File _service:tar_scm:0002-i386-Add-syscall-to-enabl... of Package gcc

File _service:tar_scm:0002-i386-Add-syscall-to-enable-AMX-for-latest-kernels.patch of Package gcc (Revision 2a87d8a4590350c4a0c82cf9b58004ea)

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From 5e377d21f1f345d8b157b9bc306e02bb9bd45e01 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..6fff5ff4631 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 __linux__
+#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 __linux__
+/* 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 __linux__
+      && request_perm_xtile_data ()
 #endif
       )
     {
-- 
2.18.2