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
135

source code of linux/arch/x86/include/asm/fpu/xstate.h