0d3b051adb
It could help to reduce the latency of the time-related functions in user space. We have referenced arm's and riscv's implementation for the patch. Signed-off-by: Guo Ren <guoren@linux.alibaba.com> Cc: Vincent Chen <vincent.chen@sifive.com> Cc: Arnd Bergmann <arnd@arndb.de>
28 lines
785 B
C
28 lines
785 B
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __ASM_CSKY_VDSO_H
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#define __ASM_CSKY_VDSO_H
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#include <linux/types.h>
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#ifndef GENERIC_TIME_VSYSCALL
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struct vdso_data {
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};
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#endif
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/*
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* The VDSO symbols are mapped into Linux so we can just use regular symbol
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* addressing to get their offsets in userspace. The symbols are mapped at an
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* offset of 0, but since the linker must support setting weak undefined
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* symbols to the absolute address 0 it also happens to support other low
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* addresses even when the code model suggests those low addresses would not
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* otherwise be availiable.
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*/
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#define VDSO_SYMBOL(base, name) \
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({ \
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extern const char __vdso_##name[]; \
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(void __user *)((unsigned long)(base) + __vdso_##name); \
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})
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#endif /* __ASM_CSKY_VDSO_H */
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