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 XSTATE_CPUID 0x0000000d
16
17 #define FXSAVE_SIZE 512
18
19 #define XSAVE_HDR_SIZE 64
20 #define XSAVE_HDR_OFFSET FXSAVE_SIZE
21
22 #define XSAVE_YMM_SIZE 256
23 #define XSAVE_YMM_OFFSET (XSAVE_HDR_SIZE + XSAVE_HDR_OFFSET)
24
25 #define XSAVE_ALIGNMENT 64
26
27 /* All currently supported user features */
28 #define XFEATURE_MASK_USER_SUPPORTED (XFEATURE_MASK_FP | \
29 XFEATURE_MASK_SSE | \
30 XFEATURE_MASK_YMM | \
31 XFEATURE_MASK_OPMASK | \
32 XFEATURE_MASK_ZMM_Hi256 | \
33 XFEATURE_MASK_Hi16_ZMM | \
34 XFEATURE_MASK_PKRU | \
35 XFEATURE_MASK_BNDREGS | \
36 XFEATURE_MASK_BNDCSR)
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 /* All currently supported supervisor features */
47 #define XFEATURE_MASK_SUPERVISOR_SUPPORTED (XFEATURE_MASK_PASID)
48
49 /*
50 * A supervisor state component may not always contain valuable information,
51 * and its size may be huge. Saving/restoring such supervisor state components
52 * at each context switch can cause high CPU and space overhead, which should
53 * be avoided. Such supervisor state components should only be saved/restored
54 * on demand. The on-demand supervisor features are set in this mask.
55 *
56 * Unlike the existing supported supervisor features, an independent supervisor
57 * feature does not allocate a buffer in task->fpu, and the corresponding
58 * supervisor state component cannot be saved/restored at each context switch.
59 *
60 * To support an independent supervisor feature, a developer should follow the
61 * dos and don'ts as below:
62 * - Do dynamically allocate a buffer for the supervisor state component.
63 * - Do manually invoke the XSAVES/XRSTORS instruction to save/restore the
64 * state component to/from the buffer.
65 * - Don't set the bit corresponding to the independent supervisor feature in
66 * IA32_XSS at run time, since it has been set at boot time.
67 */
68 #define XFEATURE_MASK_INDEPENDENT (XFEATURE_MASK_LBR)
69
70 /*
71 * Unsupported supervisor features. When a supervisor feature in this mask is
72 * supported in the future, move it to the supported supervisor feature mask.
73 */
74 #define XFEATURE_MASK_SUPERVISOR_UNSUPPORTED (XFEATURE_MASK_PT)
75
76 /* All supervisor states including supported and unsupported states. */
77 #define XFEATURE_MASK_SUPERVISOR_ALL (XFEATURE_MASK_SUPERVISOR_SUPPORTED | \
78 XFEATURE_MASK_INDEPENDENT | \
79 XFEATURE_MASK_SUPERVISOR_UNSUPPORTED)
80
81 #ifdef CONFIG_X86_64
82 #define REX_PREFIX "0x48, "
83 #else
84 #define REX_PREFIX
85 #endif
86
87 extern u64 xfeatures_mask_all;
88
xfeatures_mask_supervisor(void)89 static inline u64 xfeatures_mask_supervisor(void)
90 {
91 return xfeatures_mask_all & XFEATURE_MASK_SUPERVISOR_SUPPORTED;
92 }
93
94 /*
95 * The xfeatures which are enabled in XCR0 and expected to be in ptrace
96 * buffers and signal frames.
97 */
xfeatures_mask_uabi(void)98 static inline u64 xfeatures_mask_uabi(void)
99 {
100 return xfeatures_mask_all & XFEATURE_MASK_USER_SUPPORTED;
101 }
102
103 /*
104 * The xfeatures which are restored by the kernel when returning to user
105 * mode. This is not necessarily the same as xfeatures_mask_uabi() as the
106 * kernel does not manage all XCR0 enabled features via xsave/xrstor as
107 * some of them have to be switched eagerly on context switch and exec().
108 */
xfeatures_mask_restore_user(void)109 static inline u64 xfeatures_mask_restore_user(void)
110 {
111 return xfeatures_mask_all & XFEATURE_MASK_USER_RESTORE;
112 }
113
114 /*
115 * Like xfeatures_mask_restore_user() but additionally restors the
116 * supported supervisor states.
117 */
xfeatures_mask_fpstate(void)118 static inline u64 xfeatures_mask_fpstate(void)
119 {
120 return xfeatures_mask_all & \
121 (XFEATURE_MASK_USER_RESTORE | XFEATURE_MASK_SUPERVISOR_SUPPORTED);
122 }
123
xfeatures_mask_independent(void)124 static inline u64 xfeatures_mask_independent(void)
125 {
126 if (!boot_cpu_has(X86_FEATURE_ARCH_LBR))
127 return XFEATURE_MASK_INDEPENDENT & ~XFEATURE_MASK_LBR;
128
129 return XFEATURE_MASK_INDEPENDENT;
130 }
131
132 extern u64 xstate_fx_sw_bytes[USER_XSTATE_FX_SW_WORDS];
133
134 extern void __init update_regset_xstate_info(unsigned int size,
135 u64 xstate_mask);
136
137 void *get_xsave_addr(struct xregs_state *xsave, int xfeature_nr);
138 int xfeature_size(int xfeature_nr);
139 int copy_uabi_from_kernel_to_xstate(struct xregs_state *xsave, const void *kbuf, u32 *pkru);
140 int copy_sigframe_from_user_to_xstate(struct task_struct *tsk, const void __user *ubuf);
141
142 void xsaves(struct xregs_state *xsave, u64 mask);
143 void xrstors(struct xregs_state *xsave, u64 mask);
144
145 enum xstate_copy_mode {
146 XSTATE_COPY_FP,
147 XSTATE_COPY_FX,
148 XSTATE_COPY_XSAVE,
149 };
150
151 struct membuf;
152 void copy_xstate_to_uabi_buf(struct membuf to, struct task_struct *tsk,
153 enum xstate_copy_mode mode);
154
155 #endif
156