[PATCH v9 21/26] x86/fpu/amx: Enable the AMX feature in 64-bit mode

Chang S. Bae
2021-07-30T15:07:18Z

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

Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Reviewed-by: Len Brown <len.brown@intel.com>
Cc: x86@kernel.org
Cc: linux-kernel@vger.kernel.org
---
Changes from v5:
* Adjusted macro changes and moved the disabling code for non-64-bit mode
for the new base changes.

Changes from v4:
* Removed the irrelevant line from the changelog. (Thomas Gleixner)
---
arch/x86/include/asm/fpu/xstate.h | 3 ++-
arch/x86/kernel/fpu/xstate.c | 6 +++++-
2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h
index 912b420cb148..f934ce88c048 100644
--- a/arch/x86/include/asm/fpu/xstate.h
+++ b/arch/x86/include/asm/fpu/xstate.h
@@ -35,7 +35,8 @@
XFEATURE_MASK_Hi16_ZMM | \
XFEATURE_MASK_PKRU | \
XFEATURE_MASK_BNDREGS | \
- XFEATURE_MASK_BNDCSR)
+ XFEATURE_MASK_BNDCSR | \
+ XFEATURE_MASK_XTILE)

/*
* Features which are restored when returning to user space.
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index dac01e4d7654..96056f49bcff 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -538,7 +538,8 @@ static void __init print_xstate_offset_size(void)
XFEATURE_MASK_PKRU | \
XFEATURE_MASK_BNDREGS | \
XFEATURE_MASK_BNDCSR | \
- XFEATURE_MASK_PASID)
+ XFEATURE_MASK_PASID | \
+ XFEATURE_MASK_XTILE)

/*
* setup the xstate image representing the init state
@@ -1054,6 +1055,9 @@ void __init fpu__init_system_xstate(void)
xfeatures_mask_all &= XFEATURE_MASK_USER_SUPPORTED |
XFEATURE_MASK_SUPERVISOR_SUPPORTED;

+ if (!IS_ENABLED(CONFIG_X86_64))
+ xfeatures_mask_all &= ~XFEATURE_MASK_XTILE;
+
/* Store it for paranoia check at the end */
xfeatures = xfeatures_mask_all;
/* Do not support the dynamically allocated buffer yet. */
--
2.17.1