[PATCH v5 2/8] arm64: add macros for common adrp usages

[Ard Biesheuvel]

On 18 March 2015 at 19:05, Mark Rutland <mark.rutland at arm.com> wrote:
> On Wed, Mar 18, 2015 at 05:56:11PM +0000, Ard Biesheuvel wrote:
>> On 18 March 2015 at 18:54, Mark Rutland <mark.rutland at arm.com> wrote:
>> > On Wed, Mar 18, 2015 at 02:55:21PM +0000, Ard Biesheuvel wrote:
>> >> The adrp instruction is mostly used in combination with either
>> >> an add, a ldr or a str instruction with the low bits of the
>> >> referenced symbol in the 12-bit immediate of the followup
>> >> instruction.
>> >>
>> >> Introduce the macros adr_l, ldr_l and str_l that encapsulate
>> >> these common patterns.
>> >>
>> >> Signed-off-by: Ard Biesheuvel <ard.biesheuvel at linaro.org>
>> >> ---
>> >>  arch/arm64/include/asm/assembler.h | 29 +++++++++++++++++++++++++++++
>> >>  1 file changed, 29 insertions(+)
>> >>
>> >> diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
>> >> index 750bac4e637e..f1804d4803fb 100644
>> >> --- a/arch/arm64/include/asm/assembler.h
>> >> +++ b/arch/arm64/include/asm/assembler.h
>> >> @@ -159,4 +159,33 @@ lr       .req    x30             // link register
>> >>       orr     \rd, \lbits, \hbits, lsl #32
>> >>       .endm
>> >>
>> >> +/*
>> >> + * Pseudo-ops for PC-relative adr/ldr/str <reg>, <symbol> where
>> >> + * <symbol> is within the range +/- 4 GB of the PC.
>> >> + */
>> >
>> > It would be nice to point out that tmp for adr_l and ldr_l is only
>> > necesssary when loading a value into the SP.
>> >
>>
>> For adr_l, it is for the sp.
>> For ldr_l, it is primarily for being able to load w registers as well.
>
> Ah, I hadn't considered that. Are you happy to add something to the
> comment block mentioning those cases?
>

Sure, no problem