cfca4b5abe
The motivation is eventual ABI considerations for ARCv3 but even without
it this change us worthwhile as diffstat reduces 100 net lines
r25 is a callee saved register, normally not saved by entry code in
pt_regs. However because of its usage in CONFIG_ARC_CURR_IN_REG it needs
to be. This in turn requires a whole bunch of special casing when we
need to access r25. Then there is distinction between user mode r25 vs.
kernel mode r25 - hence distinct SAVE_CALLEE_SAVED_{USER,KERNEL}
Instead use gp which is a scratch register and thus saved already in entry
code. This cleans things up significantly and much nocer on eyes:
- SAVE_CALLEE_SAVED_{USER,KERNEL} are now exactly same
- no special user_r25 slot in pt_reggs
Note that typical global asm registers are callee-saved (r25), but gp is
not callee-saved thus needs additional -ffixed-<reg> toggle
Signed-off-by: Vineet Gupta <vgupta@kernel.org>
25 lines
548 B
C
25 lines
548 B
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
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*
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* Vineetg: May 16th, 2008
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* - Current macro is now implemented as "global register" r25
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*/
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#ifndef _ASM_ARC_CURRENT_H
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#define _ASM_ARC_CURRENT_H
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#ifndef __ASSEMBLY__
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#ifdef CONFIG_ARC_CURR_IN_REG
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register struct task_struct *curr_arc asm("gp");
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#define current (curr_arc)
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#else
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#include <asm-generic/current.h>
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#endif /* ! CONFIG_ARC_CURR_IN_REG */
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#endif /* ! __ASSEMBLY__ */
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#endif /* _ASM_ARC_CURRENT_H */
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