[PATCH v2] RISC-V: fix compile error from deduplicated __ALTERNATIVE_CFG_2

[Palmer Dabbelt]

On Thu, 05 Jan 2023 11:26:10 PST (-0800), heiko at sntech.de wrote:
> From: Heiko Stuebner <heiko.stuebner at vrull.eu>
>
> On the non-assembler-side wrapping alternative-macros inside other macros
> to prevent duplication of code works, as the end result will just be a
> string that gets fed to the asm instruction.
>
> In real assembler code, wrapping .macro blocks inside other .macro blocks
> brings more restrictions on usage it seems and the optimization done by
> commit 2ba8c7dc71c0 ("riscv: Don't duplicate __ALTERNATIVE_CFG in __ALTERNATIVE_CFG_2")
> results in a compile error like:
>
> ../arch/riscv/lib/strcmp.S: Assembler messages:
> ../arch/riscv/lib/strcmp.S:15: Error: too many positional arguments
> ../arch/riscv/lib/strcmp.S:15: Error: backward ref to unknown label "886:"
> ../arch/riscv/lib/strcmp.S:15: Error: backward ref to unknown label "887:"
> ../arch/riscv/lib/strcmp.S:15: Error: backward ref to unknown label "886:"
> ../arch/riscv/lib/strcmp.S:15: Error: backward ref to unknown label "887:"
> ../arch/riscv/lib/strcmp.S:15: Error: backward ref to unknown label "886:"
> ../arch/riscv/lib/strcmp.S:15: Error: attempt to move .org backwards
>
> Wrapping the variables containing assembler code in quotes solves this issue,
> compilation and the code in question still works and objdump also shows sane
> decompiled results of the affected code.
>
> Fixes: 2ba8c7dc71c0 ("riscv: Don't duplicate __ALTERNATIVE_CFG in __ALTERNATIVE_CFG_2")
> Signed-off-by: Heiko Stuebner <heiko.stuebner at vrull.eu>
> ---
> changes in v2:
> - don't revert the affected cleanup but use quotes around the parts
>
> Tested on qemu + Allwinner D1 + specially created test-cases using
> ALTERNATIVE_2 in full assembler .S files
>
>  arch/riscv/include/asm/alternative-macros.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/riscv/include/asm/alternative-macros.h b/arch/riscv/include/asm/alternative-macros.h
> index 7226e2462584..2c0f4c887289 100644
> --- a/arch/riscv/include/asm/alternative-macros.h
> +++ b/arch/riscv/include/asm/alternative-macros.h
> @@ -46,7 +46,7 @@
>
>  .macro 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
> -	ALTERNATIVE_CFG \old_c, \new_c_1, \vendor_id_1, \errata_id_1, \enable_1
> +	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
>  .endm

Reviewed-by: Palmer Dabbelt <palmer at rivosinc.com>

I'm going to hold off on this one for this week, though -- at least to 
give it some time on the lists, but it appears this hasn't landed at 
lore/patchwork yet and thus might be stuck.  It is in the mailman 
archives...

http://lists.infradead.org/pipermail/linux-riscv/2023-January/024682.html