Messages in this thread Patch in this message | | | Date | Tue, 6 Jan 2009 23:14:53 +0000 | From | Russell King <> | Subject | Re: [PATCH 14/23] arm: introduce asm/swab.h |
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On Tue, Jan 06, 2009 at 11:12:35PM +0000, Russell King wrote: > Thanks for bypassing me. > > We've had this patch in the kernel before, then it got reverted.
Correction - we've had something similar to this before.
> Application: ae82cbfc8beaa69007aa09966d3983ac938c3577 > Reversion: b35de672e74ceea6482b4f690ad053aec8465c5d > > Revert "[ARM] use the new byteorder headers" > > This reverts commit ae82cbfc8beaa69007aa09966d3983ac938c3577. It > needs the new byteorder headers to be exported to userspace, and > they aren't yet -- and probably shouldn't be, at this point in the > 2.6.27 release cycle (or ever, for that matter). > > Signed-off-by: David Woodhouse <David.Woodhouse@intel.com> > Acked-by: Russell King <rmk+kernel@arm.linux.org.uk> > > Please explain what's changed to make this acceptable now. > > On Tue, Jan 06, 2009 at 01:30:52PM -0800, Harvey Harrison wrote: > > Convert to the new-style arch overrides as well. > > > > Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> > > --- > > arch/arm/include/asm/Kbuild | 1 + > > arch/arm/include/asm/byteorder.h | 33 +------------------------ > > arch/arm/include/asm/swab.h | 50 ++++++++++++++++++++++++++++++++++++++ > > 3 files changed, 52 insertions(+), 32 deletions(-) > > > > diff --git a/arch/arm/include/asm/Kbuild b/arch/arm/include/asm/Kbuild > > index 73237bd..43b0b2b 100644 > > --- a/arch/arm/include/asm/Kbuild > > +++ b/arch/arm/include/asm/Kbuild > > @@ -1,3 +1,4 @@ > > include include/asm-generic/Kbuild.asm > > > > unifdef-y += hwcap.h > > +unifdef-y += swab.h > > diff --git a/arch/arm/include/asm/byteorder.h b/arch/arm/include/asm/byteorder.h > > index 4fbfb22..c02b6fc 100644 > > --- a/arch/arm/include/asm/byteorder.h > > +++ b/arch/arm/include/asm/byteorder.h > > @@ -15,38 +15,7 @@ > > #ifndef __ASM_ARM_BYTEORDER_H > > #define __ASM_ARM_BYTEORDER_H > > > > -#include <linux/compiler.h> > > -#include <asm/types.h> > > - > > -static inline __attribute_const__ __u32 ___arch__swab32(__u32 x) > > -{ > > - __u32 t; > > - > > -#ifndef __thumb__ > > - if (!__builtin_constant_p(x)) { > > - /* > > - * The compiler needs a bit of a hint here to always do the > > - * right thing and not screw it up to different degrees > > - * depending on the gcc version. > > - */ > > - asm ("eor\t%0, %1, %1, ror #16" : "=r" (t) : "r" (x)); > > - } else > > -#endif > > - t = x ^ ((x << 16) | (x >> 16)); /* eor r1,r0,r0,ror #16 */ > > - > > - x = (x << 24) | (x >> 8); /* mov r0,r0,ror #8 */ > > - t &= ~0x00FF0000; /* bic r1,r1,#0x00FF0000 */ > > - x ^= (t >> 8); /* eor r0,r0,r1,lsr #8 */ > > - > > - return x; > > -} > > - > > -#define __arch__swab32(x) ___arch__swab32(x) > > - > > -#if !defined(__STRICT_ANSI__) || defined(__KERNEL__) > > -# define __BYTEORDER_HAS_U64__ > > -# define __SWAB_64_THRU_32__ > > -#endif > > +#include <asm/swab.h> > > > > #ifdef __ARMEB__ > > #include <linux/byteorder/big_endian.h> > > diff --git a/arch/arm/include/asm/swab.h b/arch/arm/include/asm/swab.h > > new file mode 100644 > > index 0000000..27a689b > > --- /dev/null > > +++ b/arch/arm/include/asm/swab.h > > @@ -0,0 +1,50 @@ > > +/* > > + * arch/arm/include/asm/byteorder.h > > + * > > + * ARM Endian-ness. In little endian mode, the data bus is connected such > > + * that byte accesses appear as: > > + * 0 = d0...d7, 1 = d8...d15, 2 = d16...d23, 3 = d24...d31 > > + * and word accesses (data or instruction) appear as: > > + * d0...d31 > > + * > > + * When in big endian mode, byte accesses appear as: > > + * 0 = d24...d31, 1 = d16...d23, 2 = d8...d15, 3 = d0...d7 > > + * and word accesses (data or instruction) appear as: > > + * d0...d31 > > + */ > > +#ifndef __ASM_ARM_SWAB_H > > +#define __ASM_ARM_SWAB_H > > + > > +#include <linux/compiler.h> > > +#include <asm/types.h> > > + > > +#if !defined(__STRICT_ANSI__) || defined(__KERNEL__) > > +# define __SWAB_64_THRU_32__ > > +#endif > > + > > +static inline __attribute_const__ __u32 __arch_swab32(__u32 x) > > +{ > > + __u32 t; > > + > > +#ifndef __thumb__ > > + if (!__builtin_constant_p(x)) { > > + /* > > + * The compiler needs a bit of a hint here to always do the > > + * right thing and not screw it up to different degrees > > + * depending on the gcc version. > > + */ > > + asm ("eor\t%0, %1, %1, ror #16" : "=r" (t) : "r" (x)); > > + } else > > +#endif > > + t = x ^ ((x << 16) | (x >> 16)); /* eor r1,r0,r0,ror #16 */ > > + > > + x = (x << 24) | (x >> 8); /* mov r0,r0,ror #8 */ > > + t &= ~0x00FF0000; /* bic r1,r1,#0x00FF0000 */ > > + x ^= (t >> 8); /* eor r0,r0,r1,lsr #8 */ > > + > > + return x; > > +} > > +#define __arch_swab32 __arch_swab32 > > + > > +#endif > > + > > -- > > 1.6.1.94.g9388 > > > > -- > Russell King > Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ > maintainer of:
-- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of:
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