[Blackfin] arch: change the trace buffer control start/stop logic in the exception handlers

To save/restore the trace buffer control so that if we take an exception
after turning off the trace buffer at a higher level we dont inadvertently
turn the trace buffer back on

Signed-off-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>

2 files changed, 24 insertions, 23 deletions

diff --git a/arch/blackfin/mach-common/entry.S b/arch/blackfin/mach-common/entry.S
index fdd9bf43361e..2cbb7a0bc38e 100644
--- a/arch/blackfin/mach-common/entry.S
+++ b/arch/blackfin/mach-common/entry.S
@@ -121,6 +121,7 @@ ENTRY(_ex_icplb_miss)
         (R7:6,P5:4) = [sp++];
         ASTAT = [sp++];
         SAVE_ALL_SYS
+        DEBUG_HWTRACE_SAVE(p5, r7)
 #ifdef CONFIG_MPU
         R0 = SEQSTAT;
         R1 = SP;
@@ -132,14 +133,13 @@ ENTRY(_ex_icplb_miss)
 #else
         call __cplb_hdr;
 #endif
-        DEBUG_START_HWTRACE(p5, r7)
+        DEBUG_HWTRACE_RESTORE(p5, r7)
         RESTORE_ALL_SYS
         SP = EX_SCRATCH_REG;
         rtx;
 ENDPROC(_ex_icplb_miss)
 
 ENTRY(_ex_syscall)
-        DEBUG_START_HWTRACE(p5, r7)
         (R7:6,P5:4) = [sp++];
         ASTAT = [sp++];
         raise 15;               /* invoked by TRAP #0, for sys call */
@@ -178,7 +178,6 @@ ENTRY(_ex_single_step)
 ENDPROC(_ex_single_step)
 
 ENTRY(_bfin_return_from_exception)
-        DEBUG_START_HWTRACE(p5, r7)
 #if ANOMALY_05000257
         R7=LC0;
         LC0=R7;
@@ -200,10 +199,9 @@ ENTRY(_handle_bad_cplb)
          * need to make a CPLB exception look like a normal exception
          */
 
-        DEBUG_START_HWTRACE(p5, r7)
         RESTORE_ALL_SYS
         [--sp] = ASTAT;
-        [--sp] = (R7:6, P5:4);
+        [--sp] = (R7:6,P5:4);
 
 ENTRY(_ex_replaceable)
         nop;
@@ -253,7 +251,6 @@ ENTRY(_ex_trap_c)
         R6 = SEQSTAT;
         [P5] = R6;
 
-        DEBUG_START_HWTRACE(p5, r7)
         (R7:6,P5:4) = [sp++];
         ASTAT = [sp++];
         SP = EX_SCRATCH_REG;
@@ -382,8 +379,7 @@ ENTRY(_trap) /* Exception: 4th entry into system event table(supervisor mode)*/
         sp.h = _exception_stack_top;
         /* Try to deal with syscalls quickly.  */
         [--sp] = ASTAT;
-        [--sp] = (R7:6, P5:4);
-        DEBUG_STOP_HWTRACE(p5, r7)
+        [--sp] = (R7:6,P5:4);
         r7 = SEQSTAT;           /* reason code is in bit 5:0 */
         r6.l = lo(SEQSTAT_EXCAUSE);
         r6.h = hi(SEQSTAT_EXCAUSE);
diff --git a/include/asm-blackfin/trace.h b/include/asm-blackfin/trace.h
index 6313aace9d59..ef18afbc2101 100644
--- a/include/asm-blackfin/trace.h
+++ b/include/asm-blackfin/trace.h
@@ -46,42 +46,47 @@ extern unsigned long software_trace_buff[];
 
 #ifdef CONFIG_DEBUG_BFIN_HWTRACE_ON
 
-#define TRACE_BUFFER_START(preg, dreg) trace_buffer_start(preg, dreg)
-#define TRACE_BUFFER_STOP(preg, dreg)  trace_buffer_stop(preg, dreg)
-
 #define trace_buffer_stop(preg, dreg)   \
         preg.L = LO(TBUFCTL);           \
         preg.H = HI(TBUFCTL);           \
         dreg = 0x1;                     \
         [preg] = dreg;
 
-#define trace_buffer_start(preg, dreg)  \
-        preg.L = LO(TBUFCTL);           \
-        preg.H = HI(TBUFCTL);           \
-        dreg = BFIN_TRACE_ON;           \
-        [preg] = dreg;
-
 #define trace_buffer_init(preg, dreg) \
         preg.L = LO(TBUFCTL);         \
         preg.H = HI(TBUFCTL);         \
         dreg = BFIN_TRACE_INIT;       \
         [preg] = dreg;
 
+#define trace_buffer_save(preg, dreg) \
+        preg.L = LO(TBUFCTL); \
+        preg.H = HI(TBUFCTL); \
+        dreg = [preg]; \
+        [sp++] = dreg; \
+        dreg = 0x1; \
+        [preg] = dreg;
+
+#define trace_buffer_restore(preg, dreg) \
+        preg.L = LO(TBUFCTL); \
+        preg.H = HI(TBUFCTL); \
+        dreg = [sp--]; \
+        [preg] = dreg;
+
 #else /* CONFIG_DEBUG_BFIN_HWTRACE_ON */
 
 #define trace_buffer_stop(preg, dreg)
-#define trace_buffer_start(preg, dreg)
 #define trace_buffer_init(preg, dreg)
+#define trace_buffer_save(preg, dreg)
+#define trace_buffer_restore(preg, dreg)
 
 #endif /* CONFIG_DEBUG_BFIN_HWTRACE_ON */
 
 #ifdef CONFIG_DEBUG_BFIN_NO_KERN_HWTRACE
-# define DEBUG_START_HWTRACE(preg, dreg) trace_buffer_start(preg, dreg)
-# define DEBUG_STOP_HWTRACE(preg, dreg) trace_buffer_stop(preg, dreg)
-
+# define DEBUG_HWTRACE_SAVE(preg, dreg)    trace_buffer_save(preg, dreg)
+# define DEBUG_HWTRACE_RESTORE(preg, dreg) trace_buffer_restore(preg, dreg)
 #else
-# define DEBUG_START_HWTRACE(preg, dreg)
-# define DEBUG_STOP_HWTRACE(preg, dreg)
+# define DEBUG_HWTRACE_SAVE(preg, dreg)
+# define DEBUG_HWTRACE_RESTORE(preg, dreg)
 #endif
 
 #endif /* __ASSEMBLY__ */