linux-kernel - Re: [PATCH v4 1/7] riscv: asm: alternative-macros: Introduce ALTERNATIVE

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Message-ID: <Y3/LgZkR1hkblJ8D@spud>
Date:   Thu, 24 Nov 2022 19:52:33 +0000
From:   Conor Dooley <conor@...nel.org>
To:     Prabhakar <prabhakar.csengg@...il.com>
Cc:     Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Magnus Damm <magnus.damm@...il.com>,
        Heiko Stuebner <heiko@...ech.de>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Conor Dooley <conor.dooley@...rochip.com>,
        Guo Ren <guoren@...nel.org>,
        Jisheng Zhang <jszhang@...nel.org>,
        Atish Patra <atishp@...osinc.com>,
        Anup Patel <apatel@...tanamicro.com>,
        Andrew Jones <ajones@...tanamicro.com>,
        Nathan Chancellor <nathan@...nel.org>,
        Philipp Tomsich <philipp.tomsich@...ll.eu>,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-riscv@...ts.infradead.org, linux-renesas-soc@...r.kernel.org,
        Biju Das <biju.das.jz@...renesas.com>,
        Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
Subject: Re: [PATCH v4 1/7] riscv: asm: alternative-macros: Introduce
 ALTERNATIVE_3() macro

On Thu, Nov 24, 2022 at 05:22:01PM +0000, Prabhakar wrote:
> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
> 
> Introduce ALTERNATIVE_3() macro.

Bit perfunctory I think! There's a lovely comment down below that would
make for a better commit message if you were to yoink it.
Content looks about what I'd expect to see though.

> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
> ---
> RFC v3 -> v4
> * New patch
> ---
>  arch/riscv/include/asm/alternative-macros.h | 94 +++++++++++++++++++++
>  1 file changed, 94 insertions(+)
> 
> diff --git a/arch/riscv/include/asm/alternative-macros.h b/arch/riscv/include/asm/alternative-macros.h
> index ec2f3f1b836f..1caf4306b3d6 100644
> --- a/arch/riscv/include/asm/alternative-macros.h
> +++ b/arch/riscv/include/asm/alternative-macros.h
> @@ -69,6 +69,34 @@
>  				   new_c_2, vendor_id_2, errata_id_2,	\
>  					IS_ENABLED(CONFIG_k_2)
>  
> +.macro __ALTERNATIVE_CFG_3 old_c, new_c_1, vendor_id_1, errata_id_1, enable_1, \
> +				  new_c_2, vendor_id_2, errata_id_2, enable_2, \
> +				  new_c_3, vendor_id_3, errata_id_3, enable_3
> +886 :
> +	.option push
> +	.option norvc
> +	.option norelax
> +	\old_c
> +	.option pop
> +887 :
> +	ALT_NEW_CONTENT \vendor_id_1, \errata_id_1, \enable_1, \new_c_1
> +	ALT_NEW_CONTENT \vendor_id_2, \errata_id_2, \enable_2, \new_c_2
> +	ALT_NEW_CONTENT \vendor_id_3, \errata_id_3, \enable_3, \new_c_3
> +.endm
> +
> +#define _ALTERNATIVE_CFG_3(old_c, new_c_1, vendor_id_1, errata_id_1,	\
> +					CONFIG_k_1,			\
> +				  new_c_2, vendor_id_2, errata_id_2,	\
> +					CONFIG_k_2,			\
> +				  new_c_3, vendor_id_3, errata_id_3,	\
> +					CONFIG_k_3)			\
> +	__ALTERNATIVE_CFG_3 old_c, new_c_1, vendor_id_1, errata_id_1,	\
> +					IS_ENABLED(CONFIG_k_1),		\
> +				   new_c_2, vendor_id_2, errata_id_2,	\
> +					IS_ENABLED(CONFIG_k_2),		\
> +				   new_c_3, vendor_id_3, errata_id_3,	\
> +					IS_ENABLED(CONFIG_k_3)
> +
>  #else /* !__ASSEMBLY__ */
>  
>  #include <asm/asm.h>
> @@ -135,6 +163,36 @@
>  				   new_c_2, vendor_id_2, errata_id_2,	\
>  					IS_ENABLED(CONFIG_k_2))
>  
> +#define __ALTERNATIVE_CFG_3(old_c, new_c_1, vendor_id_1, errata_id_1,	\
> +					enable_1,			\
> +				   new_c_2, vendor_id_2, errata_id_2,	\
> +					enable_2,			\
> +				   new_c_3, vendor_id_3, errata_id_3,	\
> +					enable_3)			\
> +	"886 :\n"							\
> +	".option push\n"						\
> +	".option norvc\n"						\
> +	".option norelax\n"						\
> +	old_c "\n"							\
> +	".option pop\n"							\
> +	"887 :\n"							\
> +	ALT_NEW_CONTENT(vendor_id_1, errata_id_1, enable_1, new_c_1)	\
> +	ALT_NEW_CONTENT(vendor_id_2, errata_id_2, enable_2, new_c_2)	\
> +	ALT_NEW_CONTENT(vendor_id_3, errata_id_3, enable_3, new_c_3)
> +
> +#define _ALTERNATIVE_CFG_3(old_c, new_c_1, vendor_id_1, errata_id_1,	\
> +					CONFIG_k_1,			\
> +				  new_c_2, vendor_id_2, errata_id_2,	\
> +					CONFIG_k_2,			\
> +				  new_c_3, vendor_id_3, errata_id_3,	\
> +					CONFIG_k_3)			\
> +	__ALTERNATIVE_CFG_3(old_c, new_c_1, vendor_id_1, errata_id_1,	\
> +					IS_ENABLED(CONFIG_k_1),		\
> +				   new_c_2, vendor_id_2, errata_id_2,	\
> +					IS_ENABLED(CONFIG_k_2),	\
> +				   new_c_3, vendor_id_3, errata_id_3,	\
> +					IS_ENABLED(CONFIG_k_3))
> +
>  #endif /* __ASSEMBLY__ */
>  
>  #else /* CONFIG_RISCV_ALTERNATIVE */
> @@ -153,6 +211,14 @@
>  					CONFIG_k_2)			\
>         __ALTERNATIVE_CFG old_c
>  
> +#define _ALTERNATIVE_CFG_3(old_c, new_c_1, vendor_id_1, errata_id_1,	\
> +					CONFIG_k_1,			\
> +				  new_c_2, vendor_id_2, errata_id_2,	\
> +					CONFIG_k_2,			\
> +				  new_c_3, vendor_id_3, errata_id_3,	\
> +					CONFIG_k_3)			\
> +       __ALTERNATIVE_CFG old_c
> +
>  #else /* !__ASSEMBLY__ */
>  
>  #define __ALTERNATIVE_CFG(old_c)  \
> @@ -167,6 +233,14 @@
>  					CONFIG_k_2) \
>         __ALTERNATIVE_CFG(old_c)
>  
> +#define _ALTERNATIVE_CFG_3(old_c, new_c_1, vendor_id_1, errata_id_1,	\
> +					CONFIG_k_1,			\
> +				  new_c_2, vendor_id_2, errata_id_2,	\
> +					CONFIG_k_2,			\
> +				  new_c_3, vendor_id_3, errata_id_3,	\
> +					CONFIG_k_3) \
> +       __ALTERNATIVE_CFG(old_c)
> +
>  #endif /* __ASSEMBLY__ */
>  #endif /* CONFIG_RISCV_ALTERNATIVE */
>  
> @@ -202,4 +276,24 @@
>  					new_content_2, vendor_id_2,	\
>  					    errata_id_2, CONFIG_k_2)
>  
> +/*
> + * A vendor wants to replace an old_content, but another vendor has used
> + * ALTERNATIVE_2() to patch its customized content at the same location. In
> + * this case, this vendor can create a new macro ALTERNATIVE_3() based
> + * on the following sample code and then replace ALTERNATIVE_2() with
> + * ALTERNATIVE_3() to append its customized content.
> + */
> +#define ALTERNATIVE_3(old_content, new_content_1, vendor_id_1,		\
> +					errata_id_1, CONFIG_k_1,	\
> +				   new_content_2, vendor_id_2,		\
> +					errata_id_2, CONFIG_k_2,	\
> +				   new_content_3, vendor_id_3,		\
> +					errata_id_3, CONFIG_k_3)	\
> +	_ALTERNATIVE_CFG_3(old_content, new_content_1, vendor_id_1,	\
> +					    errata_id_1, CONFIG_k_1,	\
> +					new_content_2, vendor_id_2,	\
> +					    errata_id_2, CONFIG_k_2,	\
> +					new_content_3, vendor_id_3,	\
> +					    errata_id_3, CONFIG_k_3)
> +
>  #endif
> -- 
> 2.25.1
>