Author: kientzle
Date: Sat May 11 22:32:43 2013
New Revision: 250531
URL: http://svnweb.freebsd.org/changeset/base/250531
Log:
Don't use the old stack-walking code with
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.
Modified:
head/sys/arm/arm/stack_machdep.c
Modified: head/sys/arm/arm/stack_machdep.c
==============================================================================
--- head/sys/arm/arm/stack_machdep.c Sat May 11 22:13:24 2013
(r250530)
+++ head/sys/arm/arm/stack_machdep.c Sat May 11 22:32:43 2013
(r250531)
@@ -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 t
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);
}
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