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    SubjectRE: [PATCH v4 2/4] RISC-V: Factor out common code of __cpu_resume_enter()
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    > -----Original Message-----
    > From: Andrew Jones <ajones@ventanamicro.com>
    > Sent: Thursday, 23 February, 2023 2:52 PM
    > To: JeeHeng Sia <jeeheng.sia@starfivetech.com>
    > Cc: paul.walmsley@sifive.com; palmer@dabbelt.com; aou@eecs.berkeley.edu; linux-riscv@lists.infradead.org; linux-
    > kernel@vger.kernel.org; Leyfoon Tan <leyfoon.tan@starfivetech.com>; Mason Huo <mason.huo@starfivetech.com>
    > Subject: Re: [PATCH v4 2/4] RISC-V: Factor out common code of __cpu_resume_enter()
    >
    > On Tue, Feb 21, 2023 at 10:35:21AM +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@starfivetech.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..727a97735493
    > > --- /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@starfivetech.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/asm-offsets.h>
    > > +#include <asm/csr.h>
    > > +
    > > +/*
    > > + * restore_csr - restore hart's CSR value
    > > + */
    > > + .macro restore_csr
    >
    > Since there are more than one, 'restore_csrs' would be more appropriate
    > and s/CSR value/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
    > > + .endm
    > > +
    > > +/*
    > > + * restore_reg - Restore registers (except A0 and T0-T6)
    > > + */
    > > + .macro restore_reg
    >
    > restore_regs
    >
    > > + 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
    > >
    >
    > Otherwise,
    >
    > Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
    noted with thanks
    >
    > Thanks,
    > drew

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