Re: [07/36] AArch64: Assembly macros and definitions

From: Catalin Marinas
Date: Tue Jul 24 2012 - 12:40:30 EST


On Fri, Jul 20, 2012 at 03:22:04PM +0100, Christopher Covington wrote:
> On 01/-10/-28163 02:59 PM, Catalin Marinas wrote:
> > This patch introduces several assembly macros and definitions used in
> > the .S files across arch/aarch64/ like IRQ disabling/enabling, together
> > with asm-offsets.c.
>
> [...]
>
> > diff --git a/arch/aarch64/include/asm/assembler.h b/arch/aarch64/include/asm/assembler.h
> > new file mode 100644
> > index 0000000..c6ac3cf
> > --- /dev/null
> > +++ b/arch/aarch64/include/asm/assembler.h
>
> [...]
>
> > +#define USER(x...) \
> > +9999: x; \
> > + .section __ex_table,"a"; \
> > + .align 3; \
> > + .quad 9999b,9001f; \
> > + .previous
>
> It appears that this macro depends on a 9001 label being defined in the
> source file somewhere after the macro is used. It might be preferable to
> incorporate the label into the macro if possible, or pass the label as
> an argument to the macro.

Good point, I changed to USER(l, x...).

> > +/*
> > + * User access macros.
> > + */
> > + .macro usracc, instr, reg, reg2, ptr, inc, rept, abort
> > + .rept \rept
> > +9999:
> > + .if \inc == 1
> > + \instr\()b \reg, [\ptr], #\inc
> > + .elseif \inc == 4
> > + \instr\() \reg, [\ptr], #\inc
> > + .elseif \inc == 8
> > + \instr\() \reg, [\ptr], #\inc
> > + .elseif \inc == 16
> > + \instr\() \reg, \reg2, [\ptr], #\inc
> > + .else
> > + .error "Unsupported inc macro argument"
> > + .endif
> > +
> > + .section __ex_table,"a"
> > + .align 3
> > + .quad 9999b, \abort
> > + .previous
>
> Could you use the USER preprocessor macro here to reduce this small
> duplication of directives?
>
> > + .endr
> > + .endm
> > +
> > + .macro ldrusr, reg, ptr, inc, rept=1, abort=9001f
> > + usracc ldr, \reg, \reg, \ptr, \inc, \rept, \abort
> > + .endm
> > +
> > + .macro ldrpusr, reg, reg2, ptr, rept=1, abort=9001f
> > + usracc ldp, \reg, \reg2, \ptr, 16, \rept, \abort
> > + .endm
>
> How about "ldpusr" to more directly match the assembly?
>
> (Also, the 9001 label strikes again.)

For now I removed these entirely. I have additional patches for
optimised library functions that make use of these but I don't plan to
push any of them until I can benchmark on real hardware.

Thanks.

--
Catalin
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