projects / linux-2.6-block.git / blame
| Commit | Line | Data |
|---|---|---|
| 50596b75 AB |
1 | /* SPDX-License-Identifier: GPL-2.0-only */ |
| 2 | /* | |
| 3 | * Copyright (c) 2021 Keith Packard <keithp@keithp.com> | |
| 4 | * Copyright (c) 2021 Google, LLC <ardb@kernel.org> | |
| 5 | */ | |
| 6 | ||
| 7 | #ifndef _ASM_ARM_CURRENT_H | |
| 8 | #define _ASM_ARM_CURRENT_H | |
| 9 | ||
| 10 | #ifndef __ASSEMBLY__ | |
| 9c46929e | 11 | #include <asm/insn.h> |
| 50596b75 AB |
12 | |
| 13 | struct task_struct; | |
| 14 | ||
| 9c46929e | 15 | extern struct task_struct *__current; |
| 50596b75 | 16 | |
| 4d5a643e | 17 | static __always_inline __attribute_const__ struct task_struct *get_current(void) |
| 50596b75 AB |
18 | { |
| 19 | struct task_struct *cur; | |
| 20 | ||
| c1e42efa | 21 | #if __has_builtin(__builtin_thread_pointer) && \ |
| 9c46929e | 22 | defined(CONFIG_CURRENT_POINTER_IN_TPIDRURO) && \ |
| c1e42efa AB |
23 | !(defined(CONFIG_THUMB2_KERNEL) && \ |
| 24 | defined(CONFIG_CC_IS_CLANG) && CONFIG_CLANG_VERSION < 130001) | |
| 50596b75 AB |
25 | /* |
| 26 | * Use the __builtin helper when available - this results in better | |
| 27 | * code, especially when using GCC in combination with the per-task | |
| 28 | * stack protector, as the compiler will recognize that it needs to | |
| 29 | * load the TLS register only once in every function. | |
| c1e42efa AB |
30 | * |
| 31 | * Clang < 13.0.1 gets this wrong for Thumb2 builds: | |
| 32 | * https://github.com/ClangBuiltLinux/linux/issues/1485 | |
| 50596b75 AB |
33 | */ |
| 34 | cur = __builtin_thread_pointer(); | |
| 9c46929e AB |
35 | #elif defined(CONFIG_CURRENT_POINTER_IN_TPIDRURO) || defined(CONFIG_SMP) |
| 36 | asm("0: mrc p15, 0, %0, c13, c0, 3 \n\t" | |
| 37 | #ifdef CONFIG_CPU_V6 | |
| 38 | "1: \n\t" | |
| 39 | " .subsection 1 \n\t" | |
| d6905849 AB |
40 | #if defined(CONFIG_ARM_HAS_GROUP_RELOCS) && \ |
| 41 | !(defined(MODULE) && defined(CONFIG_ARM_MODULE_PLTS)) | |
| 9c46929e AB |
42 | "2: " LOAD_SYM_ARMV6(%0, __current) " \n\t" |
| 43 | " b 1b \n\t" | |
| 5fe41793 AB |
44 | #else |
| 45 | "2: ldr %0, 3f \n\t" | |
| 46 | " ldr %0, [%0] \n\t" | |
| 47 | " b 1b \n\t" | |
| 48 | "3: .long __current \n\t" | |
| 49 | #endif | |
| 9c46929e AB |
50 | " .previous \n\t" |
| 51 | " .pushsection \".alt.smp.init\", \"a\" \n\t" | |
| 52 | " .long 0b - . \n\t" | |
| 53 | " b . + (2b - 0b) \n\t" | |
| 54 | " .popsection \n\t" | |
| 55 | #endif | |
| 56 | : "=r"(cur)); | |
| 5fe41793 | 57 | #elif __LINUX_ARM_ARCH__>= 7 || \ |
| d6905849 AB |
58 | !defined(CONFIG_ARM_HAS_GROUP_RELOCS) || \ |
| 59 | (defined(MODULE) && defined(CONFIG_ARM_MODULE_PLTS)) | |
| 9c46929e | 60 | cur = __current; |
| 50596b75 | 61 | #else |
| 9c46929e | 62 | asm(LOAD_SYM_ARMV6(%0, __current) : "=r"(cur)); |
| 50596b75 AB |
63 | #endif |
| 64 | return cur; | |
| 65 | } | |
| 66 | ||
| 67 | #define current get_current() | |
| 50596b75 AB |
68 | |
| 69 | #endif /* __ASSEMBLY__ */ | |
| 70 | ||
| 71 | #endif /* _ASM_ARM_CURRENT_H */ |