linux-kernel - [tip: timers/vdso] x86/vdso: Access rng vdso data without vvar.h

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Message-ID: <173054822020.3137.3720813213021613578.tip-bot2@tip-bot2>
Date: Sat, 02 Nov 2024 11:50:20 -0000
From:
 tip-bot2 for Thomas Weißschuh <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: thomas.weissschuh@...utronix.de, Thomas Gleixner <tglx@...utronix.de>,
 x86@...nel.org, linux-kernel@...r.kernel.org
Subject: [tip: timers/vdso] x86/vdso: Access rng vdso data without vvar.h

The following commit has been merged into the timers/vdso branch of tip:

Commit-ID:     c3a190d425916e84bbda65873f9fc27ce4b82893
Gitweb:        https://git.kernel.org/tip/c3a190d425916e84bbda65873f9fc27ce4b82893
Author:        Thomas Weißschuh <thomas.weissschuh@...utronix.de>
AuthorDate:    Thu, 10 Oct 2024 09:01:18 +02:00
Committer:     Thomas Gleixner <tglx@...utronix.de>
CommitterDate: Sat, 02 Nov 2024 12:37:34 +01:00

x86/vdso: Access rng vdso data without vvar.h

The vdso_rng_data is at a well-known offset in the vvar page.
Make use of this invariant to remove the usage of vvar.h.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@...utronix.de>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Link: https://lore.kernel.org/all/20241010-vdso-generic-base-v1-16-b64f0842d512@linutronix.de

---
 arch/x86/entry/vdso/vdso-layout.lds.S | 2 ++
 arch/x86/include/asm/vdso/getrandom.h | 8 ++++----
 arch/x86/include/asm/vvar.h           | 5 -----
 3 files changed, 6 insertions(+), 9 deletions(-)

diff --git a/arch/x86/entry/vdso/vdso-layout.lds.S b/arch/x86/entry/vdso/vdso-layout.lds.S
index 51c0cc0..acce607 100644
--- a/arch/x86/entry/vdso/vdso-layout.lds.S
+++ b/arch/x86/entry/vdso/vdso-layout.lds.S
@@ -24,6 +24,8 @@ SECTIONS
 #include <asm/vvar.h>
 #undef EMIT_VVAR
 
+	vdso_rng_data = vvar_page + __VDSO_RND_DATA_OFFSET;
+
 	pvclock_page = vvar_start + PAGE_SIZE;
 	hvclock_page = vvar_start + 2 * PAGE_SIZE;
 	timens_page  = vvar_start + 3 * PAGE_SIZE;
diff --git a/arch/x86/include/asm/vdso/getrandom.h b/arch/x86/include/asm/vdso/getrandom.h
index d0713c8..2bf9c0e 100644
--- a/arch/x86/include/asm/vdso/getrandom.h
+++ b/arch/x86/include/asm/vdso/getrandom.h
@@ -8,7 +8,6 @@
 #ifndef __ASSEMBLY__
 
 #include <asm/unistd.h>
-#include <asm/vvar.h>
 
 /**
  * getrandom_syscall - Invoke the getrandom() syscall.
@@ -28,13 +27,14 @@ static __always_inline ssize_t getrandom_syscall(void *buffer, size_t len, unsig
 	return ret;
 }
 
-#define __vdso_rng_data (VVAR(_vdso_rng_data))
+extern struct vdso_rng_data vdso_rng_data
+	__attribute__((visibility("hidden")));
 
 static __always_inline const struct vdso_rng_data *__arch_get_vdso_rng_data(void)
 {
 	if (IS_ENABLED(CONFIG_TIME_NS) && __arch_get_vdso_data()->clock_mode == VDSO_CLOCKMODE_TIMENS)
-		return (void *)&__vdso_rng_data + ((void *)&timens_page - (void *)__arch_get_vdso_data());
-	return &__vdso_rng_data;
+		return (void *)&vdso_rng_data + ((void *)&timens_page - (void *)__arch_get_vdso_data());
+	return &vdso_rng_data;
 }
 
 #endif /* !__ASSEMBLY__ */
diff --git a/arch/x86/include/asm/vvar.h b/arch/x86/include/asm/vvar.h
index fe3434d..b605914 100644
--- a/arch/x86/include/asm/vvar.h
+++ b/arch/x86/include/asm/vvar.h
@@ -62,11 +62,6 @@ extern char __vvar_page;
 
 DECLARE_VVAR(0, struct vdso_data, _vdso_data)
 
-#if !defined(_SINGLE_DATA)
-#define _SINGLE_DATA
-DECLARE_VVAR_SINGLE(__VDSO_RND_DATA_OFFSET, struct vdso_rng_data, _vdso_rng_data)
-#endif
-
 #undef DECLARE_VVAR
 #undef DECLARE_VVAR_SINGLE