v4.19.13 snapshot.
diff --git a/arch/mips/include/asm/hazards.h b/arch/mips/include/asm/hazards.h
new file mode 100644
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--- /dev/null
+++ b/arch/mips/include/asm/hazards.h
@@ -0,0 +1,418 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * 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/stringify.h>
+#include <asm/compiler.h>
+
+#define ___ssnop \
+ sll $0, $0, 1
+
+#define ___ehb \
+ sll $0, $0, 3
+
+/*
+ * TLB hazards
+ */
+#if (defined(CONFIG_CPU_MIPSR2) || defined(CONFIG_CPU_MIPSR6)) && \
+ !defined(CONFIG_CPU_CAVIUM_OCTEON) && !defined(CONFIG_LOONGSON3_ENHANCEMENT)
+
+/*
+ * MIPSR2 defines ehb for hazard avoidance
+ */
+
+#define __mtc0_tlbw_hazard \
+ ___ehb
+
+#define __mtc0_tlbr_hazard \
+ ___ehb
+
+#define __tlbw_use_hazard \
+ ___ehb
+
+#define __tlb_read_hazard \
+ ___ehb
+
+#define __tlb_probe_hazard \
+ ___ehb
+
+#define __irq_enable_hazard \
+ ___ehb
+
+#define __irq_disable_hazard \
+ ___ehb
+
+#define __back_to_back_c0_hazard \
+ ___ehb
+
+/*
+ * 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 alternative 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 "MIPS_ISA_LEVEL" \n" \
+ " dla %0, 1f \n" \
+ " jr.hb %0 \n" \
+ " .set mips0 \n" \
+ "1: \n" \
+ : "=r" (tmp)); \
+} while (0)
+
+#elif (defined(CONFIG_CPU_MIPSR1) && !defined(CONFIG_MIPS_ALCHEMY)) || \
+ defined(CONFIG_CPU_BMIPS)
+
+/*
+ * These are slightly complicated by the fact that we guarantee R1 kernels to
+ * run fine on R2 processors.
+ */
+
+#define __mtc0_tlbw_hazard \
+ ___ssnop; \
+ ___ssnop; \
+ ___ehb
+
+#define __mtc0_tlbr_hazard \
+ ___ssnop; \
+ ___ssnop; \
+ ___ehb
+
+#define __tlbw_use_hazard \
+ ___ssnop; \
+ ___ssnop; \
+ ___ssnop; \
+ ___ehb
+
+#define __tlb_read_hazard \
+ ___ssnop; \
+ ___ssnop; \
+ ___ssnop; \
+ ___ehb
+
+#define __tlb_probe_hazard \
+ ___ssnop; \
+ ___ssnop; \
+ ___ssnop; \
+ ___ehb
+
+#define __irq_enable_hazard \
+ ___ssnop; \
+ ___ssnop; \
+ ___ssnop; \
+ ___ehb
+
+#define __irq_disable_hazard \
+ ___ssnop; \
+ ___ssnop; \
+ ___ssnop; \
+ ___ehb
+
+#define __back_to_back_c0_hazard \
+ ___ssnop; \
+ ___ssnop; \
+ ___ssnop; \
+ ___ehb
+
+/*
+ * 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 alternative 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 instruction_hazard() \
+do { \
+ if (cpu_has_mips_r2_r6) \
+ __instruction_hazard(); \
+} while (0)
+
+#elif defined(CONFIG_MIPS_ALCHEMY) || defined(CONFIG_CPU_CAVIUM_OCTEON) || \
+ defined(CONFIG_CPU_LOONGSON2) || defined(CONFIG_LOONGSON3_ENHANCEMENT) || \
+ defined(CONFIG_CPU_R10000) || defined(CONFIG_CPU_R5500) || defined(CONFIG_CPU_XLR)
+
+/*
+ * R10000 rocks - all hazards handled in hardware, so this becomes a nobrainer.
+ */
+
+#define __mtc0_tlbw_hazard
+
+#define __mtc0_tlbr_hazard
+
+#define __tlbw_use_hazard
+
+#define __tlb_read_hazard
+
+#define __tlb_probe_hazard
+
+#define __irq_enable_hazard
+
+#define __irq_disable_hazard
+
+#define __back_to_back_c0_hazard
+
+#define instruction_hazard() do { } while (0)
+
+#elif defined(CONFIG_CPU_SB1)
+
+/*
+ * Mostly like R4000 for historic reasons
+ */
+#define __mtc0_tlbw_hazard
+
+#define __mtc0_tlbr_hazard
+
+#define __tlbw_use_hazard
+
+#define __tlb_read_hazard
+
+#define __tlb_probe_hazard
+
+#define __irq_enable_hazard
+
+#define __irq_disable_hazard \
+ ___ssnop; \
+ ___ssnop; \
+ ___ssnop
+
+#define __back_to_back_c0_hazard
+
+#define instruction_hazard() do { } while (0)
+
+#else
+
+/*
+ * 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.
+ */
+#define __mtc0_tlbw_hazard \
+ nop; \
+ nop
+
+#define __mtc0_tlbr_hazard \
+ nop; \
+ nop
+
+#define __tlbw_use_hazard \
+ nop; \
+ nop; \
+ nop
+
+#define __tlb_read_hazard \
+ nop; \
+ nop; \
+ nop
+
+#define __tlb_probe_hazard \
+ nop; \
+ nop; \
+ nop
+
+#define __irq_enable_hazard \
+ ___ssnop; \
+ ___ssnop; \
+ ___ssnop
+
+#define __irq_disable_hazard \
+ nop; \
+ nop; \
+ nop
+
+#define __back_to_back_c0_hazard \
+ ___ssnop; \
+ ___ssnop; \
+ ___ssnop
+
+#define instruction_hazard() do { } while (0)
+
+#endif
+
+
+/* FPU hazards */
+
+#if defined(CONFIG_CPU_SB1)
+
+#define __enable_fpu_hazard \
+ .set push; \
+ .set mips64; \
+ .set noreorder; \
+ ___ssnop; \
+ bnezl $0, .+4; \
+ ___ssnop; \
+ .set pop
+
+#define __disable_fpu_hazard
+
+#elif defined(CONFIG_CPU_MIPSR2) || defined(CONFIG_CPU_MIPSR6)
+
+#define __enable_fpu_hazard \
+ ___ehb
+
+#define __disable_fpu_hazard \
+ ___ehb
+
+#else
+
+#define __enable_fpu_hazard \
+ nop; \
+ nop; \
+ nop; \
+ nop
+
+#define __disable_fpu_hazard \
+ ___ehb
+
+#endif
+
+#ifdef __ASSEMBLY__
+
+#define _ssnop ___ssnop
+#define _ehb ___ehb
+#define mtc0_tlbw_hazard __mtc0_tlbw_hazard
+#define mtc0_tlbr_hazard __mtc0_tlbr_hazard
+#define tlbw_use_hazard __tlbw_use_hazard
+#define tlb_read_hazard __tlb_read_hazard
+#define tlb_probe_hazard __tlb_probe_hazard
+#define irq_enable_hazard __irq_enable_hazard
+#define irq_disable_hazard __irq_disable_hazard
+#define back_to_back_c0_hazard __back_to_back_c0_hazard
+#define enable_fpu_hazard __enable_fpu_hazard
+#define disable_fpu_hazard __disable_fpu_hazard
+
+#else
+
+#define _ssnop() \
+do { \
+ __asm__ __volatile__( \
+ __stringify(___ssnop) \
+ ); \
+} while (0)
+
+#define _ehb() \
+do { \
+ __asm__ __volatile__( \
+ __stringify(___ehb) \
+ ); \
+} while (0)
+
+
+#define mtc0_tlbw_hazard() \
+do { \
+ __asm__ __volatile__( \
+ __stringify(__mtc0_tlbw_hazard) \
+ ); \
+} while (0)
+
+
+#define mtc0_tlbr_hazard() \
+do { \
+ __asm__ __volatile__( \
+ __stringify(__mtc0_tlbr_hazard) \
+ ); \
+} while (0)
+
+
+#define tlbw_use_hazard() \
+do { \
+ __asm__ __volatile__( \
+ __stringify(__tlbw_use_hazard) \
+ ); \
+} while (0)
+
+
+#define tlb_read_hazard() \
+do { \
+ __asm__ __volatile__( \
+ __stringify(__tlb_read_hazard) \
+ ); \
+} while (0)
+
+
+#define tlb_probe_hazard() \
+do { \
+ __asm__ __volatile__( \
+ __stringify(__tlb_probe_hazard) \
+ ); \
+} while (0)
+
+
+#define irq_enable_hazard() \
+do { \
+ __asm__ __volatile__( \
+ __stringify(__irq_enable_hazard) \
+ ); \
+} while (0)
+
+
+#define irq_disable_hazard() \
+do { \
+ __asm__ __volatile__( \
+ __stringify(__irq_disable_hazard) \
+ ); \
+} while (0)
+
+
+#define back_to_back_c0_hazard() \
+do { \
+ __asm__ __volatile__( \
+ __stringify(__back_to_back_c0_hazard) \
+ ); \
+} while (0)
+
+
+#define enable_fpu_hazard() \
+do { \
+ __asm__ __volatile__( \
+ __stringify(__enable_fpu_hazard) \
+ ); \
+} while (0)
+
+
+#define disable_fpu_hazard() \
+do { \
+ __asm__ __volatile__( \
+ __stringify(__disable_fpu_hazard) \
+ ); \
+} while (0)
+
+/*
+ * MIPS R2 instruction hazard barrier. Needs to be called as a subroutine.
+ */
+extern void mips_ihb(void);
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* _ASM_HAZARDS_H */