[PATCH 13/28] x86: vdso: Access rng data from kernel without vvar

[Thomas Weißschuh]

Remove the usage of the vvar _vdso_rng_data from the kernel-space code,
as the x86 vvar machinery is about to be removed.
The definition of the structure is unnecessary, as the data lives in a
page pre-allocated by the linker anyways.
The vdso user-space access to the rng data will be switched soon.

DEFINE_VVAR_SINGLE() is now unused. It will be removed later togehter
with the rest of vvar.h.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@xxxxxxxxxxxxx>
---
 arch/x86/entry/vdso/vma.c            | 1 -
 arch/x86/include/asm/vdso/vsyscall.h | 2 +-
 arch/x86/include/asm/vvar.h          | 4 +++-
 3 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c
index b8fed8b8b9ccdb2cdd9912d5ec4cfd6366a6012e..8437906fd4b353ad0fe208d811817a1b6f8f8dcb 100644
--- a/arch/x86/entry/vdso/vma.c
+++ b/arch/x86/entry/vdso/vma.c
@@ -39,7 +39,6 @@ struct vdso_data *arch_get_vdso_data(void *vvar_page)
 #undef EMIT_VVAR
 
 DEFINE_VVAR(struct vdso_data, _vdso_data);
-DEFINE_VVAR_SINGLE(struct vdso_rng_data, _vdso_rng_data);
 
 unsigned int vclocks_used __read_mostly;
 
diff --git a/arch/x86/include/asm/vdso/vsyscall.h b/arch/x86/include/asm/vdso/vsyscall.h
index 67fedf1698b5e2b710e0504686318949c738bf29..2cbb32a8a45e2f5c7bc02172af0fa09173f33924 100644
--- a/arch/x86/include/asm/vdso/vsyscall.h
+++ b/arch/x86/include/asm/vdso/vsyscall.h
@@ -22,7 +22,7 @@ struct vdso_data *__x86_get_k_vdso_data(void)
 static __always_inline
 struct vdso_rng_data *__x86_get_k_vdso_rng_data(void)
 {
-	return &_vdso_rng_data;
+	return (void *)&__vvar_page + __VDSO_RND_DATA_OFFSET;
 }
 #define __arch_get_k_vdso_rng_data __x86_get_k_vdso_rng_data
 
diff --git a/arch/x86/include/asm/vvar.h b/arch/x86/include/asm/vvar.h
index 01e60e0f671e9625669dc8fdacf3cdddf8cbf4fb..fe3434d3b5b1eef806e8328b86650e001b177de2 100644
--- a/arch/x86/include/asm/vvar.h
+++ b/arch/x86/include/asm/vvar.h
@@ -19,6 +19,8 @@
 #ifndef _ASM_X86_VVAR_H
 #define _ASM_X86_VVAR_H
 
+#define __VDSO_RND_DATA_OFFSET  640
+
 #ifdef EMIT_VVAR
 /*
  * EMIT_VVAR() is used by the kernel linker script to put vvars in the
@@ -62,7 +64,7 @@ DECLARE_VVAR(0, struct vdso_data, _vdso_data)
 
 #if !defined(_SINGLE_DATA)
 #define _SINGLE_DATA
-DECLARE_VVAR_SINGLE(640, struct vdso_rng_data, _vdso_rng_data)
+DECLARE_VVAR_SINGLE(__VDSO_RND_DATA_OFFSET, struct vdso_rng_data, _vdso_rng_data)
 #endif
 
 #undef DECLARE_VVAR

-- 
2.47.0