tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * Copyright (C) 2015 Imagination Technologies
3 * Author: Alex Smith <alex.smith@imgtec.com>
4 *
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License as published by the
7 * Free Software Foundation; either version 2 of the License, or (at your
8 * option) any later version.
9 */
10
11#include <asm/sgidefs.h>
12
13#if _MIPS_SIM != _MIPS_SIM_ABI64 && defined(CONFIG_64BIT)
14
15/* Building 32-bit VDSO for the 64-bit kernel. Fake a 32-bit Kconfig. */
16#undef CONFIG_64BIT
17#define CONFIG_32BIT 1
18#ifndef __ASSEMBLY__
19#include <asm-generic/atomic64.h>
20#endif
21#endif
22
23#ifndef __ASSEMBLY__
24
25#include <asm/asm.h>
26#include <asm/page.h>
27#include <asm/vdso.h>
28
29static inline unsigned long get_vdso_base(void)
30{
31 unsigned long addr;
32
33 /*
34 * We can't use cpu_has_mips_r6 since it needs the cpu_data[]
35 * kernel symbol.
36 */
37#ifdef CONFIG_CPU_MIPSR6
38 /*
39 * lapc <symbol> is an alias to addiupc reg, <symbol> - .
40 *
41 * We can't use addiupc because there is no label-label
42 * support for the addiupc reloc
43 */
44 __asm__("lapc %0, _start \n"
45 : "=r" (addr) : :);
46#else
47 /*
48 * Get the base load address of the VDSO. We have to avoid generating
49 * relocations and references to the GOT because ld.so does not peform
50 * relocations on the VDSO. We use the current offset from the VDSO base
51 * and perform a PC-relative branch which gives the absolute address in
52 * ra, and take the difference. The assembler chokes on
53 * "li %0, _start - .", so embed the offset as a word and branch over
54 * it.
55 *
56 */
57
58 __asm__(
59 " .set push \n"
60 " .set noreorder \n"
61 " bal 1f \n"
62 " nop \n"
63 " .word _start - . \n"
64 "1: lw %0, 0($31) \n"
65 " " STR(PTR_ADDU) " %0, $31, %0 \n"
66 " .set pop \n"
67 : "=r" (addr)
68 :
69 : "$31");
70#endif /* CONFIG_CPU_MIPSR6 */
71
72 return addr;
73}
74
75static inline const union mips_vdso_data *get_vdso_data(void)
76{
77 return (const union mips_vdso_data *)(get_vdso_base() - PAGE_SIZE);
78}
79
80#ifdef CONFIG_CLKSRC_MIPS_GIC
81
82static inline void __iomem *get_gic(const union mips_vdso_data *data)
83{
84 return (void __iomem *)data - PAGE_SIZE;
85}
86
87#endif /* CONFIG_CLKSRC_MIPS_GIC */
88
89#endif /* __ASSEMBLY__ */