[PATCH v4 19/22] x86/fpu/amx: Enable the AMX feature in 64-bit mode

[Chang S. Bae]

In 64-bit mode, include the AMX state components in
XFEATURE_MASK_USER_SUPPORTED.

The XFD feature will be used to dynamically expand the xstate per-task
buffer on the first use.

Signed-off-by: Chang S. Bae <chang.seok.bae@xxxxxxxxx>
Reviewed-by: Len Brown <len.brown@xxxxxxxxx>
Cc: x86@xxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
 arch/x86/include/asm/fpu/xstate.h | 3 ++-
 arch/x86/kernel/fpu/init.c        | 8 ++++++--
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h
index 4112dbf05f19..9e5c28f3beaa 100644
--- a/arch/x86/include/asm/fpu/xstate.h
+++ b/arch/x86/include/asm/fpu/xstate.h
@@ -34,7 +34,8 @@
 				      XFEATURE_MASK_Hi16_ZMM	 | \
 				      XFEATURE_MASK_PKRU | \
 				      XFEATURE_MASK_BNDREGS | \
-				      XFEATURE_MASK_BNDCSR)
+				      XFEATURE_MASK_BNDCSR | \
+				      XFEATURE_MASK_XTILE)
 
 /* All currently supported supervisor features */
 #define XFEATURE_MASK_SUPERVISOR_SUPPORTED (XFEATURE_MASK_PASID)
diff --git a/arch/x86/kernel/fpu/init.c b/arch/x86/kernel/fpu/init.c
index f2fcdcc979e7..046889f31037 100644
--- a/arch/x86/kernel/fpu/init.c
+++ b/arch/x86/kernel/fpu/init.c
@@ -219,8 +219,12 @@ static void __init fpu__init_system_xstate_size_legacy(void)
  */
 u64 __init fpu__get_supported_xfeatures_mask(void)
 {
-	return XFEATURE_MASK_USER_SUPPORTED |
-	       XFEATURE_MASK_SUPERVISOR_SUPPORTED;
+	u64 mask = XFEATURE_MASK_USER_SUPPORTED | XFEATURE_MASK_SUPERVISOR_SUPPORTED;
+
+	if (!IS_ENABLED(CONFIG_X86_64))
+		mask &= ~(XFEATURE_MASK_XTILE);
+
+	return mask;
 }
 
 /* Legacy code to initialize eager fpu mode. */
-- 
2.17.1