Commit a39060b0 authored by Will Deacon's avatar Will Deacon
Browse files

arm64: compat: Allow 32-bit vdso and sigpage to co-exist 



In preparation for removing the signal trampoline from the compat vDSO,
allow the sigpage and the compat vDSO to co-exist.

For the moment the vDSO signal trampoline will still be used when built.
Subsequent patches will move to the sigpage consistently.

Acked-by: default avatarDave Martin <Dave.Martin@arm.com>
Reviewed-by: default avatarVincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: default avatarArd Biesheuvel <ardb@kernel.org>
Reviewed-by: default avatarMark Rutland <mark.rutland@arm.com>
Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent 87676cfc

arch/arm64/include/asm/mmu.h

+3 −0
Original line number Diff line number Diff line
@@ -19,6 +19,9 @@ 


typedef struct {

	atomic64_t	id;

#ifdef CONFIG_COMPAT

	void		*sigpage;

#endif

	void		*vdso;

	unsigned long	flags;

} mm_context_t;

arch/arm64/kernel/Makefile

+0 −2
Original line number Diff line number Diff line
@@ -29,9 +29,7 @@ $(obj)/%.stub.o: $(obj)/%.o FORCE 


obj-$(CONFIG_COMPAT)			+= sys32.o signal32.o			\

					   sys_compat.o

ifneq ($(CONFIG_COMPAT_VDSO), y)

obj-$(CONFIG_COMPAT)			+= sigreturn32.o

endif

obj-$(CONFIG_KUSER_HELPERS)		+= kuser32.o

obj-$(CONFIG_FUNCTION_TRACER)		+= ftrace.o entry-ftrace.o

obj-$(CONFIG_MODULES)			+= module.o

arch/arm64/kernel/signal32.c

+1 −1
Original line number Diff line number Diff line
@@ -371,7 +371,7 @@ static void compat_setup_return(struct pt_regs *regs, struct k_sigaction *ka, 
		if (ka->sa.sa_flags & SA_SIGINFO)

			idx += 3;



		retcode = (unsigned long)current->mm->context.vdso +

		retcode = (unsigned long)current->mm->context.sigpage +

			  (idx << 2) + thumb;

#endif

	}

arch/arm64/kernel/vdso.c

+28 −33
Original line number Diff line number Diff line
@@ -191,15 +191,12 @@ enum aarch32_map { 
#ifdef CONFIG_COMPAT_VDSO

	AA32_MAP_VVAR,

	AA32_MAP_VDSO,

#else

	AA32_MAP_SIGPAGE

#endif

	AA32_MAP_SIGPAGE

};



static struct page *aarch32_vectors_page __ro_after_init;

#ifndef CONFIG_COMPAT_VDSO

static struct page *aarch32_sig_page __ro_after_init;

#endif



static struct vm_special_mapping aarch32_vdso_maps[] = {

	[AA32_MAP_VECTORS] = {
@@ -214,12 +211,11 @@ static struct vm_special_mapping aarch32_vdso_maps[] = { 
		.name = "[vdso]",

		.mremap = aarch32_vdso_mremap,

	},

#else

#endif /* CONFIG_COMPAT_VDSO */

	[AA32_MAP_SIGPAGE] = {

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

		.pages	= &aarch32_sig_page,

	},

#endif /* CONFIG_COMPAT_VDSO */

};



static int aarch32_alloc_kuser_vdso_page(void)
@@ -242,27 +238,11 @@ static int aarch32_alloc_kuser_vdso_page(void) 
	return 0;

}



#ifdef CONFIG_COMPAT_VDSO

static int __aarch32_alloc_vdso_pages(void)

{

	int ret;



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

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



	ret = __vdso_init(VDSO_ABI_AA32);

	if (ret)

		return ret;



	return aarch32_alloc_kuser_vdso_page();

}

#else

static int __aarch32_alloc_vdso_pages(void)

static int aarch32_alloc_sigpage(void)

{

	extern char __aarch32_sigret_code_start[], __aarch32_sigret_code_end[];

	int sigret_sz = __aarch32_sigret_code_end - __aarch32_sigret_code_start;

	unsigned long sigpage;

	int ret;



	sigpage = get_zeroed_page(GFP_ATOMIC);

	if (!sigpage)
@@ -271,18 +251,34 @@ static int __aarch32_alloc_vdso_pages(void) 
	memcpy((void *)sigpage, __aarch32_sigret_code_start, sigret_sz);

	aarch32_sig_page = virt_to_page(sigpage);

	flush_dcache_page(aarch32_sig_page);

	return 0;

}



	ret = aarch32_alloc_kuser_vdso_page();

	if (ret)

		free_page(sigpage);

#ifdef CONFIG_COMPAT_VDSO

static int __aarch32_alloc_vdso_pages(void)

{

	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 ret;

	return __vdso_init(VDSO_ABI_AA32);

}

#endif /* CONFIG_COMPAT_VDSO */



static int __init aarch32_alloc_vdso_pages(void)

{

	return __aarch32_alloc_vdso_pages();

	int ret;



#ifdef CONFIG_COMPAT_VDSO

	ret = __aarch32_alloc_vdso_pages();

	if (ret)

		return ret;

#endif



	ret = aarch32_alloc_sigpage();

	if (ret)

		return ret;



	return aarch32_alloc_kuser_vdso_page();

}

arch_initcall(aarch32_alloc_vdso_pages);
@@ -305,7 +301,6 @@ 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;
@@ -328,12 +323,11 @@ static int aarch32_sigreturn_setup(struct mm_struct *mm) 
	if (IS_ERR(ret))

		goto out;



	mm->context.vdso = (void *)addr;

	mm->context.sigpage = (void *)addr;



out:

	return PTR_ERR_OR_ZERO(ret);

}

#endif /* !CONFIG_COMPAT_VDSO */



int aarch32_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)

{
@@ -352,10 +346,11 @@ int aarch32_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) 
				       mm,

				       bprm,

				       uses_interp);

#else

	ret = aarch32_sigreturn_setup(mm);

	if (ret)

		goto out;

#endif /* CONFIG_COMPAT_VDSO */



	ret = aarch32_sigreturn_setup(mm);

out:

	mmap_write_unlock(mm);

	return ret;

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