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Diffstat (limited to 'arch/mips/vdso/vdso.h')
| -rw-r--r-- | arch/mips/vdso/vdso.h | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/arch/mips/vdso/vdso.h b/arch/mips/vdso/vdso.h new file mode 100644 index 000000000..921589b45 --- /dev/null +++ b/arch/mips/vdso/vdso.h @@ -0,0 +1,89 @@ +/* + * 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 *)((unsigned long)data & PAGE_MASK) - PAGE_SIZE; +} + +#endif /* CONFIG_CLKSRC_MIPS_GIC */ + +#endif /* __ASSEMBLY__ */ |