arch/x86/include/asm/fpu/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 XSTATE_CPUID            0x0000000d
  16
  17 #define TILE_CPUID              0x0000001d
  18
  19 #define FXSAVE_SIZE     512
  20
  21 #define XSAVE_HDR_SIZE      64
  22 #define XSAVE_HDR_OFFSET    FXSAVE_SIZE
  23
  24 #define XSAVE_YMM_SIZE      256
  25 #define XSAVE_YMM_OFFSET    (XSAVE_HDR_SIZE + XSAVE_HDR_OFFSET)
  26
  27 #define XSAVE_ALIGNMENT     64
  28
  29 /* All currently supported user features */
  30 #define XFEATURE_MASK_USER_SUPPORTED (XFEATURE_MASK_FP | \
  31                                       XFEATURE_MASK_SSE | \
  32                                       XFEATURE_MASK_YMM | \
  33                                       XFEATURE_MASK_OPMASK | \
  34                                       XFEATURE_MASK_ZMM_Hi256 | \
  35                                       XFEATURE_MASK_Hi16_ZMM     | \
  36                                       XFEATURE_MASK_PKRU | \
  37                                       XFEATURE_MASK_BNDREGS | \
  38                                       XFEATURE_MASK_BNDCSR | \
  39                                       XFEATURE_MASK_XTILE)
  40
  41 /*
  42  * Features which are restored when returning to user space.
  43  * PKRU is not restored on return to user space because PKRU
  44  * is switched eagerly in switch_to() and flush_thread()
  45  */
  46 #define XFEATURE_MASK_USER_RESTORE      \
  47         (XFEATURE_MASK_USER_SUPPORTED & ~XFEATURE_MASK_PKRU)
  48
  49 /* Features which are dynamically enabled for a process on request */
  50 #define XFEATURE_MASK_USER_DYNAMIC      XFEATURE_MASK_XTILE_DATA
  51
  52 /* All currently supported supervisor features */
  53 #define XFEATURE_MASK_SUPERVISOR_SUPPORTED (XFEATURE_MASK_PASID)
  54
  55 /*
  56  * A supervisor state component may not always contain valuable information,
  57  * and its size may be huge. Saving/restoring such supervisor state components
  58  * at each context switch can cause high CPU and space overhead, which should
  59  * be avoided. Such supervisor state components should only be saved/restored
  60  * on demand. The on-demand supervisor features are set in this mask.
  61  *
  62  * Unlike the existing supported supervisor features, an independent supervisor
  63  * feature does not allocate a buffer in task->fpu, and the corresponding
  64  * supervisor state component cannot be saved/restored at each context switch.
  65  *
  66  * To support an independent supervisor feature, a developer should follow the
  67  * dos and don'ts as below:
  68  * - Do dynamically allocate a buffer for the supervisor state component.
  69  * - Do manually invoke the XSAVES/XRSTORS instruction to save/restore the
  70  *   state component to/from the buffer.
  71  * - Don't set the bit corresponding to the independent supervisor feature in
  72  *   IA32_XSS at run time, since it has been set at boot time.
  73  */
  74 #define XFEATURE_MASK_INDEPENDENT (XFEATURE_MASK_LBR)
  75
  76 /*
  77  * Unsupported supervisor features. When a supervisor feature in this mask is
  78  * supported in the future, move it to the supported supervisor feature mask.
  79  */
  80 #define XFEATURE_MASK_SUPERVISOR_UNSUPPORTED (XFEATURE_MASK_PT)
  81
  82 /* All supervisor states including supported and unsupported states. */
  83 #define XFEATURE_MASK_SUPERVISOR_ALL (XFEATURE_MASK_SUPERVISOR_SUPPORTED | \
  84                                       XFEATURE_MASK_INDEPENDENT | \
  85                                       XFEATURE_MASK_SUPERVISOR_UNSUPPORTED)
  86
  87 /*
  88  * The feature mask required to restore FPU state:
  89  * - All user states which are not eagerly switched in switch_to()/exec()
  90  * - The suporvisor states
  91  */
  92 #define XFEATURE_MASK_FPSTATE   (XFEATURE_MASK_USER_RESTORE | \
  93                                  XFEATURE_MASK_SUPERVISOR_SUPPORTED)
  94
  95 /*
  96  * Features in this mask have space allocated in the signal frame, but may not
  97  * have that space initialized when the feature is in its init state.
  98  */
  99 #define XFEATURE_MASK_SIGFRAME_INITOPT  (XFEATURE_MASK_XTILE | \
 100                                          XFEATURE_MASK_USER_DYNAMIC)
 101
 102 extern u64 xstate_fx_sw_bytes[USER_XSTATE_FX_SW_WORDS];
 103
 104 extern void __init update_regset_xstate_info(unsigned int size,
 105                                              u64 xstate_mask);
 106
 107 int xfeature_size(int xfeature_nr);
 108
 109 void xsaves(struct xregs_state *xsave, u64 mask);
 110 void xrstors(struct xregs_state *xsave, u64 mask);
 111
 112 int xfd_enable_feature(u64 xfd_err);
 113
 114 #ifdef CONFIG_X86_64
 115 DECLARE_STATIC_KEY_FALSE(__fpu_state_size_dynamic);
 116 #endif
 117
 118 #ifdef CONFIG_X86_64
 119 DECLARE_STATIC_KEY_FALSE(__fpu_state_size_dynamic);
 120
 121 static __always_inline __pure bool fpu_state_size_dynamic(void)
 122 {
 123         return static_branch_unlikely(&__fpu_state_size_dynamic);
 124 }
 125 #else
 126 static __always_inline __pure bool fpu_state_size_dynamic(void)
 127 {
 128         return false;
 129 }
 130 #endif
 131
 132 #endif