Commit 461c9668 authored by Thomas Weißschuh's avatar Thomas Weißschuh Committed by Thomas Gleixner
Browse files

arm64: vdso: Use only one single vvar mapping 



The vvar mapping is the same for all processes. Use a single mapping to
simplify the logic and align it with the other architectures.

In addition this will enable the move of the vvar handling into generic code.

Signed-off-by: default avatarThomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Tested-by: default avatarWill Deacon <will@kernel.org>
Acked-by: default avatarWill Deacon <will@kernel.org>
Link: https://lore.kernel.org/all/20241010-vdso-generic-base-v1-5-b64f0842d512@linutronix.de
parent 0973fed6

arch/arm64/kernel/vdso.c

+13 −30
Original line number Diff line number Diff line
@@ -38,8 +38,6 @@ struct vdso_abi_info { 
	const char *vdso_code_start;

	const char *vdso_code_end;

	unsigned long vdso_pages;

	/* Data Mapping */

	struct vm_special_mapping *dm;

	/* Code Mapping */

	struct vm_special_mapping *cm;

};
@@ -112,6 +110,8 @@ struct vdso_data *arch_get_vdso_data(void *vvar_page) 
	return (struct vdso_data *)(vvar_page);

}



static const struct vm_special_mapping vvar_map;



/*

 * The vvar mapping contains data for a specific time namespace, so when a task

 * changes namespace we must unmap its vvar data for the old namespace.
@@ -128,12 +128,8 @@ int vdso_join_timens(struct task_struct *task, struct time_namespace *ns) 
	mmap_read_lock(mm);



	for_each_vma(vmi, vma) {

		if (vma_is_special_mapping(vma, vdso_info[VDSO_ABI_AA64].dm))

			zap_vma_pages(vma);

#ifdef CONFIG_COMPAT_VDSO

		if (vma_is_special_mapping(vma, vdso_info[VDSO_ABI_AA32].dm))

		if (vma_is_special_mapping(vma, &vvar_map))

			zap_vma_pages(vma);

#endif

	}



	mmap_read_unlock(mm);
@@ -175,6 +171,11 @@ static vm_fault_t vvar_fault(const struct vm_special_mapping *sm, 
	return vmf_insert_pfn(vma, vmf->address, pfn);

}



static const struct vm_special_mapping vvar_map = {

	.name   = "[vvar]",

	.fault = vvar_fault,

};



static int __setup_additional_pages(enum vdso_abi abi,

				    struct mm_struct *mm,

				    struct linux_binprm *bprm,
@@ -198,7 +199,7 @@ static int __setup_additional_pages(enum vdso_abi abi, 


	ret = _install_special_mapping(mm, vdso_base, VVAR_NR_PAGES * PAGE_SIZE,

				       VM_READ|VM_MAYREAD|VM_PFNMAP,

				       vdso_info[abi].dm);

				       &vvar_map);

	if (IS_ERR(ret))

		goto up_fail;
@@ -228,7 +229,6 @@ static int __setup_additional_pages(enum vdso_abi abi, 
enum aarch32_map {

	AA32_MAP_VECTORS, /* kuser helpers */

	AA32_MAP_SIGPAGE,

	AA32_MAP_VVAR,

	AA32_MAP_VDSO,

};
@@ -253,10 +253,6 @@ static struct vm_special_mapping aarch32_vdso_maps[] = { 
		.pages	= &aarch32_sig_page,

		.mremap	= aarch32_sigpage_mremap,

	},

	[AA32_MAP_VVAR] = {

		.name = "[vvar]",

		.fault = vvar_fault,

	},

	[AA32_MAP_VDSO] = {

		.name = "[vdso]",

		.mremap = vdso_mremap,
@@ -306,7 +302,6 @@ static int __init __aarch32_alloc_vdso_pages(void) 
	if (!IS_ENABLED(CONFIG_COMPAT_VDSO))

		return 0;



	vdso_info[VDSO_ABI_AA32].dm = &aarch32_vdso_maps[AA32_MAP_VVAR];

	vdso_info[VDSO_ABI_AA32].cm = &aarch32_vdso_maps[AA32_MAP_VDSO];



	return __vdso_init(VDSO_ABI_AA32);
@@ -401,26 +396,14 @@ int aarch32_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) 
}

#endif /* CONFIG_COMPAT */



enum aarch64_map {

	AA64_MAP_VVAR,

	AA64_MAP_VDSO,

};



static struct vm_special_mapping aarch64_vdso_maps[] __ro_after_init = {

	[AA64_MAP_VVAR] = {

		.name	= "[vvar]",

		.fault = vvar_fault,

	},

	[AA64_MAP_VDSO] = {

static struct vm_special_mapping aarch64_vdso_map __ro_after_init = {

	.name	= "[vdso]",

	.mremap = vdso_mremap,

	},

};



static int __init vdso_init(void)

{

	vdso_info[VDSO_ABI_AA64].dm = &aarch64_vdso_maps[AA64_MAP_VVAR];

	vdso_info[VDSO_ABI_AA64].cm = &aarch64_vdso_maps[AA64_MAP_VDSO];

	vdso_info[VDSO_ABI_AA64].cm = &aarch64_vdso_map;



	return __vdso_init(VDSO_ABI_AA64);

}