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android_kernel_xiaomi_sm8350/arch/mips/include/asm/hazards.h
Paul Burton 378ed6f0e3
MIPS: Avoid using .set mips0 to restore ISA 
We currently have 2 commonly used methods for switching ISA within
assembly code, then restoring the original ISA.

  1) Using a pair of .set push & .set pop directives. For example:

     .set	push
     .set	mips32r2
     <some_insn>
     .set	pop

  2) Using .set mips0 to restore the ISA originally specified on the
     command line. For example:

     .set	mips32r2
     <some_insn>
     .set	mips0

Unfortunately method 2 does not work with nanoMIPS toolchains, where the
assembler rejects the .set mips0 directive like so:

     Error: cannot change ISA from nanoMIPS to mips0

In preparation for supporting nanoMIPS builds, switch all instances of
method 2 in generic non-platform-specific code to use push & pop as in
method 1 instead. The .set push & .set pop is arguably cleaner anyway,
and if nothing else it's good to consistently use one method.

Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/21037/
Cc: linux-mips@linux-mips.org
2018-11-09 10:23:19 -08:00

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/*
* 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 push \n" \
" .set "MIPS_ISA_LEVEL" \n" \
" dla %0, 1f \n" \
" jr.hb %0 \n" \
" .set pop \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 push \n" \
" .set mips64r2 \n" \
" dla %0, 1f \n" \
" jr.hb %0 \n" \
" .set pop \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 */
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