diff options
Diffstat (limited to 'arch/arm/include/asm/current.h')
-rw-r--r-- | arch/arm/include/asm/current.h | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/arch/arm/include/asm/current.h b/arch/arm/include/asm/current.h new file mode 100644 index 000000000000..6bf0aad672c3 --- /dev/null +++ b/arch/arm/include/asm/current.h @@ -0,0 +1,55 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (c) 2021 Keith Packard <keithp@keithp.com> + * Copyright (c) 2021 Google, LLC <ardb@kernel.org> + */ + +#ifndef _ASM_ARM_CURRENT_H +#define _ASM_ARM_CURRENT_H + +#ifndef __ASSEMBLY__ + +struct task_struct; + +static inline void set_current(struct task_struct *cur) +{ + if (!IS_ENABLED(CONFIG_CURRENT_POINTER_IN_TPIDRURO)) + return; + + /* Set TPIDRURO */ + asm("mcr p15, 0, %0, c13, c0, 3" :: "r"(cur) : "memory"); +} + +#ifdef CONFIG_CURRENT_POINTER_IN_TPIDRURO + +static inline struct task_struct *get_current(void) +{ + struct task_struct *cur; + +#if __has_builtin(__builtin_thread_pointer) && \ + !(defined(CONFIG_THUMB2_KERNEL) && \ + defined(CONFIG_CC_IS_CLANG) && CONFIG_CLANG_VERSION < 130001) + /* + * Use the __builtin helper when available - this results in better + * code, especially when using GCC in combination with the per-task + * stack protector, as the compiler will recognize that it needs to + * load the TLS register only once in every function. + * + * Clang < 13.0.1 gets this wrong for Thumb2 builds: + * https://github.com/ClangBuiltLinux/linux/issues/1485 + */ + cur = __builtin_thread_pointer(); +#else + asm("mrc p15, 0, %0, c13, c0, 3" : "=r"(cur)); +#endif + return cur; +} + +#define current get_current() +#else +#include <asm-generic/current.h> +#endif /* CONFIG_CURRENT_POINTER_IN_TPIDRURO */ + +#endif /* __ASSEMBLY__ */ + +#endif /* _ASM_ARM_CURRENT_H */ |