124,8 @@ dtrace_next_sp_pc(uintptr_t sp, uintptr_t *nsp, uintptr_t *pc)
*nsp = frame->fixreg[1];
if (pc != NULL)
*pc = frame->srr0;
if (lr != NULL)
*lr = frame->lr;
return;
}
@ -128,6 +133,9 @@ dtrace_next_sp_pc(uintptr_t sp, uintptr_t *nsp, uintptr_t *pc)
*nsp = *(uintptr_t *)sp;
if (pc != NULL)
*pc = callpc;
/* lr is only valid for trap frames */
if (lr != NULL)
*lr = 0;
}
void
@ -135,7 +143,7 @@ dtrace_getpcstack(pc_t *pcstack, int pcstack_limit, int aframes,
uint32_t *intrpc)
{
int depth = 0;
uintptr_t osp, sp;
uintptr_t osp, sp, lr = 0;
vm_offset_t callpc;
pc_t caller = (pc_t) solaris_cpu[curcpu].cpu_dtrace_caller;
@ -154,7 +162,7 @@ dtrace_getpcstack(pc_t *pcstack, int pcstack_limit, int aframes,
if (!dtrace_sp_inkernel(sp))
break;
osp = sp;
dtrace_next_sp_pc(osp, &sp, &callpc);
dtrace_next_sp_pc(osp, &sp, &callpc, &lr);
if (aframes > 0) {
aframes--;
@ -513,7 +521,7 @@ dtrace_getstackdepth(int aframes)
depth++;
osp = sp;
dtrace_next_sp_pc(sp, &sp, NULL);
dtrace_next_sp_pc(sp, &sp, NULL, NULL);
}
if (depth < aframes)
return (0);