1 files changed, 132 insertions, 0 deletions
diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h
new file mode 100644
index 000000000..cd3dd170e
--- /dev/null
+++ b/arch/x86/include/asm/fpu/xstate.h
@@ -0,0 +1,132 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __ASM_X86_XSAVE_H
+#define __ASM_X86_XSAVE_H
+
+#include <linux/uaccess.h>
+#include <linux/types.h>
+
+#include <asm/processor.h>
+#include <asm/fpu/api.h>
+#include <asm/user.h>
+
+/* Bit 63 of XCR0 is reserved for future expansion */
+#define XFEATURE_MASK_EXTEND	(~(XFEATURE_MASK_FPSSE | (1ULL << 63)))
+
+#define XSTATE_CPUID		0x0000000d
+
+#define TILE_CPUID		0x0000001d
+
+#define FXSAVE_SIZE	512
+
+#define XSAVE_HDR_SIZE	    64
+#define XSAVE_HDR_OFFSET    FXSAVE_SIZE
+
+#define XSAVE_YMM_SIZE	    256
+#define XSAVE_YMM_OFFSET    (XSAVE_HDR_SIZE + XSAVE_HDR_OFFSET)
+
+#define XSAVE_ALIGNMENT     64
+
+/* All currently supported user features */
+#define XFEATURE_MASK_USER_SUPPORTED (XFEATURE_MASK_FP | \
+				      XFEATURE_MASK_SSE | \
+				      XFEATURE_MASK_YMM | \
+				      XFEATURE_MASK_OPMASK | \
+				      XFEATURE_MASK_ZMM_Hi256 | \
+				      XFEATURE_MASK_Hi16_ZMM	 | \
+				      XFEATURE_MASK_PKRU | \
+				      XFEATURE_MASK_BNDREGS | \
+				      XFEATURE_MASK_BNDCSR | \
+				      XFEATURE_MASK_XTILE)
+
+/*
+ * Features which are restored when returning to user space.
+ * PKRU is not restored on return to user space because PKRU
+ * is switched eagerly in switch_to() and flush_thread()
+ */
+#define XFEATURE_MASK_USER_RESTORE	\
+	(XFEATURE_MASK_USER_SUPPORTED & ~XFEATURE_MASK_PKRU)
+
+/* Features which are dynamically enabled for a process on request */
+#define XFEATURE_MASK_USER_DYNAMIC	XFEATURE_MASK_XTILE_DATA
+
+/* All currently supported supervisor features */
+#define XFEATURE_MASK_SUPERVISOR_SUPPORTED (XFEATURE_MASK_PASID)
+
+/*
+ * A supervisor state component may not always contain valuable information,
+ * and its size may be huge. Saving/restoring such supervisor state components
+ * at each context switch can cause high CPU and space overhead, which should
+ * be avoided. Such supervisor state components should only be saved/restored
+ * on demand. The on-demand supervisor features are set in this mask.
+ *
+ * Unlike the existing supported supervisor features, an independent supervisor
+ * feature does not allocate a buffer in task->fpu, and the corresponding
+ * supervisor state component cannot be saved/restored at each context switch.
+ *
+ * To support an independent supervisor feature, a developer should follow the
+ * dos and don'ts as below:
+ * - Do dynamically allocate a buffer for the supervisor state component.
+ * - Do manually invoke the XSAVES/XRSTORS instruction to save/restore the
+ *   state component to/from the buffer.
+ * - Don't set the bit corresponding to the independent supervisor feature in
+ *   IA32_XSS at run time, since it has been set at boot time.
+ */
+#define XFEATURE_MASK_INDEPENDENT (XFEATURE_MASK_LBR)
+
+/*
+ * Unsupported supervisor features. When a supervisor feature in this mask is
+ * supported in the future, move it to the supported supervisor feature mask.
+ */
+#define XFEATURE_MASK_SUPERVISOR_UNSUPPORTED (XFEATURE_MASK_PT)
+
+/* All supervisor states including supported and unsupported states. */
+#define XFEATURE_MASK_SUPERVISOR_ALL (XFEATURE_MASK_SUPERVISOR_SUPPORTED | \
+				      XFEATURE_MASK_INDEPENDENT | \
+				      XFEATURE_MASK_SUPERVISOR_UNSUPPORTED)
+
+/*
+ * The feature mask required to restore FPU state:
+ * - All user states which are not eagerly switched in switch_to()/exec()
+ * - The suporvisor states
+ */
+#define XFEATURE_MASK_FPSTATE	(XFEATURE_MASK_USER_RESTORE | \
+				 XFEATURE_MASK_SUPERVISOR_SUPPORTED)
+
+/*
+ * Features in this mask have space allocated in the signal frame, but may not
+ * have that space initialized when the feature is in its init state.
+ */
+#define XFEATURE_MASK_SIGFRAME_INITOPT	(XFEATURE_MASK_XTILE | \
+					 XFEATURE_MASK_USER_DYNAMIC)
+
+extern u64 xstate_fx_sw_bytes[USER_XSTATE_FX_SW_WORDS];
+
+extern void __init update_regset_xstate_info(unsigned int size,
+					     u64 xstate_mask);
+
+int xfeature_size(int xfeature_nr);
+
+void xsaves(struct xregs_state *xsave, u64 mask);
+void xrstors(struct xregs_state *xsave, u64 mask);
+
+int xfd_enable_feature(u64 xfd_err);
+
+#ifdef CONFIG_X86_64
+DECLARE_STATIC_KEY_FALSE(__fpu_state_size_dynamic);
+#endif
+
+#ifdef CONFIG_X86_64
+DECLARE_STATIC_KEY_FALSE(__fpu_state_size_dynamic);
+
+static __always_inline __pure bool fpu_state_size_dynamic(void)
+{
+	return static_branch_unlikely(&__fpu_state_size_dynamic);
+}
+#else
+static __always_inline __pure bool fpu_state_size_dynamic(void)
+{
+	return false;
+}
+#endif
+
+#endif