| Message ID | 20130131145947.f62474a0600848df86548b96@freescale.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Thu, Jan 31, 2013 at 02:59:47PM -0600, Kim Phillips wrote: > - add new ARCH_DEFINES_BUILTIN_BSWAP (see Kconfig help). > - if set, generic compiler header does not set HAVE_BUILTIN_BSWAPxx > - not too sure about this having to be a new CONFIG_, but it's hard > to find a place for it given linux/compiler.h doesn't include any > arch-specific files. Yeah, me neither. It seems to me the whole deal can be simplified even further without introducing CONFIG_ARCH_DEFINES_BUILTIN_BSWAP. And, we don't even want to use CONFIG_ARCH_USE_BUILTIN_BSWAP on arm due to different compiler versions supporting it (correct me if I'm wrong here) vs the generic thing in include/linux/compiler-gcc4.h which we want off. If so, you'd need to simply put the following from below in arch/arm/include/asm/swab.h #if GCC_VERSION >= 40600 #define __HAVE_BUILTIN_BSWAP32__ #define __HAVE_BUILTIN_BSWAP64__ #if GCC_VERSION >= 40800 #define __HAVE_BUILTIN_BSWAP16__ #endif /* GCC_VERSION >= 40800 */ #endif /* GCC_VERSION >= 40600 */ and that's it. Makes sense or am I over-simplifying this? Thanks.
On Thu, 2013-01-31 at 14:59 -0600, Kim Phillips wrote: > > - add new ARCH_DEFINES_BUILTIN_BSWAP (see Kconfig help). Ick, no. > - if set, generic compiler header does not set HAVE_BUILTIN_BSWAPxx It won't do that anyway if !ARCH_USE_BUILTIN_BSWAP. I don't see the point in adding a new config option just for this. If you want to define __HAVE_BUILTIN_BSWAPxx__ for yourself manually, just go ahead and do so. As I said, if lots of architectures end up doing it then we'll worry about cleaning things up when we've got a better picture of who needs what.
On Thu, Jan 31, 2013 at 02:59:47PM -0600, Kim Phillips wrote: > On Thu, 31 Jan 2013 09:28:01 +0000 > Russell King - ARM Linux <linux@arm.linux.org.uk> wrote: > > > On Wed, Jan 30, 2013 at 08:09:00PM -0600, Kim Phillips wrote: > > > v2: > > > - at91 and lpd270 builds fixed by limiting to ARMv6 and above > > > (i.e., ARM cores that have support for the 'rev' instruction). > > > Otherwise, the compiler emits calls to libgcc's __bswapsi2 on > > > these ARMv4/v5 builds (and arch ARM doesn't link with libgcc). > > > > Which compiler version? gcc 4.5.4 doesn't do this, except for the 16-bit > > swap, so I doubt that any later compiler does. > > I've tried both gcc 4.6.3 [1] and 4.6.4 [2]. If you can point me to > a 4.5.x, I'll try that, too, but as it stands now, if one moves the > code added to swab.h below outside of its armv6 protection, > gcc adds calls to __bswapsi2. Take a look at the message I sent on the 29th towards the beginning of this thread for details of gcc 4.5.4 behaviour.
On Fri, 2013-02-01 at 01:17 +0000, Russell King - ARM Linux wrote: > > > I've tried both gcc 4.6.3 [1] and 4.6.4 [2]. If you can point me to > > a 4.5.x, I'll try that, too, but as it stands now, if one moves the > > code added to swab.h below outside of its armv6 protection, > > gcc adds calls to __bswapsi2. > > Take a look at the message I sent on the 29th towards the beginning of > this thread for details of gcc 4.5.4 behaviour. I'd like to see a comment (with PR# if appropriate) explaining clearly *why* it isn't enabled for <ARMv6 even with a bleeding-edge compiler. Russell's test also seemed to indicate that the 32-bit and 64-bit swap support was present and functional in GCC 4.5.4 (as indeed it should have been since 4.4), so I'm still not quite sure why you require 4.6 for that.
diff --git a/arch/Kconfig b/arch/Kconfig index 40e2b12..bc5ed77 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -141,6 +141,10 @@ config ARCH_USE_BUILTIN_BSWAP instructions should set this. And it shouldn't hurt to set it on architectures that don't have such instructions. +config ARCH_DEFINES_BUILTIN_BSWAP + depends on ARCH_USE_BUILTIN_BSWAP + bool + config HAVE_SYSCALL_WRAPPERS bool diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 73027aa..b5868c2 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -57,6 +57,8 @@ config ARM select CLONE_BACKWARDS select OLD_SIGSUSPEND3 select OLD_SIGACTION + select ARCH_USE_BUILTIN_BSWAP + select ARCH_DEFINES_BUILTIN_BSWAP help The ARM series is a line of low-power-consumption RISC chip designs licensed by ARM Ltd and targeted at embedded applications and diff --git a/arch/arm/include/asm/swab.h b/arch/arm/include/asm/swab.h index 537fc9b..e56acff 100644 --- a/arch/arm/include/asm/swab.h +++ b/arch/arm/include/asm/swab.h @@ -34,5 +34,13 @@ static inline __attribute_const__ __u32 __arch_swab32(__u32 x) } #define __arch_swab32 __arch_swab32 +#if GCC_VERSION >= 40600 +#define __HAVE_BUILTIN_BSWAP32__ +#define __HAVE_BUILTIN_BSWAP64__ +#if GCC_VERSION >= 40800 +#define __HAVE_BUILTIN_BSWAP16__ +#endif +#endif + #endif #endif diff --git a/include/linux/compiler-gcc4.h b/include/linux/compiler-gcc4.h index 68b162d..fce39cb 100644 --- a/include/linux/compiler-gcc4.h +++ b/include/linux/compiler-gcc4.h @@ -66,7 +66,8 @@ #endif -#ifdef CONFIG_ARCH_USE_BUILTIN_BSWAP +#if defined(CONFIG_ARCH_USE_BUILTIN_BSWAP) && \ + !defined(CONFIG_ARCH_DEFINES_BUILTIN_BSWAP) #if GCC_VERSION >= 40400 #define __HAVE_BUILTIN_BSWAP32__ #define __HAVE_BUILTIN_BSWAP64__