Re: [PATCH v5 1/6] riscv: asm: alternative-macros: Introduce ALTERNATIVE_3() macro

Andrew Jones
2022-12-14T15:46:17Z

On Tue, Dec 13, 2022 at 05:49:32PM +0000, Lad, Prabhakar wrote:
> Hi Geert,
>
> Thank you for the review.
>
> On Tue, Dec 13, 2022 at 5:21 PM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> >
> > Hi Prabhakar,
> >
> > On Mon, Dec 12, 2022 at 12:58 PM Prabhakar <prabhakar.csengg@gmail.com> wrote:
> > > From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> > >
> > > Introduce ALTERNATIVE_3() macro.
> > >
> > > 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 use macro ALTERNATIVE_3() and then replace
> > > ALTERNATIVE_2() with ALTERNATIVE_3() to append its customized content.
> > >
> > > While at it update comment above ALTERNATIVE_2() macro and make it generic
> > > so that the comment holds good for any new addition of ALTERNATIVE_X()
> > > macros.
> > >
> > > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> > > ---
> > > v4->v5
> > > * Rebased the patch on top of Andrew's series (now in Palmers for next-branch)
> > > * Updated comment for ALTERNATIVE_x() as suggested by Heiko
> >
> > Thanks for the update!
> >
> > > --- a/arch/riscv/include/asm/alternative-macros.h
> > > +++ b/arch/riscv/include/asm/alternative-macros.h
> > > @@ -50,8 +50,17 @@
> > > ALT_NEW_CONTENT \vendor_id_2, \errata_id_2, \enable_2, \new_c_2
> > > .endm
> > >
> > > +.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
> > > + ALTERNATIVE_CFG_2 \old_c, \new_c_1, \vendor_id_1, \errata_id_1, \enable_1, \
> > > + \new_c_2, \vendor_id_2, \errata_id_2, \enable_2
> > > + ALT_NEW_CONTENT \vendor_id_3, \errata_id_3, \enable_3, \new_c_3
> > > +.endm
> > > +
> > > #define __ALTERNATIVE_CFG(...) ALTERNATIVE_CFG __VA_ARGS__
> > > #define __ALTERNATIVE_CFG_2(...) ALTERNATIVE_CFG_2 __VA_ARGS__
> > > +#define __ALTERNATIVE_CFG_3(...) ALTERNATIVE_CFG_3 __VA_ARGS__
> > >
> > > #else /* !__ASSEMBLY__ */
> > >
> > > @@ -98,6 +107,13 @@
> > > __ALTERNATIVE_CFG(old_c, new_c_1, vendor_id_1, errata_id_1, enable_1) \
> > > ALT_NEW_CONTENT(vendor_id_2, errata_id_2, enable_2, new_c_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) \
> > > + __ALTERNATIVE_CFG_2(old_c, new_c_1, vendor_id_1, errata_id_1, enable_1, \
> > > + new_c_2, vendor_id_2, errata_id_2, enable_2) \
> > > + ALT_NEW_CONTENT(vendor_id_3, errata_id_3, enable_3, new_c_3)
> > > +
> > > #endif /* __ASSEMBLY__ */
> > >
> > > #define _ALTERNATIVE_CFG(old_c, new_c, vendor_id, errata_id, CONFIG_k) \
> > > @@ -108,6 +124,13 @@
> > > __ALTERNATIVE_CFG_2(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))
> > >
> > > +#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 /* CONFIG_RISCV_ALTERNATIVE */
> >
> > To avoid breaking the build for K210 (and VexRiscv), you need to provide
> > _ALTERNATIVE_CFG_3() for the !CONFIG_RISCV_ALTERNATIVE case, too:
> >
> Thanks for testing this.
>
> > @@ -144,6 +144,9 @@
> > #define _ALTERNATIVE_CFG_2(old_c, ...) \
> > ALTERNATIVE_CFG old_c
> >
> > +#define _ALTERNATIVE_CFG_3(old_c, ...) \
> > + ALTERNATIVE_CFG old_c
> > +
> > #else /* !__ASSEMBLY__ */
> >
> > #define __ALTERNATIVE_CFG(old_c) \
> > @@ -155,6 +158,9 @@
> > #define _ALTERNATIVE_CFG_2(old_c, ...) \
> > __ALTERNATIVE_CFG(old_c)
> >
> > +#define _ALTERNATIVE_CFG_3(old_c, ...) \
> > + __ALTERNATIVE_CFG(old_c)
> > +
> > #endif /* __ASSEMBLY__ */
> > #endif /* CONFIG_RISCV_ALTERNATIVE */
> >
> > Else it fails (on riscv/for-next) with:
> >
> I'll include the above hunk in next version.

Yes, those two hunks are in my example in [1] as well.

[1] https://lore.kernel.org/all/20221129150053.50464-1-ajones@ventanamicro.com/

Thanks,
drew

>
> > arch/riscv/mm/pmem.c: In function ‘arch_wb_cache_pmem’:
> > arch/riscv/include/asm/alternative-macros.h:198:8: error: expected
> > string literal before ‘_ALTERNATIVE_CFG_3’
> > 198 | _ALTERNATIVE_CFG_3(old_content, new_content_1,
> > vendor_id_1, errata_id_1, CONFIG_k_1, \
> > | ^~~~~~~~~~~~~~~~~~
> > arch/riscv/include/asm/errata_list.h:128:14: note: in expansion of
> > macro ‘ALTERNATIVE_3’
> > 128 | asm volatile(ALTERNATIVE_3( \
> > | ^~~~~~~~~~~~~
> > arch/riscv/mm/pmem.c:13:2: note: in expansion of macro ‘ALT_CMO_OP’
> > 13 | ALT_CMO_OP(clean, addr, size, riscv_cbom_block_size, 0, 0);
> > | ^~~~~~~~~~
> >
> > Gr{oetje,eeting}s,
> >
> > Geert
> >
> > --
> > Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
> >
> > In personal conversations with technical people, I call myself a hacker. But
> > when I'm talking to journalists I just say "programmer" or something like that.
> > -- Linus Torvalds