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acf02be3c7
Use atomic_try_cmpxchg_acquire(*ptr, &old, new) instead of atomic_cmpxchg_acquire(*ptr, old, new) == old in kexec_trylock(). x86 CMPXCHG instruction returns success in ZF flag, so this change saves a compare after cmpxchg. Link: https://lkml.kernel.org/r/20240719103937.53742-1-ubizjak@gmail.com Signed-off-by: Uros Bizjak <ubizjak@gmail.com> Acked-by: Baoquan He <bhe@redhat.com> Cc: Eric Biederman <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
42 lines
1.3 KiB
C
42 lines
1.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef LINUX_KEXEC_INTERNAL_H
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#define LINUX_KEXEC_INTERNAL_H
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#include <linux/kexec.h>
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struct kexec_segment;
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struct kimage *do_kimage_alloc_init(void);
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int sanity_check_segment_list(struct kimage *image);
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void kimage_free_page_list(struct list_head *list);
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void kimage_free(struct kimage *image);
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int kimage_load_segment(struct kimage *image, struct kexec_segment *segment);
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void kimage_terminate(struct kimage *image);
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int kimage_is_destination_range(struct kimage *image,
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unsigned long start, unsigned long end);
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/*
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* Whatever is used to serialize accesses to the kexec_crash_image needs to be
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* NMI safe, as __crash_kexec() can happen during nmi_panic(), so here we use a
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* "simple" atomic variable that is acquired with a cmpxchg().
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*/
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extern atomic_t __kexec_lock;
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static inline bool kexec_trylock(void)
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{
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int old = 0;
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return atomic_try_cmpxchg_acquire(&__kexec_lock, &old, 1);
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}
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static inline void kexec_unlock(void)
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{
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atomic_set_release(&__kexec_lock, 0);
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}
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#ifdef CONFIG_KEXEC_FILE
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#include <linux/purgatory.h>
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void kimage_file_post_load_cleanup(struct kimage *image);
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extern char kexec_purgatory[];
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extern size_t kexec_purgatory_size;
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#else /* CONFIG_KEXEC_FILE */
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static inline void kimage_file_post_load_cleanup(struct kimage *image) { }
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#endif /* CONFIG_KEXEC_FILE */
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#endif /* LINUX_KEXEC_INTERNAL_H */
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