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/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright (c) 2021 Keith Packard <[email protected]>
* Copyright (c) 2021 Google, LLC <[email protected]>
*/
#ifndef _ASM_ARM_CURRENT_H
#define _ASM_ARM_CURRENT_H
#ifndef __ASSEMBLY__
#include <asm/insn.h>
struct task_struct;
extern struct task_struct *__current;
static __always_inline __attribute_const__ struct task_struct *get_current(void)
{
struct task_struct *cur;
#if __has_builtin(__builtin_thread_pointer) && \
defined(CONFIG_CURRENT_POINTER_IN_TPIDRURO) && \
!(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();
#elif defined(CONFIG_CURRENT_POINTER_IN_TPIDRURO) || defined(CONFIG_SMP)
asm("0: mrc p15, 0, %0, c13, c0, 3 \n\t"
#ifdef CONFIG_CPU_V6
"1: \n\t"
" .subsection 1 \n\t"
#if defined(CONFIG_ARM_HAS_GROUP_RELOCS) && \
!(defined(MODULE) && defined(CONFIG_ARM_MODULE_PLTS))
"2: " LOAD_SYM_ARMV6(%0, __current) " \n\t"
" b 1b \n\t"
#else
"2: ldr %0, 3f \n\t"
" ldr %0, [%0] \n\t"
" b 1b \n\t"
"3: .long __current \n\t"
#endif
" .previous \n\t"
" .pushsection \".alt.smp.init\", \"a\" \n\t"
" .long 0b - . \n\t"
" b . + (2b - 0b) \n\t"
" .popsection \n\t"
#endif
: "=r"(cur));
#elif __LINUX_ARM_ARCH__>= 7 || \
!defined(CONFIG_ARM_HAS_GROUP_RELOCS) || \
(defined(MODULE) && defined(CONFIG_ARM_MODULE_PLTS))
cur = __current;
#else
asm(LOAD_SYM_ARMV6(%0, __current) : "=r"(cur));
#endif
return cur;
}
#define current get_current()
#endif /* __ASSEMBLY__ */
#endif /* _ASM_ARM_CURRENT_H */
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