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 /* All currently supported supervisor features */ 50 #define XFEATURE_MASK_SUPERVISOR_SUPPORTED (XFEATURE_MASK_PASID | \ 51 XFEATURE_MASK_CET_USER) 52 53 /* 54 * A supervisor state component may not always contain valuable information, 55 * and its size may be huge. Saving/restoring such supervisor state components 56 * at each context switch can cause high CPU and space overhead, which should 57 * be avoided. Such supervisor state components should only be saved/restored 58 * on demand. The on-demand supervisor features are set in this mask. 59 * 60 * Unlike the existing supported supervisor features, an independent supervisor 61 * feature does not allocate a buffer in task->fpu, and the corresponding 62 * supervisor state component cannot be saved/restored at each context switch. 63 * 64 * To support an independent supervisor feature, a developer should follow the 65 * dos and don'ts as below: 66 * - Do dynamically allocate a buffer for the supervisor state component. 67 * - Do manually invoke the XSAVES/XRSTORS instruction to save/restore the 68 * state component to/from the buffer. 69 * - Don't set the bit corresponding to the independent supervisor feature in 70 * IA32_XSS at run time, since it has been set at boot time. 71 */ 72 #define XFEATURE_MASK_INDEPENDENT (XFEATURE_MASK_LBR) 73 74 /* 75 * Unsupported supervisor features. When a supervisor feature in this mask is 76 * supported in the future, move it to the supported supervisor feature mask. 77 */ 78 #define XFEATURE_MASK_SUPERVISOR_UNSUPPORTED (XFEATURE_MASK_PT | \ 79 XFEATURE_MASK_CET_KERNEL) 80 81 /* All supervisor states including supported and unsupported states. */ 82 #define XFEATURE_MASK_SUPERVISOR_ALL (XFEATURE_MASK_SUPERVISOR_SUPPORTED | \ 83 XFEATURE_MASK_INDEPENDENT | \ 84 XFEATURE_MASK_SUPERVISOR_UNSUPPORTED) 85 86 /* 87 * The feature mask required to restore FPU state: 88 * - All user states which are not eagerly switched in switch_to()/exec() 89 * - The suporvisor states 90 */ 91 #define XFEATURE_MASK_FPSTATE (XFEATURE_MASK_USER_RESTORE | \ 92 XFEATURE_MASK_SUPERVISOR_SUPPORTED) 93 94 /* 95 * Features in this mask have space allocated in the signal frame, but may not 96 * have that space initialized when the feature is in its init state. 97 */ 98 #define XFEATURE_MASK_SIGFRAME_INITOPT (XFEATURE_MASK_XTILE | \ 99 XFEATURE_MASK_USER_DYNAMIC) 100 101 extern u64 xstate_fx_sw_bytes[USER_XSTATE_FX_SW_WORDS]; 102 103 extern void __init update_regset_xstate_info(unsigned int size, 104 u64 xstate_mask); 105 106 int xfeature_size(int xfeature_nr); 107 108 void xsaves(struct xregs_state *xsave, u64 mask); 109 void xrstors(struct xregs_state *xsave, u64 mask); 110 111 int xfd_enable_feature(u64 xfd_err); 112 113 #ifdef CONFIG_X86_64 114 DECLARE_STATIC_KEY_FALSE(__fpu_state_size_dynamic); 115 #endif 116 117 #ifdef CONFIG_X86_64 118 DECLARE_STATIC_KEY_FALSE(__fpu_state_size_dynamic); 119 120 static __always_inline __pure bool fpu_state_size_dynamic(void) 121 { 122 return static_branch_unlikely(&__fpu_state_size_dynamic); 123 } 124 #else 125 static __always_inline __pure bool fpu_state_size_dynamic(void) 126 { 127 return false; 128 } 129 #endif 130 131 #endif 132