Files
linux/arch/powerpc/kernel/vdso/gettimeofday.S
Christophe Leroy c39b1dcf05 powerpc/vdso: Add a page for non-time data
The page containing VDSO time data is swapped with the one containing
TIME namespace data when a process uses a non-root time namespace.
For other data like powerpc specific data and RNG data, it means
tracking whether time namespace is the root one or not to know which
page to use.

Simplify the logic behind by moving time data out of first data page
so that the first data page which contains everything else always
remains the first page. Time data is in the second or third page
depending on selected time namespace.

While we are playing with get_datapage macro, directly take into
account the data offset inside the macro instead of adding that offset
afterwards.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://patch.msgid.link/0557d3ec898c1d0ea2fc59fa8757618e524c5d94.1727858295.git.christophe.leroy@csgroup.eu
2024-10-16 11:08:20 +11:00

116 lines
2.7 KiB
ArmAsm

/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* Userland implementation of gettimeofday() for processes
* for use in the vDSO
*
* Copyright (C) 2004 Benjamin Herrenschmuidt (benh@kernel.crashing.org,
* IBM Corp.
*/
#include <asm/processor.h>
#include <asm/ppc_asm.h>
#include <asm/vdso.h>
#include <asm/vdso_datapage.h>
#include <asm/asm-offsets.h>
#include <asm/unistd.h>
/*
* The macro sets two stack frames, one for the caller and one for the callee
* because there are no requirement for the caller to set a stack frame when
* calling VDSO so it may have omitted to set one, especially on PPC64
*/
.macro cvdso_call funct call_time=0
.cfi_startproc
PPC_STLU r1, -PPC_MIN_STKFRM(r1)
.cfi_adjust_cfa_offset PPC_MIN_STKFRM
mflr r0
PPC_STLU r1, -PPC_MIN_STKFRM(r1)
.cfi_adjust_cfa_offset PPC_MIN_STKFRM
PPC_STL r0, PPC_MIN_STKFRM + PPC_LR_STKOFF(r1)
.cfi_rel_offset lr, PPC_MIN_STKFRM + PPC_LR_STKOFF
#ifdef __powerpc64__
PPC_STL r2, PPC_MIN_STKFRM + STK_GOT(r1)
.cfi_rel_offset r2, PPC_MIN_STKFRM + STK_GOT
#endif
.ifeq \call_time
get_datapage r5 VDSO_DATA_OFFSET
.else
get_datapage r4 VDSO_DATA_OFFSET
.endif
bl CFUNC(DOTSYM(\funct))
PPC_LL r0, PPC_MIN_STKFRM + PPC_LR_STKOFF(r1)
#ifdef __powerpc64__
PPC_LL r2, PPC_MIN_STKFRM + STK_GOT(r1)
.cfi_restore r2
#endif
.ifeq \call_time
cmpwi r3, 0
.endif
mtlr r0
addi r1, r1, 2 * PPC_MIN_STKFRM
.cfi_restore lr
.cfi_def_cfa_offset 0
crclr so
.ifeq \call_time
beqlr+
crset so
neg r3, r3
.endif
blr
.cfi_endproc
.endm
.text
/*
* Exact prototype of gettimeofday
*
* int __kernel_gettimeofday(struct timeval *tv, struct timezone *tz);
*
*/
V_FUNCTION_BEGIN(__kernel_gettimeofday)
cvdso_call __c_kernel_gettimeofday
V_FUNCTION_END(__kernel_gettimeofday)
/*
* Exact prototype of clock_gettime()
*
* int __kernel_clock_gettime(clockid_t clock_id, struct timespec *tp);
*
*/
V_FUNCTION_BEGIN(__kernel_clock_gettime)
cvdso_call __c_kernel_clock_gettime
V_FUNCTION_END(__kernel_clock_gettime)
/*
* Exact prototype of clock_gettime64()
*
* int __kernel_clock_gettime64(clockid_t clock_id, struct __timespec64 *ts);
*
*/
#ifndef __powerpc64__
V_FUNCTION_BEGIN(__kernel_clock_gettime64)
cvdso_call __c_kernel_clock_gettime64
V_FUNCTION_END(__kernel_clock_gettime64)
#endif
/*
* Exact prototype of clock_getres()
*
* int __kernel_clock_getres(clockid_t clock_id, struct timespec *res);
*
*/
V_FUNCTION_BEGIN(__kernel_clock_getres)
cvdso_call __c_kernel_clock_getres
V_FUNCTION_END(__kernel_clock_getres)
/*
* Exact prototype of time()
*
* time_t time(time *t);
*
*/
V_FUNCTION_BEGIN(__kernel_time)
cvdso_call __c_kernel_time call_time=1
V_FUNCTION_END(__kernel_time)