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Nathan Chancellor 19336376bd ARM: remove Thumb2 __builtin_thread_pointer workaround for Clang
Now that the minimum supported version of LLVM for building the kernel has
been bumped to 13.0.1, the conditional expression added to get_current()
by commit c1e42efacb ("ARM: 9151/1: Thumb2: avoid
__builtin_thread_pointer() on Clang") is always true, as the build will
fail during the configuration stage for older LLVM versions.  Remove it,
effectively reverting the aforementioned change.

Link: https://lkml.kernel.org/r/20240125-bump-min-llvm-ver-to-13-0-1-v1-4-f5ff9bda41c5@kernel.org
Signed-off-by: Nathan Chancellor <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Cc: Albert Ou <[email protected]>
Cc: "Aneesh Kumar K.V (IBM)" <[email protected]>
Cc: Ard Biesheuvel <[email protected]>
Cc: Borislav Petkov (AMD) <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Conor Dooley <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Masahiro Yamada <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: "Naveen N. Rao" <[email protected]>
Cc: Nicholas Piggin <[email protected]>
Cc: Nicolas Schier <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
Cc: Paul Walmsley <[email protected]>
Cc: Russell King <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Will Deacon <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
2024-02-22 15:38:54 -08:00

66 lines
1.8 KiB
C

/* 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)
/*
* 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.
*/
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 */