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

["Jiang, Haochen" <haochen.jiang@intel.com>]

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> -----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.

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
> >

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From 7b2ad89821e8c318f9c592a339389aa60325ad6b Mon Sep 17 00:00:00 2001
From: Haochen Jiang <haochen.jiang@intel.com>
Date: Thu, 16 Jun 2022 00:15:53 -0700
Subject: [PATCH] i386: Add syscall to enable AMX for latest kernels

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 | 30 +++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/gcc/testsuite/gcc.target/i386/amx-check.h b/gcc/testsuite/gcc.target/i386/amx-check.h
index 434b0e59703..694b25ed2eb 100644
--- a/gcc/testsuite/gcc.target/i386/amx-check.h
+++ b/gcc/testsuite/gcc.target/i386/amx-check.h
@@ -4,11 +4,24 @@
 #include <stdlib.h>
 #include <string.h>
 #include <stdint.h>
+#include <unistd.h>
+#ifdef __unix__
+#include <sys/syscall.h>
+#endif
 #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 +57,20 @@ typedef struct __tile
 /* Stride (colum width in byte) used for tileload/store */
 #define _STRIDE 64
 
+#ifdef __unix__
+/* 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;
+}
+#endif
+
 /* Initialize tile config by setting all tmm size to 16x64 */
 void init_tile_config (__tilecfg_u *dst)
 {
@@ -185,6 +212,9 @@ main ()
 #endif
 #ifdef AMX_BF16
       && __builtin_cpu_supports ("amx-bf16")
+#endif
+#ifdef __unix__
+      && request_perm_xtile_data ()
 #endif
       )
     {
-- 
2.18.2