[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>

5 files changed, 29 insertions, 15 deletions

diff --git a/arch/mips/kernel/scall32-o32.S b/arch/mips/kernel/scall32-o32.S
index e71785102206..61362e6fa9ec 100644
--- a/arch/mips/kernel/scall32-o32.S
+++ b/arch/mips/kernel/scall32-o32.S
@@ -28,18 +28,7 @@
 NESTED(handle_sys, PT_SIZE, sp)
         .set    noat
         SAVE_SOME
-#ifdef CONFIG_TRACE_IRQFLAGS
-        TRACE_IRQS_ON
-#ifdef CONFIG_64BIT
-        LONG_L  $8, PT_R8(sp)
-        LONG_L  $9, PT_R9(sp)
-#endif
-        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
+        TRACE_IRQS_ON_RELOAD
         STI
         .set    at
 
diff --git a/arch/mips/kernel/scall64-64.S b/arch/mips/kernel/scall64-64.S
index 4c22d0b4825d..6c7b5ed0ea6e 100644
--- a/arch/mips/kernel/scall64-64.S
+++ b/arch/mips/kernel/scall64-64.S
@@ -34,7 +34,7 @@ NESTED(handle_sys64, PT_SIZE, sp)
          */
         .set    noat
         SAVE_SOME
-        TRACE_IRQS_ON
+        TRACE_IRQS_ON_RELOAD
         STI
         .set    at
 #endif
diff --git a/arch/mips/kernel/scall64-n32.S b/arch/mips/kernel/scall64-n32.S
index f25c2a2f1038..6d9f18727ac5 100644
--- a/arch/mips/kernel/scall64-n32.S
+++ b/arch/mips/kernel/scall64-n32.S
@@ -33,7 +33,7 @@ NESTED(handle_sysn32, PT_SIZE, sp)
 #ifndef CONFIG_MIPS32_O32
         .set    noat
         SAVE_SOME
-        TRACE_IRQS_ON
+        TRACE_IRQS_ON_RELOAD
         STI
         .set    at
 #endif
diff --git a/arch/mips/kernel/scall64-o32.S b/arch/mips/kernel/scall64-o32.S
index 288ee4ac4dbb..2e6d0673163e 100644
--- a/arch/mips/kernel/scall64-o32.S
+++ b/arch/mips/kernel/scall64-o32.S
@@ -28,7 +28,7 @@
 NESTED(handle_sys, PT_SIZE, sp)
         .set    noat
         SAVE_SOME
-        TRACE_IRQS_ON
+        TRACE_IRQS_ON_RELOAD
         STI
         .set    at
         ld      t1, PT_EPC(sp)          # skip syscall on return
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