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-rw-r--r--arch/arm/kernel/hw_breakpoint.c16
1 files changed, 16 insertions, 0 deletions
diff --git a/arch/arm/kernel/hw_breakpoint.c b/arch/arm/kernel/hw_breakpoint.c
index 188180b..be3b3fb 100644
--- a/arch/arm/kernel/hw_breakpoint.c
+++ b/arch/arm/kernel/hw_breakpoint.c
@@ -1063,6 +1063,22 @@ static int __init arch_hw_breakpoint_init(void)
return 0;
}
+ /*
+ * Scorpion CPUs (at least those in APQ8060) seem to set DBGPRSR.SPD
+ * whenever a WFI is issued, even if the core is not powered down, in
+ * violation of the architecture. When DBGPRSR.SPD is set, accesses to
+ * breakpoint and watchpoint registers are treated as undefined, so
+ * this results in boot time and runtime failures when these are
+ * accessed and we unexpectedly take a trap.
+ *
+ * It's not clear if/how this can be worked around, so we blacklist
+ * Scorpion CPUs to avoid these issues.
+ */
+ if (read_cpuid_part() == ARM_CPU_PART_SCORPION) {
+ pr_info("Scorpion CPU detected. Hardware breakpoints and watchpoints disabled\n");
+ return 0;
+ }
+
has_ossr = core_has_os_save_restore();
/* Determine how many BRPs/WRPs are available. */
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