Commit 31e9fa2b authored by Thomas Weißschuh's avatar Thomas Weißschuh Committed by Thomas Gleixner
Browse files

arm: vdso: Switch to generic storage implementation 



The generic storage implementation provides the same features as the
custom one. However it can be shared between architectures, making
maintenance easier.

Co-developed-by: default avatarNam Cao <namcao@linutronix.de>
Signed-off-by: default avatarNam Cao <namcao@linutronix.de>
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/20250204-vdso-store-rng-v3-11-13a4669dfc8c@linutronix.de
parent d2862bb9

arch/arm/include/asm/vdso.h

+2 −0
Original line number Diff line number Diff line
@@ -4,6 +4,8 @@ 


#ifdef __KERNEL__



#define __VDSO_PAGES	4



#ifndef __ASSEMBLY__



struct mm_struct;

arch/arm/include/asm/vdso/gettimeofday.h

+1 −6
Original line number Diff line number Diff line
@@ -112,7 +112,7 @@ static inline bool arm_vdso_hres_capable(void) 
#define __arch_vdso_hres_capable arm_vdso_hres_capable



static __always_inline u64 __arch_get_hw_counter(int clock_mode,

						 const struct vdso_data *vd)

						 const struct vdso_time_data *vd)

{

#ifdef CONFIG_ARM_ARCH_TIMER

	u64 cycle_now;
@@ -135,11 +135,6 @@ static __always_inline u64 __arch_get_hw_counter(int clock_mode, 
#endif

}



static __always_inline const struct vdso_data *__arch_get_vdso_data(void)

{

	return _vdso_data;

}



#endif /* !__ASSEMBLY__ */



#endif /* __ASM_VDSO_GETTIMEOFDAY_H */

arch/arm/include/asm/vdso/vsyscall.h

+2 −10
Original line number Diff line number Diff line
@@ -7,22 +7,14 @@ 
#include <vdso/datapage.h>

#include <asm/cacheflush.h>



extern struct vdso_data *vdso_data;

extern bool cntvct_ok;



static __always_inline

struct vdso_data *__arm_get_k_vdso_data(void)

{

	return vdso_data;

}

#define __arch_get_k_vdso_data __arm_get_k_vdso_data



static __always_inline

void __arm_sync_vdso_data(struct vdso_data *vdata)

void __arch_sync_vdso_time_data(struct vdso_time_data *vdata)

{

	flush_dcache_page(virt_to_page(vdata));

}

#define __arch_sync_vdso_data __arm_sync_vdso_data

#define __arch_sync_vdso_time_data __arch_sync_vdso_time_data



/* The asm-generic header needs to be included after the definitions above */

#include <asm-generic/vdso/vsyscall.h>

arch/arm/kernel/asm-offsets.c

+0 −4
Original line number Diff line number Diff line
@@ -153,10 +153,6 @@ int main(void) 
  DEFINE(CACHE_WRITEBACK_ORDER, __CACHE_WRITEBACK_ORDER);

  DEFINE(CACHE_WRITEBACK_GRANULE, __CACHE_WRITEBACK_GRANULE);

  BLANK();

#ifdef CONFIG_VDSO

  DEFINE(VDSO_DATA_SIZE,	sizeof(union vdso_data_store));

#endif

  BLANK();

#ifdef CONFIG_ARM_MPU

  DEFINE(MPU_RNG_INFO_RNGS,	offsetof(struct mpu_rgn_info, rgns));

  DEFINE(MPU_RNG_INFO_USED,	offsetof(struct mpu_rgn_info, used));

arch/arm/kernel/vdso.c

+7 −27
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ 
 */



#include <linux/cache.h>

#include <linux/vdso_datastore.h>

#include <linux/elf.h>

#include <linux/err.h>

#include <linux/kernel.h>
@@ -33,15 +34,6 @@ extern char vdso_start[], vdso_end[]; 
/* Total number of pages needed for the data and text portions of the VDSO. */

unsigned int vdso_total_pages __ro_after_init;



static union vdso_data_store vdso_data_store __page_aligned_data;

struct vdso_data *vdso_data = vdso_data_store.data;



static struct page *vdso_data_page __ro_after_init;

static const struct vm_special_mapping vdso_data_mapping = {

	.name = "[vvar]",

	.pages = &vdso_data_page,

};



static int vdso_mremap(const struct vm_special_mapping *sm,

		struct vm_area_struct *new_vma)

{
@@ -192,9 +184,6 @@ static int __init vdso_init(void) 
	if (vdso_text_pagelist == NULL)

		return -ENOMEM;



	/* Grab the VDSO data page. */

	vdso_data_page = virt_to_page(vdso_data);



	/* Grab the VDSO text pages. */

	for (i = 0; i < text_pages; i++) {

		struct page *page;
@@ -205,7 +194,7 @@ static int __init vdso_init(void) 


	vdso_text_mapping.pages = vdso_text_pagelist;



	vdso_total_pages = 1; /* for the data/vvar page */

	vdso_total_pages = VDSO_NR_PAGES; /* for the data/vvar pages */

	vdso_total_pages += text_pages;



	cntvct_ok = cntvct_functional();
@@ -216,16 +205,7 @@ static int __init vdso_init(void) 
}

arch_initcall(vdso_init);



static int install_vvar(struct mm_struct *mm, unsigned long addr)

{

	struct vm_area_struct *vma;



	vma = _install_special_mapping(mm, addr, PAGE_SIZE,

				       VM_READ | VM_MAYREAD,

				       &vdso_data_mapping);



	return PTR_ERR_OR_ZERO(vma);

}

static_assert(__VDSO_PAGES == VDSO_NR_PAGES);



/* assumes mmap_lock is write-locked */

void arm_install_vdso(struct mm_struct *mm, unsigned long addr)
@@ -238,12 +218,12 @@ void arm_install_vdso(struct mm_struct *mm, unsigned long addr) 
	if (vdso_text_pagelist == NULL)

		return;



	if (install_vvar(mm, addr))

	if (IS_ERR(vdso_install_vvar_mapping(mm, addr)))

		return;



	/* Account for vvar page. */

	addr += PAGE_SIZE;

	len = (vdso_total_pages - 1) << PAGE_SHIFT;

	/* Account for vvar pages. */

	addr += VDSO_NR_PAGES * PAGE_SIZE;

	len = (vdso_total_pages - VDSO_NR_PAGES) << PAGE_SHIFT;



	vma = _install_special_mapping(mm, addr, len,

		VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,