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