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

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

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.

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;
>
>