736706bee3
Every in-kernel use of this function defined it to KERNEL_DS (either as an actual define, or as an inline function). It's an entirely historical artifact, and long long long ago used to actually read the segment selector valueof '%ds' on x86. Which in the kernel is always KERNEL_DS. Inspired by a patch from Jann Horn that just did this for a very small subset of users (the ones in fs/), along with Al who suggested a script. I then just took it to the logical extreme and removed all the remaining gunk. Roughly scripted with git grep -l '(get_ds())' -- :^tools/ | xargs sed -i 's/(get_ds())/(KERNEL_DS)/' git grep -lw 'get_ds' -- :^tools/ | xargs sed -i '/^#define get_ds()/d' plus manual fixups to remove a few unusual usage patterns, the couple of inline function cases and to fix up a comment that had become stale. The 'get_ds()' function remains in an x86 kvm selftest, since in user space it actually does something relevant. Inspired-by: Jann Horn <jannh@google.com> Inspired-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
35 lines
850 B
C
35 lines
850 B
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __ASM_SH_SEGMENT_H
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#define __ASM_SH_SEGMENT_H
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#ifndef __ASSEMBLY__
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typedef struct {
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unsigned long seg;
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} mm_segment_t;
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#define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
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/*
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* The fs value determines whether argument validity checking should be
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* performed or not. If get_fs() == USER_DS, checking is performed, with
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* get_fs() == KERNEL_DS, checking is bypassed.
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*
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* For historical reasons, these macros are grossly misnamed.
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*/
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#define KERNEL_DS MAKE_MM_SEG(0xFFFFFFFFUL)
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#ifdef CONFIG_MMU
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#define USER_DS MAKE_MM_SEG(PAGE_OFFSET)
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#else
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#define USER_DS KERNEL_DS
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#endif
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#define segment_eq(a, b) ((a).seg == (b).seg)
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#define get_fs() (current_thread_info()->addr_limit)
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#define set_fs(x) (current_thread_info()->addr_limit = (x))
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#endif /* __ASSEMBLY__ */
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#endif /* __ASM_SH_SEGMENT_H */
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