linux/arch/powerpc/kernel/vdso64/datapage.S
Benjamin Herrenschmidt 5d66da3d71 [PATCH] powerpc: Make the vDSO functions set error code (#2)
The vDSO functions should have the same calling convention as a syscall.
Unfortunately, they currently don't set the cr0.so bit which is used to
indicate an error. This patch makes them clear this bit unconditionally
since all functions currently succeed. The syscall fallback done by some
of them will eventually override this if the syscall fails.

This also changes the symbol version of all vdso exports to make sure
glibc can differenciate between old and fixed calls for existing ones
like __kernel_gettimeofday.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-11-16 14:05:11 +11:00

87 lines
2.0 KiB
ArmAsm

/*
* Access to the shared data page by the vDSO & syscall map
*
* Copyright (C) 2004 Benjamin Herrenschmuidt (benh@kernel.crashing.org), IBM Corp.
*
* 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 <linux/config.h>
#include <asm/processor.h>
#include <asm/ppc_asm.h>
#include <asm/asm-offsets.h>
#include <asm/unistd.h>
#include <asm/vdso.h>
.text
V_FUNCTION_BEGIN(__get_datapage)
.cfi_startproc
/* We don't want that exposed or overridable as we want other objects
* to be able to bl directly to here
*/
.protected __get_datapage
.hidden __get_datapage
mflr r0
.cfi_register lr,r0
bcl 20,31,1f
.global __kernel_datapage_offset;
__kernel_datapage_offset:
.long 0
1:
mflr r3
mtlr r0
lwz r0,0(r3)
add r3,r0,r3
blr
.cfi_endproc
V_FUNCTION_END(__get_datapage)
/*
* void *__kernel_get_syscall_map(unsigned int *syscall_count) ;
*
* returns a pointer to the syscall map. the map is agnostic to the
* size of "long", unlike kernel bitops, it stores bits from top to
* bottom so that memory actually contains a linear bitmap
* check for syscall N by testing bit (0x80000000 >> (N & 0x1f)) of
* 32 bits int at N >> 5.
*/
V_FUNCTION_BEGIN(__kernel_get_syscall_map)
.cfi_startproc
mflr r12
.cfi_register lr,r12
mr r4,r3
bl V_LOCAL_FUNC(__get_datapage)
mtlr r12
addi r3,r3,CFG_SYSCALL_MAP64
cmpli cr0,r4,0
crclr cr0*4+so
beqlr
li r0,__NR_syscalls
stw r0,0(r4)
blr
.cfi_endproc
V_FUNCTION_END(__kernel_get_syscall_map)
/*
* void unsigned long __kernel_get_tbfreq(void);
*
* returns the timebase frequency in HZ
*/
V_FUNCTION_BEGIN(__kernel_get_tbfreq)
.cfi_startproc
mflr r12
.cfi_register lr,r12
bl V_LOCAL_FUNC(__get_datapage)
ld r3,CFG_TB_TICKS_PER_SEC(r3)
mtlr r12
crclr cr0*4+so
blr
.cfi_endproc
V_FUNCTION_END(__kernel_get_tbfreq)