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Commit 7c1deeeb authored by Vincenzo Frascino's avatar Vincenzo Frascino Committed by Thomas Gleixner
Browse files

arm64: compat: VDSO setup for compat layer 



If CONFIG_GENERIC_COMPAT_VDSO is enabled, compat vDSO is installed in a
compat (32 bit) process instead of sigpage.

Add the necessary code to setup the vDSO required pages.

Signed-off-by: default avatarVincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Tested-by: default avatarShijith Thotton <sthotton@marvell.com>
Tested-by: default avatarAndre Przywara <andre.przywara@arm.com>
Cc: linux-arch@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-mips@vger.kernel.org
Cc: linux-kselftest@vger.kernel.org
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Mark Salyzyn <salyzyn@android.com>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Huw Davies <huw@codeweavers.com>
Link: https://lkml.kernel.org/r/20190621095252.32307-13-vincenzo.frascino@arm.com
parent c7aa2d71

arch/arm64/kernel/vdso.c

+88 −2
Original line number Diff line number Diff line
@@ -29,12 +29,22 @@ 
#include <asm/vdso.h>



extern char vdso_start[], vdso_end[];

#ifdef CONFIG_COMPAT_VDSO

extern char vdso32_start[], vdso32_end[];

#endif /* CONFIG_COMPAT_VDSO */



/* vdso_lookup arch_index */

enum arch_vdso_type {

	ARM64_VDSO = 0,

#ifdef CONFIG_COMPAT_VDSO

	ARM64_VDSO32 = 1,

#endif /* CONFIG_COMPAT_VDSO */

};

#ifdef CONFIG_COMPAT_VDSO

#define VDSO_TYPES		(ARM64_VDSO32 + 1)

#else

#define VDSO_TYPES		(ARM64_VDSO + 1)

#endif /* CONFIG_COMPAT_VDSO */



struct __vdso_abi {

	const char *name;
@@ -53,6 +63,13 @@ static struct __vdso_abi vdso_lookup[VDSO_TYPES] __ro_after_init = { 
		.vdso_code_start = vdso_start,

		.vdso_code_end = vdso_end,

	},

#ifdef CONFIG_COMPAT_VDSO

	{

		.name = "vdso32",

		.vdso_code_start = vdso32_start,

		.vdso_code_end = vdso32_end,

	},

#endif /* CONFIG_COMPAT_VDSO */

};



/*
@@ -163,24 +180,52 @@ static int __setup_additional_pages(enum arch_vdso_type arch_index, 
/*

 * Create and map the vectors page for AArch32 tasks.

 */

#ifdef CONFIG_COMPAT_VDSO

static int aarch32_vdso_mremap(const struct vm_special_mapping *sm,

		struct vm_area_struct *new_vma)

{

	return __vdso_remap(ARM64_VDSO32, sm, new_vma);

}

#endif /* CONFIG_COMPAT_VDSO */



/*

 * aarch32_vdso_pages:

 * 0 - kuser helpers

 * 1 - sigreturn code

 * or (CONFIG_COMPAT_VDSO):

 * 0 - kuser helpers

 * 1 - vdso data

 * 2 - vdso code

 */

#define C_VECTORS	0

#ifdef CONFIG_COMPAT_VDSO

#define C_VVAR		1

#define C_VDSO		2

#define C_PAGES		(C_VDSO + 1)

#else

#define C_SIGPAGE	1

#define C_PAGES		(C_SIGPAGE + 1)

#endif /* CONFIG_COMPAT_VDSO */

static struct page *aarch32_vdso_pages[C_PAGES] __ro_after_init;

static const struct vm_special_mapping aarch32_vdso_spec[C_PAGES] = {

static struct vm_special_mapping aarch32_vdso_spec[C_PAGES] = {

	{

		.name	= "[vectors]", /* ABI */

		.pages	= &aarch32_vdso_pages[C_VECTORS],

	},

#ifdef CONFIG_COMPAT_VDSO

	{

		.name = "[vvar]",

	},

	{

		.name = "[vdso]",

		.mremap = aarch32_vdso_mremap,

	},

#else

	{

		.name	= "[sigpage]", /* ABI */

		.pages	= &aarch32_vdso_pages[C_SIGPAGE],

	},

#endif /* CONFIG_COMPAT_VDSO */

};



static int aarch32_alloc_kuser_vdso_page(void)
@@ -203,7 +248,33 @@ static int aarch32_alloc_kuser_vdso_page(void) 
	return 0;

}



static int __init aarch32_alloc_vdso_pages(void)

#ifdef CONFIG_COMPAT_VDSO

static int __aarch32_alloc_vdso_pages(void)

{

	int ret;



	vdso_lookup[ARM64_VDSO32].dm = &aarch32_vdso_spec[C_VVAR];

	vdso_lookup[ARM64_VDSO32].cm = &aarch32_vdso_spec[C_VDSO];



	ret = __vdso_init(ARM64_VDSO32);

	if (ret)

		return ret;



	ret = aarch32_alloc_kuser_vdso_page();

	if (ret) {

		unsigned long c_vvar =

			(unsigned long)page_to_virt(aarch32_vdso_pages[C_VVAR]);

		unsigned long c_vdso =

			(unsigned long)page_to_virt(aarch32_vdso_pages[C_VDSO]);



		free_page(c_vvar);

		free_page(c_vdso);

	}



	return ret;

}

#else

static int __aarch32_alloc_vdso_pages(void)

{

	extern char __aarch32_sigret_code_start[], __aarch32_sigret_code_end[];

	int sigret_sz = __aarch32_sigret_code_end - __aarch32_sigret_code_start;
@@ -224,6 +295,12 @@ static int __init aarch32_alloc_vdso_pages(void) 


	return ret;

}

#endif /* CONFIG_COMPAT_VDSO */



static int __init aarch32_alloc_vdso_pages(void)

{

	return __aarch32_alloc_vdso_pages();

}

arch_initcall(aarch32_alloc_vdso_pages);



static int aarch32_kuser_helpers_setup(struct mm_struct *mm)
@@ -245,6 +322,7 @@ static int aarch32_kuser_helpers_setup(struct mm_struct *mm) 
	return PTR_ERR_OR_ZERO(ret);

}



#ifndef CONFIG_COMPAT_VDSO

static int aarch32_sigreturn_setup(struct mm_struct *mm)

{

	unsigned long addr;
@@ -272,6 +350,7 @@ static int aarch32_sigreturn_setup(struct mm_struct *mm) 
out:

	return PTR_ERR_OR_ZERO(ret);

}

#endif /* !CONFIG_COMPAT_VDSO */



int aarch32_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)

{
@@ -285,7 +364,14 @@ int aarch32_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) 
	if (ret)

		goto out;



#ifdef CONFIG_COMPAT_VDSO

	ret = __setup_additional_pages(ARM64_VDSO32,

				       mm,

				       bprm,

				       uses_interp);

#else

	ret = aarch32_sigreturn_setup(mm);

#endif /* CONFIG_COMPAT_VDSO */



out:

	up_write(&mm->mmap_sem);