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ARM: vdso: Remove assembly for datapage access

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vdso/datapage.h provides a hidden declaration for _vdso_data.
When using it the compiler will automatically generate PC-relative
accesses which avoids the need for a custom assembly-based accessor.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20241010-vdso-generic-base-v1-7-b64f0842d512@linutronix.de
This commit is contained in:
Thomas Weißschuh 2024-10-10 09:01:09 +02:00 committed by Thomas Gleixner
parent d34b60752f
commit 2bb79470e5
4 changed files with 4 additions and 21 deletions
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4
arch/arm/include/asm/vdso/gettimeofday.h
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@ -15,8 +15,6 @@
#define VDSO_HAS_CLOCK_GETRES 1
extern struct vdso_data *__get_datapage(void);
static __always_inline int gettimeofday_fallback(
struct __kernel_old_timeval *_tv,
struct timezone *_tz)
@ -139,7 +137,7 @@ static __always_inline u64 __arch_get_hw_counter(int clock_mode,
static __always_inline const struct vdso_data *__arch_get_vdso_data(void)
{
return __get_datapage();
return _vdso_data;
}
#endif /* !__ASSEMBLY__ */

2
arch/arm/vdso/Makefile
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@ -5,7 +5,7 @@ include $(srctree)/lib/vdso/Makefile
hostprogs := vdsomunge
obj-vdso := vgettimeofday.o datapage.o note.o
obj-vdso := vgettimeofday.o note.o
# Build rules
targets := $(obj-vdso) vdso.so vdso.so.dbg vdso.so.raw vdso.lds

16
arch/arm/vdso/datapage.S
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@ -1,16 +0,0 @@
/* SPDX-License-Identifier: GPL-2.0 */
#include <linux/linkage.h>
#include <asm/asm-offsets.h>
.align 2
.L_vdso_data_ptr:
.long _start - . - VDSO_DATA_SIZE
ENTRY(__get_datapage)
.fnstart
adr r0, .L_vdso_data_ptr
ldr r1, [r0]
add r0, r0, r1
bx lr
.fnend
ENDPROC(__get_datapage)

3
arch/arm/vdso/vdso.lds.S
View File

@ -11,6 +11,7 @@
*/
#include <linux/const.h>
#include <asm/asm-offsets.h>
#include <asm/page.h>
#include <asm/vdso.h>
@ -19,7 +20,7 @@ OUTPUT_ARCH(arm)
SECTIONS
{
PROVIDE(_start = .);
PROVIDE(_vdso_data = . - VDSO_DATA_SIZE);
. = SIZEOF_HEADERS;