RE: [PATCH] i386: Add syscall to enable AMX for latest kernels

["Liu, Hongtao" <hongtao.liu@intel.com>]

> -----Original Message-----
> From: Jiang, Haochen <haochen.jiang@intel.com>
> Sent: Thursday, September 22, 2022 2:23 PM
> To: Uros Bizjak <ubizjak@gmail.com>
> Cc: gcc-patches@gcc.gnu.org; Liu, Hongtao <hongtao.liu@intel.com>
> Subject: RE: [PATCH] i386: Add syscall to enable AMX for latest kernels
> 
> Hi all,
> 
> I would like to backport this patch to GCC 12 release branch as machines with
> the version of default GCC is 12.x (which is always using newer kernels), if the
> patch is not backported, the amx tests will always fail.
> 
> Ok for backport?
Ok.
> 
> BRs,
> Haochen
> 
> > -----Original Message-----
> > From: Uros Bizjak <ubizjak@gmail.com>
> > Sent: Tuesday, June 21, 2022 10:53 PM
> > To: Jiang, Haochen <haochen.jiang@intel.com>
> > Cc: gcc-patches@gcc.gnu.org; Liu, Hongtao <hongtao.liu@intel.com>
> > Subject: Re: [PATCH] i386: Add syscall to enable AMX for latest
> > kernels
> >
> > On Tue, Jun 21, 2022 at 9:41 AM Jiang, Haochen
> > <haochen.jiang@intel.com>
> > wrote:
> > >
> > > > -----Original Message-----
> > > > From: Uros Bizjak <ubizjak@gmail.com>
> > > > Sent: Tuesday, June 21, 2022 3:06 PM
> > > > To: Jiang, Haochen <haochen.jiang@intel.com>
> > > > Cc: gcc-patches@gcc.gnu.org; Liu, Hongtao <hongtao.liu@intel.com>
> > > > Subject: Re: [PATCH] i386: Add syscall to enable AMX for latest
> > > > kernels
> > > >
> > > > On Tue, Jun 21, 2022 at 4:23 AM Jiang, Haochen
> > > > <haochen.jiang@intel.com>
> > > > wrote:
> > > > >
> > > > > > -----Original Message-----
> > > > > > From: Uros Bizjak <ubizjak@gmail.com>
> > > > > > Sent: Monday, June 20, 2022 10:54 PM
> > > > > > To: Jiang, Haochen <haochen.jiang@intel.com>
> > > > > > Cc: gcc-patches@gcc.gnu.org; Liu, Hongtao
> > > > > > <hongtao.liu@intel.com>
> > > > > > Subject: Re: [PATCH] i386: Add syscall to enable AMX for
> > > > > > latest kernels
> > > > > >
> > > > > > On Mon, Jun 20, 2022 at 10:04 AM Haochen Jiang
> > > > > > <haochen.jiang@intel.com>
> > > > > > wrote:
> > > > > > >
> > > > > > > From: "Jiang, Haochen" <haochen.jiang@intel.com>
> > > > > > >
> > > > > > > Hi all,
> > > > > > >
> > > > > > > We need syscall to enable AMX for kernels>=5.4. It is
> > > > > > > missing in current amx tests, which will cause test fail.
> > > > > >
> > > > > > So this new code is only valid for linux & co?
> > > > >
> > > > > Thanks for reminding me for that, I only test on linux since the
> > > > > header file is
> > > > only in linux.
> > > > >
> > > > > Just updated a patch wrapping with a macro not to change the
> > > > > behavior on
> > > > windows.
> > > >
> > > > I think you want __linux__ there, not __unix__.
> > >
> > > Fixed with __linux__.
> >
> > OK.
> >
> > Thanks,
> > Uros.
> >
> > >
> > > Thx,
> > > Haochen
> > >
> > > >
> > > > Uros.
> > > >
> > > > >
> > > > > Regtested on x86_64-pc-linux-gnu.
> > > > >
> > > > > Thx,
> > > > > Haochen
> > > > > >
> > > > > > Uros.
> > > > > >
> > > > > > >
> > > > > > > This patch aims to add them to fix this bug.
> > > > > > >
> > > > > > > BRs,
> > > > > > > Haochen
> > > > > > >
> > > > > > > gcc/testsuite/ChangeLog:
> > > > > > >
> > > > > > >         * gcc.target/i386/amx-check.h (request_perm_xtile_data):
> > > > > > >         New function to check if AMX is usable and enable AMX.
> > > > > > >         (main): Run test if AMX is usable.
> > > > > > > ---
> > > > > > >  gcc/testsuite/gcc.target/i386/amx-check.h | 24
> > > > > > > +++++++++++++++++++++++
> > > > > > >  1 file changed, 24 insertions(+)
> > > > > > >
> > > > > > > diff --git a/gcc/testsuite/gcc.target/i386/amx-check.h
> > > > > > > b/gcc/testsuite/gcc.target/i386/amx-check.h
> > > > > > > index 434b0e59703..92ed8669304 100644
> > > > > > > --- a/gcc/testsuite/gcc.target/i386/amx-check.h
> > > > > > > +++ b/gcc/testsuite/gcc.target/i386/amx-check.h
> > > > > > > @@ -4,11 +4,22 @@
> > > > > > >  #include <stdlib.h>
> > > > > > >  #include <string.h>
> > > > > > >  #include <stdint.h>
> > > > > > > +#include <unistd.h>
> > > > > > > +#include <sys/syscall.h>
> > > > > > >  #ifdef DEBUG
> > > > > > >  #include <stdio.h>
> > > > > > >  #endif
> > > > > > >  #include "cpuid.h"
> > > > > > >
> > > > > > > +#define XFEATURE_XTILECFG      17
> > > > > > > +#define XFEATURE_XTILEDATA     18
> > > > > > > +#define XFEATURE_MASK_XTILECFG (1 << XFEATURE_XTILECFG)
> > > > > > > +#define XFEATURE_MASK_XTILEDATA        (1 <<
> XFEATURE_XTILEDATA)
> > > > > > > +#define XFEATURE_MASK_XTILE    (XFEATURE_MASK_XTILECFG |
> > > > > > XFEATURE_MASK_XTILEDATA)
> > > > > > > +
> > > > > > > +#define ARCH_GET_XCOMP_PERM    0x1022
> > > > > > > +#define ARCH_REQ_XCOMP_PERM    0x1023
> > > > > > > +
> > > > > > >  /* TODO: The tmm emulation is temporary for current
> > > > > > >     AMX implementation with no tmm regclass, should
> > > > > > >     be changed in the future. */ @@ -44,6 +55,18 @@ typedef
> > > > > > > struct __tile
> > > > > > >  /* Stride (colum width in byte) used for tileload/store */
> > > > > > > #define _STRIDE 64
> > > > > > >
> > > > > > > +/* We need syscall to use amx functions */ int
> > > > > > > +request_perm_xtile_data() {
> > > > > > > +  unsigned long bitmask;
> > > > > > > +
> > > > > > > +  if (syscall (SYS_arch_prctl, ARCH_REQ_XCOMP_PERM,
> > > > > > XFEATURE_XTILEDATA) ||
> > > > > > > +      syscall (SYS_arch_prctl, ARCH_GET_XCOMP_PERM, &bitmask))
> > > > > > > +    return 0;
> > > > > > > +
> > > > > > > +  return (bitmask & XFEATURE_MASK_XTILE) != 0; }
> > > > > > > +
> > > > > > >  /* Initialize tile config by setting all tmm size to 16x64
> > > > > > > */ void init_tile_config (__tilecfg_u *dst)  { @@ -186,6
> > > > > > > +209,7 @@ main () #ifdef AMX_BF16
> > > > > > >        && __builtin_cpu_supports ("amx-bf16")  #endif
> > > > > > > +      && request_perm_xtile_data ()
> > > > > > >        )
> > > > > > >      {
> > > > > > >        DO_TEST ();
> > > > > > > --
> > > > > > > 2.18.2
> > > > > > >