On 20/08/13 17:16, Will Deacon wrote: > On Tue, Aug 20, 2013 at 03:27:33PM +0100, Sudeep KarkadaNagesha wrote: >> On 20/08/13 14:27, Will Deacon wrote: >>> On Tue, Aug 13, 2013 at 06:29:42PM +0100, Sudeep KarkadaNagesha wrote: >>>> diff --git a/arch/arm64/include/asm/hwcap.h >>>> b/arch/arm64/include/asm/hwcap.h >>>> index 6d4482f..effd8f9 100644 >>>> --- a/arch/arm64/include/asm/hwcap.h >>>> +++ b/arch/arm64/include/asm/hwcap.h >>>> @@ -30,6 +30,7 @@ >>>> #define COMPAT_HWCAP_IDIVA (1 << 17) >>>> #define COMPAT_HWCAP_IDIVT (1 << 18) >>>> #define COMPAT_HWCAP_IDIV (COMPAT_HWCAP_IDIVA|COMPAT_HWCAP_IDIVT) >>>> +#define COMPAT_HWCAP_EVTSTRM (1 << 21) >>> >>> Looking at the context, we should also add COMPAT_HWCAP_LPAE as a separate >>> patch (not part of this series). >>> >> Ok make sense, I can do that. IIUC even this needs at least under some >> config option, assuming can't be dynamic ? > > I'm not sure I follow you... if you're asking whether the LPAE HWCAP should > be dynamic for ARMv8, then no, since the capabilities offered by LPAE are > included in ARMv8 as far as userspace is concerned. > Ok, then it can be in the default list of compat hwcap.
>>>> #ifndef __ASSEMBLY__ >>>> /* >>>> @@ -41,7 +42,8 @@ >>>> COMPAT_HWCAP_FAST_MULT|COMPAT_HWCAP_EDSP|\ >>>> COMPAT_HWCAP_TLS|COMPAT_HWCAP_VFP|\ >>>> COMPAT_HWCAP_VFPv3|COMPAT_HWCAP_VFPv4|\ >>>> - COMPAT_HWCAP_NEON|COMPAT_HWCAP_IDIV) >>>> + COMPAT_HWCAP_NEON|COMPAT_HWCAP_IDIV|\ >>>> + COMPAT_HWCAP_EVTSTRM) >>> >>> So here you're hardcoding COMPAT_HWCAP_EVTSTRM in the COMPAT_ELF_HWCAP, yet >>> we only enable the native one from the arch-timer driver. The question then >>> is >>> "Can we rely on the event-stream working for AArch64?". If so, we don't need >>> the native hwcap at all. If not, then we need to make the compat hwcap >>> dynamic. >> >> How about something like this ? I am not sure if >> arch/arm64/kernel/setup.c is apt place for compat_elf_hwcap though. > > Looks like the right sort of idea, yes. I can't think of a better place to > put it. You could adjust it slightly so that COMPAT_ELF_HWCAP stays like it > is, with an extra '| compat_dyn_elf_hwcap' on the end, but I have no real > preference. > Yes that's better, will do this way. Regards, Sudeep -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
