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

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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@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20241010-vdso-generic-base-v1-16-b64f0842d512@linutronix.de
This commit is contained in:
Thomas Weißschuh
2024-10-10 09:01:18 +02:00
committed by Thomas Gleixner
parent 59b7761638
commit c3a190d425
3 changed files with 6 additions and 9 deletions
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2
arch/x86/entry/vdso/vdso-layout.lds.S
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@@ -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;

8
arch/x86/include/asm/vdso/getrandom.h
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@@ -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__ */

5
arch/x86/include/asm/vvar.h
View File

@@ -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