[PATCH 18/28] x86: vdso: Access vdso data without vvar.h

From: Thomas Weißschuh
Date: Thu Oct 10 2024 - 04:13:01 EST


The vdso_data is at the start of the vvar page.
Make use of this invariant to remove the usage of vvar.h.
This also matches the logic for the timens data.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@xxxxxxxxxxxxx>
---
arch/x86/entry/vdso/vdso-layout.lds.S | 5 -----
arch/x86/include/asm/vdso/gettimeofday.h | 6 +++---
2 files changed, 3 insertions(+), 8 deletions(-)

diff --git a/arch/x86/entry/vdso/vdso-layout.lds.S b/arch/x86/entry/vdso/vdso-layout.lds.S
index c7e194b6e47def3bfa681b3ec5d45cfffbe839d2..9e602c0615243f8667498ac245c2aaf1b35dcd16 100644
--- a/arch/x86/entry/vdso/vdso-layout.lds.S
+++ b/arch/x86/entry/vdso/vdso-layout.lds.S
@@ -20,11 +20,6 @@ SECTIONS
vvar_start = . - 4 * PAGE_SIZE;
vvar_page = vvar_start;

- /* Place all vvars at the offsets in asm/vvar.h. */
-#define EMIT_VVAR(name, offset) vvar_ ## name = vvar_page + offset;
-#include <asm/vvar.h>
-#undef EMIT_VVAR
-
vdso_rng_data = vvar_page + __VDSO_RND_DATA_OFFSET;

pvclock_page = vvar_start + PAGE_SIZE;
diff --git a/arch/x86/include/asm/vdso/gettimeofday.h b/arch/x86/include/asm/vdso/gettimeofday.h
index 1e6116172a65cd07ef29092dba6241d719f07448..375a34b0f365792ec108381d7c7229f8351448f7 100644
--- a/arch/x86/include/asm/vdso/gettimeofday.h
+++ b/arch/x86/include/asm/vdso/gettimeofday.h
@@ -14,13 +14,13 @@

#include <uapi/linux/time.h>
#include <asm/vgtod.h>
-#include <asm/vvar.h>
#include <asm/unistd.h>
#include <asm/msr.h>
#include <asm/pvclock.h>
#include <clocksource/hyperv_timer.h>

-#define __vdso_data (VVAR(_vdso_data))
+extern struct vdso_data vvar_page
+ __attribute__((visibility("hidden")));

extern struct vdso_data timens_page
__attribute__((visibility("hidden")));
@@ -277,7 +277,7 @@ static inline u64 __arch_get_hw_counter(s32 clock_mode,

static __always_inline const struct vdso_data *__arch_get_vdso_data(void)
{
- return __vdso_data;
+ return &vvar_page;
}

static inline bool arch_vdso_clocksource_ok(const struct vdso_data *vd)

--
2.47.0