[PATCH 1/7] ARM: hw_breakpoint: only clear OS lock when implemented on v7
Will Deacon
will.deacon at arm.com
Wed Oct 17 11:31:35 EDT 2012
The OS save and restore register are optional in debug architecture v7,
so check the status register before attempting to clear the OS lock.
Signed-off-by: Will Deacon <will.deacon at arm.com>
---
arch/arm/kernel/hw_breakpoint.c | 10 +++++++++-
1 files changed, 9 insertions(+), 1 deletions(-)
diff --git a/arch/arm/kernel/hw_breakpoint.c b/arch/arm/kernel/hw_breakpoint.c
index 281bf33..ec16ada 100644
--- a/arch/arm/kernel/hw_breakpoint.c
+++ b/arch/arm/kernel/hw_breakpoint.c
@@ -929,6 +929,13 @@ static void reset_ctrl_regs(void *unused)
asm volatile("mrc p14, 0, %0, c1, c5, 4" : "=r" (dbg_power));
if ((dbg_power & 0x1) == 0)
err = -EPERM;
+
+ /*
+ * Check whether we implement OS save and restore.
+ */
+ asm volatile("mrc p14, 0, %0, c1, c1, 4" : "=r" (dbg_power));
+ if ((dbg_power & 0x9) == 0)
+ goto clear_vcr;
break;
case ARM_DEBUG_ARCH_V7_1:
/*
@@ -947,7 +954,7 @@ static void reset_ctrl_regs(void *unused)
}
/*
- * Unconditionally clear the lock by writing a value
+ * Unconditionally clear the OS lock by writing a value
* other than 0xC5ACCE55 to the access register.
*/
asm volatile("mcr p14, 0, %0, c1, c0, 4" : : "r" (0));
@@ -957,6 +964,7 @@ static void reset_ctrl_regs(void *unused)
* Clear any configured vector-catch events before
* enabling monitor mode.
*/
+clear_vcr:
asm volatile("mcr p14, 0, %0, c0, c7, 0" : : "r" (0));
isb();
--
1.7.4.1
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