[MIPS] Cleanup hazard handling.
authorRalf Baechle <ralf@linux-mips.org>
Fri, 8 Sep 2006 02:13:49 +0000 (04:13 +0200)
committerRalf Baechle <ralf@linux-mips.org>
Wed, 27 Sep 2006 12:37:53 +0000 (13:37 +0100)
Mostly based on patch by Chris Dearman and cleanups from Yoichi.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
include/asm-mips/hazards.h

index 25f5e8a4177d1378fb60645483a4e364c1e879c1..bf0b80404946a6dbf7849faf1627d099ae48228d 100644 (file)
 #define _ASM_HAZARDS_H
 
 
-#ifdef __ASSEMBLY__
-
-       .macro  _ssnop
-       sll     $0, $0, 1
-       .endm
-
-       .macro  _ehb
-       sll     $0, $0, 3
-       .endm
-
-/*
- * RM9000 hazards.  When the JTLB is updated by tlbwi or tlbwr, a subsequent
- * use of the JTLB for instructions should not occur for 4 cpu cycles and use
- * for data translations should not occur for 3 cpu cycles.
- */
-#ifdef CONFIG_CPU_RM9000
-
-       .macro  mtc0_tlbw_hazard
-       .set    push
-       .set    mips32
-       _ssnop; _ssnop; _ssnop; _ssnop
-       .set    pop
-       .endm
-
-       .macro  tlbw_eret_hazard
-       .set    push
-       .set    mips32
-       _ssnop; _ssnop; _ssnop; _ssnop
-       .set    pop
-       .endm
-
+#ifdef __ASSEMBLER__
+#define ASMMACRO(name, code...) .macro name; code; .endm
 #else
 
-/*
- * The taken branch will result in a two cycle penalty for the two killed
- * instructions on R4000 / R4400.  Other processors only have a single cycle
- * hazard so this is nice trick to have an optimal code for a range of
- * processors.
- */
-       .macro  mtc0_tlbw_hazard
-       b       . + 8
-       .endm
+#define ASMMACRO(name, code...)                                                \
+__asm__(".macro " #name "; " #code "; .endm");                         \
+                                                                       \
+static inline void name(void)                                          \
+{                                                                      \
+       __asm__ __volatile__ (#name);                                   \
+}
 
-       .macro  tlbw_eret_hazard
-       .endm
 #endif
 
+ASMMACRO(_ssnop,
+        sll    $0, $0, 1
+       )
+
+ASMMACRO(_ehb,
+        sll    $0, $0, 3
+       )
+
 /*
- * mtc0->mfc0 hazard
- * The 24K has a 2 cycle mtc0/mfc0 execution hazard.
- * It is a MIPS32R2 processor so ehb will clear the hazard.
+ * TLB hazards
  */
+#if defined(CONFIG_CPU_MIPSR2)
 
-#ifdef CONFIG_CPU_MIPSR2
 /*
- * Use a macro for ehb unless explicit support for MIPSR2 is enabled
+ * MIPSR2 defines ehb for hazard avoidance
  */
 
-#define irq_enable_hazard                                              \
+ASMMACRO(mtc0_tlbw_hazard,
+        _ehb
+       )
+ASMMACRO(tlbw_use_hazard,
+        _ehb
+       )
+ASMMACRO(tlb_probe_hazard,
+        _ehb
+       )
+ASMMACRO(irq_enable_hazard,
+       )
+ASMMACRO(irq_disable_hazard,
        _ehb
-
-#define irq_disable_hazard                                             \
-       _ehb
-
-#elif defined(CONFIG_CPU_R10000) || defined(CONFIG_CPU_RM9000)
-
+       )
+ASMMACRO(back_to_back_c0_hazard,
+        _ehb
+       )
 /*
- * R10000 rocks - all hazards handled in hardware, so this becomes a nobrainer.
+ * gcc has a tradition of misscompiling the previous construct using the
+ * address of a label as argument to inline assembler.  Gas otoh has the
+ * annoying difference between la and dla which are only usable for 32-bit
+ * rsp. 64-bit code, so can't be used without conditional compilation.
+ * The alterantive is switching the assembler to 64-bit code which happens
+ * to work right even for 32-bit code ...
  */
+#define instruction_hazard()                                           \
+do {                                                                   \
+       unsigned long tmp;                                              \
+                                                                       \
+       __asm__ __volatile__(                                           \
+       "       .set    mips64r2                                \n"     \
+       "       dla     %0, 1f                                  \n"     \
+       "       jr.hb   %0                                      \n"     \
+       "       .set    mips0                                   \n"     \
+       "1:                                                     \n"     \
+       : "=r" (tmp));                                                  \
+} while (0)
 
-#define irq_enable_hazard
-
-#define irq_disable_hazard
-
-#else
+#elif defined(CONFIG_CPU_R10000)
 
 /*
- * Classic MIPS needs 1 - 3 nops or ssnops
+ * R10000 rocks - all hazards handled in hardware, so this becomes a nobrainer.
  */
-#define irq_enable_hazard
-#define irq_disable_hazard                                             \
-       _ssnop; _ssnop; _ssnop
 
-#endif
-
-#else /* __ASSEMBLY__ */
-
-__asm__(
-       "       .macro  _ssnop                                  \n"
-       "       sll     $0, $0, 1                               \n"
-       "       .endm                                           \n"
-       "                                                       \n"
-       "       .macro  _ehb                                    \n"
-       "       sll     $0, $0, 3                               \n"
-       "       .endm                                           \n");
+ASMMACRO(mtc0_tlbw_hazard,
+       )
+ASMMACRO(tlbw_use_hazard,
+       )
+ASMMACRO(tlb_probe_hazard,
+       )
+ASMMACRO(irq_enable_hazard,
+       )
+ASMMACRO(irq_disable_hazard,
+       )
+ASMMACRO(back_to_back_c0_hazard,
+       )
+#define instruction_hazard() do { } while (0)
 
-#ifdef CONFIG_CPU_RM9000
+#elif defined(CONFIG_CPU_RM9000)
 
 /*
  * RM9000 hazards.  When the JTLB is updated by tlbwi or tlbwr, a subsequent
@@ -115,176 +108,73 @@ __asm__(
  * for data translations should not occur for 3 cpu cycles.
  */
 
-#define mtc0_tlbw_hazard()                                             \
-       __asm__ __volatile__(                                           \
-       "       .set    mips32                                  \n"     \
-       "       _ssnop                                          \n"     \
-       "       _ssnop                                          \n"     \
-       "       _ssnop                                          \n"     \
-       "       _ssnop                                          \n"     \
-       "       .set    mips0                                   \n")
-
-#define tlbw_use_hazard()                                              \
-       __asm__ __volatile__(                                           \
-       "       .set    mips32                                  \n"     \
-       "       _ssnop                                          \n"     \
-       "       _ssnop                                          \n"     \
-       "       _ssnop                                          \n"     \
-       "       _ssnop                                          \n"     \
-       "       .set    mips0                                   \n")
-
-#else
-
-/*
- * Overkill warning ...
- */
-#define mtc0_tlbw_hazard()                                             \
-       __asm__ __volatile__(                                           \
-       "       .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"     \
-       "       nop                                             \n"     \
-       "       nop                                             \n"     \
-       "       nop                                             \n"     \
-       "       nop                                             \n"     \
-       "       nop                                             \n"     \
-       "       nop                                             \n"     \
-       "       .set    reorder                                 \n")
-
-#endif
-
-/*
- * Interrupt enable/disable hazards
- * Some processors have hazards when modifying
- * the status register to change the interrupt state
- */
-
-#ifdef CONFIG_CPU_MIPSR2
-
-__asm__("      .macro  irq_enable_hazard                       \n"
-       "       _ehb                                            \n"
-       "       .endm                                           \n"
-       "                                                       \n"
-       "       .macro  irq_disable_hazard                      \n"
-       "       _ehb                                            \n"
-       "       .endm                                           \n");
+ASMMACRO(mtc0_tlbw_hazard,
+        _ssnop; _ssnop; _ssnop; _ssnop
+       )
+ASMMACRO(tlbw_use_hazard,
+        _ssnop; _ssnop; _ssnop; _ssnop
+       )
+ASMMACRO(tlb_probe_hazard,
+        _ssnop; _ssnop; _ssnop; _ssnop
+       )
+ASMMACRO(irq_enable_hazard,
+       )
+ASMMACRO(irq_disable_hazard,
+       )
+ASMMACRO(back_to_back_c0_hazard,
+       )
+#define instruction_hazard() do { } while (0)
 
-#elif defined(CONFIG_CPU_R10000) || defined(CONFIG_CPU_RM9000)
+#elif defined(CONFIG_CPU_SB1)
 
 /*
- * R10000 rocks - all hazards handled in hardware, so this becomes a nobrainer.
+ * Mostly like R4000 for historic reasons
  */
-
-__asm__(
-       "       .macro  irq_enable_hazard                       \n"
-       "       .endm                                           \n"
-       "                                                       \n"
-       "       .macro  irq_disable_hazard                      \n"
-       "       .endm                                           \n");
+ASMMACRO(mtc0_tlbw_hazard,
+       )
+ASMMACRO(tlbw_use_hazard,
+       )
+ASMMACRO(tlb_probe_hazard,
+       )
+ASMMACRO(irq_enable_hazard,
+       )
+ASMMACRO(irq_disable_hazard,
+        _ssnop; _ssnop; _ssnop
+       )
+ASMMACRO(back_to_back_c0_hazard,
+       )
+#define instruction_hazard() do { } while (0)
 
 #else
 
 /*
- * Default for classic MIPS processors.  Assume worst case hazards but don't
- * care about the irq_enable_hazard - sooner or later the hardware will
- * enable it and we don't care when exactly.
- */
-
-__asm__(
-       "       #                                               \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");
-
-#endif
-
-#define irq_enable_hazard()                                            \
-       __asm__ __volatile__("irq_enable_hazard")
-#define irq_disable_hazard()                                           \
-       __asm__ __volatile__("irq_disable_hazard")
-
-
-/*
- * Back-to-back hazards -
+ * Finally the catchall case for all other processors including R4000, R4400,
+ * R4600, R4700, R5000, RM7000, NEC VR41xx etc.
  *
- * 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
- * address of a label as argument to inline assembler.  Gas otoh has the
- * annoying difference between la and dla which are only usable for 32-bit
- * rsp. 64-bit code, so can't be used without conditional compilation.
- * The alterantive is switching the assembler to 64-bit code which happens
- * to work right even for 32-bit code ...
+ * The taken branch will result in a two cycle penalty for the two killed
+ * instructions on R4000 / R4400.  Other processors only have a single cycle
+ * hazard so this is nice trick to have an optimal code for a range of
+ * processors.
  */
-#define instruction_hazard()                                           \
-do {                                                                   \
-       unsigned long tmp;                                              \
-                                                                       \
-       __asm__ __volatile__(                                           \
-       "       .set    mips64r2                                \n"     \
-       "       dla     %0, 1f                                  \n"     \
-       "       jr.hb   %0                                      \n"     \
-       "       .set    mips0                                   \n"     \
-       "1:                                                     \n"     \
-       : "=r" (tmp));                                                  \
-} while (0)
-
-#else
+ASMMACRO(mtc0_tlbw_hazard,
+       nop
+       )
+ASMMACRO(tlbw_use_hazard,
+       nop; nop; nop
+       )
+ASMMACRO(tlb_probe_hazard,
+        nop; nop; nop
+       )
+ASMMACRO(irq_enable_hazard,
+       )
+ASMMACRO(irq_disable_hazard,
+       nop; nop; nop
+       )
+ASMMACRO(back_to_back_c0_hazard,
+        _ssnop; _ssnop; _ssnop;
+       )
 #define instruction_hazard() do { } while (0)
-#endif
-
-extern void mips_ihb(void);
 
-#endif /* __ASSEMBLY__ */
+#endif
 
 #endif /* _ASM_HAZARDS_H */