1/*
2 * Access to the shared data page by the vDSO & syscall map
3 *
4 * Copyright (C) 2004 Benjamin Herrenschmuidt (benh@kernel.crashing.org), IBM Corp.
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12#include <asm/processor.h>
13#include <asm/ppc_asm.h>
14#include <asm/asm-offsets.h>
15#include <asm/unistd.h>
16#include <asm/vdso.h>
17
18	.text
19V_FUNCTION_BEGIN(__get_datapage)
20  .cfi_startproc
21	/* We don't want that exposed or overridable as we want other objects
22	 * to be able to bl directly to here
23	 */
24	.protected __get_datapage
25	.hidden __get_datapage
26
27	mflr	r0
28  .cfi_register lr,r0
29
30	bcl	20,31,1f
31	.global	__kernel_datapage_offset;
32__kernel_datapage_offset:
33	.long	0
341:
35	mflr	r3
36	mtlr	r0
37	lwz	r0,0(r3)
38	add	r3,r0,r3
39	blr
40  .cfi_endproc
41V_FUNCTION_END(__get_datapage)
42
43/*
44 * void *__kernel_get_syscall_map(unsigned int *syscall_count) ;
45 *
46 * returns a pointer to the syscall map. the map is agnostic to the
47 * size of "long", unlike kernel bitops, it stores bits from top to
48 * bottom so that memory actually contains a linear bitmap
49 * check for syscall N by testing bit (0x80000000 >> (N & 0x1f)) of
50 * 32 bits int at N >> 5.
51 */
52V_FUNCTION_BEGIN(__kernel_get_syscall_map)
53  .cfi_startproc
54	mflr	r12
55  .cfi_register lr,r12
56	mr	r4,r3
57	bl	V_LOCAL_FUNC(__get_datapage)
58	mtlr	r12
59	addi	r3,r3,CFG_SYSCALL_MAP64
60	cmpli	cr0,r4,0
61	crclr	cr0*4+so
62	beqlr
63	li	r0,__NR_syscalls
64	stw	r0,0(r4)
65	blr
66  .cfi_endproc
67V_FUNCTION_END(__kernel_get_syscall_map)
68
69
70/*
71 * void unsigned long  __kernel_get_tbfreq(void);
72 *
73 * returns the timebase frequency in HZ
74 */
75V_FUNCTION_BEGIN(__kernel_get_tbfreq)
76  .cfi_startproc
77	mflr	r12
78  .cfi_register lr,r12
79	bl	V_LOCAL_FUNC(__get_datapage)
80	ld	r3,CFG_TB_TICKS_PER_SEC(r3)
81	mtlr	r12
82	crclr	cr0*4+so
83	blr
84  .cfi_endproc
85V_FUNCTION_END(__kernel_get_tbfreq)
86