arch/loongarch/include/asm/lbt.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * Author: Qi Hu <huqi@loongson.cn>
   4  *         Huacai Chen <chenhuacai@loongson.cn>
   5  * Copyright (C) 2020-2023 Loongson Technology Corporation Limited
   6  */
   7 #ifndef _ASM_LBT_H
   8 #define _ASM_LBT_H
   9
  10 #include <asm/cpu.h>
  11 #include <asm/current.h>
  12 #include <asm/loongarch.h>
  13 #include <asm/processor.h>
  14
  15 extern void _init_lbt(void);
  16 extern void _save_lbt(struct loongarch_lbt *);
  17 extern void _restore_lbt(struct loongarch_lbt *);
  18
  19 static inline int is_lbt_enabled(void)
  20 {
  21         if (!cpu_has_lbt)
  22                 return 0;
  23
  24         return (csr_read32(LOONGARCH_CSR_EUEN) & CSR_EUEN_LBTEN) ?
  25                 1 : 0;
  26 }
  27
  28 static inline int is_lbt_owner(void)
  29 {
  30         return test_thread_flag(TIF_USEDLBT);
  31 }
  32
  33 #ifdef CONFIG_CPU_HAS_LBT
  34
  35 static inline void enable_lbt(void)
  36 {
  37         if (cpu_has_lbt)
  38                 csr_xchg32(CSR_EUEN_LBTEN, CSR_EUEN_LBTEN, LOONGARCH_CSR_EUEN);
  39 }
  40
  41 static inline void disable_lbt(void)
  42 {
  43         if (cpu_has_lbt)
  44                 csr_xchg32(0, CSR_EUEN_LBTEN, LOONGARCH_CSR_EUEN);
  45 }
  46
  47 static inline void __own_lbt(void)
  48 {
  49         enable_lbt();
  50         set_thread_flag(TIF_USEDLBT);
  51         KSTK_EUEN(current) |= CSR_EUEN_LBTEN;
  52 }
  53
  54 static inline void own_lbt_inatomic(int restore)
  55 {
  56         if (cpu_has_lbt && !is_lbt_owner()) {
  57                 __own_lbt();
  58                 if (restore)
  59                         _restore_lbt(&current->thread.lbt);
  60         }
  61 }
  62
  63 static inline void own_lbt(int restore)
  64 {
  65         preempt_disable();
  66         own_lbt_inatomic(restore);
  67         preempt_enable();
  68 }
  69
  70 static inline void lose_lbt_inatomic(int save, struct task_struct *tsk)
  71 {
  72         if (cpu_has_lbt && is_lbt_owner()) {
  73                 if (save)
  74                         _save_lbt(&tsk->thread.lbt);
  75
  76                 disable_lbt();
  77                 clear_tsk_thread_flag(tsk, TIF_USEDLBT);
  78         }
  79         KSTK_EUEN(tsk) &= ~(CSR_EUEN_LBTEN);
  80 }
  81
  82 static inline void lose_lbt(int save)
  83 {
  84         preempt_disable();
  85         lose_lbt_inatomic(save, current);
  86         preempt_enable();
  87 }
  88
  89 static inline void init_lbt(void)
  90 {
  91         __own_lbt();
  92         _init_lbt();
  93 }
  94 #else
  95 static inline void own_lbt_inatomic(int restore) {}
  96 static inline void lose_lbt_inatomic(int save, struct task_struct *tsk) {}
  97 static inline void init_lbt(void) {}
  98 static inline void lose_lbt(int save) {}
  99 #endif
 100
 101 static inline int thread_lbt_context_live(void)
 102 {
 103         if (!cpu_has_lbt)
 104                 return 0;
 105
 106         return test_thread_flag(TIF_LBT_CTX_LIVE);
 107 }
 108
 109 #endif /* _ASM_LBT_H */