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ARM: hw_breakpoint: don't try to clear v6 debug registers during boot

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v6 cores do not provide a way to clear the debug registers without first
enabling monitor mode, meaning that we could take spurious debug
exceptions. Instead, rely on the registers being in a sane state when we
boot as they are defined to be disabled out of reset anyway.

Tested-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
This commit is contained in:
Will Deacon 2012-09-21 17:53:08 +01:00
parent 614bea500a
commit 7f4050a07b
1 changed files with 3 additions and 3 deletions
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6
arch/arm/kernel/hw_breakpoint.c
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@ -912,8 +912,8 @@ static void reset_ctrl_regs(void *unused)
switch (debug_arch) {
case ARM_DEBUG_ARCH_V6:
case ARM_DEBUG_ARCH_V6_1:
/* ARMv6 cores just need to reset the registers. */
goto reset_regs;
/* ARMv6 cores clear the registers out of reset. */
goto out_mdbgen;
case ARM_DEBUG_ARCH_V7_ECP14:
/*
* Ensure sticky power-down is clear (i.e. debug logic is
@ -966,7 +966,6 @@ static void reset_ctrl_regs(void *unused)
return;
}
reset_regs:
/*
* The control/value register pairs are UNKNOWN out of reset so
* clear them to avoid spurious debug events.
@ -991,6 +990,7 @@ static void reset_ctrl_regs(void *unused)
* Have a crack at enabling monitor mode. We don't actually need
* it yet, but reporting an error early is useful if it fails.
*/
out_mdbgen:
if (enable_monitor_mode())
cpumask_or(&debug_err_mask, &debug_err_mask, cpumask_of(cpu));
}