Commit c3a190d4 authored by Thomas Weißschuh's avatar Thomas Weißschuh Committed by Thomas Gleixner
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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: default avatarThomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20241010-vdso-generic-base-v1-16-b64f0842d512@linutronix.de
parent 59b77616

arch/x86/entry/vdso/vdso-layout.lds.S

+2 −0
Original line number Diff line number Diff line
@@ -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;

arch/x86/include/asm/vdso/getrandom.h

+4 −4
Original line number Diff line number Diff line
@@ -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__ */

arch/x86/include/asm/vvar.h

+0 −5
Original line number Diff line number Diff line
@@ -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