![Ralf Baechle](/assets/img/avatar_default.png)
local_irq_restore -> raw_local_irq_restore -> irq_restore_epilog -> smtc_ipi_replay -> smtc_ipi_dq -> spin_unlock_irqrestore -> _spin_unlock_irqrestore -> local_irq_restore The recursion does abort when there is no more IPI queued for a CPU, so this isn't usually fatal which is why we got away with this for so long until this was discovered by code inspection. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
264 lines
6.2 KiB
C
264 lines
6.2 KiB
C
/*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*
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* Copyright (C) 1994, 95, 96, 97, 98, 99, 2003 by Ralf Baechle
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* Copyright (C) 1996 by Paul M. Antoine
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* Copyright (C) 1999 Silicon Graphics
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* Copyright (C) 2000 MIPS Technologies, Inc.
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*/
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#ifndef _ASM_IRQFLAGS_H
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#define _ASM_IRQFLAGS_H
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#ifndef __ASSEMBLY__
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#include <linux/compiler.h>
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#include <asm/hazards.h>
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__asm__ (
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" .macro raw_local_irq_enable \n"
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" .set push \n"
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" .set reorder \n"
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" .set noat \n"
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#ifdef CONFIG_MIPS_MT_SMTC
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" mfc0 $1, $2, 1 # SMTC - clear TCStatus.IXMT \n"
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" ori $1, 0x400 \n"
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" xori $1, 0x400 \n"
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" mtc0 $1, $2, 1 \n"
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#elif defined(CONFIG_CPU_MIPSR2)
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" ei \n"
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#else
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" mfc0 $1,$12 \n"
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" ori $1,0x1f \n"
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" xori $1,0x1e \n"
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" mtc0 $1,$12 \n"
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#endif
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" irq_enable_hazard \n"
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" .set pop \n"
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" .endm");
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static inline void raw_local_irq_enable(void)
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{
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__asm__ __volatile__(
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"raw_local_irq_enable"
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: /* no outputs */
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: /* no inputs */
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: "memory");
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}
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/*
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* For cli() we have to insert nops to make sure that the new value
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* has actually arrived in the status register before the end of this
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* macro.
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* R4000/R4400 need three nops, the R4600 two nops and the R10000 needs
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* no nops at all.
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*/
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/*
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* For TX49, operating only IE bit is not enough.
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*
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* If mfc0 $12 follows store and the mfc0 is last instruction of a
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* page and fetching the next instruction causes TLB miss, the result
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* of the mfc0 might wrongly contain EXL bit.
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*
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* ERT-TX49H2-027, ERT-TX49H3-012, ERT-TX49HL3-006, ERT-TX49H4-008
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*
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* Workaround: mask EXL bit of the result or place a nop before mfc0.
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*/
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__asm__ (
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" .macro raw_local_irq_disable\n"
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" .set push \n"
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" .set noat \n"
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#ifdef CONFIG_MIPS_MT_SMTC
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" mfc0 $1, $2, 1 \n"
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" ori $1, 0x400 \n"
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" .set noreorder \n"
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" mtc0 $1, $2, 1 \n"
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#elif defined(CONFIG_CPU_MIPSR2)
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" di \n"
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#else
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" mfc0 $1,$12 \n"
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" ori $1,0x1f \n"
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" xori $1,0x1f \n"
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" .set noreorder \n"
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" mtc0 $1,$12 \n"
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#endif
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" irq_disable_hazard \n"
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" .set pop \n"
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" .endm \n");
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static inline void raw_local_irq_disable(void)
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{
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__asm__ __volatile__(
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"raw_local_irq_disable"
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: /* no outputs */
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: /* no inputs */
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: "memory");
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}
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__asm__ (
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" .macro raw_local_save_flags flags \n"
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" .set push \n"
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" .set reorder \n"
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#ifdef CONFIG_MIPS_MT_SMTC
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" mfc0 \\flags, $2, 1 \n"
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#else
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" mfc0 \\flags, $12 \n"
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#endif
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" .set pop \n"
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" .endm \n");
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#define raw_local_save_flags(x) \
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__asm__ __volatile__( \
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"raw_local_save_flags %0" \
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: "=r" (x))
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__asm__ (
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" .macro raw_local_irq_save result \n"
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" .set push \n"
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" .set reorder \n"
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" .set noat \n"
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#ifdef CONFIG_MIPS_MT_SMTC
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" mfc0 \\result, $2, 1 \n"
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" ori $1, \\result, 0x400 \n"
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" .set noreorder \n"
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" mtc0 $1, $2, 1 \n"
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" andi \\result, \\result, 0x400 \n"
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#elif defined(CONFIG_CPU_MIPSR2)
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" di \\result \n"
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" andi \\result, 1 \n"
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#else
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" mfc0 \\result, $12 \n"
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" ori $1, \\result, 0x1f \n"
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" xori $1, 0x1f \n"
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" .set noreorder \n"
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" mtc0 $1, $12 \n"
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#endif
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" irq_disable_hazard \n"
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" .set pop \n"
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" .endm \n");
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#define raw_local_irq_save(x) \
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__asm__ __volatile__( \
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"raw_local_irq_save\t%0" \
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: "=r" (x) \
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: /* no inputs */ \
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: "memory")
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__asm__ (
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" .macro raw_local_irq_restore flags \n"
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" .set push \n"
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" .set noreorder \n"
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" .set noat \n"
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#ifdef CONFIG_MIPS_MT_SMTC
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"mfc0 $1, $2, 1 \n"
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"andi \\flags, 0x400 \n"
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"ori $1, 0x400 \n"
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"xori $1, 0x400 \n"
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"or \\flags, $1 \n"
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"mtc0 \\flags, $2, 1 \n"
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#elif defined(CONFIG_CPU_MIPSR2) && defined(CONFIG_IRQ_CPU)
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/*
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* Slow, but doesn't suffer from a relativly unlikely race
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* condition we're having since days 1.
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*/
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" beqz \\flags, 1f \n"
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" di \n"
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" ei \n"
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"1: \n"
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#elif defined(CONFIG_CPU_MIPSR2)
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/*
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* Fast, dangerous. Life is fun, life is good.
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*/
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" mfc0 $1, $12 \n"
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" ins $1, \\flags, 0, 1 \n"
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" mtc0 $1, $12 \n"
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#else
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" mfc0 $1, $12 \n"
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" andi \\flags, 1 \n"
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" ori $1, 0x1f \n"
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" xori $1, 0x1f \n"
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" or \\flags, $1 \n"
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" mtc0 \\flags, $12 \n"
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#endif
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" irq_disable_hazard \n"
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" .set pop \n"
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" .endm \n");
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extern void smtc_ipi_replay(void);
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static inline void raw_local_irq_restore(unsigned long flags)
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{
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unsigned long __tmp1;
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#ifdef CONFIG_MIPS_MT_SMTC_INSTANT_REPLAY
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/*
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* CONFIG_MIPS_MT_SMTC_INSTANT_REPLAY does prompt replay of deferred
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* IPIs, at the cost of branch and call overhead on each
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* local_irq_restore()
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*/
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if (unlikely(!(flags & 0x0400)))
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smtc_ipi_replay();
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#endif
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__asm__ __volatile__(
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"raw_local_irq_restore\t%0"
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: "=r" (__tmp1)
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: "0" (flags)
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: "memory");
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}
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static inline int raw_irqs_disabled_flags(unsigned long flags)
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{
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#ifdef CONFIG_MIPS_MT_SMTC
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/*
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* SMTC model uses TCStatus.IXMT to disable interrupts for a thread/CPU
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*/
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return flags & 0x400;
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#else
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return !(flags & 1);
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#endif
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}
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#endif
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/*
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* Do the CPU's IRQ-state tracing from assembly code.
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*/
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#ifdef CONFIG_TRACE_IRQFLAGS
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/* Reload some registers clobbered by trace_hardirqs_on */
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#ifdef CONFIG_64BIT
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# define TRACE_IRQS_RELOAD_REGS \
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LONG_L $11, PT_R11(sp); \
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LONG_L $10, PT_R10(sp); \
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LONG_L $9, PT_R9(sp); \
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LONG_L $8, PT_R8(sp); \
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LONG_L $7, PT_R7(sp); \
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LONG_L $6, PT_R6(sp); \
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LONG_L $5, PT_R5(sp); \
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LONG_L $4, PT_R4(sp); \
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LONG_L $2, PT_R2(sp)
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#else
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# define TRACE_IRQS_RELOAD_REGS \
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LONG_L $7, PT_R7(sp); \
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LONG_L $6, PT_R6(sp); \
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LONG_L $5, PT_R5(sp); \
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LONG_L $4, PT_R4(sp); \
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LONG_L $2, PT_R2(sp)
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#endif
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# define TRACE_IRQS_ON \
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CLI; /* make sure trace_hardirqs_on() is called in kernel level */ \
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jal trace_hardirqs_on
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# define TRACE_IRQS_ON_RELOAD \
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TRACE_IRQS_ON; \
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TRACE_IRQS_RELOAD_REGS
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# define TRACE_IRQS_OFF \
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jal trace_hardirqs_off
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#else
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# define TRACE_IRQS_ON
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# define TRACE_IRQS_ON_RELOAD
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# define TRACE_IRQS_OFF
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#endif
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#endif /* _ASM_IRQFLAGS_H */
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