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git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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d6905849f8
Nathan reports the group relocations go out of range in pathological cases such as allyesconfig kernels, which have little chance of actually booting but are still used in validation. So add a Kconfig symbol for this feature, and make it depend on !COMPILE_TEST. Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
71 lines
2 KiB
C
71 lines
2 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Copyright (c) 2021 Keith Packard <keithp@keithp.com>
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* Copyright (c) 2021 Google, LLC <ardb@kernel.org>
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*/
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#ifndef _ASM_ARM_CURRENT_H
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#define _ASM_ARM_CURRENT_H
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#ifndef __ASSEMBLY__
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#include <asm/insn.h>
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struct task_struct;
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extern struct task_struct *__current;
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static inline __attribute_const__ struct task_struct *get_current(void)
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{
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struct task_struct *cur;
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#if __has_builtin(__builtin_thread_pointer) && \
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defined(CONFIG_CURRENT_POINTER_IN_TPIDRURO) && \
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!(defined(CONFIG_THUMB2_KERNEL) && \
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defined(CONFIG_CC_IS_CLANG) && CONFIG_CLANG_VERSION < 130001)
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/*
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* Use the __builtin helper when available - this results in better
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* code, especially when using GCC in combination with the per-task
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* stack protector, as the compiler will recognize that it needs to
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* load the TLS register only once in every function.
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*
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* Clang < 13.0.1 gets this wrong for Thumb2 builds:
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* https://github.com/ClangBuiltLinux/linux/issues/1485
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*/
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cur = __builtin_thread_pointer();
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#elif defined(CONFIG_CURRENT_POINTER_IN_TPIDRURO) || defined(CONFIG_SMP)
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asm("0: mrc p15, 0, %0, c13, c0, 3 \n\t"
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#ifdef CONFIG_CPU_V6
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"1: \n\t"
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" .subsection 1 \n\t"
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#if defined(CONFIG_ARM_HAS_GROUP_RELOCS) && \
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!(defined(MODULE) && defined(CONFIG_ARM_MODULE_PLTS))
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"2: " LOAD_SYM_ARMV6(%0, __current) " \n\t"
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" b 1b \n\t"
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#else
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"2: ldr %0, 3f \n\t"
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" ldr %0, [%0] \n\t"
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" b 1b \n\t"
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"3: .long __current \n\t"
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#endif
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" .previous \n\t"
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" .pushsection \".alt.smp.init\", \"a\" \n\t"
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" .long 0b - . \n\t"
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" b . + (2b - 0b) \n\t"
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" .popsection \n\t"
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#endif
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: "=r"(cur));
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#elif __LINUX_ARM_ARCH__>= 7 || \
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!defined(CONFIG_ARM_HAS_GROUP_RELOCS) || \
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(defined(MODULE) && defined(CONFIG_ARM_MODULE_PLTS))
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cur = __current;
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#else
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asm(LOAD_SYM_ARMV6(%0, __current) : "=r"(cur));
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#endif
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return cur;
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}
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#define current get_current()
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#endif /* __ASSEMBLY__ */
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#endif /* _ASM_ARM_CURRENT_H */
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