vdso.h
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/*
* Copyright (C) 2015 Imagination Technologies
* Author: Alex Smith <alex.smith@imgtec.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*/
#include <asm/sgidefs.h>
#if _MIPS_SIM != _MIPS_SIM_ABI64 && defined(CONFIG_64BIT)
/* Building 32-bit VDSO for the 64-bit kernel. Fake a 32-bit Kconfig. */
#undef CONFIG_64BIT
#define CONFIG_32BIT 1
#ifndef __ASSEMBLY__
#include <asm-generic/atomic64.h>
#endif
#endif
#ifndef __ASSEMBLY__
#include <asm/asm.h>
#include <asm/page.h>
#include <asm/vdso.h>
static inline unsigned long get_vdso_base(void)
{
unsigned long addr;
/*
* We can't use cpu_has_mips_r6 since it needs the cpu_data[]
* kernel symbol.
*/
#ifdef CONFIG_CPU_MIPSR6
/*
* lapc <symbol> is an alias to addiupc reg, <symbol> - .
*
* We can't use addiupc because there is no label-label
* support for the addiupc reloc
*/
__asm__("lapc %0, _start \n"
: "=r" (addr) : :);
#else
/*
* Get the base load address of the VDSO. We have to avoid generating
* relocations and references to the GOT because ld.so does not peform
* relocations on the VDSO. We use the current offset from the VDSO base
* and perform a PC-relative branch which gives the absolute address in
* ra, and take the difference. The assembler chokes on
* "li %0, _start - .", so embed the offset as a word and branch over
* it.
*
*/
__asm__(
" .set push \n"
" .set noreorder \n"
" bal 1f \n"
" nop \n"
" .word _start - . \n"
"1: lw %0, 0($31) \n"
" " STR(PTR_ADDU) " %0, $31, %0 \n"
" .set pop \n"
: "=r" (addr)
:
: "$31");
#endif /* CONFIG_CPU_MIPSR6 */
return addr;
}
static inline const union mips_vdso_data *get_vdso_data(void)
{
return (const union mips_vdso_data *)(get_vdso_base() - PAGE_SIZE);
}
#ifdef CONFIG_CLKSRC_MIPS_GIC
static inline void __iomem *get_gic(const union mips_vdso_data *data)
{
return (void __iomem *)data - PAGE_SIZE;
}
#endif /* CONFIG_CLKSRC_MIPS_GIC */
#endif /* __ASSEMBLY__ */