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Don't use the old stack-walking code with

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EABI ARM kernels or clang-compiled ARM kernels.

This fixes a crash seen in clang-compiled ARM
kernels that include WITNESS.

This code could be easily modified to walk the stack
for current clang-generated code (including EABI)
but Andrew Turner has raised concerns that the
stack frame currently emitted by clang isn't actually
required by EABI so such a change might cause problems
down the road.

In case anyone wants to experiment, the change
to support current clang-compiled kernels
involves simply setting FR_RFP=0 and FR_SCP=1.
This commit is contained in:
Tim Kientzle 2013-05-11 22:32:43 +00:00
parent 60bf56fd82
commit dc7584ffdc
1 changed files with 5 additions and 4 deletions
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9
sys/arm/arm/stack_machdep.c
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@ -39,17 +39,16 @@ __FBSDID("$FreeBSD$");
static void
stack_capture(struct stack *st, u_int32_t *frame)
{
#if !defined(__ARM_EABI__) && !defined(__clang__)
vm_offset_t callpc;
stack_zero(st);
while (1) {
if (!INKERNEL(frame))
break;
while (INKERNEL(frame)) {
callpc = frame[FR_SCP];
if (stack_put(st, callpc) == -1)
break;
frame = (u_int32_t *)(frame[FR_RFP]);
}
#endif
}
void
@ -63,6 +62,7 @@ stack_save_td(struct stack *st, struct thread *td)
panic("stack_save_td: running");
frame = (u_int32_t *)td->td_pcb->un_32.pcb32_r11;
stack_zero(st);
stack_capture(st, frame);
}
@ -72,5 +72,6 @@ stack_save(struct stack *st)
u_int32_t *frame;
frame = (u_int32_t *)__builtin_frame_address(0);
stack_zero(st);
stack_capture(st, frame);
}