Re: [PATCH v4 1/7] riscv: asm: alternative-macros: Introduce ALTERNATIVE_3() macro

From: "Heiko Stübner" <heiko@sntech.de>
To: Prabhakar <prabhakar.csengg@gmail.com>, Conor Dooley <conor@kernel.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	Magnus Damm <magnus.damm@gmail.com>,
	Rob Herring <robh+dt@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Conor Dooley <conor.dooley@microchip.com>,
	Guo Ren <guoren@kernel.org>, Jisheng Zhang <jszhang@kernel.org>,
	Atish Patra <atishp@rivosinc.com>,
	Anup Patel <apatel@ventanamicro.com>,
	Andrew Jones <ajones@ventanamicro.com>,
	Nathan Chancellor <nathan@kernel.org>,
	Philipp Tomsich <philipp.tomsich@vrull.eu>,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-riscv@lists.infradead.org,
	linux-renesas-soc@vger.kernel.org,
	Biju Das <biju.das.jz@bp.renesas.com>,
	Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Subject: Re: [PATCH v4 1/7] riscv: asm: alternative-macros: Introduce ALTERNATIVE_3() macro
Date: Thu, 24 Nov 2022 20:58:41 +0100	[thread overview]
Message-ID: <4801607.MHq7AAxBmi@diego> (raw)
In-Reply-To: <Y3/LgZkR1hkblJ8D@spud>

Am Donnerstag, 24. November 2022, 20:52:33 CET schrieb Conor Dooley:
> On Thu, Nov 24, 2022 at 05:22:01PM +0000, Prabhakar wrote:
> > From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.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.

Also both the comment on the original ALTERNATIVE_2 and the new ALTERNATIVE_3
should probably be merged into a single comment explaining this once for all
ALTERNATIVE_x variants.

Especially with the dma stuff, I'm pretty sure we'll get at least an ALTERNATIVE_4
if not even more ;-) . So we defnitly don't want to repeat this multiple times.

Heiko

> > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.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
> 

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