s390/vdso: use _install_special_mapping to establish vdso (35bb092a) · Commits · 戴 / test

arch/s390/kernel/vdso.c

+64 −27

Original line number	Diff line number	Diff line
		@@ -50,6 +50,56 @@ static struct page **vdso64_pagelist;
		*/
		unsigned int __read_mostly vdso_enabled = 1;

		static int vdso_fault(const struct vm_special_mapping *sm,
		struct vm_area_struct vma, struct vm_fault vmf)
		{
		struct page **vdso_pagelist;
		unsigned long vdso_pages;

		vdso_pagelist = vdso64_pagelist;
		vdso_pages = vdso64_pages;
		#ifdef CONFIG_COMPAT
		if (is_compat_task()) {
		vdso_pagelist = vdso32_pagelist;
		vdso_pages = vdso32_pages;
		}
		#endif

		if (vmf->pgoff >= vdso_pages)
		return VM_FAULT_SIGBUS;

		vmf->page = vdso_pagelist[vmf->pgoff];
		get_page(vmf->page);
		return 0;
		}

		static int vdso_mremap(const struct vm_special_mapping *sm,
		struct vm_area_struct *vma)
		{
		unsigned long vdso_pages;

		vdso_pages = vdso64_pages;
		#ifdef CONFIG_COMPAT
		if (is_compat_task())
		vdso_pages = vdso32_pages;
		#endif

		if ((vdso_pages << PAGE_SHIFT) != vma->vm_end - vma->vm_start)
		return -EINVAL;

		if (WARN_ON_ONCE(current->mm != vma->vm_mm))
		return -EFAULT;

		current->mm->context.vdso_base = vma->vm_start;
		return 0;
		}

		static const struct vm_special_mapping vdso_mapping = {
		.name = "[vdso]",
		.fault = vdso_fault,
		.mremap = vdso_mremap,
		};

		static int __init vdso_setup(char *s)
		{
		unsigned long val;
		@@ -181,7 +231,7 @@ static void vdso_init_cr5(void)
		int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
		{
		struct mm_struct *mm = current->mm;
		struct page **vdso_pagelist;
		struct vm_area_struct *vma;
		unsigned long vdso_pages;
		unsigned long vdso_base;
		int rc;
		@@ -194,13 +244,10 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
		if (!uses_interp)
		return 0;

		vdso_pagelist = vdso64_pagelist;
		vdso_pages = vdso64_pages;
		#ifdef CONFIG_COMPAT
		if (is_compat_task()) {
		vdso_pagelist = vdso32_pagelist;
		if (is_compat_task())
		vdso_pages = vdso32_pages;
		}
		#endif
		/*
		* vDSO has a problem and was disabled, just don't "enable" it for
		@@ -209,8 +256,6 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
		if (vdso_pages == 0)
		return 0;

		current->mm->context.vdso_base = 0;

		/*
		* pick a base address for the vDSO in process space. We try to put
		* it at vdso_base which is the "natural" base for it, but we might
		@@ -224,13 +269,6 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
		goto out_up;
		}

		/*
		* Put vDSO base into mm struct. We need to do this before calling
		* install_special_mapping or the perf counter mmap tracking code
		* will fail to recognise it as a vDSO (since arch_vma_name fails).
		*/
		current->mm->context.vdso_base = vdso_base;

		/*
		* our vma flags don't have VM_WRITE so by default, the process
		* isn't allowed to write those pages.
		@@ -241,24 +279,23 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
		* It's fine to use that for setting breakpoints in the vDSO code
		* pages though.
		*/
		rc = install_special_mapping(mm, vdso_base, vdso_pages << PAGE_SHIFT,
		vma = _install_special_mapping(mm, vdso_base, vdso_pages << PAGE_SHIFT,
		VM_READ\|VM_EXEC\|
		VM_MAYREAD\|VM_MAYWRITE\|VM_MAYEXEC,
		vdso_pagelist);
		if (rc)
		current->mm->context.vdso_base = 0;
		&vdso_mapping);
		if (IS_ERR(vma)) {
		rc = PTR_ERR(vma);
		goto out_up;
		}

		current->mm->context.vdso_base = vdso_base;
		rc = 0;

		out_up:
		up_write(&mm->mmap_sem);
		return rc;
		}

		const char arch_vma_name(struct vm_area_struct vma)
		{
		if (vma->vm_mm && vma->vm_start == vma->vm_mm->context.vdso_base)
		return "[vdso]";
		return NULL;
		}

		static int __init vdso_init(void)
		{
		int i;

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