76 lines
1.7 KiB
C
76 lines
1.7 KiB
C
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/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* Copyright (C) 2015 Imagination Technologies
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* Author: Alex Smith <alex.smith@imgtec.com>
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*/
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#include <asm/sgidefs.h>
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#ifndef __ASSEMBLY__
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#include <asm/asm.h>
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#include <asm/page.h>
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#include <asm/vdso.h>
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static inline unsigned long get_vdso_base(void)
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{
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unsigned long addr;
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/*
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* We can't use cpu_has_mips_r6 since it needs the cpu_data[]
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* kernel symbol.
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*/
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#ifdef CONFIG_CPU_MIPSR6
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/*
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* lapc <symbol> is an alias to addiupc reg, <symbol> - .
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*
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* We can't use addiupc because there is no label-label
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* support for the addiupc reloc
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*/
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__asm__("lapc %0, _start \n"
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: "=r" (addr) : :);
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#else
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/*
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* Get the base load address of the VDSO. We have to avoid generating
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* relocations and references to the GOT because ld.so does not peform
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* relocations on the VDSO. We use the current offset from the VDSO base
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* and perform a PC-relative branch which gives the absolute address in
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* ra, and take the difference. The assembler chokes on
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* "li %0, _start - .", so embed the offset as a word and branch over
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* it.
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*
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*/
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__asm__(
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" .set push \n"
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" .set noreorder \n"
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" bal 1f \n"
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" nop \n"
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" .word _start - . \n"
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"1: lw %0, 0($31) \n"
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" " STR(PTR_ADDU) " %0, $31, %0 \n"
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" .set pop \n"
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: "=r" (addr)
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:
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: "$31");
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#endif /* CONFIG_CPU_MIPSR6 */
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return addr;
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}
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static inline const struct vdso_data *get_vdso_data(void)
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{
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return (const struct vdso_data *)(get_vdso_base() - PAGE_SIZE);
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}
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#ifdef CONFIG_CLKSRC_MIPS_GIC
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static inline void __iomem *get_gic(const struct vdso_data *data)
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{
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return (void __iomem *)((unsigned long)data & PAGE_MASK) - PAGE_SIZE;
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}
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#endif /* CONFIG_CLKSRC_MIPS_GIC */
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#endif /* __ASSEMBLY__ */
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