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Diffstat (limited to 'arch/arm/kernel/hw_breakpoint.c')
-rw-r--r--arch/arm/kernel/hw_breakpoint.c62
1 files changed, 44 insertions, 18 deletions
diff --git a/arch/arm/kernel/hw_breakpoint.c b/arch/arm/kernel/hw_breakpoint.c
index ba386bd..281bf33 100644
--- a/arch/arm/kernel/hw_breakpoint.c
+++ b/arch/arm/kernel/hw_breakpoint.c
@@ -159,6 +159,12 @@ static int debug_arch_supported(void)
arch >= ARM_DEBUG_ARCH_V7_1;
}
+/* Can we determine the watchpoint access type from the fsr? */
+static int debug_exception_updates_fsr(void)
+{
+ return 0;
+}
+
/* Determine number of WRP registers available. */
static int get_num_wrp_resources(void)
{
@@ -604,13 +610,14 @@ int arch_validate_hwbkpt_settings(struct perf_event *bp)
/* Aligned */
break;
case 1:
- /* Allow single byte watchpoint. */
- if (info->ctrl.len == ARM_BREAKPOINT_LEN_1)
- break;
case 2:
/* Allow halfword watchpoints and breakpoints. */
if (info->ctrl.len == ARM_BREAKPOINT_LEN_2)
break;
+ case 3:
+ /* Allow single byte watchpoint. */
+ if (info->ctrl.len == ARM_BREAKPOINT_LEN_1)
+ break;
default:
ret = -EINVAL;
goto out;
@@ -619,18 +626,35 @@ int arch_validate_hwbkpt_settings(struct perf_event *bp)
info->address &= ~alignment_mask;
info->ctrl.len <<= offset;
- /*
- * Currently we rely on an overflow handler to take
- * care of single-stepping the breakpoint when it fires.
- * In the case of userspace breakpoints on a core with V7 debug,
- * we can use the mismatch feature as a poor-man's hardware
- * single-step, but this only works for per-task breakpoints.
- */
- if (!bp->overflow_handler && (arch_check_bp_in_kernelspace(bp) ||
- !core_has_mismatch_brps() || !bp->hw.bp_target)) {
- pr_warning("overflow handler required but none found\n");
- ret = -EINVAL;
+ if (!bp->overflow_handler) {
+ /*
+ * Mismatch breakpoints are required for single-stepping
+ * breakpoints.
+ */
+ if (!core_has_mismatch_brps())
+ return -EINVAL;
+
+ /* We don't allow mismatch breakpoints in kernel space. */
+ if (arch_check_bp_in_kernelspace(bp))
+ return -EPERM;
+
+ /*
+ * Per-cpu breakpoints are not supported by our stepping
+ * mechanism.
+ */
+ if (!bp->hw.bp_target)
+ return -EINVAL;
+
+ /*
+ * We only support specific access types if the fsr
+ * reports them.
+ */
+ if (!debug_exception_updates_fsr() &&
+ (info->ctrl.type == ARM_BREAKPOINT_LOAD ||
+ info->ctrl.type == ARM_BREAKPOINT_STORE))
+ return -EINVAL;
}
+
out:
return ret;
}
@@ -706,10 +730,12 @@ static void watchpoint_handler(unsigned long addr, unsigned int fsr,
goto unlock;
/* Check that the access type matches. */
- access = (fsr & ARM_FSR_ACCESS_MASK) ? HW_BREAKPOINT_W :
- HW_BREAKPOINT_R;
- if (!(access & hw_breakpoint_type(wp)))
- goto unlock;
+ if (debug_exception_updates_fsr()) {
+ access = (fsr & ARM_FSR_ACCESS_MASK) ?
+ HW_BREAKPOINT_W : HW_BREAKPOINT_R;
+ if (!(access & hw_breakpoint_type(wp)))
+ goto unlock;
+ }
/* We have a winner. */
info->trigger = addr;