[MIPS] lockdep: fix TRACE_IRQFLAGS_SUPPORT

In handle_sys and its variants, we must reload some registers which
might be clobbered by trace_hardirqs_on().
Also we must make sure trace_hardirqs_on() called in kernel level (not
exception level).

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 25 insertions, 0 deletions

diff --git a/include/asm-mips/irqflags.h b/include/asm-mips/irqflags.h
index 43ca09a3a3d0..46bf5de5ac72 100644
--- a/include/asm-mips/irqflags.h
+++ b/include/asm-mips/irqflags.h
@@ -213,12 +213,37 @@ static inline int raw_irqs_disabled_flags(unsigned long flags)
  * Do the CPU's IRQ-state tracing from assembly code.
  */
 #ifdef CONFIG_TRACE_IRQFLAGS
+/* Reload some registers clobbered by trace_hardirqs_on */
+#ifdef CONFIG_64BIT
+# define TRACE_IRQS_RELOAD_REGS                                         \
+        LONG_L  $11, PT_R11(sp);                                        \
+        LONG_L  $10, PT_R10(sp);                                        \
+        LONG_L  $9, PT_R9(sp);                                          \
+        LONG_L  $8, PT_R8(sp);                                          \
+        LONG_L  $7, PT_R7(sp);                                          \
+        LONG_L  $6, PT_R6(sp);                                          \
+        LONG_L  $5, PT_R5(sp);                                          \
+        LONG_L  $4, PT_R4(sp);                                          \
+        LONG_L  $2, PT_R2(sp)
+#else
+# define TRACE_IRQS_RELOAD_REGS                                         \
+        LONG_L  $7, PT_R7(sp);                                          \
+        LONG_L  $6, PT_R6(sp);                                          \
+        LONG_L  $5, PT_R5(sp);                                          \
+        LONG_L  $4, PT_R4(sp);                                          \
+        LONG_L  $2, PT_R2(sp)
+#endif
 # define TRACE_IRQS_ON                                                  \
+        CLI;    /* make sure trace_hardirqs_on() is called in kernel level */ \
         jal     trace_hardirqs_on
+# define TRACE_IRQS_ON_RELOAD                                           \
+        TRACE_IRQS_ON;                                                  \
+        TRACE_IRQS_RELOAD_REGS
 # define TRACE_IRQS_OFF                                                 \
         jal     trace_hardirqs_off
 #else
 # define TRACE_IRQS_ON
+# define TRACE_IRQS_ON_RELOAD
 # define TRACE_IRQS_OFF
 #endif