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[S390] Add dynamic size check for usercopy functions.
Use a wrapper for copy_to/from_user to chose the best usercopy method. The mvcos instruction is better for sizes greater than 256 bytes, if mvcos is not available a page table walk is better for sizes greater than 1024 bytes. Also removed the redundant copy_to/from_user_std_small functions. Signed-off-by: Gerald Schaefer <geraldsc@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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Gerald Schaefer
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Martin Schwidefsky
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Dec 4, 2006
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,153 @@ | ||
| /* | ||
| * arch/s390/lib/uaccess_pt.c | ||
| * | ||
| * User access functions based on page table walks. | ||
| * | ||
| * Copyright IBM Corp. 2006 | ||
| * Author(s): Gerald Schaefer (gerald.schaefer@de.ibm.com) | ||
| */ | ||
|
|
||
| #include <linux/errno.h> | ||
| #include <asm/uaccess.h> | ||
| #include <linux/mm.h> | ||
| #include <asm/futex.h> | ||
|
|
||
| static inline int __handle_fault(struct mm_struct *mm, unsigned long address, | ||
| int write_access) | ||
| { | ||
| struct vm_area_struct *vma; | ||
| int ret = -EFAULT; | ||
|
|
||
| down_read(&mm->mmap_sem); | ||
| vma = find_vma(mm, address); | ||
| if (unlikely(!vma)) | ||
| goto out; | ||
| if (unlikely(vma->vm_start > address)) { | ||
| if (!(vma->vm_flags & VM_GROWSDOWN)) | ||
| goto out; | ||
| if (expand_stack(vma, address)) | ||
| goto out; | ||
| } | ||
|
|
||
| if (!write_access) { | ||
| /* page not present, check vm flags */ | ||
| if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))) | ||
| goto out; | ||
| } else { | ||
| if (!(vma->vm_flags & VM_WRITE)) | ||
| goto out; | ||
| } | ||
|
|
||
| survive: | ||
| switch (handle_mm_fault(mm, vma, address, write_access)) { | ||
| case VM_FAULT_MINOR: | ||
| current->min_flt++; | ||
| break; | ||
| case VM_FAULT_MAJOR: | ||
| current->maj_flt++; | ||
| break; | ||
| case VM_FAULT_SIGBUS: | ||
| goto out_sigbus; | ||
| case VM_FAULT_OOM: | ||
| goto out_of_memory; | ||
| default: | ||
| BUG(); | ||
| } | ||
| ret = 0; | ||
| out: | ||
| up_read(&mm->mmap_sem); | ||
| return ret; | ||
|
|
||
| out_of_memory: | ||
| up_read(&mm->mmap_sem); | ||
| if (current->pid == 1) { | ||
| yield(); | ||
| goto survive; | ||
| } | ||
| printk("VM: killing process %s\n", current->comm); | ||
| return ret; | ||
|
|
||
| out_sigbus: | ||
| up_read(&mm->mmap_sem); | ||
| current->thread.prot_addr = address; | ||
| current->thread.trap_no = 0x11; | ||
| force_sig(SIGBUS, current); | ||
| return ret; | ||
| } | ||
|
|
||
| static inline size_t __user_copy_pt(unsigned long uaddr, void *kptr, | ||
| size_t n, int write_user) | ||
| { | ||
| struct mm_struct *mm = current->mm; | ||
| unsigned long offset, pfn, done, size; | ||
| pgd_t *pgd; | ||
| pmd_t *pmd; | ||
| pte_t *pte; | ||
| void *from, *to; | ||
|
|
||
| done = 0; | ||
| retry: | ||
| spin_lock(&mm->page_table_lock); | ||
| do { | ||
| pgd = pgd_offset(mm, uaddr); | ||
| if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) | ||
| goto fault; | ||
|
|
||
| pmd = pmd_offset(pgd, uaddr); | ||
| if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) | ||
| goto fault; | ||
|
|
||
| pte = pte_offset_map(pmd, uaddr); | ||
| if (!pte || !pte_present(*pte) || | ||
| (write_user && !pte_write(*pte))) | ||
| goto fault; | ||
|
|
||
| pfn = pte_pfn(*pte); | ||
| if (!pfn_valid(pfn)) | ||
| goto out; | ||
|
|
||
| offset = uaddr & (PAGE_SIZE - 1); | ||
| size = min(n - done, PAGE_SIZE - offset); | ||
| if (write_user) { | ||
| to = (void *)((pfn << PAGE_SHIFT) + offset); | ||
| from = kptr + done; | ||
| } else { | ||
| from = (void *)((pfn << PAGE_SHIFT) + offset); | ||
| to = kptr + done; | ||
| } | ||
| memcpy(to, from, size); | ||
| done += size; | ||
| uaddr += size; | ||
| } while (done < n); | ||
| out: | ||
| spin_unlock(&mm->page_table_lock); | ||
| return n - done; | ||
| fault: | ||
| spin_unlock(&mm->page_table_lock); | ||
| if (__handle_fault(mm, uaddr, write_user)) | ||
| return n - done; | ||
| goto retry; | ||
| } | ||
|
|
||
| size_t copy_from_user_pt(size_t n, const void __user *from, void *to) | ||
| { | ||
| size_t rc; | ||
|
|
||
| if (segment_eq(get_fs(), KERNEL_DS)) { | ||
| memcpy(to, (void __kernel __force *) from, n); | ||
| return 0; | ||
| } | ||
| rc = __user_copy_pt((unsigned long) from, to, n, 0); | ||
| if (unlikely(rc)) | ||
| memset(to + n - rc, 0, rc); | ||
| return rc; | ||
| } | ||
|
|
||
| size_t copy_to_user_pt(size_t n, void __user *to, const void *from) | ||
| { | ||
| if (segment_eq(get_fs(), KERNEL_DS)) { | ||
| memcpy((void __kernel __force *) to, from, n); | ||
| return 0; | ||
| } | ||
| return __user_copy_pt((unsigned long) to, (void *) from, n, 1); | ||
| } |
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