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References: <20220928162007.3791-1-jszhang@kernel.org> <20220928162007.3791-5-jszhang@kernel.org>
In-Reply-To: <20220928162007.3791-5-jszhang@kernel.org>
From:   Guo Ren <guoren@kernel.org>
Date:   Thu, 29 Sep 2022 11:59:00 +0800
Message-ID: <CAJF2gTTADq-JpUtitSr0nw1aDPZrsB6f1jA-04WmOVcrxYeakw@mail.gmail.com>
Subject: Re: [PATCH v2 4/4] riscv: entry: consolidate general regs saving into save_gp
To:     Jisheng Zhang <jszhang@kernel.org>
Cc:     Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
        llvm@lists.linux.dev
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On Thu, Sep 29, 2022 at 12:29 AM Jisheng Zhang <jszhang@kernel.org> wrote:
>
> Consolidate the saving/restoring GPs(except ra, sp and tp) into
> save_gp/restore_gp macro.
>
> No functional change intended.
>
> Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
> ---
>  arch/riscv/include/asm/asm.h   | 65 +++++++++++++++++++++++++
>  arch/riscv/kernel/entry.S      | 87 ++--------------------------------
>  arch/riscv/kernel/mcount-dyn.S | 58 +----------------------
>  3 files changed, 70 insertions(+), 140 deletions(-)
>
> diff --git a/arch/riscv/include/asm/asm.h b/arch/riscv/include/asm/asm.h
> index 1b471ff73178..2f3b49536e9d 100644
> --- a/arch/riscv/include/asm/asm.h
> +++ b/arch/riscv/include/asm/asm.h
> @@ -68,6 +68,7 @@
>  #endif
>
>  #ifdef __ASSEMBLY__
> +#include <asm/asm-offsets.h>
>
>  /* Common assembly source macros */
>
> @@ -80,6 +81,70 @@
>         .endr
>  .endm
>
> +       /* save all GPs except ra, sp and tp */
> +       .macro save_gp
How about leave x3(gp) out of the macro, and define:
.marco save_from_x5_to_x31
.marco restore_from_x5_to_x31

> +       REG_S x3,  PT_GP(sp)
> +       REG_S x5,  PT_T0(sp)
> +       REG_S x6,  PT_T1(sp)
> +       REG_S x7,  PT_T2(sp)
> +       REG_S x8,  PT_S0(sp)
> +       REG_S x9,  PT_S1(sp)
> +       REG_S x10, PT_A0(sp)
> +       REG_S x11, PT_A1(sp)
> +       REG_S x12, PT_A2(sp)
> +       REG_S x13, PT_A3(sp)
> +       REG_S x14, PT_A4(sp)
> +       REG_S x15, PT_A5(sp)
> +       REG_S x16, PT_A6(sp)
> +       REG_S x17, PT_A7(sp)
> +       REG_S x18, PT_S2(sp)
> +       REG_S x19, PT_S3(sp)
> +       REG_S x20, PT_S4(sp)
> +       REG_S x21, PT_S5(sp)
> +       REG_S x22, PT_S6(sp)
> +       REG_S x23, PT_S7(sp)
> +       REG_S x24, PT_S8(sp)
> +       REG_S x25, PT_S9(sp)
> +       REG_S x26, PT_S10(sp)
> +       REG_S x27, PT_S11(sp)
> +       REG_S x28, PT_T3(sp)
> +       REG_S x29, PT_T4(sp)
> +       REG_S x30, PT_T5(sp)
> +       REG_S x31, PT_T6(sp)
> +       .endm
> +
> +       /* restore all GPs except ra, sp and tp */
> +       .macro restore_gp
> +       REG_L x3,  PT_GP(sp)
> +       REG_L x5,  PT_T0(sp)
> +       REG_L x6,  PT_T1(sp)
> +       REG_L x7,  PT_T2(sp)
> +       REG_L x8,  PT_S0(sp)
> +       REG_L x9,  PT_S1(sp)
> +       REG_L x10, PT_A0(sp)
> +       REG_L x11, PT_A1(sp)
> +       REG_L x12, PT_A2(sp)
> +       REG_L x13, PT_A3(sp)
> +       REG_L x14, PT_A4(sp)
> +       REG_L x15, PT_A5(sp)
> +       REG_L x16, PT_A6(sp)
> +       REG_L x17, PT_A7(sp)
> +       REG_L x18, PT_S2(sp)
> +       REG_L x19, PT_S3(sp)
> +       REG_L x20, PT_S4(sp)
> +       REG_L x21, PT_S5(sp)
> +       REG_L x22, PT_S6(sp)
> +       REG_L x23, PT_S7(sp)
> +       REG_L x24, PT_S8(sp)
> +       REG_L x25, PT_S9(sp)
> +       REG_L x26, PT_S10(sp)
> +       REG_L x27, PT_S11(sp)
> +       REG_L x28, PT_T3(sp)
> +       REG_L x29, PT_T4(sp)
> +       REG_L x30, PT_T5(sp)
> +       REG_L x31, PT_T6(sp)
> +       .endm
> +
>  #endif /* __ASSEMBLY__ */
>
>  #endif /* _ASM_RISCV_ASM_H */
> diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S
> index 5a6171a90d81..a90f17ed2822 100644
> --- a/arch/riscv/kernel/entry.S
> +++ b/arch/riscv/kernel/entry.S
> @@ -40,34 +40,7 @@ _save_context:
>         REG_L sp, TASK_TI_KERNEL_SP(tp)
>         addi sp, sp, -(PT_SIZE_ON_STACK)
>         REG_S x1,  PT_RA(sp)
> -       REG_S x3,  PT_GP(sp)
> -       REG_S x5,  PT_T0(sp)
> -       REG_S x6,  PT_T1(sp)
> -       REG_S x7,  PT_T2(sp)
> -       REG_S x8,  PT_S0(sp)
> -       REG_S x9,  PT_S1(sp)
> -       REG_S x10, PT_A0(sp)
> -       REG_S x11, PT_A1(sp)
> -       REG_S x12, PT_A2(sp)
> -       REG_S x13, PT_A3(sp)
> -       REG_S x14, PT_A4(sp)
> -       REG_S x15, PT_A5(sp)
> -       REG_S x16, PT_A6(sp)
> -       REG_S x17, PT_A7(sp)
> -       REG_S x18, PT_S2(sp)
> -       REG_S x19, PT_S3(sp)
> -       REG_S x20, PT_S4(sp)
> -       REG_S x21, PT_S5(sp)
> -       REG_S x22, PT_S6(sp)
> -       REG_S x23, PT_S7(sp)
> -       REG_S x24, PT_S8(sp)
> -       REG_S x25, PT_S9(sp)
> -       REG_S x26, PT_S10(sp)
> -       REG_S x27, PT_S11(sp)
> -       REG_S x28, PT_T3(sp)
> -       REG_S x29, PT_T4(sp)
> -       REG_S x30, PT_T5(sp)
> -       REG_S x31, PT_T6(sp)
> +       save_gp
>
>         /*
>          * Disable user-mode memory access as it should only be set in the
> @@ -182,35 +155,8 @@ ENTRY(ret_from_exception)
>         csrw CSR_STATUS, a0
>
>         REG_L x1,  PT_RA(sp)
> -       REG_L x3,  PT_GP(sp)
>         REG_L x4,  PT_TP(sp)
> -       REG_L x5,  PT_T0(sp)
> -       REG_L x6,  PT_T1(sp)
> -       REG_L x7,  PT_T2(sp)
> -       REG_L x8,  PT_S0(sp)
> -       REG_L x9,  PT_S1(sp)
> -       REG_L x10, PT_A0(sp)
> -       REG_L x11, PT_A1(sp)
> -       REG_L x12, PT_A2(sp)
> -       REG_L x13, PT_A3(sp)
> -       REG_L x14, PT_A4(sp)
> -       REG_L x15, PT_A5(sp)
> -       REG_L x16, PT_A6(sp)
> -       REG_L x17, PT_A7(sp)
> -       REG_L x18, PT_S2(sp)
> -       REG_L x19, PT_S3(sp)
> -       REG_L x20, PT_S4(sp)
> -       REG_L x21, PT_S5(sp)
> -       REG_L x22, PT_S6(sp)
> -       REG_L x23, PT_S7(sp)
> -       REG_L x24, PT_S8(sp)
> -       REG_L x25, PT_S9(sp)
> -       REG_L x26, PT_S10(sp)
> -       REG_L x27, PT_S11(sp)
> -       REG_L x28, PT_T3(sp)
> -       REG_L x29, PT_T4(sp)
> -       REG_L x30, PT_T5(sp)
> -       REG_L x31, PT_T6(sp)
> +       restore_gp
>
>         REG_L x2,  PT_SP(sp)
>
> @@ -237,34 +183,7 @@ ENTRY(handle_kernel_stack_overflow)
>
>         //save context to overflow stack
>         REG_S x1,  PT_RA(sp)
> -       REG_S x3,  PT_GP(sp)
> -       REG_S x5,  PT_T0(sp)
> -       REG_S x6,  PT_T1(sp)
> -       REG_S x7,  PT_T2(sp)
> -       REG_S x8,  PT_S0(sp)
> -       REG_S x9,  PT_S1(sp)
> -       REG_S x10, PT_A0(sp)
> -       REG_S x11, PT_A1(sp)
> -       REG_S x12, PT_A2(sp)
> -       REG_S x13, PT_A3(sp)
> -       REG_S x14, PT_A4(sp)
> -       REG_S x15, PT_A5(sp)
> -       REG_S x16, PT_A6(sp)
> -       REG_S x17, PT_A7(sp)
> -       REG_S x18, PT_S2(sp)
> -       REG_S x19, PT_S3(sp)
> -       REG_S x20, PT_S4(sp)
> -       REG_S x21, PT_S5(sp)
> -       REG_S x22, PT_S6(sp)
> -       REG_S x23, PT_S7(sp)
> -       REG_S x24, PT_S8(sp)
> -       REG_S x25, PT_S9(sp)
> -       REG_S x26, PT_S10(sp)
> -       REG_S x27, PT_S11(sp)
> -       REG_S x28, PT_T3(sp)
> -       REG_S x29, PT_T4(sp)
> -       REG_S x30, PT_T5(sp)
> -       REG_S x31, PT_T6(sp)
> +       save_gp
>
>         REG_L s0, TASK_TI_KERNEL_SP(tp)
>         csrr s1, CSR_STATUS
> diff --git a/arch/riscv/kernel/mcount-dyn.S b/arch/riscv/kernel/mcount-dyn.S
> index d171eca623b6..1b4b0aecf4f5 100644
> --- a/arch/riscv/kernel/mcount-dyn.S
> +++ b/arch/riscv/kernel/mcount-dyn.S
> @@ -68,35 +68,8 @@
>         REG_L x1,  PT_EPC(sp)
>
>         REG_S x2,  PT_SP(sp)
> -       REG_S x3,  PT_GP(sp)
>         REG_S x4,  PT_TP(sp)
> -       REG_S x5,  PT_T0(sp)
> -       REG_S x6,  PT_T1(sp)
> -       REG_S x7,  PT_T2(sp)
> -       REG_S x8,  PT_S0(sp)
> -       REG_S x9,  PT_S1(sp)
> -       REG_S x10, PT_A0(sp)
> -       REG_S x11, PT_A1(sp)
> -       REG_S x12, PT_A2(sp)
> -       REG_S x13, PT_A3(sp)
> -       REG_S x14, PT_A4(sp)
> -       REG_S x15, PT_A5(sp)
> -       REG_S x16, PT_A6(sp)
> -       REG_S x17, PT_A7(sp)
> -       REG_S x18, PT_S2(sp)
> -       REG_S x19, PT_S3(sp)
> -       REG_S x20, PT_S4(sp)
> -       REG_S x21, PT_S5(sp)
> -       REG_S x22, PT_S6(sp)
> -       REG_S x23, PT_S7(sp)
> -       REG_S x24, PT_S8(sp)
> -       REG_S x25, PT_S9(sp)
> -       REG_S x26, PT_S10(sp)
> -       REG_S x27, PT_S11(sp)
> -       REG_S x28, PT_T3(sp)
> -       REG_S x29, PT_T4(sp)
> -       REG_S x30, PT_T5(sp)
> -       REG_S x31, PT_T6(sp)
> +       save_gp
>         .endm
>
>         .macro RESTORE_ALL
> @@ -106,35 +79,8 @@
>         addi    sp, sp, -PT_SIZE_ON_STACK
>         REG_L x1,  PT_EPC(sp)
>         REG_L x2,  PT_SP(sp)
> -       REG_L x3,  PT_GP(sp)
>         REG_L x4,  PT_TP(sp)
> -       REG_L x5,  PT_T0(sp)
> -       REG_L x6,  PT_T1(sp)
> -       REG_L x7,  PT_T2(sp)
> -       REG_L x8,  PT_S0(sp)
> -       REG_L x9,  PT_S1(sp)
> -       REG_L x10, PT_A0(sp)
> -       REG_L x11, PT_A1(sp)
> -       REG_L x12, PT_A2(sp)
> -       REG_L x13, PT_A3(sp)
> -       REG_L x14, PT_A4(sp)
> -       REG_L x15, PT_A5(sp)
> -       REG_L x16, PT_A6(sp)
> -       REG_L x17, PT_A7(sp)
> -       REG_L x18, PT_S2(sp)
> -       REG_L x19, PT_S3(sp)
> -       REG_L x20, PT_S4(sp)
> -       REG_L x21, PT_S5(sp)
> -       REG_L x22, PT_S6(sp)
> -       REG_L x23, PT_S7(sp)
> -       REG_L x24, PT_S8(sp)
> -       REG_L x25, PT_S9(sp)
> -       REG_L x26, PT_S10(sp)
> -       REG_L x27, PT_S11(sp)
> -       REG_L x28, PT_T3(sp)
> -       REG_L x29, PT_T4(sp)
> -       REG_L x30, PT_T5(sp)
> -       REG_L x31, PT_T6(sp)
> +       restore_gp
>
>         addi    sp, sp, PT_SIZE_ON_STACK
>         addi    sp, sp, SZREG
> --
> 2.34.1
>


-- 
Best Regards
 Guo Ren