Linux-libre 4.6.2-gnu

1 files changed, 52 insertions, 17 deletions

diff --git a/arch/xtensa/kernel/traps.c b/arch/xtensa/kernel/traps.c
index 42d441f78..d02fc304b 100644
--- a/arch/xtensa/kernel/traps.c
+++ b/arch/xtensa/kernel/traps.c
@@ -39,11 +39,7 @@
 #include <asm/pgtable.h>
 #include <asm/processor.h>
 #include <asm/traps.h>
-
-#ifdef CONFIG_KGDB
-extern int gdb_enter;
-extern int return_from_debug_flag;
-#endif
+#include <asm/hw_breakpoint.h>
 
 /*
  * Machine specific interrupt handlers
@@ -162,6 +158,8 @@ COPROCESSOR(7),
 
 DEFINE_PER_CPU(unsigned long, exc_table[EXC_TABLE_SIZE/4]);
 
+DEFINE_PER_CPU(struct debug_table, debug_table);
+
 void die(const char*, struct pt_regs*, long);
 
 static inline void
@@ -205,6 +203,32 @@ extern void do_IRQ(int, struct pt_regs *);
 
 #if XTENSA_FAKE_NMI
 
+#define IS_POW2(v) (((v) & ((v) - 1)) == 0)
+
+#if !(PROFILING_INTLEVEL == XCHAL_EXCM_LEVEL && \
+      IS_POW2(XTENSA_INTLEVEL_MASK(PROFILING_INTLEVEL)))
+#warning "Fake NMI is requested for PMM, but there are other IRQs at or above its level."
+#warning "Fake NMI will be used, but there will be a bugcheck if one of those IRQs fire."
+
+static inline void check_valid_nmi(void)
+{
+	unsigned intread = get_sr(interrupt);
+	unsigned intenable = get_sr(intenable);
+
+	BUG_ON(intread & intenable &
+	       ~(XTENSA_INTLEVEL_ANDBELOW_MASK(PROFILING_INTLEVEL) ^
+		 XTENSA_INTLEVEL_MASK(PROFILING_INTLEVEL) ^
+		 BIT(XCHAL_PROFILING_INTERRUPT)));
+}
+
+#else
+
+static inline void check_valid_nmi(void)
+{
+}
+
+#endif
+
 irqreturn_t xtensa_pmu_irq_handler(int irq, void *dev_id);
 
 DEFINE_PER_CPU(unsigned long, nmi_count);
@@ -219,6 +243,7 @@ void do_nmi(struct pt_regs *regs)
 	old_regs = set_irq_regs(regs);
 	nmi_enter();
 	++*this_cpu_ptr(&nmi_count);
+	check_valid_nmi();
 	xtensa_pmu_irq_handler(0, NULL);
 	nmi_exit();
 	set_irq_regs(old_regs);
@@ -314,23 +339,22 @@ do_unaligned_user (struct pt_regs *regs)
 }
 #endif
 
+/* Handle debug events.
+ * When CONFIG_HAVE_HW_BREAKPOINT is on this handler is called with
+ * preemption disabled to avoid rescheduling and keep mapping of hardware
+ * breakpoint structures to debug registers intact, so that
+ * DEBUGCAUSE.DBNUM could be used in case of data breakpoint hit.
+ */
 void
 do_debug(struct pt_regs *regs)
 {
-#ifdef CONFIG_KGDB
-	/* If remote debugging is configured AND enabled, we give control to
-	 * kgdb.  Otherwise, we fall through, perhaps giving control to the
-	 * native debugger.
-	 */
-
-	if (gdb_enter) {
-		extern void gdb_handle_exception(struct pt_regs *);
-		gdb_handle_exception(regs);
-		return_from_debug_flag = 1;
+#ifdef CONFIG_HAVE_HW_BREAKPOINT
+	int ret = check_hw_breakpoint(regs);
+
+	preempt_enable();
+	if (ret == 0)
 		return;
-	}
 #endif
-
 	__die_if_kernel("Breakpoint in kernel", regs, SIGKILL);
 
 	/* If in user mode, send SIGTRAP signal to current process */
@@ -364,6 +388,15 @@ static void trap_init_excsave(void)
 	__asm__ __volatile__("wsr  %0, excsave1\n" : : "a" (excsave1));
 }
 
+static void trap_init_debug(void)
+{
+	unsigned long debugsave = (unsigned long)this_cpu_ptr(&debug_table);
+
+	this_cpu_ptr(&debug_table)->debug_exception = debug_exception;
+	__asm__ __volatile__("wsr %0, excsave" __stringify(XCHAL_DEBUGLEVEL)
+			     :: "a"(debugsave));
+}
+
 /*
  * Initialize dispatch tables.
  *
@@ -407,12 +440,14 @@ void __init trap_init(void)
 
 	/* Initialize EXCSAVE_1 to hold the address of the exception table. */
 	trap_init_excsave();
+	trap_init_debug();
 }
 
 #ifdef CONFIG_SMP
 void secondary_trap_init(void)
 {
 	trap_init_excsave();
+	trap_init_debug();
 }
 #endif