* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
- * Copyright (C) 2003, 2004 Ralf Baechle
+ * Copyright (C) 2003, 04, 07 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
-#include <linux/config.h>
-
#ifdef __ASSEMBLY__
+#define ASMMACRO(name, code...) .macro name; code; .endm
+#else
- .macro _ssnop
- sll $0, $0, 1
- .endm
+#include <asm/cpu-features.h>
- .macro _ehb
- sll $0, $0, 3
- .endm
+#define ASMMACRO(name, code...) \
+__asm__(".macro " #name "; " #code "; .endm"); \
+ \
+static inline void name(void) \
+{ \
+ __asm__ __volatile__ (#name); \
+}
/*
- * 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.
+ * MIPS R2 instruction hazard barrier. Needs to be called as a subroutine.
*/
-#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
+extern void mips_ihb(void);
-#else
+#endif
-/*
- * 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
+ASMMACRO(_ssnop,
+ sll $0, $0, 1
+ )
- .macro tlbw_eret_hazard
- .endm
-#endif
+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
- _ehb
-
-#define irq_disable_hazard
+ASMMACRO(mtc0_tlbw_hazard,
+ _ehb
+ )
+ASMMACRO(tlbw_use_hazard,
+ _ehb
+ )
+ASMMACRO(tlb_probe_hazard,
+ _ehb
+ )
+ASMMACRO(irq_enable_hazard,
+ _ehb
+ )
+ASMMACRO(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_MIPSR1)
/*
- * Classic MIPS needs 1 - 3 nops or ssnops
+ * These are slightly complicated by the fact that we guarantee R1 kernels to
+ * run fine on R2 processors.
*/
-#define irq_enable_hazard
-#define irq_disable_hazard \
- _ssnop; _ssnop; _ssnop
-
-#endif
-
-#else /* __ASSEMBLY__ */
-
-__asm__(
- " .macro _ssnop \n\t"
- " sll $0, $2, 1 \n\t"
- " .endm \n\t"
- " \n\t"
- " .macro _ehb \n\t"
- " sll $0, $0, 3 \n\t"
- " .endm \n\t");
-
-#ifdef CONFIG_CPU_RM9000
-
+ASMMACRO(mtc0_tlbw_hazard,
+ _ssnop; _ssnop; _ehb
+ )
+ASMMACRO(tlbw_use_hazard,
+ _ssnop; _ssnop; _ssnop; _ehb
+ )
+ASMMACRO(tlb_probe_hazard,
+ _ssnop; _ssnop; _ssnop; _ehb
+ )
+ASMMACRO(irq_enable_hazard,
+ _ssnop; _ssnop; _ssnop; _ehb
+ )
+ASMMACRO(irq_disable_hazard,
+ _ssnop; _ssnop; _ssnop; _ehb
+ )
+ASMMACRO(back_to_back_c0_hazard,
+ _ssnop; _ssnop; _ssnop; _ehb
+ )
/*
- * 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.
+ * 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 mtc0_tlbw_hazard() \
- __asm__ __volatile__( \
- ".set\tmips32\n\t" \
- "_ssnop; _ssnop; _ssnop; _ssnop\n\t" \
- ".set\tmips0")
-
-#define tlbw_use_hazard() \
+#define __instruction_hazard() \
+do { \
+ unsigned long tmp; \
+ \
__asm__ __volatile__( \
- ".set\tmips32\n\t" \
- "_ssnop; _ssnop; _ssnop; _ssnop\n\t" \
- ".set\tmips0")
-
-#define back_to_back_c0_hazard() do { } while (0)
-
-#else
+ " .set mips64r2 \n" \
+ " dla %0, 1f \n" \
+ " jr.hb %0 \n" \
+ " .set mips0 \n" \
+ "1: \n" \
+ : "=r" (tmp)); \
+} while (0)
+
+#define instruction_hazard() \
+do { \
+ if (cpu_has_mips_r2) \
+ __instruction_hazard(); \
+} while (0)
+
+#elif defined(CONFIG_CPU_R10000)
/*
- * Overkill warning ...
+ * R10000 rocks - all hazards handled in hardware, so this becomes a nobrainer.
*/
-#define mtc0_tlbw_hazard() \
- __asm__ __volatile__( \
- ".set noreorder\n\t" \
- "nop; nop; nop; nop; nop; nop;\n\t" \
- ".set reorder\n\t")
-
-#define tlbw_use_hazard() \
- __asm__ __volatile__( \
- ".set noreorder\n\t" \
- "nop; nop; nop; nop; nop; nop;\n\t" \
- ".set reorder\n\t")
-#endif
+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)
+
+#elif defined(CONFIG_CPU_RM9000)
/*
- * mtc0->mfc0 hazard
- * The 24K has a 2 cycle mtc0/mfc0 execution hazard.
- * It is a MIPS32R2 processor so ehb will clear the hazard.
- */
-
-#ifdef CONFIG_CPU_MIPSR2
-/*
- * Use a macro for ehb unless explicit support for MIPSR2 is enabled
+ * 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.
*/
-__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");
-
-#define irq_enable_hazard() \
- __asm__ __volatile__( \
- "_ehb\t\t\t\t# irq_enable_hazard")
-
-#define irq_disable_hazard() \
- __asm__ __volatile__( \
- "_ehb\t\t\t\t# irq_disable_hazard")
-
-#define back_to_back_c0_hazard() \
- __asm__ __volatile__( \
- "_ehb\t\t\t\t# back_to_back_c0_hazard")
-#elif defined(CONFIG_CPU_R10000) || defined(CONFIG_CPU_RM9000)
+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_SB1)
/*
- * R10000 rocks - all hazards handled in hardware, so this becomes a nobrainer.
+ * Mostly like R4000 for historic reasons
*/
-
-__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)
+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.
+ * Finally the catchall case for all other processors including R4000, R4400,
+ * R4600, R4700, R5000, RM7000, NEC VR41xx etc.
+ *
+ * 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.
*/
+ASMMACRO(mtc0_tlbw_hazard,
+ nop; nop
+ )
+ASMMACRO(tlbw_use_hazard,
+ nop; nop; nop
+ )
+ASMMACRO(tlb_probe_hazard,
+ nop; nop; nop
+ )
+ASMMACRO(irq_enable_hazard,
+ _ssnop; _ssnop; _ssnop;
+ )
+ASMMACRO(irq_disable_hazard,
+ nop; nop; nop
+ )
+ASMMACRO(back_to_back_c0_hazard,
+ _ssnop; _ssnop; _ssnop;
+ )
+#define instruction_hazard() do { } while (0)
-__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");
-
-#define irq_enable_hazard() do { } while (0)
-#define irq_disable_hazard() \
- __asm__ __volatile__( \
- "_ssnop; _ssnop; _ssnop;\t\t# irq_disable_hazard")
+#endif
-#define back_to_back_c0_hazard() \
- __asm__ __volatile__( \
- " .set noreorder \n" \
- " nop; nop; nop \n" \
- " .set reorder \n")
+/* FPU hazards */
+
+#if defined(CONFIG_CPU_SB1)
+ASMMACRO(enable_fpu_hazard,
+ .set push;
+ .set mips64;
+ .set noreorder;
+ _ssnop;
+ bnezl $0, .+4;
+ _ssnop;
+ .set pop
+)
+ASMMACRO(disable_fpu_hazard,
+)
+
+#elif defined(CONFIG_CPU_MIPSR2)
+ASMMACRO(enable_fpu_hazard,
+ _ehb
+)
+ASMMACRO(disable_fpu_hazard,
+ _ehb
+)
+#else
+ASMMACRO(enable_fpu_hazard,
+ nop; nop; nop; nop
+)
+ASMMACRO(disable_fpu_hazard,
+ _ehb
+)
#endif
-#endif /* __ASSEMBLY__ */
-
#endif /* _ASM_HAZARDS_H */