| Message ID | 1426690527-14258-3-git-send-email-ard.biesheuvel@linaro.org |
|---|---|
| State | New |
| Headers | show |
On 18 March 2015 at 18:54, Mark Rutland <mark.rutland@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@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. > Otherwise this looks fine. > > Mark. > >> + .macro adr_l, dst, sym, tmp= >> + .ifb \tmp >> + adrp \dst, \sym >> + add \dst, \dst, :lo12:\sym >> + .else >> + adrp \tmp, \sym >> + add \dst, \tmp, :lo12:\sym >> + .endif >> + .endm >> + >> + .macro ldr_l, dst, sym, tmp= >> + .ifb \tmp >> + adrp \dst, \sym >> + ldr \dst, [\dst, :lo12:\sym] >> + .else >> + adrp \tmp, \sym >> + ldr \dst, [\tmp, :lo12:\sym] >> + .endif >> + .endm >> + >> + .macro str_l, src, sym, tmp >> + adrp \tmp, \sym >> + str \src, [\tmp, :lo12:\sym] >> + .endm >> + >> #endif /* __ASM_ASSEMBLER_H */ >> -- >> 1.8.3.2 >> >>
On 18 March 2015 at 19:05, Mark Rutland <mark.rutland@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@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@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
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. + */ + .macro adr_l, dst, sym, tmp= + .ifb \tmp + adrp \dst, \sym + add \dst, \dst, :lo12:\sym + .else + adrp \tmp, \sym + add \dst, \tmp, :lo12:\sym + .endif + .endm + + .macro ldr_l, dst, sym, tmp= + .ifb \tmp + adrp \dst, \sym + ldr \dst, [\dst, :lo12:\sym] + .else + adrp \tmp, \sym + ldr \dst, [\tmp, :lo12:\sym] + .endif + .endm + + .macro str_l, src, sym, tmp + adrp \tmp, \sym + str \src, [\tmp, :lo12:\sym] + .endm + #endif /* __ASM_ASSEMBLER_H */
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@linaro.org> --- arch/arm64/include/asm/assembler.h | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+)