linux-kernel - RE: [PATCH v3 2/4] RISC-V: Factor out common code of __cpu_resume

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Date:   Wed, 1 Feb 2023 06:19:20 +0000
From:   JeeHeng Sia <jeeheng.sia@...rfivetech.com>
To:     Conor Dooley <conor@...nel.org>
CC:     "paul.walmsley@...ive.com" <paul.walmsley@...ive.com>,
        "palmer@...belt.com" <palmer@...belt.com>,
        "aou@...s.berkeley.edu" <aou@...s.berkeley.edu>,
        "linux-riscv@...ts.infradead.org" <linux-riscv@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Leyfoon Tan <leyfoon.tan@...rfivetech.com>,
        Mason Huo <mason.huo@...rfivetech.com>
Subject: RE: [PATCH v3 2/4] RISC-V: Factor out common code of
 __cpu_resume_enter()



> -----Original Message-----
> From: Conor Dooley <conor@...nel.org>
> Sent: Tuesday, 31 January, 2023 5:49 AM
> To: JeeHeng Sia <jeeheng.sia@...rfivetech.com>
> Cc: paul.walmsley@...ive.com; palmer@...belt.com; aou@...s.berkeley.edu; linux-riscv@...ts.infradead.org; linux-
> kernel@...r.kernel.org; Leyfoon Tan <leyfoon.tan@...rfivetech.com>; Mason Huo <mason.huo@...rfivetech.com>
> Subject: Re: [PATCH v3 2/4] RISC-V: Factor out common code of __cpu_resume_enter()
> 
> On Fri, Jan 27, 2023 at 05:10:49PM +0800, Sia Jee Heng wrote:
> > The cpu_resume() function is very similar for the suspend to disk and
> > suspend to ram cases. Factor out the common code into restore_csr macro
> > and restore_reg macro.
> >
> > Signed-off-by: Sia Jee Heng <jeeheng.sia@...rfivetech.com>
> > ---
> >  arch/riscv/include/asm/assembler.h | 62 ++++++++++++++++++++++++++++++
> >  arch/riscv/kernel/suspend_entry.S  | 34 ++--------------
> >  2 files changed, 65 insertions(+), 31 deletions(-)
> >  create mode 100644 arch/riscv/include/asm/assembler.h
> >
> > diff --git a/arch/riscv/include/asm/assembler.h b/arch/riscv/include/asm/assembler.h
> > new file mode 100644
> > index 000000000000..ef1283d04b70
> > --- /dev/null
> > +++ b/arch/riscv/include/asm/assembler.h
> > @@ -0,0 +1,62 @@
> > +/* SPDX-License-Identifier: GPL-2.0-only */
> > +/*
> > + * Copyright (C) 2023 StarFive Technology Co., Ltd.
> > + *
> > + * Author: Jee Heng Sia <jeeheng.sia@...rfivetech.com>
> > + */
> > +
> > +#ifndef __ASSEMBLY__
> > +#error "Only include this from assembly code"
> > +#endif
> > +
> > +#ifndef __ASM_ASSEMBLER_H
> > +#define __ASM_ASSEMBLER_H
> > +
> > +#include <asm/asm.h>
> > +#include <asm/csr.h>
> > +#include <asm/asm-offsets.h>
> > +
> > +/**
> > + * restore_csr - restore hart's CSR value
> > + */
> > +	.macro restore_csr
> > +		REG_L	t0, (SUSPEND_CONTEXT_REGS + PT_EPC)(a0)
> > +		csrw	CSR_EPC, t0
> > +		REG_L	t0, (SUSPEND_CONTEXT_REGS + PT_STATUS)(a0)
> > +		csrw	CSR_STATUS, t0
> > +		REG_L	t0, (SUSPEND_CONTEXT_REGS + PT_BADADDR)(a0)
> > +		csrw	CSR_TVAL, t0
> > +		REG_L	t0, (SUSPEND_CONTEXT_REGS + PT_CAUSE)(a0)
> > +		csrw	CSR_CAUSE, t0
> > +	.endm
> > +
> > +/**
> > + * restore_reg - Restore registers (except A0 and T0-T6)
> 
> arch/riscv/include/asm/assembler.h:34: warning: Incorrect use of kernel-doc format:  * restore_reg - Restore registers (except A0 and
> T0-T6)
Ok, will use '/*' instead of '/**'
> 
> Otherwise, LGTM.
> 
> > + */
> > +	.macro restore_reg
> > +		REG_L	ra, (SUSPEND_CONTEXT_REGS + PT_RA)(a0)
> > +		REG_L	sp, (SUSPEND_CONTEXT_REGS + PT_SP)(a0)
> > +		REG_L	gp, (SUSPEND_CONTEXT_REGS + PT_GP)(a0)
> > +		REG_L	tp, (SUSPEND_CONTEXT_REGS + PT_TP)(a0)
> > +		REG_L	s0, (SUSPEND_CONTEXT_REGS + PT_S0)(a0)
> > +		REG_L	s1, (SUSPEND_CONTEXT_REGS + PT_S1)(a0)
> > +		REG_L	a1, (SUSPEND_CONTEXT_REGS + PT_A1)(a0)
> > +		REG_L	a2, (SUSPEND_CONTEXT_REGS + PT_A2)(a0)
> > +		REG_L	a3, (SUSPEND_CONTEXT_REGS + PT_A3)(a0)
> > +		REG_L	a4, (SUSPEND_CONTEXT_REGS + PT_A4)(a0)
> > +		REG_L	a5, (SUSPEND_CONTEXT_REGS + PT_A5)(a0)
> > +		REG_L	a6, (SUSPEND_CONTEXT_REGS + PT_A6)(a0)
> > +		REG_L	a7, (SUSPEND_CONTEXT_REGS + PT_A7)(a0)
> > +		REG_L	s2, (SUSPEND_CONTEXT_REGS + PT_S2)(a0)
> > +		REG_L	s3, (SUSPEND_CONTEXT_REGS + PT_S3)(a0)
> > +		REG_L	s4, (SUSPEND_CONTEXT_REGS + PT_S4)(a0)
> > +		REG_L	s5, (SUSPEND_CONTEXT_REGS + PT_S5)(a0)
> > +		REG_L	s6, (SUSPEND_CONTEXT_REGS + PT_S6)(a0)
> > +		REG_L	s7, (SUSPEND_CONTEXT_REGS + PT_S7)(a0)
> > +		REG_L	s8, (SUSPEND_CONTEXT_REGS + PT_S8)(a0)
> > +		REG_L	s9, (SUSPEND_CONTEXT_REGS + PT_S9)(a0)
> > +		REG_L	s10, (SUSPEND_CONTEXT_REGS + PT_S10)(a0)
> > +		REG_L	s11, (SUSPEND_CONTEXT_REGS + PT_S11)(a0)
> > +	.endm
> > +
> > +#endif	/* __ASM_ASSEMBLER_H */
> > diff --git a/arch/riscv/kernel/suspend_entry.S b/arch/riscv/kernel/suspend_entry.S
> > index aafcca58c19d..74a8fab8e0f6 100644
> > --- a/arch/riscv/kernel/suspend_entry.S
> > +++ b/arch/riscv/kernel/suspend_entry.S
> > @@ -7,6 +7,7 @@
> >  #include <linux/linkage.h>
> >  #include <asm/asm.h>
> >  #include <asm/asm-offsets.h>
> > +#include <asm/assembler.h>
> >  #include <asm/csr.h>
> >  #include <asm/xip_fixup.h>
> >
> > @@ -83,39 +84,10 @@ ENTRY(__cpu_resume_enter)
> >  	add	a0, a1, zero
> >
> >  	/* Restore CSRs */
> > -	REG_L	t0, (SUSPEND_CONTEXT_REGS + PT_EPC)(a0)
> > -	csrw	CSR_EPC, t0
> > -	REG_L	t0, (SUSPEND_CONTEXT_REGS + PT_STATUS)(a0)
> > -	csrw	CSR_STATUS, t0
> > -	REG_L	t0, (SUSPEND_CONTEXT_REGS + PT_BADADDR)(a0)
> > -	csrw	CSR_TVAL, t0
> > -	REG_L	t0, (SUSPEND_CONTEXT_REGS + PT_CAUSE)(a0)
> > -	csrw	CSR_CAUSE, t0
> > +	restore_csr
> >
> >  	/* Restore registers (except A0 and T0-T6) */
> > -	REG_L	ra, (SUSPEND_CONTEXT_REGS + PT_RA)(a0)
> > -	REG_L	sp, (SUSPEND_CONTEXT_REGS + PT_SP)(a0)
> > -	REG_L	gp, (SUSPEND_CONTEXT_REGS + PT_GP)(a0)
> > -	REG_L	tp, (SUSPEND_CONTEXT_REGS + PT_TP)(a0)
> > -	REG_L	s0, (SUSPEND_CONTEXT_REGS + PT_S0)(a0)
> > -	REG_L	s1, (SUSPEND_CONTEXT_REGS + PT_S1)(a0)
> > -	REG_L	a1, (SUSPEND_CONTEXT_REGS + PT_A1)(a0)
> > -	REG_L	a2, (SUSPEND_CONTEXT_REGS + PT_A2)(a0)
> > -	REG_L	a3, (SUSPEND_CONTEXT_REGS + PT_A3)(a0)
> > -	REG_L	a4, (SUSPEND_CONTEXT_REGS + PT_A4)(a0)
> > -	REG_L	a5, (SUSPEND_CONTEXT_REGS + PT_A5)(a0)
> > -	REG_L	a6, (SUSPEND_CONTEXT_REGS + PT_A6)(a0)
> > -	REG_L	a7, (SUSPEND_CONTEXT_REGS + PT_A7)(a0)
> > -	REG_L	s2, (SUSPEND_CONTEXT_REGS + PT_S2)(a0)
> > -	REG_L	s3, (SUSPEND_CONTEXT_REGS + PT_S3)(a0)
> > -	REG_L	s4, (SUSPEND_CONTEXT_REGS + PT_S4)(a0)
> > -	REG_L	s5, (SUSPEND_CONTEXT_REGS + PT_S5)(a0)
> > -	REG_L	s6, (SUSPEND_CONTEXT_REGS + PT_S6)(a0)
> > -	REG_L	s7, (SUSPEND_CONTEXT_REGS + PT_S7)(a0)
> > -	REG_L	s8, (SUSPEND_CONTEXT_REGS + PT_S8)(a0)
> > -	REG_L	s9, (SUSPEND_CONTEXT_REGS + PT_S9)(a0)
> > -	REG_L	s10, (SUSPEND_CONTEXT_REGS + PT_S10)(a0)
> > -	REG_L	s11, (SUSPEND_CONTEXT_REGS + PT_S11)(a0)
> > +	restore_reg
> >
> >  	/* Return zero value */
> >  	add	a0, zero, zero
> > --
> > 2.34.1
> >