diff options
| -rw-r--r-- | arch/s390/kernel/vdso.c | 91 |
1 files changed, 64 insertions, 27 deletions
diff --git a/arch/s390/kernel/vdso.c b/arch/s390/kernel/vdso.c index 10516ae3b55e..b89d19f6f2ab 100644 --- a/arch/s390/kernel/vdso.c +++ b/arch/s390/kernel/vdso.c @@ -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 @@ -225,13 +270,6 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) } /* - * 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. * gdb can break that with ptrace interface, and thus trigger COW @@ -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, - VM_READ|VM_EXEC| - VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC, - vdso_pagelist); - if (rc) - current->mm->context.vdso_base = 0; + vma = _install_special_mapping(mm, vdso_base, vdso_pages << PAGE_SHIFT, + VM_READ|VM_EXEC| + VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC, + &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; |