[MIPS] SB1: Fix interrupt disable hazard.
Ralf Baechle [Mon, 13 Mar 2006 16:16:29 +0000 (16:16 +0000)]
The SB1 core has a three cycle interrupt disable hazard but we were
wrongly treating it as fully interlocked.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

include/asm-mips/hazards.h

index 6111a0c..feb29a7 100644 (file)
@@ -3,7 +3,9 @@
  * License.  See the file "COPYING" in the main directory of this archive
  * for more details.
  *
- * Copyright (C) 2003, 2004 Ralf Baechle
+ * Copyright (C) 2003, 2004 Ralf Baechle <ralf@linux-mips.org>
+ * Copyright (C) MIPS Technologies, Inc.
+ *   written by Ralf Baechle <ralf@linux-mips.org>
  */
 #ifndef _ASM_HAZARDS_H
 #define _ASM_HAZARDS_H
@@ -74,8 +76,7 @@
 #define irq_disable_hazard
        _ehb
 
-#elif defined(CONFIG_CPU_R10000) || defined(CONFIG_CPU_RM9000) || \
-      defined(CONFIG_CPU_SB1)
+#elif defined(CONFIG_CPU_R10000) || defined(CONFIG_CPU_RM9000)
 
 /*
  * R10000 rocks - all hazards handled in hardware, so this becomes a nobrainer.
 #else /* __ASSEMBLY__ */
 
 __asm__(
-       "       .macro  _ssnop                                  \n\t"
-       "       sll     $0, $0, 1                               \n\t"
-       "       .endm                                           \n\t"
-       "                                                       \n\t"
-       "       .macro  _ehb                                    \n\t"
-       "       sll     $0, $0, 3                               \n\t"
-       "       .endm                                           \n\t");
+       "       .macro  _ssnop                                  \n"
+       "       sll     $0, $0, 1                               \n"
+       "       .endm                                           \n"
+       "                                                       \n"
+       "       .macro  _ehb                                    \n"
+       "       sll     $0, $0, 3                               \n"
+       "       .endm                                           \n");
 
 #ifdef CONFIG_CPU_RM9000
 
@@ -117,17 +118,21 @@ __asm__(
 
 #define mtc0_tlbw_hazard()                                             \
        __asm__ __volatile__(                                           \
-               ".set\tmips32\n\t"                                      \
-               "_ssnop; _ssnop; _ssnop; _ssnop\n\t"                    \
-               ".set\tmips0")
+       "       .set    mips32                                  \n"     \
+       "       _ssnop                                          \n"     \
+       "       _ssnop                                          \n"     \
+       "       _ssnop                                          \n"     \
+       "       _ssnop                                          \n"     \
+       "       .set    mips0                                   \n")
 
 #define tlbw_use_hazard()                                              \
        __asm__ __volatile__(                                           \
-               ".set\tmips32\n\t"                                      \
-               "_ssnop; _ssnop; _ssnop; _ssnop\n\t"                    \
-               ".set\tmips0")
-
-#define back_to_back_c0_hazard()       do { } while (0)
+       "       .set    mips32                                  \n"     \
+       "       _ssnop                                          \n"     \
+       "       _ssnop                                          \n"     \
+       "       _ssnop                                          \n"     \
+       "       _ssnop                                          \n"     \
+       "       .set    mips0                                   \n")
 
 #else
 
@@ -136,15 +141,25 @@ __asm__(
  */
 #define mtc0_tlbw_hazard()                                             \
        __asm__ __volatile__(                                           \
-               ".set noreorder\n\t"                                    \
-               "nop; nop; nop; nop; nop; nop;\n\t"                     \
-               ".set reorder\n\t")
+       "       .set    noreorder                               \n"     \
+       "       nop                                             \n"     \
+       "       nop                                             \n"     \
+       "       nop                                             \n"     \
+       "       nop                                             \n"     \
+       "       nop                                             \n"     \
+       "       nop                                             \n"     \
+       "       .set    reorder                                 \n")
 
 #define tlbw_use_hazard()                                              \
        __asm__ __volatile__(                                           \
-               ".set noreorder\n\t"                                    \
-               "nop; nop; nop; nop; nop; nop;\n\t"                     \
-               ".set reorder\n\t")
+       "       .set    noreorder                               \n"     \
+       "       nop                                             \n"     \
+       "       nop                                             \n"     \
+       "       nop                                             \n"     \
+       "       nop                                             \n"     \
+       "       nop                                             \n"     \
+       "       nop                                             \n"     \
+       "       .set    reorder                                 \n")
 
 #endif
 
@@ -156,49 +171,26 @@ __asm__(
 
 #ifdef CONFIG_CPU_MIPSR2
 
-__asm__(
-       "       .macro\tirq_enable_hazard                       \n\t"
-       "       _ehb                                            \n\t"
-       "       .endm                                           \n\t"
-       "                                                       \n\t"
-       "       .macro\tirq_disable_hazard                      \n\t"
-       "       _ehb                                            \n\t"
-       "       .endm                                           \n\t"
-       "                                                       \n\t"
-       "       .macro\tback_to_back_c0_hazard                  \n\t"
-       "       _ehb                                            \n\t"
-       "       .endm");
-
-#define irq_enable_hazard()                                            \
-       __asm__ __volatile__(                                           \
-       "irq_enable_hazard")
+__asm__("      .macro  irq_enable_hazard                       \n"
+       "       _ehb                                            \n"
+       "       .endm                                           \n"
+       "                                                       \n"
+       "       .macro  irq_disable_hazard                      \n"
+       "       _ehb                                            \n"
+       "       .endm                                           \n");
 
-#define irq_disable_hazard()                                           \
-       __asm__ __volatile__(                                           \
-       "irq_disable_hazard")
-
-#define back_to_back_c0_hazard()                                       \
-       __asm__ __volatile__(                                           \
-       "back_to_back_c0_hazard")
-
-#elif defined(CONFIG_CPU_R10000) || defined(CONFIG_CPU_RM9000) || \
-      defined(CONFIG_CPU_SB1)
+#elif defined(CONFIG_CPU_R10000) || defined(CONFIG_CPU_RM9000)
 
 /*
  * R10000 rocks - all hazards handled in hardware, so this becomes a nobrainer.
  */
 
 __asm__(
-       "       .macro\tirq_enable_hazard                       \n\t"
-       "       .endm                                           \n\t"
-       "                                                       \n\t"
-       "       .macro\tirq_disable_hazard                      \n\t"
-       "       .endm");
-
-#define irq_enable_hazard()    do { } while (0)
-#define irq_disable_hazard()   do { } while (0)
-
-#define back_to_back_c0_hazard()       do { } while (0)
+       "       .macro  irq_enable_hazard                       \n"
+       "       .endm                                           \n"
+       "                                                       \n"
+       "       .macro  irq_disable_hazard                      \n"
+       "       .endm                                           \n");
 
 #else
 
@@ -209,29 +201,63 @@ __asm__(
  */
 
 __asm__(
-       "       #                                               \n\t"
-       "       # There is a hazard but we do not care          \n\t"
-       "       #                                               \n\t"
-       "       .macro\tirq_enable_hazard                       \n\t"
-       "       .endm                                           \n\t"
-       "                                                       \n\t"
-       "       .macro\tirq_disable_hazard                      \n\t"
-       "       _ssnop; _ssnop; _ssnop                          \n\t"
-       "       .endm");
+       "       #                                               \n"
+       "       # There is a hazard but we do not care          \n"
+       "       #                                               \n"
+       "       .macro\tirq_enable_hazard                       \n"
+       "       .endm                                           \n"
+       "                                                       \n"
+       "       .macro\tirq_disable_hazard                      \n"
+       "       _ssnop                                          \n"
+       "       _ssnop                                          \n"
+       "       _ssnop                                          \n"
+       "       .endm                                           \n");
 
-#define irq_enable_hazard()    do { } while (0)
+#endif
+
+#define irq_enable_hazard()                                            \
+       __asm__ __volatile__("irq_enable_hazard")
 #define irq_disable_hazard()                                           \
-       __asm__ __volatile__(                                           \
-       "irq_disable_hazard")
+       __asm__ __volatile__("irq_disable_hazard")
 
-#define back_to_back_c0_hazard()                                       \
-       __asm__ __volatile__(                                           \
-       "       .set noreorder                          \n"             \
-       "       nop; nop; nop                           \n"             \
-       "       .set reorder                            \n")
+
+/*
+ * Back-to-back hazards -
+ *
+ * What is needed to separate a move to cp0 from a subsequent read from the
+ * same cp0 register?
+ */
+#ifdef CONFIG_CPU_MIPSR2
+
+__asm__("      .macro  back_to_back_c0_hazard                  \n"
+       "       _ehb                                            \n"
+       "       .endm                                           \n");
+
+#elif defined(CONFIG_CPU_R10000) || defined(CONFIG_CPU_RM9000) || \
+      defined(CONFIG_CPU_SB1)
+
+__asm__("      .macro  back_to_back_c0_hazard                  \n"
+       "       .endm                                           \n");
+
+#else
+
+__asm__("      .macro  back_to_back_c0_hazard                  \n"
+       "       .set    noreorder                               \n"
+       "       _ssnop                                          \n"
+       "       _ssnop                                          \n"
+       "       _ssnop                                          \n"
+       "       .set    reorder                                 \n"
+       "       .endm");
 
 #endif
 
+#define back_to_back_c0_hazard()                                       \
+       __asm__ __volatile__("back_to_back_c0_hazard")
+
+
+/*
+ * Instruction execution hazard
+ */
 #ifdef CONFIG_CPU_MIPSR2
 /*
  * gcc has a tradition of misscompiling the previous construct using the