Re: [PATCH 24/25] arm64:ilp32: add vdso-ilp32 and use for signal return

["Zhangjian (Bamvor)" <bamvor.zhangjian@huawei.com>]

Hi, yury

On 2016/4/13 23:55, Yury Norov wrote:
> Hi Bamvor,
>
> On Wed, Apr 13, 2016 at 05:19:28PM +0800, Zhangjian (Bamvor) wrote:
>> Hi, Yury and Philipp
>>
>> There is a small fix for this patch. Othervise our tools of living
>> patch could not work.
>>
>> Regards
>>
>> Bamvor
>>
>>  From e05770efca9f040e0039a4a9c4e0d7d3b2bd13e8 Mon Sep 17 00:00:00 2001
>> From: Bamvor Jian Zhang <bamvor.zhangjian@huawei.com>
>> Date: Wed, 13 Apr 2016 15:46:28 +0800
>> Subject: [PATCH] arm64: ilp32: do not check vdso-ilp32-offsets.h when ILP32
>>   disabled
>>
>> vdso-ilp32-offsets.h is the dependency of all the arm64-obj-y. And
>> it does not exist when CONFIG_ARM64_ILP32 is disable which lead to
>> all the arm64-obj-y are re-built unnecessarily.
>>
>> Such rebuild may confuse the sofware(e.g. tools of living patch)
>> which need to know exactly which file(s) is(are) updated.
>>
>> This patch fix this issue by adding the config checker.
>
> It looks reasonable and correct.
>
> I'll apply your patch in next submission (if it will be needed),
> otherwise I think, Arnd may apply it.
>
> Though, I don't understand much, what 'tools of living patch' means.
> Could you explain in details what you do, and what goes wrong?
Our tools need to monitor the what *.o is changed after recompile.
But without this patch, all the object in arch/arm64/kernel is
recompiled. Because the vdso-ilp32-offsets.h is dependency of
these files, reference this line of patch:
+$(call objectify,$(arm64-obj-y)): $(obj)/vdso-ilp32/vdso-ilp32-offsets.h

Regards

Bamvor
>
> Nevertheless, thank you for your attention to this patchset.
>
> Yury.
>
>>
>> Signed-off-by: Bamvor Jian Zhang <bamvor.zhangjian@huawei.com>
>> ---
>>   arch/arm64/kernel/Makefile | 2 ++
>>   1 file changed, 2 insertions(+)
>>
>> diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
>> index b43ff12..0f27a10 100644
>> --- a/arch/arm64/kernel/Makefile
>> +++ b/arch/arm64/kernel/Makefile
>> @@ -60,5 +60,7 @@ $(call objectify,$(arm64-obj-y)): $(obj)/vdso/vdso-offsets.h
>>   $(obj)/vdso/vdso-offsets.h: $(obj)/vdso
>>
>>   # vDSO - this must be built first to generate the symbol offsets
>> +ifeq ($(CONFIG_ARM64_ILP32),y)
>>   $(call objectify,$(arm64-obj-y)): $(obj)/vdso-ilp32/vdso-ilp32-offsets.h
>>   $(obj)/vdso-ilp32/vdso-ilp32-offsets.h: $(obj)/vdso-ilp32
>> +endif
>> --
>> 1.8.4.5
>>
>> On 2016/4/6 6:08, Yury Norov wrote:
>>> From: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
>>>
>>> ILP32 VDSO exports next symbols:
>>>   __kernel_rt_sigreturn;
>>>   __kernel_gettimeofday;
>>>   __kernel_clock_gettime;
>>>   __kernel_clock_getres;
>>>
>>> What shared object to use, kernel selects depending on result of
>>> is_ilp32_compat_task() in arch/arm64/kernel/vdso.c, so it substitutes
>>> correct pages and spec.
>>>
>>> Adjusted to move the move data page before code pages in sync with
>>> commit 601255ae3c98fdeeee3a8bb4696425e4f868b4f1
>>>
>>> Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
>>> Signed-off-by: Christoph Muellner <christoph.muellner@theobroma-systems.com>
>>> Signed-off-by: Yury Norov <ynorov@caviumnetworks.com>
>>> ---
>>>   arch/arm64/include/asm/vdso.h                 |  6 ++
>>>   arch/arm64/kernel/Makefile                    |  5 ++
>>>   arch/arm64/kernel/signal.c                    |  2 +
>>>   arch/arm64/kernel/vdso-ilp32/.gitignore       |  2 +
>>>   arch/arm64/kernel/vdso-ilp32/Makefile         | 72 ++++++++++++++++++++
>>>   arch/arm64/kernel/vdso-ilp32/vdso-ilp32.S     | 33 ++++++++++
>>>   arch/arm64/kernel/vdso-ilp32/vdso-ilp32.lds.S | 95 +++++++++++++++++++++++++++
>>>   arch/arm64/kernel/vdso.c                      | 61 ++++++++++++++---
>>>   8 files changed, 266 insertions(+), 10 deletions(-)
>>>   create mode 100644 arch/arm64/kernel/vdso-ilp32/.gitignore
>>>   create mode 100644 arch/arm64/kernel/vdso-ilp32/Makefile
>>>   create mode 100644 arch/arm64/kernel/vdso-ilp32/vdso-ilp32.S
>>>   create mode 100644 arch/arm64/kernel/vdso-ilp32/vdso-ilp32.lds.S
>>>
>>> diff --git a/arch/arm64/include/asm/vdso.h b/arch/arm64/include/asm/vdso.h
>>> index 839ce00..649a9a4 100644
>>> --- a/arch/arm64/include/asm/vdso.h
>>> +++ b/arch/arm64/include/asm/vdso.h
>>> @@ -29,6 +29,12 @@
>>>
>>>   #include <generated/vdso-offsets.h>
>>>
>>> +#ifdef CONFIG_ARM64_ILP32
>>> +#include <generated/vdso-ilp32-offsets.h>
>>> +#else
>>> +#define vdso_offset_sigtramp_ilp32
>>> +#endif
>>> +
>>>   #define VDSO_SYMBOL(base, name)						   \
>>>   ({									   \
>>>   	(void *)(vdso_offset_##name - VDSO_LBASE + (unsigned long)(base)); \
>>> diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
>>> index 09e4373..b43ff12 100644
>>> --- a/arch/arm64/kernel/Makefile
>>> +++ b/arch/arm64/kernel/Makefile
>>> @@ -50,6 +50,7 @@ arm64-obj-$(CONFIG_PARAVIRT)		+= paravirt.o
>>>   arm64-obj-$(CONFIG_RANDOMIZE_BASE)	+= kaslr.o
>>>
>>>   obj-y					+= $(arm64-obj-y) vdso/
>>> +obj-$(CONFIG_ARM64_ILP32)		+= vdso-ilp32/
>>>   obj-m					+= $(arm64-obj-m)
>>>   head-y					:= head.o
>>>   extra-y					+= $(head-y) vmlinux.lds
>>> @@ -57,3 +58,7 @@ extra-y					+= $(head-y) vmlinux.lds
>>>   # vDSO - this must be built first to generate the symbol offsets
>>>   $(call objectify,$(arm64-obj-y)): $(obj)/vdso/vdso-offsets.h
>>>   $(obj)/vdso/vdso-offsets.h: $(obj)/vdso
>>> +
>>> +# vDSO - this must be built first to generate the symbol offsets
>>> +$(call objectify,$(arm64-obj-y)): $(obj)/vdso-ilp32/vdso-ilp32-offsets.h
>>> +$(obj)/vdso-ilp32/vdso-ilp32-offsets.h: $(obj)/vdso-ilp32
>>> diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c
>>> index 45bcd96..933cdcf 100644
>>> --- a/arch/arm64/kernel/signal.c
>>> +++ b/arch/arm64/kernel/signal.c
>>> @@ -264,6 +264,8 @@ void setup_return(struct pt_regs *regs, struct k_sigaction *ka,
>>>
>>>   	if (ka->sa.sa_flags & SA_RESTORER)
>>>   		sigtramp = ka->sa.sa_restorer;
>>> +	else if (is_ilp32_compat_task())
>>> +		sigtramp = VDSO_SYMBOL(current->mm->context.vdso, sigtramp_ilp32);
>>>   	else
>>>   		sigtramp = VDSO_SYMBOL(current->mm->context.vdso, sigtramp);
>>>
>>> diff --git a/arch/arm64/kernel/vdso-ilp32/.gitignore b/arch/arm64/kernel/vdso-ilp32/.gitignore
>>> new file mode 100644
>>> index 0000000..61806c3
>>> --- /dev/null
>>> +++ b/arch/arm64/kernel/vdso-ilp32/.gitignore
>>> @@ -0,0 +1,2 @@
>>> +vdso-ilp32.lds
>>> +vdso-ilp32-offsets.h
>>> diff --git a/arch/arm64/kernel/vdso-ilp32/Makefile b/arch/arm64/kernel/vdso-ilp32/Makefile
>>> new file mode 100644
>>> index 0000000..c8f5472
>>> --- /dev/null
>>> +++ b/arch/arm64/kernel/vdso-ilp32/Makefile
>>> @@ -0,0 +1,72 @@
>>> +#
>>> +# Building a vDSO image for AArch64.
>>> +#
>>> +# Author: Will Deacon <will.deacon@arm.com>
>>> +# Heavily based on the vDSO Makefiles for other archs.
>>> +#
>>> +
>>> +obj-ilp32-vdso := gettimeofday-ilp32.o note-ilp32.o sigreturn-ilp32.o
>>> +
>>> +# Build rules
>>> +targets := $(obj-ilp32-vdso) vdso-ilp32.so vdso-ilp32.so.dbg
>>> +obj-ilp32-vdso := $(addprefix $(obj)/, $(obj-ilp32-vdso))
>>> +
>>> +ccflags-y := -shared -fno-common -fno-builtin
>>> +ccflags-y += -nostdlib -Wl,-soname=linux-ilp32-vdso.so.1 \
>>> +		$(call cc-ldoption, -Wl$(comma)--hash-style=sysv)
>>> +
>>> +obj-y += vdso-ilp32.o
>>> +extra-y += vdso-ilp32.lds vdso-ilp32-offsets.h
>>> +CPPFLAGS_vdso-ilp32.lds += -P -C -U$(ARCH) -mabi=ilp32
>>> +
>>> +# Force dependency (incbin is bad)
>>> +$(obj)/vdso-ilp32.o : $(obj)/vdso-ilp32.so
>>> +
>>> +# Link rule for the .so file, .lds has to be first
>>> +$(obj)/vdso-ilp32.so.dbg: $(src)/vdso-ilp32.lds $(obj-ilp32-vdso)
>>> +	$(call if_changed,vdso-ilp32ld)
>>> +
>>> +# Strip rule for the .so file
>>> +$(obj)/%.so: OBJCOPYFLAGS := -S
>>> +$(obj)/%.so: $(obj)/%.so.dbg FORCE
>>> +	$(call if_changed,objcopy)
>>> +
>>> +# Generate VDSO offsets using helper script
>>> +gen-vdsosym := $(srctree)/$(src)/../vdso/gen_vdso_offsets.sh
>>> +quiet_cmd_vdsosym = VDSOSYM $@
>>> +define cmd_vdsosym
>>> +	$(NM) $< | $(gen-vdsosym) | LC_ALL=C sort > $@ && \
>>> +	cp $@ include/generated/
>>> +endef
>>> +
>>> +$(obj)/vdso-ilp32-offsets.h: $(obj)/vdso-ilp32.so.dbg FORCE
>>> +	$(call if_changed,vdsosym)
>>> +
>>> +# Assembly rules for the .S files
>>> +#$(obj-ilp32-vdso): %.o: $(src)/../vdso/$(subst -ilp32,,%.S)
>>> +#	$(call if_changed_dep,vdso-ilp32as)
>>> +
>>> +$(obj)/gettimeofday-ilp32.o: $(src)/../vdso/gettimeofday.S
>>> +	$(call if_changed_dep,vdso-ilp32as)
>>> +
>>> +$(obj)/note-ilp32.o: $(src)/../vdso/note.S
>>> +	$(call if_changed_dep,vdso-ilp32as)
>>> +
>>> +$(obj)/sigreturn-ilp32.o: $(src)/../vdso/sigreturn.S
>>> +	$(call if_changed_dep,vdso-ilp32as)
>>> +
>>> +# Actual build commands
>>> +quiet_cmd_vdso-ilp32ld = VDSOILP32L $@
>>> +      cmd_vdso-ilp32ld = $(CC) $(c_flags) -mabi=ilp32  -Wl,-n -Wl,-T $^ -o $@
>>> +quiet_cmd_vdso-ilp32as = VDSOILP32A $@
>>> +      cmd_vdso-ilp32as = $(CC) $(a_flags) -mabi=ilp32 -c -o $@ $<
>>> +
>>> +# Install commands for the unstripped file
>>> +quiet_cmd_vdso_install = INSTALL $@
>>> +      cmd_vdso_install = cp $(obj)/$@.dbg $(MODLIB)/vdso/$@
>>> +
>>> +vdso-ilp32.so: $(obj)/vdso-ilp32.so.dbg
>>> +	@mkdir -p $(MODLIB)/vdso
>>> +	$(call cmd,vdso_install)
>>> +
>>> +vdso_install: vdso-ilp32.so
>>> diff --git a/arch/arm64/kernel/vdso-ilp32/vdso-ilp32.S b/arch/arm64/kernel/vdso-ilp32/vdso-ilp32.S
>>> new file mode 100644
>>> index 0000000..46ac072
>>> --- /dev/null
>>> +++ b/arch/arm64/kernel/vdso-ilp32/vdso-ilp32.S
>>> @@ -0,0 +1,33 @@
>>> +/*
>>> + * Copyright (C) 2012 ARM Limited
>>> + *
>>> + * This program is free software; you can redistribute it and/or modify
>>> + * it under the terms of the GNU General Public License version 2 as
>>> + * published by the Free Software Foundation.
>>> + *
>>> + * This program is distributed in the hope that it will be useful,
>>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>>> + * GNU General Public License for more details.
>>> + *
>>> + * You should have received a copy of the GNU General Public License
>>> + * along with this program.  If not, see <http://www.gnu.org/licenses/>.
>>> + *
>>> + * Author: Will Deacon <will.deacon@arm.com>
>>> + */
>>> +
>>> +#include <linux/init.h>
>>> +#include <linux/linkage.h>
>>> +#include <linux/const.h>
>>> +#include <asm/page.h>
>>> +
>>> +	__PAGE_ALIGNED_DATA
>>> +
>>> +	.globl vdso_ilp32_start, vdso_ilp32_end
>>> +	.balign PAGE_SIZE
>>> +vdso_ilp32_start:
>>> +	.incbin "arch/arm64/kernel/vdso-ilp32/vdso-ilp32.so"
>>> +	.balign PAGE_SIZE
>>> +vdso_ilp32_end:
>>> +
>>> +	.previous
>>> diff --git a/arch/arm64/kernel/vdso-ilp32/vdso-ilp32.lds.S b/arch/arm64/kernel/vdso-ilp32/vdso-ilp32.lds.S
>>> new file mode 100644
>>> index 0000000..ddc63fd
>>> --- /dev/null
>>> +++ b/arch/arm64/kernel/vdso-ilp32/vdso-ilp32.lds.S
>>> @@ -0,0 +1,95 @@
>>> +/*
>>> + * GNU linker script for the VDSO library.
>>> + *
>>> + * Copyright (C) 2012 ARM Limited
>>> + *
>>> + * This program is free software; you can redistribute it and/or modify
>>> + * it under the terms of the GNU General Public License version 2 as
>>> + * published by the Free Software Foundation.
>>> + *
>>> + * This program is distributed in the hope that it will be useful,
>>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>>> + * GNU General Public License for more details.
>>> + *
>>> + * You should have received a copy of the GNU General Public License
>>> + * along with this program.  If not, see <http://www.gnu.org/licenses/>.
>>> + *
>>> + * Author: Will Deacon <will.deacon@arm.com>
>>> + * Heavily based on the vDSO linker scripts for other archs.
>>> + */
>>> +
>>> +#include <linux/const.h>
>>> +#include <asm/page.h>
>>> +#include <asm/vdso.h>
>>> +
>>> +SECTIONS
>>> +{
>>> +	PROVIDE(_vdso_data = . - PAGE_SIZE);
>>> +	. = VDSO_LBASE + SIZEOF_HEADERS;
>>> +
>>> +	.hash		: { *(.hash) }			:text
>>> +	.gnu.hash	: { *(.gnu.hash) }
>>> +	.dynsym		: { *(.dynsym) }
>>> +	.dynstr		: { *(.dynstr) }
>>> +	.gnu.version	: { *(.gnu.version) }
>>> +	.gnu.version_d	: { *(.gnu.version_d) }
>>> +	.gnu.version_r	: { *(.gnu.version_r) }
>>> +
>>> +	.note		: { *(.note.*) }		:text	:note
>>> +
>>> +	. = ALIGN(16);
>>> +
>>> +	.text		: { *(.text*) }			:text	=0xd503201f
>>> +	PROVIDE (__etext = .);
>>> +	PROVIDE (_etext = .);
>>> +	PROVIDE (etext = .);
>>> +
>>> +	.eh_frame_hdr	: { *(.eh_frame_hdr) }		:text	:eh_frame_hdr
>>> +	.eh_frame	: { KEEP (*(.eh_frame)) }	:text
>>> +
>>> +	.dynamic	: { *(.dynamic) }		:text	:dynamic
>>> +
>>> +	.rodata		: { *(.rodata*) }		:text
>>> +
>>> +	_end = .;
>>> +	PROVIDE(end = .);
>>> +
>>> +	/DISCARD/	: {
>>> +		*(.note.GNU-stack)
>>> +		*(.data .data.* .gnu.linkonce.d.* .sdata*)
>>> +		*(.bss .sbss .dynbss .dynsbss)
>>> +	}
>>> +}
>>> +
>>> +/*
>>> + * We must supply the ELF program headers explicitly to get just one
>>> + * PT_LOAD segment, and set the flags explicitly to make segments read-only.
>>> + */
>>> +PHDRS
>>> +{
>>> +	text		PT_LOAD		FLAGS(5) FILEHDR PHDRS; /* PF_R|PF_X */
>>> +	dynamic		PT_DYNAMIC	FLAGS(4);		/* PF_R */
>>> +	note		PT_NOTE		FLAGS(4);		/* PF_R */
>>> +	eh_frame_hdr	PT_GNU_EH_FRAME;
>>> +}
>>> +
>>> +/*
>>> + * This controls what symbols we export from the DSO.
>>> + */
>>> +VERSION
>>> +{
>>> +	LINUX_2.6 {
>>> +	global:
>>> +		__kernel_rt_sigreturn;
>>> +		__kernel_gettimeofday;
>>> +		__kernel_clock_gettime;
>>> +		__kernel_clock_getres;
>>> +	local: *;
>>> +	};
>>> +}
>>> +
>>> +/*
>>> + * Make the sigreturn code visible to the kernel.
>>> + */
>>> +VDSO_sigtramp_ilp32		= __kernel_rt_sigreturn;
>>> diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c
>>> index 26352a6..521a8e4 100644
>>> --- a/arch/arm64/kernel/vdso.c
>>> +++ b/arch/arm64/kernel/vdso.c
>>> @@ -40,6 +40,12 @@ extern char vdso_start, vdso_end;
>>>   static unsigned long vdso_pages;
>>>   static struct page **vdso_pagelist;
>>>
>>> +#ifdef CONFIG_ARM64_ILP32
>>> +extern char vdso_ilp32_start, vdso_ilp32_end;
>>> +static unsigned long vdso_ilp32_pages;
>>> +static struct page **vdso_ilp32_pagelist;
>>> +#endif
>>> +
>>>   /*
>>>    * The vDSO data page.
>>>    */
>>> @@ -109,24 +115,29 @@ int aarch32_setup_vectors_page(struct linux_binprm *bprm, int uses_interp)
>>>   }
>>>   #endif /* CONFIG_AARCH32_EL0 */
>>>
>>> -static struct vm_special_mapping vdso_spec[2];
>>> -
>>> -static int __init vdso_init(void)
>>> +static int __init vdso_init_common(char *vdso_start, char *vdso_end,
>>> +					  unsigned long *vdso_pagesp,
>>> +					  struct page ***vdso_pagelistp,
>>> +					  struct vm_special_mapping* vdso_spec)
>>>   {
>>>   	int i;
>>> +	unsigned long vdso_pages;
>>> +	struct page **vdso_pagelist;
>>>
>>> -	if (memcmp(&vdso_start, "\177ELF", 4)) {
>>> +	if (memcmp(vdso_start, "\177ELF", 4)) {
>>>   		pr_err("vDSO is not a valid ELF object!\n");
>>>   		return -EINVAL;
>>>   	}
>>>
>>> -	vdso_pages = (&vdso_end - &vdso_start) >> PAGE_SHIFT;
>>> +	vdso_pages = (vdso_end - vdso_start) >> PAGE_SHIFT;
>>> +	*vdso_pagesp = vdso_pages;
>>>   	pr_info("vdso: %ld pages (%ld code @ %p, %ld data @ %p)\n",
>>> -		vdso_pages + 1, vdso_pages, &vdso_start, 1L, vdso_data);
>>> +		vdso_pages + 1, vdso_pages, vdso_start, 1L, vdso_data);
>>>
>>>   	/* Allocate the vDSO pagelist, plus a page for the data. */
>>>   	vdso_pagelist = kcalloc(vdso_pages + 1, sizeof(struct page *),
>>>   				GFP_KERNEL);
>>> +	*vdso_pagelistp = vdso_pagelist;
>>>   	if (vdso_pagelist == NULL)
>>>   		return -ENOMEM;
>>>
>>> @@ -135,7 +146,7 @@ static int __init vdso_init(void)
>>>
>>>   	/* Grab the vDSO code pages. */
>>>   	for (i = 0; i < vdso_pages; i++)
>>> -		vdso_pagelist[i + 1] = virt_to_page(&vdso_start + i * PAGE_SIZE);
>>> +		vdso_pagelist[i + 1] = virt_to_page(vdso_start + i * PAGE_SIZE);
>>>
>>>   	/* Populate the special mapping structures */
>>>   	vdso_spec[0] = (struct vm_special_mapping) {
>>> @@ -150,16 +161,46 @@ static int __init vdso_init(void)
>>>
>>>   	return 0;
>>>   }
>>> +
>>> +static struct vm_special_mapping vdso_spec[2];
>>> +
>>> +static int __init vdso_init(void)
>>> +{
>>> +	return vdso_init_common(&vdso_start, &vdso_end,
>>> +				&vdso_pages, &vdso_pagelist,
>>> +				vdso_spec);
>>> +}
>>>   arch_initcall(vdso_init);
>>>
>>> +#ifdef CONFIG_ARM64_ILP32
>>> +static struct vm_special_mapping vdso_ilp32_spec[2];
>>> +
>>> +static int __init vdso_ilp32_init(void)
>>> +{
>>> +	return vdso_init_common(&vdso_ilp32_start, &vdso_ilp32_end,
>>> +				&vdso_ilp32_pages, &vdso_ilp32_pagelist,
>>> +				vdso_ilp32_spec);
>>> +}
>>> +arch_initcall(vdso_ilp32_init);
>>> +#endif
>>> +
>>>   int arch_setup_additional_pages(struct linux_binprm *bprm,
>>>   				int uses_interp)
>>>   {
>>>   	struct mm_struct *mm = current->mm;
>>>   	unsigned long vdso_base, vdso_text_len, vdso_mapping_len;
>>>   	void *ret;
>>> +	unsigned long pages = vdso_pages;
>>> +	struct vm_special_mapping *spec = vdso_spec;
>>> +
>>> +#ifdef CONFIG_ARM64_ILP32
>>> +	if (is_ilp32_compat_task()) {
>>> +	        pages = vdso_ilp32_pages;
>>> +	        spec = vdso_ilp32_spec;
>>> +	}
>>> +#endif
>>>
>>> -	vdso_text_len = vdso_pages << PAGE_SHIFT;
>>> +	vdso_text_len = pages << PAGE_SHIFT;
>>>   	/* Be sure to map the data page */
>>>   	vdso_mapping_len = vdso_text_len + PAGE_SIZE;
>>>
>>> @@ -171,7 +212,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm,
>>>   	}
>>>   	ret = _install_special_mapping(mm, vdso_base, PAGE_SIZE,
>>>   				       VM_READ|VM_MAYREAD,
>>> -				       &vdso_spec[0]);
>>> +				       &spec[0]);
>>>   	if (IS_ERR(ret))
>>>   		goto up_fail;
>>>
>>> @@ -180,7 +221,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm,
>>>   	ret = _install_special_mapping(mm, vdso_base, vdso_text_len,
>>>   				       VM_READ|VM_EXEC|
>>>   				       VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
>>> -				       &vdso_spec[1]);
>>> +				       &spec[1]);
>>>   	if (IS_ERR(ret))
>>>   		goto up_fail;
>>>
>>>