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

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

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.

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