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
19.global	__kernel_datapage_offset;
20__kernel_datapage_offset:
21	.long	0
22
23V_FUNCTION_BEGIN(__get_datapage)
24  .cfi_startproc
25	/* We don't want that exposed or overridable as we want other objects
26	 * to be able to bl directly to here
27	 */
28	.protected __get_datapage
29	.hidden __get_datapage
30
31	mflr	r0
32  .cfi_register lr,r0
33
34	bcl	20,31,data_page_branch
35data_page_branch:
36	mflr	r3
37	mtlr	r0
38	addi	r3, r3, __kernel_datapage_offset-data_page_branch
39	lwz	r0,0(r3)
40	add	r3,r0,r3
41	blr
42  .cfi_endproc
43V_FUNCTION_END(__get_datapage)
44
45/*
46 * void *__kernel_get_syscall_map(unsigned int *syscall_count) ;
47 *
48 * returns a pointer to the syscall map. the map is agnostic to the
49 * size of "long", unlike kernel bitops, it stores bits from top to
50 * bottom so that memory actually contains a linear bitmap
51 * check for syscall N by testing bit (0x80000000 >> (N & 0x1f)) of
52 * 32 bits int at N >> 5.
53 */
54V_FUNCTION_BEGIN(__kernel_get_syscall_map)
55  .cfi_startproc
56	mflr	r12
57  .cfi_register lr,r12
58	mr	r4,r3
59	bl	V_LOCAL_FUNC(__get_datapage)
60	mtlr	r12
61	addi	r3,r3,CFG_SYSCALL_MAP64
62	cmpli	cr0,r4,0
63	crclr	cr0*4+so
64	beqlr
65	li	r0,__NR_syscalls
66	stw	r0,0(r4)
67	blr
68  .cfi_endproc
69V_FUNCTION_END(__kernel_get_syscall_map)
70
71
72/*
73 * void unsigned long  __kernel_get_tbfreq(void);
74 *
75 * returns the timebase frequency in HZ
76 */
77V_FUNCTION_BEGIN(__kernel_get_tbfreq)
78  .cfi_startproc
79	mflr	r12
80  .cfi_register lr,r12
81	bl	V_LOCAL_FUNC(__get_datapage)
82	ld	r3,CFG_TB_TICKS_PER_SEC(r3)
83	mtlr	r12
84	crclr	cr0*4+so
85	blr
86  .cfi_endproc
87V_FUNCTION_END(__kernel_get_tbfreq)
88