Re: valgrind support for glibc master

[Mark Wielaard <mjw at fedoraproject dot org>]

On Fri, 2017-06-23 at 16:47 +0530, Siddhesh Poyarekar wrote:
> On Friday 23 June 2017 04:43 PM, Florian Weimer wrote:
> > valgrind needs to mask out all unknown/unimplemented flags.  And I
> > thought it was 1?  LD_HWCAP_MASK=1 acts as a workaround, after all.
> 
> The remaining flags shouldn't actually matter to glibc since they're
> essentially assumed features (asimd, fp) but there may be programs out
> there that might read them.

I found the following arm HWCAP bits in the kernel:

#define HWCAP_FP                (1 << 0)
#define HWCAP_ASIMD             (1 << 1)
#define HWCAP_EVTSTRM           (1 << 2)
#define HWCAP_AES               (1 << 3)
#define HWCAP_PMULL             (1 << 4)
#define HWCAP_SHA1              (1 << 5)
#define HWCAP_SHA2              (1 << 6)
#define HWCAP_CRC32             (1 << 7)
#define HWCAP_ATOMICS           (1 << 8)
#define HWCAP_FPHP              (1 << 9)
#define HWCAP_ASIMDHP           (1 << 10)
#define HWCAP_CPUID             (1 << 11)
#define HWCAP_ASIMDRDM          (1 << 12)
#define HWCAP_JSCVT             (1 << 13)
#define HWCAP_FCMA              (1 << 14)
#define HWCAP_LRCPC             (1 << 15)

BTW the glibc linux/aarch64/bitshwcap.h only go up to HWCAP_ASIMDRDM.

Is there are corresponding ARM abi document that maps those values to
the corresponding arm64 cpu instruction sets? Valgrind supports some,
but certainly not all. Since valgrind emulates/translates all
instructions explicitly it makes sense to mask off anything unknown.

Thanks,

Mark