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kernel
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linux
ARC: add support for DSP-enabled userspace applications
To be able to run DSP-enabled userspace applications we need to
save and restore following DSP-related registers:
At IRQ/exception entry/exit:
* DSP_CTRL (save it and reset to value suitable for kernel)
* ACC0_LO, ACC0_HI (we already save them as r58, r59 pair)
At context switch:
* ACC0_GLO, ACC0_GHI
* DSP_BFLY0, DSP_FFT_CTRL
Reviewed-by: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
authored by
Eugeniy Paltsev
and committed by
Vineet Gupta
7321e2ea
4827d0cf
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-1
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arch/arc/Kconfig
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arch/arc/Kconfig
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config ARC_DSP_HANDLED
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def_bool n
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config ARC_DSP_SAVE_RESTORE_REGS
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def_bool n
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choice
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prompt "DSP support"
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default ARC_DSP_NONE
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DSP extension presence in HW, no support for DSP-enabled userspace
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applications. We don't save / restore DSP registers and only do
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some minimal preparations so userspace won't be able to break kernel
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config ARC_DSP_USERSPACE
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bool "Support DSP for userspace apps"
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select ARC_HAS_ACCL_REGS
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select ARC_DSP_HANDLED
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select ARC_DSP_SAVE_RESTORE_REGS
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help
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DSP extension presence in HW, support save / restore DSP registers to
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run DSP-enabled userspace applications
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endchoice
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config ARC_IRQ_NO_AUTOSAVE
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arch/arc/include/asm/arcregs.h
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arch/arc/include/asm/arcregs.h
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arch/arc/include/asm/dsp-impl.h
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arch/arc/include/asm/dsp-impl.h
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#ifndef __ASM_ARC_DSP_IMPL_H
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#define __ASM_ARC_DSP_IMPL_H
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#include <asm/dsp.h>
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#define DSP_CTRL_DISABLED_ALL 0
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#ifdef __ASSEMBLY__
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*/
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mov r10, DSP_CTRL_DISABLED_ALL
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sr r10, [ARC_AUX_DSP_CTRL]
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#endif /* ARC_DSP_KERNEL */
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#elif defined(CONFIG_ARC_DSP_SAVE_RESTORE_REGS)
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/*
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* Save DSP_CTRL register and reset it to value suitable for kernel
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* (DSP_CTRL_DISABLED_ALL)
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*/
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mov r10, DSP_CTRL_DISABLED_ALL
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aex r10, [ARC_AUX_DSP_CTRL]
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st r10, [sp, PT_DSP_CTRL]
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#endif
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.endm
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/* clobbers r10, r11 registers pair */
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.macro DSP_RESTORE_REGFILE_IRQ
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#if defined(CONFIG_ARC_DSP_SAVE_RESTORE_REGS)
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ld r10, [sp, PT_DSP_CTRL]
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sr r10, [ARC_AUX_DSP_CTRL]
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#endif
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.endm
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#else /* __ASEMBLY__ */
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#include <linux/sched.h>
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#include <asm/asserts.h>
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#include <asm/switch_to.h>
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#ifdef CONFIG_ARC_DSP_SAVE_RESTORE_REGS
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/*
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* As we save new and restore old AUX register value in the same place we
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* can optimize a bit and use AEX instruction (swap contents of an auxiliary
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* register with a core register) instead of LR + SR pair.
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*/
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#define AUX_SAVE_RESTORE(_saveto, _readfrom, _offt, _aux) \
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do { \
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long unsigned int _scratch; \
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\
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__asm__ __volatile__( \
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"ld %0, [%2, %4] \n" \
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"aex %0, [%3] \n" \
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"st %0, [%1, %4] \n" \
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: \
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"=&r" (_scratch) /* must be early clobber */ \
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: \
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"r" (_saveto), \
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"r" (_readfrom), \
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"Ir" (_aux), \
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"Ir" (_offt) \
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: \
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"memory" \
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); \
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} while (0)
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#define DSP_AUX_SAVE_RESTORE(_saveto, _readfrom, _aux) \
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AUX_SAVE_RESTORE(_saveto, _readfrom, \
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offsetof(struct dsp_callee_regs, _aux), \
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ARC_AUX_##_aux)
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static inline void dsp_save_restore(struct task_struct *prev,
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struct task_struct *next)
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{
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long unsigned int *saveto = &prev->thread.dsp.ACC0_GLO;
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long unsigned int *readfrom = &next->thread.dsp.ACC0_GLO;
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DSP_AUX_SAVE_RESTORE(saveto, readfrom, ACC0_GLO);
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DSP_AUX_SAVE_RESTORE(saveto, readfrom, ACC0_GHI);
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DSP_AUX_SAVE_RESTORE(saveto, readfrom, DSP_BFLY0);
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DSP_AUX_SAVE_RESTORE(saveto, readfrom, DSP_FFT_CTRL);
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}
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#else /* !CONFIG_ARC_DSP_SAVE_RESTORE_REGS */
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#define dsp_save_restore(p, n)
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#endif /* CONFIG_ARC_DSP_SAVE_RESTORE_REGS */
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static inline bool dsp_exist(void)
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{
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arch/arc/include/asm/dsp.h
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arch/arc/include/asm/dsp.h
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/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Copyright (C) 2020 Synopsys, Inc. (www.synopsys.com)
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*
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* Author: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
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*/
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#ifndef __ASM_ARC_DSP_H
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#define __ASM_ARC_DSP_H
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#ifndef __ASSEMBLY__
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/*
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* DSP-related saved registers - need to be saved only when you are
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* scheduled out.
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* structure fields name must correspond to aux register defenitions for
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* automatic offset calculation in DSP_AUX_SAVE_RESTORE macros
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*/
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struct dsp_callee_regs {
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unsigned long ACC0_GLO, ACC0_GHI, DSP_BFLY0, DSP_FFT_CTRL;
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};
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#endif /* !__ASSEMBLY__ */
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#endif /* __ASM_ARC_DSP_H */
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arch/arc/include/asm/entry-arcv2.h
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arch/arc/include/asm/entry-arcv2.h
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arch/arc/include/asm/processor.h
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arch/arc/include/asm/processor.h
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#ifndef __ASSEMBLY__
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#include <asm/ptrace.h>
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#include <asm/dsp.h>
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#include <asm/fpu.h>
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#ifdef CONFIG_ARC_PLAT_EZNPS
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unsigned long ksp; /* kernel mode stack pointer */
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unsigned long callee_reg; /* pointer to callee regs */
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unsigned long fault_address; /* dbls as brkpt holder as well */
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#ifdef CONFIG_ARC_DSP_SAVE_RESTORE_REGS
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struct dsp_callee_regs dsp;
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#endif
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#ifdef CONFIG_ARC_FPU_SAVE_RESTORE
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struct arc_fpu fpu;
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#endif
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arch/arc/include/asm/ptrace.h
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arch/arc/include/asm/ptrace.h
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#ifdef CONFIG_ARC_HAS_ACCL_REGS
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unsigned long r58, r59; /* ACCL/ACCH used by FPU / DSP MPY */
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#endif
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#ifdef CONFIG_ARC_DSP_SAVE_RESTORE_REGS
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unsigned long DSP_CTRL;
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#endif
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/*------- Below list auto saved by h/w -----------*/
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unsigned long r0, r1, r2, r3, r4, r5, r6, r7, r8, r9, r10, r11;
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arch/arc/include/asm/switch_to.h
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arch/arc/include/asm/switch_to.h
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#ifndef __ASSEMBLY__
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#include <linux/sched.h>
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#include <asm/dsp-impl.h>
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#include <asm/fpu.h>
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#ifdef CONFIG_ARC_PLAT_EZNPS
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#define switch_to(prev, next, last) \
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do { \
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ARC_EZNPS_DP_PREV(prev, next); \
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dsp_save_restore(prev, next); \
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fpu_save_restore(prev, next); \
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last = __switch_to(prev, next);\
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mb(); \
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arch/arc/kernel/asm-offsets.c
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arch/arc/kernel/asm-offsets.c
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#include <asm/hardirq.h>
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#include <asm/page.h>
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int main(void)
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{
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DEFINE(TASK_THREAD, offsetof(struct task_struct, thread));
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#ifdef CONFIG_ARC_HAS_ACCL_REGS
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OFFSET(PT_r58, pt_regs, r58);
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OFFSET(PT_r59, pt_regs, r59);
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#endif
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#ifdef CONFIG_ARC_DSP_SAVE_RESTORE_REGS
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OFFSET(PT_DSP_CTRL, pt_regs, DSP_CTRL);
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#endif
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return 0;