arch/arm64/kernel/vdso32/compiler.h

   1 /*
   2  * Userspace implementations of fallback calls
   3  *
   4  * Copyright (C) 2017 Cavium, Inc.
   5  * Copyright (C) 2012 ARM Limited
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  *
  19  * Author: Will Deacon <will.deacon@arm.com>
  20  * Rewriten into C by: Andrew Pinski <apinski@cavium.com>
  21  */
  22
  23 #ifndef __VDSO_COMPILER_H
  24 #define __VDSO_COMPILER_H
  25
  26 #include <asm/barrier.h>        /* for isb() & dmb()    */
  27 #include <asm/param.h>          /* for HZ               */
  28 #include <asm/unistd32.h>
  29 #include <linux/compiler.h>
  30
  31 #ifdef CONFIG_ARM_ARCH_TIMER
  32 #define ARCH_PROVIDES_TIMER
  33 #endif
  34
  35 /* can not include linux/time.h because of too much architectural cruft */
  36 #ifndef NSEC_PER_SEC
  37 #define NSEC_PER_SEC    1000000000L
  38 #endif
  39
  40 /* can not include linux/jiffies.h because of too much architectural cruft */
  41 #ifndef TICK_NSEC
  42 #define TICK_NSEC ((NSEC_PER_SEC+HZ/2)/HZ)
  43 #endif
  44
  45 /* can not include linux/hrtimer.h because of too much architectural cruft */
  46 #ifndef LOW_RES_NSEC
  47 #define LOW_RES_NSEC        TICK_NSEC
  48 #ifdef ARCH_PROVIDES_TIMER
  49 #ifdef CONFIG_HIGH_RES_TIMERS
  50 # define HIGH_RES_NSEC        1
  51 # define MONOTONIC_RES_NSEC    HIGH_RES_NSEC
  52 #else
  53 # define MONOTONIC_RES_NSEC    LOW_RES_NSEC
  54 #endif
  55 #endif
  56 #endif
  57
  58 #define DEFINE_FALLBACK(name, type_arg1, name_arg1, type_arg2, name_arg2) \
  59 static notrace long name##_fallback(type_arg1 _##name_arg1,               \
  60                                     type_arg2 _##name_arg2)               \
  61 {                                                                         \
  62         register type_arg1 name_arg1 asm("r0") = _##name_arg1;            \
  63         register type_arg2 name_arg2 asm("r1") = _##name_arg2;            \
  64         register long ret asm ("r0");                                     \
  65         register long nr asm("r7") = __NR_##name;                         \
  66                                                                           \
  67         asm volatile(                                                     \
  68         "       swi #0\n"                                                 \
  69         : "=r" (ret)                                                      \
  70         : "r" (name_arg1), "r" (name_arg2), "r" (nr)                      \
  71         : "memory");                                                      \
  72                                                                           \
  73         return ret;                                                       \
  74 }
  75
  76 /*
  77  * AArch32 implementation of arch_counter_get_cntvct() suitable for vdso
  78  */
  79 static __always_inline notrace u64 arch_vdso_read_counter(void)
  80 {
  81         u64 res;
  82
  83         /* Read the virtual counter. */
  84         isb();
  85         asm volatile("mrrc p15, 1, %Q0, %R0, c14" : "=r" (res));
  86
  87         return res;
  88 }
  89
  90 /*
  91  * Can not include asm/processor.h to pick this up because of all the
  92  * architectural components also included, so we open code a copy.
  93  */
  94 static inline void cpu_relax(void)
  95 {
  96         asm volatile("yield" ::: "memory");
  97 }
  98
  99 #undef smp_rmb
 100 #if __LINUX_ARM_ARCH__ >= 8
 101 #define smp_rmb()       dmb(ishld) /* ok on ARMv8 */
 102 #else
 103 #define smp_rmb()       dmb(ish) /* ishld does not exist on ARMv7 */
 104 #endif
 105
 106 /* Avoid unresolved references emitted by GCC */
 107
 108 void __aeabi_unwind_cpp_pr0(void)
 109 {
 110 }
 111
 112 void __aeabi_unwind_cpp_pr1(void)
 113 {
 114 }
 115
 116 void __aeabi_unwind_cpp_pr2(void)
 117 {
 118 }
 119
 120 #endif /* __VDSO_COMPILER_H */