xstate.h

  1/* SPDX-License-Identifier: GPL-2.0 */
  2#ifndef __ASM_X86_XSAVE_H
  3#define __ASM_X86_XSAVE_H
  4
  5#include <linux/uaccess.h>
  6#include <linux/types.h>
  7
  8#include <asm/processor.h>
  9#include <asm/fpu/api.h>
 10#include <asm/user.h>
 11
 12/* Bit 63 of XCR0 is reserved for future expansion */
 13#define XFEATURE_MASK_EXTEND	(~(XFEATURE_MASK_FPSSE | (1ULL << 63)))
 14
 15#define FXSAVE_SIZE	512
 16
 17#define XSAVE_HDR_SIZE	    64
 18#define XSAVE_HDR_OFFSET    FXSAVE_SIZE
 19
 20#define XSAVE_YMM_SIZE	    256
 21#define XSAVE_YMM_OFFSET    (XSAVE_HDR_SIZE + XSAVE_HDR_OFFSET)
 22
 23#define XSAVE_ALIGNMENT     64
 24
 25/* All currently supported user features */
 26#define XFEATURE_MASK_USER_SUPPORTED (XFEATURE_MASK_FP | \
 27				      XFEATURE_MASK_SSE | \
 28				      XFEATURE_MASK_YMM | \
 29				      XFEATURE_MASK_OPMASK | \
 30				      XFEATURE_MASK_ZMM_Hi256 | \
 31				      XFEATURE_MASK_Hi16_ZMM	 | \
 32				      XFEATURE_MASK_PKRU | \
 33				      XFEATURE_MASK_BNDREGS | \
 34				      XFEATURE_MASK_BNDCSR | \
 35				      XFEATURE_MASK_XTILE | \
 36				      XFEATURE_MASK_APX)
 37
 38/*
 39 * Features which are restored when returning to user space.
 40 * PKRU is not restored on return to user space because PKRU
 41 * is switched eagerly in switch_to() and flush_thread()
 42 */
 43#define XFEATURE_MASK_USER_RESTORE	\
 44	(XFEATURE_MASK_USER_SUPPORTED & ~XFEATURE_MASK_PKRU)
 45
 46/* Features which are dynamically enabled for a process on request */
 47#define XFEATURE_MASK_USER_DYNAMIC	XFEATURE_MASK_XTILE_DATA
 48
 49/* Supervisor features which are enabled only in guest FPUs */
 50#define XFEATURE_MASK_GUEST_SUPERVISOR	XFEATURE_MASK_CET_KERNEL
 51
 52/* All currently supported supervisor features */
 53#define XFEATURE_MASK_SUPERVISOR_SUPPORTED (XFEATURE_MASK_PASID | \
 54					    XFEATURE_MASK_CET_USER | \
 55					    XFEATURE_MASK_GUEST_SUPERVISOR)
 56
 57/*
 58 * A supervisor state component may not always contain valuable information,
 59 * and its size may be huge. Saving/restoring such supervisor state components
 60 * at each context switch can cause high CPU and space overhead, which should
 61 * be avoided. Such supervisor state components should only be saved/restored
 62 * on demand. The on-demand supervisor features are set in this mask.
 63 *
 64 * Unlike the existing supported supervisor features, an independent supervisor
 65 * feature does not allocate a buffer in task->fpu, and the corresponding
 66 * supervisor state component cannot be saved/restored at each context switch.
 67 *
 68 * To support an independent supervisor feature, a developer should follow the
 69 * dos and don'ts as below:
 70 * - Do dynamically allocate a buffer for the supervisor state component.
 71 * - Do manually invoke the XSAVES/XRSTORS instruction to save/restore the
 72 *   state component to/from the buffer.
 73 * - Don't set the bit corresponding to the independent supervisor feature in
 74 *   IA32_XSS at run time, since it has been set at boot time.
 75 */
 76#define XFEATURE_MASK_INDEPENDENT (XFEATURE_MASK_LBR)
 77
 78/*
 79 * Unsupported supervisor features. When a supervisor feature in this mask is
 80 * supported in the future, move it to the supported supervisor feature mask.
 81 */
 82#define XFEATURE_MASK_SUPERVISOR_UNSUPPORTED (XFEATURE_MASK_PT)
 83
 84/* All supervisor states including supported and unsupported states. */
 85#define XFEATURE_MASK_SUPERVISOR_ALL (XFEATURE_MASK_SUPERVISOR_SUPPORTED | \
 86				      XFEATURE_MASK_INDEPENDENT | \
 87				      XFEATURE_MASK_SUPERVISOR_UNSUPPORTED)
 88
 89/*
 90 * The feature mask required to restore FPU state:
 91 * - All user states which are not eagerly switched in switch_to()/exec()
 92 * - The suporvisor states
 93 */
 94#define XFEATURE_MASK_FPSTATE	(XFEATURE_MASK_USER_RESTORE | \
 95				 XFEATURE_MASK_SUPERVISOR_SUPPORTED)
 96
 97/*
 98 * Features in this mask have space allocated in the signal frame, but may not
 99 * have that space initialized when the feature is in its init state.
100 */
101#define XFEATURE_MASK_SIGFRAME_INITOPT	(XFEATURE_MASK_XTILE | \
102					 XFEATURE_MASK_USER_DYNAMIC)
103
104extern u64 xstate_fx_sw_bytes[USER_XSTATE_FX_SW_WORDS];
105
106extern void __init update_regset_xstate_info(unsigned int size,
107					     u64 xstate_mask);
108
109int xfeature_size(int xfeature_nr);
110
111void xsaves(struct xregs_state *xsave, u64 mask);
112void xrstors(struct xregs_state *xsave, u64 mask);
113
114int xfd_enable_feature(u64 xfd_err);
115
116#ifdef CONFIG_X86_64
117DECLARE_STATIC_KEY_FALSE(__fpu_state_size_dynamic);
118#endif
119
120#ifdef CONFIG_X86_64
121DECLARE_STATIC_KEY_FALSE(__fpu_state_size_dynamic);
122
123static __always_inline __pure bool fpu_state_size_dynamic(void)
124{
125	return static_branch_unlikely(&__fpu_state_size_dynamic);
126}
127#else
128static __always_inline __pure bool fpu_state_size_dynamic(void)
129{
130	return false;
131}
132#endif
133
134#endif