Re: [PATCH] ARM: unaligned.h: Use an arch-specific version

2017-09-22 Thread Arnd Bergmann
On Fri, Sep 22, 2017 at 11:36 PM, Ard Biesheuvel wrote: > On 20 September 2017 at 13:35, Arnd Bergmann wrote: >> The architectures that do use include/asm-generic/unaligned.h and >> also set HAVE_EFFICIENT_UNALIGNED_ACCESS in some configurations >> are

Re: [PATCH] ARM: unaligned.h: Use an arch-specific version

2017-09-22 Thread Arnd Bergmann
On Fri, Sep 22, 2017 at 11:36 PM, Ard Biesheuvel wrote: > On 20 September 2017 at 13:35, Arnd Bergmann wrote: >> The architectures that do use include/asm-generic/unaligned.h and >> also set HAVE_EFFICIENT_UNALIGNED_ACCESS in some configurations >> are arm, arm64, metag, s390 and arc. >> >>

Re: [PATCH] ARM: unaligned.h: Use an arch-specific version

2017-09-22 Thread Ard Biesheuvel
On 20 September 2017 at 13:35, Arnd Bergmann wrote: > On Wed, Sep 20, 2017 at 5:26 PM, Ard Biesheuvel > wrote: >> On 20 September 2017 at 08:18, Romain Izard >> wrote: >>> Add an arch-specific header to ARM, to retain other

Re: [PATCH] ARM: unaligned.h: Use an arch-specific version

2017-09-22 Thread Ard Biesheuvel
On 20 September 2017 at 13:35, Arnd Bergmann wrote: > On Wed, Sep 20, 2017 at 5:26 PM, Ard Biesheuvel > wrote: >> On 20 September 2017 at 08:18, Romain Izard >> wrote: >>> Add an arch-specific header to ARM, to retain other optimizations that >>> rely on HAVE_EFFICIENT_UNALIGNED_ACCESS, while

Re: [PATCH] ARM: unaligned.h: Use an arch-specific version

2017-09-20 Thread Arnd Bergmann
On Wed, Sep 20, 2017 at 5:26 PM, Ard Biesheuvel wrote: > On 20 September 2017 at 08:18, Romain Izard > wrote: >> Add an arch-specific header to ARM, to retain other optimizations that >> rely on HAVE_EFFICIENT_UNALIGNED_ACCESS, while making

Re: [PATCH] ARM: unaligned.h: Use an arch-specific version

2017-09-20 Thread Arnd Bergmann
On Wed, Sep 20, 2017 at 5:26 PM, Ard Biesheuvel wrote: > On 20 September 2017 at 08:18, Romain Izard > wrote: >> Add an arch-specific header to ARM, to retain other optimizations that >> rely on HAVE_EFFICIENT_UNALIGNED_ACCESS, while making sure that access >> that explicitly rely on the

Re: [PATCH] ARM: unaligned.h: Use an arch-specific version

2017-09-20 Thread Robin Murphy
Hi Romain, On 20/09/17 16:18, Romain Izard wrote: > For the 32-bit ARM architecture, unaligned access support is variable. > On a chip without a MMU, an unaligned access returns a rotated data word > and must be avoided. Nit: that sentence is not really true - there are CPUs without MMUs that

Re: [PATCH] ARM: unaligned.h: Use an arch-specific version

2017-09-20 Thread Robin Murphy
Hi Romain, On 20/09/17 16:18, Romain Izard wrote: > For the 32-bit ARM architecture, unaligned access support is variable. > On a chip without a MMU, an unaligned access returns a rotated data word > and must be avoided. Nit: that sentence is not really true - there are CPUs without MMUs that

Re: [PATCH] ARM: unaligned.h: Use an arch-specific version

2017-09-20 Thread Ard Biesheuvel
On 20 September 2017 at 08:41, Russell King - ARM Linux wrote: > On Wed, Sep 20, 2017 at 08:26:09AM -0700, Ard Biesheuvel wrote: >> Hi Romain, >> >> On 20 September 2017 at 08:18, Romain Izard >> wrote: >> > For the 32-bit ARM architecture,

Re: [PATCH] ARM: unaligned.h: Use an arch-specific version

2017-09-20 Thread Ard Biesheuvel
On 20 September 2017 at 08:41, Russell King - ARM Linux wrote: > On Wed, Sep 20, 2017 at 08:26:09AM -0700, Ard Biesheuvel wrote: >> Hi Romain, >> >> On 20 September 2017 at 08:18, Romain Izard >> wrote: >> > For the 32-bit ARM architecture, unaligned access support is variable. >> > On a chip

Re: [PATCH] ARM: unaligned.h: Use an arch-specific version

2017-09-20 Thread Russell King - ARM Linux
On Wed, Sep 20, 2017 at 08:26:09AM -0700, Ard Biesheuvel wrote: > Hi Romain, > > On 20 September 2017 at 08:18, Romain Izard > wrote: > > For the 32-bit ARM architecture, unaligned access support is variable. > > On a chip without a MMU, an unaligned access returns a

Re: [PATCH] ARM: unaligned.h: Use an arch-specific version

2017-09-20 Thread Russell King - ARM Linux
On Wed, Sep 20, 2017 at 08:26:09AM -0700, Ard Biesheuvel wrote: > Hi Romain, > > On 20 September 2017 at 08:18, Romain Izard > wrote: > > For the 32-bit ARM architecture, unaligned access support is variable. > > On a chip without a MMU, an unaligned access returns a rotated data word > > and

Re: [PATCH] ARM: unaligned.h: Use an arch-specific version

2017-09-20 Thread Ard Biesheuvel
Hi Romain, On 20 September 2017 at 08:18, Romain Izard wrote: > For the 32-bit ARM architecture, unaligned access support is variable. > On a chip without a MMU, an unaligned access returns a rotated data word > and must be avoided. > > When a MMU is available, it can

Re: [PATCH] ARM: unaligned.h: Use an arch-specific version

2017-09-20 Thread Ard Biesheuvel
Hi Romain, On 20 September 2017 at 08:18, Romain Izard wrote: > For the 32-bit ARM architecture, unaligned access support is variable. > On a chip without a MMU, an unaligned access returns a rotated data word > and must be avoided. > > When a MMU is available, it can be trapped. On ARMv6 or