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Commit a5a1d081 authored by Kevin Brodsky's avatar Kevin Brodsky Committed by Gagan Malvi
Browse files

FROMLIST: [PATCH 5/6] arm64: compat: 32-bit vDSO setup 

(cherry pick from url https://patchwork.kernel.org/patch/10060459/

)

If the compat vDSO is enabled, install it in compat processes. In this
case, the compat vDSO replaces the sigreturn page (it provides its own
sigreturn trampolines).

Signed-off-by: default avatarKevin Brodsky <kevin.brodsky@arm.com>
Signed-off-by: default avatarMark Salyzyn <salyzyn@android.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Dave Martin <Dave.Martin@arm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Bug: 63737556
Bug: 20045882
Change-Id: Ia6acf4c3ffea636bc750ac00853ea762c182e5b5
Signed-off-by: default avatarstarlight5234 <ifist2834@gmail.com>
Signed-off-by: default avatarTheSync <repo-sync@outlook.com>
parent a58b4edb

arch/arm64/kernel/vdso.c

+55 −0
Original line number Diff line number Diff line
@@ -58,6 +58,7 @@ struct vdso_data *vdso_data = &vdso_data_store.data; 
/*

 * Create and map the vectors page for AArch32 tasks.

 */

#if !defined(CONFIG_VDSO32) || defined(CONFIG_KUSER_HELPERS)

static struct page *vectors_page[] __ro_after_init;

static const struct vm_special_mapping compat_vdso_spec[] = {

	{
@@ -73,6 +74,7 @@ static const struct vm_special_mapping compat_vdso_spec[] = { 
#endif

};

static struct page *vectors_page[ARRAY_SIZE(compat_vdso_spec)] __ro_after_init;

#endif



static int __init alloc_vectors_page(void)

{
@@ -82,6 +84,7 @@ static int __init alloc_vectors_page(void) 
	unsigned long kuser_vpage;

#endif



#ifndef CONFIG_VDSO32

	extern char __aarch32_sigret_code_start[], __aarch32_sigret_code_end[];

	size_t sigret_sz =

		__aarch32_sigret_code_end - __aarch32_sigret_code_start;
@@ -90,19 +93,24 @@ static int __init alloc_vectors_page(void) 
	sigret_vpage = get_zeroed_page(GFP_ATOMIC);

	if (!sigret_vpage)

		return -ENOMEM;

#endif



#ifdef CONFIG_KUSER_HELPERS

	kuser_vpage = get_zeroed_page(GFP_ATOMIC);

	if (!kuser_vpage) {

#ifndef CONFIG_VDSO32

		free_page(sigret_vpage);

#endif

		return -ENOMEM;

	}

#endif



#ifndef CONFIG_VDSO32

	/* sigreturn code */

	memcpy((void *)sigret_vpage, __aarch32_sigret_code_start, sigret_sz);

	flush_icache_range(sigret_vpage, sigret_vpage + PAGE_SIZE);

	vectors_page[0] = virt_to_page(sigret_vpage);

#endif



#ifdef CONFIG_KUSER_HELPERS

	/* kuser helpers */
@@ -116,6 +124,7 @@ static int __init alloc_vectors_page(void) 
}

arch_initcall(alloc_vectors_page);



#ifndef CONFIG_VDSO32

int aarch32_setup_vectors_page(struct linux_binprm *bprm, int uses_interp)

{

	struct mm_struct *mm = current->mm;
@@ -151,6 +160,7 @@ int aarch32_setup_vectors_page(struct linux_binprm *bprm, int uses_interp) 


	return PTR_ERR_OR_ZERO(ret);

}

#endif /* !CONFIG_VDSO32 */

#endif /* CONFIG_COMPAT */



static int __init vdso_mappings_init(const char *name,
@@ -208,6 +218,23 @@ static int __init vdso_mappings_init(const char *name, 
	return 0;

}



#ifdef CONFIG_COMPAT

#ifdef CONFIG_VDSO32



static struct vdso_mappings vdso32_mappings __ro_after_init;



static int __init vdso32_init(void)

{

	extern char vdso32_start[], vdso32_end[];



	return vdso_mappings_init("vdso32", vdso32_start, vdso32_end,

				  &vdso32_mappings);

}

arch_initcall(vdso32_init);



#endif /* CONFIG_VDSO32 */

#endif /* CONFIG_COMPAT */



static struct vdso_mappings vdso_mappings __ro_after_init;



static int __init vdso_init(void)
@@ -250,6 +277,34 @@ static int vdso_setup(struct mm_struct *mm, 
	return PTR_ERR_OR_ZERO(ret);

}



#ifdef CONFIG_COMPAT

#ifdef CONFIG_VDSO32

int aarch32_setup_vectors_page(struct linux_binprm *bprm, int uses_interp)

{

	struct mm_struct *mm = current->mm;

	void *ret;



	if (down_write_killable(&mm->mmap_sem))

		return -EINTR;



	ret = ERR_PTR(vdso_setup(mm, &vdso32_mappings));

#ifdef CONFIG_KUSER_HELPERS

	if (!IS_ERR(ret))

		/* Map the kuser helpers at the ABI-defined high address. */

		ret = _install_special_mapping(mm, AARCH32_KUSER_HELPERS_BASE,

					       PAGE_SIZE,

					       VM_READ|VM_EXEC|

					       VM_MAYREAD|VM_MAYEXEC,

					       &compat_vdso_spec[1]);

#endif



	up_write(&mm->mmap_sem);



	return PTR_ERR_OR_ZERO(ret);

}

#endif /* CONFIG_VDSO32 */

#endif /* CONFIG_COMPAT */



int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)

{

	struct mm_struct *mm = current->mm;