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

Zhangjian (Bamvor)
2016-05-03T12:49:02Z

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;
>>>
>>>