s390/vdso: use _install_special_mapping to establish vdso
Switch to the improved _install_special_mapping function to install the vdso mapping. This has two advantages, the arch_vma_name function is not needed anymore and the vdso vma still has its name after its memory location has been changed with mremap. Tested-by: Michael Holzheu <holzheu@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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@ -50,6 +50,56 @@ static struct page **vdso64_pagelist;
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*/
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unsigned int __read_mostly vdso_enabled = 1;
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static int vdso_fault(const struct vm_special_mapping *sm,
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struct vm_area_struct *vma, struct vm_fault *vmf)
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{
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struct page **vdso_pagelist;
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unsigned long vdso_pages;
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vdso_pagelist = vdso64_pagelist;
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vdso_pages = vdso64_pages;
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#ifdef CONFIG_COMPAT
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if (is_compat_task()) {
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vdso_pagelist = vdso32_pagelist;
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vdso_pages = vdso32_pages;
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}
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#endif
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if (vmf->pgoff >= vdso_pages)
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return VM_FAULT_SIGBUS;
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vmf->page = vdso_pagelist[vmf->pgoff];
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get_page(vmf->page);
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return 0;
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}
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static int vdso_mremap(const struct vm_special_mapping *sm,
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struct vm_area_struct *vma)
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{
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unsigned long vdso_pages;
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vdso_pages = vdso64_pages;
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#ifdef CONFIG_COMPAT
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if (is_compat_task())
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vdso_pages = vdso32_pages;
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#endif
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if ((vdso_pages << PAGE_SHIFT) != vma->vm_end - vma->vm_start)
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return -EINVAL;
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if (WARN_ON_ONCE(current->mm != vma->vm_mm))
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return -EFAULT;
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current->mm->context.vdso_base = vma->vm_start;
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return 0;
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}
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static const struct vm_special_mapping vdso_mapping = {
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.name = "[vdso]",
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.fault = vdso_fault,
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.mremap = vdso_mremap,
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};
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static int __init vdso_setup(char *s)
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{
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unsigned long val;
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@ -181,7 +231,7 @@ static void vdso_init_cr5(void)
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int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
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{
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struct mm_struct *mm = current->mm;
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struct page **vdso_pagelist;
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struct vm_area_struct *vma;
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unsigned long vdso_pages;
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unsigned long vdso_base;
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int rc;
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@ -194,13 +244,10 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
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if (!uses_interp)
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return 0;
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vdso_pagelist = vdso64_pagelist;
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vdso_pages = vdso64_pages;
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#ifdef CONFIG_COMPAT
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if (is_compat_task()) {
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vdso_pagelist = vdso32_pagelist;
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if (is_compat_task())
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vdso_pages = vdso32_pages;
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}
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#endif
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/*
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* vDSO has a problem and was disabled, just don't "enable" it for
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@ -209,8 +256,6 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
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if (vdso_pages == 0)
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return 0;
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current->mm->context.vdso_base = 0;
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/*
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* pick a base address for the vDSO in process space. We try to put
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* it at vdso_base which is the "natural" base for it, but we might
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@ -224,13 +269,6 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
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goto out_up;
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}
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/*
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* Put vDSO base into mm struct. We need to do this before calling
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* install_special_mapping or the perf counter mmap tracking code
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* will fail to recognise it as a vDSO (since arch_vma_name fails).
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*/
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current->mm->context.vdso_base = vdso_base;
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/*
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* our vma flags don't have VM_WRITE so by default, the process
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* isn't allowed to write those pages.
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@ -241,24 +279,23 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
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* It's fine to use that for setting breakpoints in the vDSO code
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* pages though.
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*/
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rc = install_special_mapping(mm, vdso_base, vdso_pages << PAGE_SHIFT,
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vma = _install_special_mapping(mm, vdso_base, vdso_pages << PAGE_SHIFT,
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VM_READ|VM_EXEC|
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VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
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vdso_pagelist);
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if (rc)
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current->mm->context.vdso_base = 0;
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&vdso_mapping);
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if (IS_ERR(vma)) {
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rc = PTR_ERR(vma);
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goto out_up;
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}
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current->mm->context.vdso_base = vdso_base;
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rc = 0;
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out_up:
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up_write(&mm->mmap_sem);
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return rc;
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}
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const char *arch_vma_name(struct vm_area_struct *vma)
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{
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if (vma->vm_mm && vma->vm_start == vma->vm_mm->context.vdso_base)
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return "[vdso]";
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return NULL;
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}
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static int __init vdso_init(void)
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{
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int i;
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