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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>
59 lines
1.3 KiB
C
59 lines
1.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _M68K_SEGMENT_H
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#define _M68K_SEGMENT_H
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/* define constants */
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/* Address spaces (FC0-FC2) */
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#define USER_DATA (1)
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#ifndef __USER_DS
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#define __USER_DS (USER_DATA)
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#endif
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#define USER_PROGRAM (2)
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#define SUPER_DATA (5)
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#ifndef __KERNEL_DS
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#define __KERNEL_DS (SUPER_DATA)
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#endif
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#define SUPER_PROGRAM (6)
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#define CPU_SPACE (7)
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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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#ifdef CONFIG_CPU_HAS_ADDRESS_SPACES
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/*
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* Get/set the SFC/DFC registers for MOVES instructions
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*/
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#define USER_DS MAKE_MM_SEG(__USER_DS)
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#define KERNEL_DS MAKE_MM_SEG(__KERNEL_DS)
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static inline mm_segment_t get_fs(void)
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{
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mm_segment_t _v;
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__asm__ ("movec %/dfc,%0":"=r" (_v.seg):);
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return _v;
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}
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static inline void set_fs(mm_segment_t val)
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{
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__asm__ __volatile__ ("movec %0,%/sfc\n\t"
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"movec %0,%/dfc\n\t"
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: /* no outputs */ : "r" (val.seg) : "memory");
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}
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#else
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#define USER_DS MAKE_MM_SEG(TASK_SIZE)
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#define KERNEL_DS MAKE_MM_SEG(0xFFFFFFFF)
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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
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#define segment_eq(a, b) ((a).seg == (b).seg)
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#endif /* __ASSEMBLY__ */
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#endif /* _M68K_SEGMENT_H */
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