Hallo Geert, On Thu, 3 Dec 2020 at 13:19, Geert Uytterhoeven <geert+renesas@xxxxxxxxx> wrote: > > DTB stores all values as 32-bit big-endian integers. > Add a macro to convert such values to native CPU endianness, to reduce > duplication. > > Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx> > --- > v10: > - New. > --- > arch/arm/boot/compressed/head.S | 26 ++++++++++++-------------- > 1 file changed, 12 insertions(+), 14 deletions(-) > > diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S > index 835ce64f1674c9a2..aabdc544c03aafdc 100644 > --- a/arch/arm/boot/compressed/head.S > +++ b/arch/arm/boot/compressed/head.S > @@ -165,6 +165,16 @@ > orr \res, \res, \tmp1, lsl #24 > .endm > > + .macro be32tocpu, val, tmp > +#ifndef __ARMEB__ > + /* convert to little endian */ > + eor \tmp, \val, \val, ror #16 > + bic \tmp, \tmp, #0x00ff0000 > + mov \val, \val, ror #8 > + eor \val, \val, \tmp, lsr #8 > +#endif > + .endm > + Thanks for cleaning this up. This patch is fine as is. Reviewed-by: Ard Biesheuvel <ardb@xxxxxxxxxx> However, I would like to note that, since we are touching this code, we might do it properly. (Given the v10, feel free to ignore or defer to a later time) - put this into asm/assembler.h so other .S files can use it - use rev instructions when supported - factor out the difference between xx_to cpu and bswap I.e., .macro bswap32, val, tmp .if __LINUX_ARM_ARCH__ >= 6 rev \val, \val .else eor \tmp, \val, \val, ror #16 bic \tmp, \tmp, #0x00ff0000 mov \val, \val, ror #8 eor \val, \val, \tmp, lsr #8 .endif .endm .macro be32tocpu, val, tmp #ifndef __ARMEB__ bswap32 \val, \tmp #endif .endm .macro le32tocpu, val, tmp #ifdef __ARMEB__ bswap32 \val, \tmp #endif .endm This would allow us to reuse this macro in arch/arm/crypto/aes-cipher-core.S, and replace the __rev macro it defines. > .section ".start", "ax" > /* > * sort out different calling conventions > @@ -345,13 +355,7 @@ restart: adr r0, LC1 > > /* Get the initial DTB size */ > ldr r5, [r6, #4] > -#ifndef __ARMEB__ > - /* convert to little endian */ > - eor r1, r5, r5, ror #16 > - bic r1, r1, #0x00ff0000 > - mov r5, r5, ror #8 > - eor r5, r5, r1, lsr #8 > -#endif > + be32tocpu r5, r1 > dbgadtb r6, r5 > /* 50% DTB growth should be good enough */ > add r5, r5, r5, lsr #1 > @@ -403,13 +407,7 @@ restart: adr r0, LC1 > > /* Get the current DTB size */ > ldr r5, [r6, #4] > -#ifndef __ARMEB__ > - /* convert r5 (dtb size) to little endian */ > - eor r1, r5, r5, ror #16 > - bic r1, r1, #0x00ff0000 > - mov r5, r5, ror #8 > - eor r5, r5, r1, lsr #8 > -#endif > + be32tocpu r5, r1 > > /* preserve 64-bit alignment */ > add r5, r5, #7 > -- > 2.25.1 >
