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* [PATCH v3 08/23] elf/vdso: Modify arch_setup_additional_pages() parameters
       [not found] <20210611180242.711399-1-dima@arista.com>
@ 2021-06-11 18:02 ` Dmitry Safonov
  0 siblings, 0 replies; only message in thread
From: Dmitry Safonov @ 2021-06-11 18:02 UTC (permalink / raw)
  To: linux-kernel
  Cc: Dmitry Safonov, Dmitry Safonov, Alexander Viro, Andrew Morton,
	Andy Lutomirski, Arnd Bergmann, Borislav Petkov, Catalin Marinas,
	Christophe Leroy, Guo Ren, H. Peter Anvin, Ingo Molnar,
	Oleg Nesterov, Russell King, Thomas Bogendoerfer,
	Thomas Gleixner, Vincenzo Frascino, Will Deacon, x86, Albert Ou,
	David S. Miller, Palmer Dabbelt, Paul Walmsley, linux-fsdevel

Both parameters of arch_setup_additional_pages() are currently unused.
commit fc5243d98ac2 ("[S390] arch_setup_additional_pages arguments")
tried to introduce useful arguments, but they still are not used.

Remove old parameters and introduce sysinfo_ehdr argument that will be
used to return vdso address to put as AT_SYSINFO_EHDR tag in auxiliary
vector. The reason to add this parameter is that many architectures
have vDSO pointer saved in their mm->context with the only purpose
to use it later in ARCH_DLINFO. That's the macro for elf loader
to setup sysinfo_ehdr tag.

Return sysinfo_ehdr address that will be later used by ARCH_DLINFO as
an argument. That will allow to drop vDSO pointer from mm->context
and any code responsible to track vDSO position on platforms that
don't use vDSO as a landing in userspace (arm/s390/sparc).

Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/arm/include/asm/vdso.h        |  6 ++++--
 arch/arm/kernel/process.c          |  4 ++--
 arch/arm/kernel/vdso.c             | 10 +++++++---
 arch/arm64/kernel/vdso.c           | 17 ++++++++---------
 arch/csky/kernel/vdso.c            | 11 ++++++-----
 arch/hexagon/kernel/vdso.c         |  3 ++-
 arch/mips/kernel/vdso.c            |  3 ++-
 arch/nds32/kernel/vdso.c           |  3 ++-
 arch/nios2/mm/init.c               |  2 +-
 arch/powerpc/kernel/vdso.c         | 12 +++++++-----
 arch/riscv/kernel/vdso.c           | 11 ++++++-----
 arch/s390/kernel/vdso.c            |  3 ++-
 arch/sh/kernel/vsyscall/vsyscall.c |  3 ++-
 arch/sparc/vdso/vma.c              | 14 +++++++-------
 arch/x86/entry/vdso/vma.c          | 26 +++++++++++++++-----------
 arch/x86/um/vdso/vma.c             |  2 +-
 fs/binfmt_elf.c                    |  3 ++-
 fs/binfmt_elf_fdpic.c              |  3 ++-
 include/linux/elf.h                | 17 ++++++++++++-----
 19 files changed, 90 insertions(+), 63 deletions(-)

diff --git a/arch/arm/include/asm/vdso.h b/arch/arm/include/asm/vdso.h
index 5b85889f82ee..6b2b3b1fe833 100644
--- a/arch/arm/include/asm/vdso.h
+++ b/arch/arm/include/asm/vdso.h
@@ -10,13 +10,15 @@ struct mm_struct;
 
 #ifdef CONFIG_VDSO
 
-void arm_install_vdso(struct mm_struct *mm, unsigned long addr);
+void arm_install_vdso(struct mm_struct *mm, unsigned long addr,
+		      unsigned long *sysinfo_ehdr);
 
 extern unsigned int vdso_total_pages;
 
 #else /* CONFIG_VDSO */
 
-static inline void arm_install_vdso(struct mm_struct *mm, unsigned long addr)
+static inline void arm_install_vdso(struct mm_struct *mm, unsigned long addr,
+				    unsigned long *sysinfo_ehdr)
 {
 }
 
diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
index 6324f4db9b02..5897ccb88bca 100644
--- a/arch/arm/kernel/process.c
+++ b/arch/arm/kernel/process.c
@@ -400,7 +400,7 @@ static const struct vm_special_mapping sigpage_mapping = {
 	.mremap = sigpage_mremap,
 };
 
-int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
+int arch_setup_additional_pages(unsigned long *sysinfo_ehdr)
 {
 	struct mm_struct *mm = current->mm;
 	struct vm_area_struct *vma;
@@ -441,7 +441,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 	 * to be fatal to the process, so no error check needed
 	 * here.
 	 */
-	arm_install_vdso(mm, addr + PAGE_SIZE);
+	arm_install_vdso(mm, addr + PAGE_SIZE, sysinfo_ehdr);
 
  up_fail:
 	mmap_write_unlock(mm);
diff --git a/arch/arm/kernel/vdso.c b/arch/arm/kernel/vdso.c
index 015eff0a6e93..de516f8ba85a 100644
--- a/arch/arm/kernel/vdso.c
+++ b/arch/arm/kernel/vdso.c
@@ -233,7 +233,8 @@ static int install_vvar(struct mm_struct *mm, unsigned long addr)
 }
 
 /* assumes mmap_lock is write-locked */
-void arm_install_vdso(struct mm_struct *mm, unsigned long addr)
+void arm_install_vdso(struct mm_struct *mm, unsigned long addr,
+		      unsigned long *sysinfo_ehdr)
 {
 	struct vm_area_struct *vma;
 	unsigned long len;
@@ -252,7 +253,10 @@ void arm_install_vdso(struct mm_struct *mm, unsigned long addr)
 		VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
 		&vdso_text_mapping);
 
-	if (!IS_ERR(vma))
-		mm->context.vdso = addr;
+	if (IS_ERR(vma))
+		return;
+
+	mm->context.vdso = addr;
+	*sysinfo_ehdr = addr;
 }
 
diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c
index 1bc8adefa293..c0512c2e8183 100644
--- a/arch/arm64/kernel/vdso.c
+++ b/arch/arm64/kernel/vdso.c
@@ -213,8 +213,7 @@ static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,
 
 static int __setup_additional_pages(enum vdso_abi abi,
 				    struct mm_struct *mm,
-				    struct linux_binprm *bprm,
-				    int uses_interp)
+				    unsigned long *sysinfo_ehdr)
 {
 	unsigned long vdso_base, vdso_text_len, vdso_mapping_len;
 	unsigned long gp_flags = 0;
@@ -248,6 +247,8 @@ static int __setup_additional_pages(enum vdso_abi abi,
 		return PTR_ERR(ret);
 
 	mm->context.vdso = (void *)vdso_base;
+	*sysinfo_ehdr = vdso_base;
+
 	return 0;
 }
 
@@ -405,8 +406,7 @@ static int aarch32_sigreturn_setup(struct mm_struct *mm)
 	return PTR_ERR_OR_ZERO(ret);
 }
 
-static int aarch32_setup_additional_pages(struct linux_binprm *bprm,
-					  int uses_interp)
+static int aarch32_setup_additional_pages(unsigned long *sysinfo_ehdr)
 {
 	struct mm_struct *mm = current->mm;
 	int ret;
@@ -416,8 +416,7 @@ static int aarch32_setup_additional_pages(struct linux_binprm *bprm,
 		return ret;
 
 	if (IS_ENABLED(CONFIG_COMPAT_VDSO)) {
-		ret = __setup_additional_pages(VDSO_ABI_AA32, mm, bprm,
-					       uses_interp);
+		ret = __setup_additional_pages(VDSO_ABI_AA32, mm, sysinfo_ehdr);
 		if (ret)
 			return ret;
 	}
@@ -451,7 +450,7 @@ static int __init vdso_init(void)
 }
 arch_initcall(vdso_init);
 
-int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
+int arch_setup_additional_pages(unsigned long *sysinfo_ehdr)
 {
 	struct mm_struct *mm = current->mm;
 	int ret;
@@ -460,9 +459,9 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 		return -EINTR;
 
 	if (is_compat_task())
-		ret = aarch32_setup_additional_pages(bprm, uses_interp);
+		ret = aarch32_setup_additional_pages(sysinfo_ehdr);
 	else
-		ret = __setup_additional_pages(VDSO_ABI_AA64, mm, bprm, uses_interp);
+		ret = __setup_additional_pages(VDSO_ABI_AA64, mm, sysinfo_ehdr);
 
 	mmap_write_unlock(mm);
 
diff --git a/arch/csky/kernel/vdso.c b/arch/csky/kernel/vdso.c
index 16c20d64d165..30160e64ee2d 100644
--- a/arch/csky/kernel/vdso.c
+++ b/arch/csky/kernel/vdso.c
@@ -52,11 +52,10 @@ static int __init vdso_init(void)
 }
 arch_initcall(vdso_init);
 
-int arch_setup_additional_pages(struct linux_binprm *bprm,
-	int uses_interp)
+int arch_setup_additional_pages(unsigned long *sysinfo_ehdr)
 {
 	struct mm_struct *mm = current->mm;
-	unsigned long vdso_base, vdso_len;
+	unsigned long vdso_base, vvar_base, vdso_len;
 	int ret;
 
 	vdso_len = (vdso_pages + 1) << PAGE_SHIFT;
@@ -85,12 +84,14 @@ int arch_setup_additional_pages(struct linux_binprm *bprm,
 		goto end;
 	}
 
-	vdso_base += (vdso_pages << PAGE_SHIFT);
-	ret = install_special_mapping(mm, vdso_base, PAGE_SIZE,
+	vvar_base = vdso_base + (vdso_pages << PAGE_SHIFT);
+	ret = install_special_mapping(mm, vvar_base, PAGE_SIZE,
 		(VM_READ | VM_MAYREAD), &vdso_pagelist[vdso_pages]);
 
 	if (unlikely(ret))
 		mm->context.vdso = NULL;
+	else
+		*sysinfo_ehdr = vdso_base;
 end:
 	mmap_write_unlock(mm);
 	return ret;
diff --git a/arch/hexagon/kernel/vdso.c b/arch/hexagon/kernel/vdso.c
index b70970ac809f..39e78fe82b99 100644
--- a/arch/hexagon/kernel/vdso.c
+++ b/arch/hexagon/kernel/vdso.c
@@ -46,7 +46,7 @@ arch_initcall(vdso_init);
 /*
  * Called from binfmt_elf.  Create a VMA for the vDSO page.
  */
-int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
+int arch_setup_additional_pages(unsigned long *sysinfo_ehdr)
 {
 	int ret;
 	unsigned long vdso_base;
@@ -74,6 +74,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 		goto up_fail;
 
 	mm->context.vdso = (void *)vdso_base;
+	*sysinfo_ehdr = vdso_base;
 
 up_fail:
 	mmap_write_unlock(mm);
diff --git a/arch/mips/kernel/vdso.c b/arch/mips/kernel/vdso.c
index 3d0cf471f2fe..9b2e1d2250b4 100644
--- a/arch/mips/kernel/vdso.c
+++ b/arch/mips/kernel/vdso.c
@@ -86,7 +86,7 @@ static unsigned long vdso_base(void)
 	return base;
 }
 
-int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
+int arch_setup_additional_pages(unsigned long *sysinfo_ehdr)
 {
 	struct mips_vdso_image *image = current->thread.abi->vdso;
 	struct mm_struct *mm = current->mm;
@@ -185,6 +185,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 	}
 
 	mm->context.vdso = (void *)vdso_addr;
+	*sysinfo_ehdr = vdso_addr;
 	ret = 0;
 
 out:
diff --git a/arch/nds32/kernel/vdso.c b/arch/nds32/kernel/vdso.c
index 2d1d51a0fc64..1d35a33389e5 100644
--- a/arch/nds32/kernel/vdso.c
+++ b/arch/nds32/kernel/vdso.c
@@ -111,7 +111,7 @@ unsigned long inline vdso_random_addr(unsigned long vdso_mapping_len)
 	return addr;
 }
 
-int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
+int arch_setup_additional_pages(unsigned long *sysinfo_ehdr)
 {
 	struct mm_struct *mm = current->mm;
 	unsigned long vdso_base, vdso_text_len, vdso_mapping_len;
@@ -185,6 +185,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 	}
 
 	mm->context.vdso = (void *)vdso_base;
+	*sysinfo_ehdr = vdso_base;
 
 up_fail:
 	mmap_write_unlock(mm);
diff --git a/arch/nios2/mm/init.c b/arch/nios2/mm/init.c
index 613fcaa5988a..0164f5cdb255 100644
--- a/arch/nios2/mm/init.c
+++ b/arch/nios2/mm/init.c
@@ -103,7 +103,7 @@ static int alloc_kuser_page(void)
 }
 arch_initcall(alloc_kuser_page);
 
-int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
+int arch_setup_additional_pages(unsigned long *sysinfo_ehdr)
 {
 	struct mm_struct *mm = current->mm;
 	int ret;
diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c
index 76e898b56002..6d6e575630c1 100644
--- a/arch/powerpc/kernel/vdso.c
+++ b/arch/powerpc/kernel/vdso.c
@@ -190,7 +190,7 @@ static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,
  * This is called from binfmt_elf, we create the special vma for the
  * vDSO and insert it into the mm struct tree
  */
-static int __arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
+static int __arch_setup_additional_pages(unsigned long *sysinfo_ehdr)
 {
 	unsigned long vdso_size, vdso_base, mappings_size;
 	struct vm_special_mapping *vdso_spec;
@@ -248,15 +248,17 @@ static int __arch_setup_additional_pages(struct linux_binprm *bprm, int uses_int
 	vma = _install_special_mapping(mm, vdso_base + vvar_size, vdso_size,
 				       VM_READ | VM_EXEC | VM_MAYREAD |
 				       VM_MAYWRITE | VM_MAYEXEC, vdso_spec);
-	if (IS_ERR(vma))
+	if (IS_ERR(vma)) {
 		do_munmap(mm, vdso_base, vvar_size, NULL);
-	else
+	} else {
 		mm->context.vdso = (void __user *)vdso_base + vvar_size;
+		*sysinfo_ehdr = vdso_base + vvar_size;
+	}
 
 	return PTR_ERR_OR_ZERO(vma);
 }
 
-int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
+int arch_setup_additional_pages(unsigned long *sysinfo_ehdr)
 {
 	struct mm_struct *mm = current->mm;
 	int rc;
@@ -266,7 +268,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 	if (mmap_write_lock_killable(mm))
 		return -EINTR;
 
-	rc = __arch_setup_additional_pages(bprm, uses_interp);
+	rc = __arch_setup_additional_pages(sysinfo_ehdr);
 	if (rc)
 		mm->context.vdso = NULL;
 
diff --git a/arch/riscv/kernel/vdso.c b/arch/riscv/kernel/vdso.c
index 25a3b8849599..9cbbad8e48da 100644
--- a/arch/riscv/kernel/vdso.c
+++ b/arch/riscv/kernel/vdso.c
@@ -56,11 +56,10 @@ static int __init vdso_init(void)
 }
 arch_initcall(vdso_init);
 
-int arch_setup_additional_pages(struct linux_binprm *bprm,
-	int uses_interp)
+int arch_setup_additional_pages(unsigned long *sysinfo_ehdr)
 {
 	struct mm_struct *mm = current->mm;
-	unsigned long vdso_base, vdso_len;
+	unsigned long vdso_base, vvar_base, vdso_len;
 	int ret;
 
 	vdso_len = (vdso_pages + 1) << PAGE_SHIFT;
@@ -89,12 +88,14 @@ int arch_setup_additional_pages(struct linux_binprm *bprm,
 		goto end;
 	}
 
-	vdso_base += (vdso_pages << PAGE_SHIFT);
-	ret = install_special_mapping(mm, vdso_base, PAGE_SIZE,
+	vvar_base = vdso_base + (vdso_pages << PAGE_SHIFT);
+	ret = install_special_mapping(mm, vvar_base, PAGE_SIZE,
 		(VM_READ | VM_MAYREAD), &vdso_pagelist[vdso_pages]);
 
 	if (unlikely(ret))
 		mm->context.vdso = NULL;
+	else
+		*sysinfo_ehdr = vdso_base;
 end:
 	mmap_write_unlock(mm);
 	return ret;
diff --git a/arch/s390/kernel/vdso.c b/arch/s390/kernel/vdso.c
index 8c4e07d533c8..8a72fdedbae9 100644
--- a/arch/s390/kernel/vdso.c
+++ b/arch/s390/kernel/vdso.c
@@ -167,7 +167,7 @@ int vdso_getcpu_init(void)
 }
 early_initcall(vdso_getcpu_init); /* Must be called before SMP init */
 
-int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
+int arch_setup_additional_pages(unsigned long *sysinfo_ehdr)
 {
 	unsigned long vdso_text_len, vdso_mapping_len;
 	unsigned long vvar_start, vdso_text_start;
@@ -204,6 +204,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 		rc = PTR_ERR(vma);
 	} else {
 		current->mm->context.vdso_base = vdso_text_start;
+		*sysinfo_ehdr = vdso_text_start;
 		rc = 0;
 	}
 out:
diff --git a/arch/sh/kernel/vsyscall/vsyscall.c b/arch/sh/kernel/vsyscall/vsyscall.c
index 1bd85a6949c4..de8df3261b4f 100644
--- a/arch/sh/kernel/vsyscall/vsyscall.c
+++ b/arch/sh/kernel/vsyscall/vsyscall.c
@@ -55,7 +55,7 @@ int __init vsyscall_init(void)
 }
 
 /* Setup a VMA at program startup for the vsyscall page */
-int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
+int arch_setup_additional_pages(unsigned long *sysinfo_ehdr)
 {
 	struct mm_struct *mm = current->mm;
 	unsigned long addr;
@@ -78,6 +78,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 		goto up_fail;
 
 	current->mm->context.vdso = (void *)addr;
+	*sysinfo_ehdr = addr;
 
 up_fail:
 	mmap_write_unlock(mm);
diff --git a/arch/sparc/vdso/vma.c b/arch/sparc/vdso/vma.c
index d8a344f6c914..ae635893f9b3 100644
--- a/arch/sparc/vdso/vma.c
+++ b/arch/sparc/vdso/vma.c
@@ -346,8 +346,6 @@ static int __init init_vdso(void)
 }
 subsys_initcall(init_vdso);
 
-struct linux_binprm;
-
 /* Shuffle the vdso up a bit, randomly. */
 static unsigned long vdso_addr(unsigned long start, unsigned int len)
 {
@@ -359,7 +357,8 @@ static unsigned long vdso_addr(unsigned long start, unsigned int len)
 }
 
 static int map_vdso(const struct vdso_image *image,
-		struct vm_special_mapping *vdso_mapping)
+		    struct vm_special_mapping *vdso_mapping,
+		    unsigned long *sysinfo_ehdr)
 {
 	struct mm_struct *mm = current->mm;
 	struct vm_area_struct *vma;
@@ -416,6 +415,7 @@ static int map_vdso(const struct vdso_image *image,
 		do_munmap(mm, text_start, image->size, NULL);
 	} else {
 		current->mm->context.vdso = (void __user *)text_start;
+		*sysinfo_ehdr = text_start;
 	}
 
 up_fail:
@@ -423,7 +423,7 @@ static int map_vdso(const struct vdso_image *image,
 	return ret;
 }
 
-int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
+int arch_setup_additional_pages(unsigned long *sysinfo_ehdr)
 {
 
 	if (!vdso_enabled)
@@ -431,11 +431,11 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 
 #if defined CONFIG_COMPAT
 	if (!(is_32bit_task()))
-		return map_vdso(&vdso_image_64_builtin, &vdso_mapping64);
+		return map_vdso(&vdso_image_64_builtin, &vdso_mapping64, sysinfo_ehdr);
 	else
-		return map_vdso(&vdso_image_32_builtin, &vdso_mapping32);
+		return map_vdso(&vdso_image_32_builtin, &vdso_mapping32, sysinfo_ehdr);
 #else
-	return map_vdso(&vdso_image_64_builtin, &vdso_mapping64);
+	return map_vdso(&vdso_image_64_builtin, &vdso_mapping64, sysinfo_ehdr);
 #endif
 
 }
diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c
index 99415ffb9501..f1abe43aadb9 100644
--- a/arch/x86/entry/vdso/vma.c
+++ b/arch/x86/entry/vdso/vma.c
@@ -243,7 +243,8 @@ static const struct vm_special_mapping vvar_mapping = {
  * @image          - blob to map
  * @addr           - request a specific address (zero to map at free addr)
  */
-static int map_vdso(const struct vdso_image *image, unsigned long addr)
+static int map_vdso(const struct vdso_image *image, unsigned long addr,
+		    unsigned long *sysinfo_ehdr)
 {
 	struct mm_struct *mm = current->mm;
 	struct vm_area_struct *vma;
@@ -290,6 +291,7 @@ static int map_vdso(const struct vdso_image *image, unsigned long addr)
 	} else {
 		current->mm->context.vdso = (void __user *)text_start;
 		current->mm->context.vdso_image = image;
+		*sysinfo_ehdr = text_start;
 	}
 
 up_fail:
@@ -342,11 +344,12 @@ static unsigned long vdso_addr(unsigned long start, unsigned len)
 	return addr;
 }
 
-static int map_vdso_randomized(const struct vdso_image *image)
+static int map_vdso_randomized(const struct vdso_image *image,
+			       unsigned long *sysinfo_ehdr)
 {
 	unsigned long addr = vdso_addr(current->mm->start_stack, image->size-image->sym_vvar_start);
 
-	return map_vdso(image, addr);
+	return map_vdso(image, addr, sysinfo_ehdr);
 }
 #endif
 
@@ -354,6 +357,7 @@ int map_vdso_once(const struct vdso_image *image, unsigned long addr)
 {
 	struct mm_struct *mm = current->mm;
 	struct vm_area_struct *vma;
+	unsigned long unused;
 
 	mmap_write_lock(mm);
 	/*
@@ -372,41 +376,41 @@ int map_vdso_once(const struct vdso_image *image, unsigned long addr)
 	}
 	mmap_write_unlock(mm);
 
-	return map_vdso(image, addr);
+	return map_vdso(image, addr, &unused);
 }
 
 #ifdef CONFIG_X86_64
-static int load_vdso_64(void)
+static int load_vdso_64(unsigned long *sysinfo_ehdr)
 {
 	if (!vdso64_enabled)
 		return 0;
 
 #ifdef CONFIG_X86_X32_ABI
 	if (in_x32_syscall())
-		return map_vdso_randomized(&vdso_image_x32);
+		return map_vdso_randomized(&vdso_image_x32, sysinfo_ehdr);
 #endif
 
-	return map_vdso_randomized(&vdso_image_64);
+	return map_vdso_randomized(&vdso_image_64, sysinfo_ehdr);
 }
 #else
-static int load_vdso_64(void)
+static int load_vdso_64(unsigned long *sysinfo_ehdr)
 {
 	WARN_ON_ONCE(1);
 	return -ENODATA;
 }
 #endif
 
-int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
+int arch_setup_additional_pages(unsigned long *sysinfo_ehdr)
 {
 #if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION)
 	if (in_ia32_syscall()) {
 		if (vdso32_enabled != 1)  /* Other values all mean "disabled" */
 			return 0;
-		return map_vdso(&vdso_image_32, 0);
+		return map_vdso(&vdso_image_32, 0, sysinfo_ehdr);
 	}
 #endif
 
-	return load_vdso_64();
+	return load_vdso_64(sysinfo_ehdr);
 }
 
 bool arch_syscall_is_vdso_sigreturn(struct pt_regs *regs)
diff --git a/arch/x86/um/vdso/vma.c b/arch/x86/um/vdso/vma.c
index 76d9f6ce7a3d..77488065f7cc 100644
--- a/arch/x86/um/vdso/vma.c
+++ b/arch/x86/um/vdso/vma.c
@@ -50,7 +50,7 @@ static int __init init_vdso(void)
 }
 subsys_initcall(init_vdso);
 
-int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
+int arch_setup_additional_pages(unsigned long *sysinfo_ehdr)
 {
 	int err;
 	struct mm_struct *mm = current->mm;
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index dac2713c10ee..62741e55e3d1 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -836,6 +836,7 @@ static int load_elf_binary(struct linux_binprm *bprm)
 	unsigned long interp_load_addr = 0;
 	unsigned long start_code, end_code, start_data, end_data;
 	unsigned long reloc_func_desc __maybe_unused = 0;
+	unsigned long sysinfo_ehdr = 0;
 	int executable_stack = EXSTACK_DEFAULT;
 	struct elfhdr *elf_ex = (struct elfhdr *)bprm->buf;
 	struct elfhdr *interp_elf_ex = NULL;
@@ -1252,7 +1253,7 @@ static int load_elf_binary(struct linux_binprm *bprm)
 
 	set_binfmt(&elf_format);
 
-	retval = arch_setup_additional_pages(bprm, !!interpreter);
+	retval = arch_setup_additional_pages(&sysinfo_ehdr);
 	if (retval < 0)
 		goto out;
 
diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
index 11cbf20b19da..421a09bc6ee6 100644
--- a/fs/binfmt_elf_fdpic.c
+++ b/fs/binfmt_elf_fdpic.c
@@ -183,6 +183,7 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm)
 {
 	struct elf_fdpic_params exec_params, interp_params;
 	struct pt_regs *regs = current_pt_regs();
+	unsigned long sysinfo_ehdr = 0;
 	struct elf_phdr *phdr;
 	unsigned long stack_size, entryaddr;
 #ifdef ELF_FDPIC_PLAT_INIT
@@ -375,7 +376,7 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm)
 	if (retval < 0)
 		goto error;
 
-	retval = arch_setup_additional_pages(bprm, !!interpreter_name);
+	retval = arch_setup_additional_pages(&sysinfo_ehdr);
 	if (retval < 0)
 		goto error;
 #endif
diff --git a/include/linux/elf.h b/include/linux/elf.h
index 95bf7a1abaef..a8bea5611a4b 100644
--- a/include/linux/elf.h
+++ b/include/linux/elf.h
@@ -104,13 +104,20 @@ static inline int arch_elf_adjust_prot(int prot,
 }
 #endif
 
-struct linux_binprm;
 #ifdef CONFIG_ARCH_HAS_SETUP_ADDITIONAL_PAGES
-extern int arch_setup_additional_pages(struct linux_binprm *bprm,
-				       int uses_interp);
+/**
+ * arch_setup_additional_pages - Premap VMAs in a new-execed process
+ * @sysinfo_ehdr:	Returns vDSO position to be set in the initial
+ *			auxiliary vector (tag AT_SYSINFO_EHDR) by binfmt
+ *			loader. On failure isn't initialized.
+ *			As address == 0 is never used, it allows to check
+ *			if the tag should be set.
+ *
+ * Return: Zero if successful, or a negative error code on failure.
+ */
+extern int arch_setup_additional_pages(unsigned long *sysinfo_ehdr);
 #else
-static inline int arch_setup_additional_pages(struct linux_binprm *bprm,
-				       int uses_interp)
+static inline int arch_setup_additional_pages(unsigned long *sysinfo_ehdr)
 {
 	return 0;
 }
-- 
2.31.1


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2021-06-11 18:02 ` [PATCH v3 08/23] elf/vdso: Modify arch_setup_additional_pages() parameters Dmitry Safonov

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