From 6c1e3e79430615d0472dbf9f8fed89c571e66423 Mon Sep 17 00:00:00 2001 From: Gerald Schaefer Date: Mon, 7 Dec 2009 12:51:47 +0100 Subject: [PATCH] [S390] Use do_exception() in pagetable walk usercopy functions. The pagetable walk usercopy functions have used a modified copy of the do_exception() function for fault handling. This lead to inconsistencies with recent changes to do_exception(), e.g. performance counters. This patch changes the pagetable walk usercopy code to call do_exception() directly, eliminating the redundancy. A new parameter is added to do_exception() to specify the fault address. Signed-off-by: Gerald Schaefer Signed-off-by: Martin Schwidefsky --- arch/s390/include/asm/uaccess.h | 2 + arch/s390/lib/uaccess_pt.c | 147 +++++++++++--------------------- arch/s390/mm/fault.c | 23 +++++ 3 files changed, 76 insertions(+), 96 deletions(-) diff --git a/arch/s390/include/asm/uaccess.h b/arch/s390/include/asm/uaccess.h index 8377e91533d2..cbf0a8745bf4 100644 --- a/arch/s390/include/asm/uaccess.h +++ b/arch/s390/include/asm/uaccess.h @@ -93,6 +93,8 @@ extern struct uaccess_ops uaccess_mvcos; extern struct uaccess_ops uaccess_mvcos_switch; extern struct uaccess_ops uaccess_pt; +extern int __handle_fault(unsigned long, unsigned long, int); + static inline int __put_user_fn(size_t size, void __user *ptr, void *x) { size = uaccess.copy_to_user_small(size, ptr, x); diff --git a/arch/s390/lib/uaccess_pt.c b/arch/s390/lib/uaccess_pt.c index cb5d59eab0ee..404f2de296dc 100644 --- a/arch/s390/lib/uaccess_pt.c +++ b/arch/s390/lib/uaccess_pt.c @@ -23,86 +23,21 @@ static inline pte_t *follow_table(struct mm_struct *mm, unsigned long addr) pgd = pgd_offset(mm, addr); if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) - return NULL; + return (pte_t *) 0x3a; pud = pud_offset(pgd, addr); if (pud_none(*pud) || unlikely(pud_bad(*pud))) - return NULL; + return (pte_t *) 0x3b; pmd = pmd_offset(pud, addr); if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) - return NULL; + return (pte_t *) 0x10; return pte_offset_map(pmd, addr); } -static int __handle_fault(struct mm_struct *mm, unsigned long address, - int write_access) -{ - struct vm_area_struct *vma; - int ret = -EFAULT; - int fault; - - if (in_atomic()) - return ret; - 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: - fault = handle_mm_fault(mm, vma, address, write_access ? FAULT_FLAG_WRITE : 0); - if (unlikely(fault & VM_FAULT_ERROR)) { - if (fault & VM_FAULT_OOM) - goto out_of_memory; - else if (fault & VM_FAULT_SIGBUS) - goto out_sigbus; - BUG(); - } - if (fault & VM_FAULT_MAJOR) - current->maj_flt++; - else - current->min_flt++; - ret = 0; -out: - up_read(&mm->mmap_sem); - return ret; - -out_of_memory: - up_read(&mm->mmap_sem); - if (is_global_init(current)) { - yield(); - down_read(&mm->mmap_sem); - 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 size_t __user_copy_pt(unsigned long uaddr, void *kptr, - size_t n, int write_user) +static __always_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; @@ -114,12 +49,17 @@ retry: spin_lock(&mm->page_table_lock); do { pte = follow_table(mm, uaddr); - if (!pte || !pte_present(*pte) || - (write_user && !pte_write(*pte))) + if ((unsigned long) pte < 0x1000) goto fault; + if (!pte_present(*pte)) { + pte = (pte_t *) 0x11; + goto fault; + } else if (write_user && !pte_write(*pte)) { + pte = (pte_t *) 0x04; + goto fault; + } pfn = pte_pfn(*pte); - offset = uaddr & (PAGE_SIZE - 1); size = min(n - done, PAGE_SIZE - offset); if (write_user) { @@ -137,7 +77,7 @@ retry: return n - done; fault: spin_unlock(&mm->page_table_lock); - if (__handle_fault(mm, uaddr, write_user)) + if (__handle_fault(uaddr, (unsigned long) pte, write_user)) return n - done; goto retry; } @@ -146,30 +86,31 @@ fault: * Do DAT for user address by page table walk, return kernel address. * This function needs to be called with current->mm->page_table_lock held. */ -static unsigned long __dat_user_addr(unsigned long uaddr) +static __always_inline unsigned long __dat_user_addr(unsigned long uaddr) { struct mm_struct *mm = current->mm; - unsigned long pfn, ret; + unsigned long pfn; pte_t *pte; int rc; - ret = 0; retry: pte = follow_table(mm, uaddr); - if (!pte || !pte_present(*pte)) + if ((unsigned long) pte < 0x1000) goto fault; + if (!pte_present(*pte)) { + pte = (pte_t *) 0x11; + goto fault; + } pfn = pte_pfn(*pte); - ret = (pfn << PAGE_SHIFT) + (uaddr & (PAGE_SIZE - 1)); -out: - return ret; + return (pfn << PAGE_SHIFT) + (uaddr & (PAGE_SIZE - 1)); fault: spin_unlock(&mm->page_table_lock); - rc = __handle_fault(mm, uaddr, 0); + rc = __handle_fault(uaddr, (unsigned long) pte, 0); spin_lock(&mm->page_table_lock); - if (rc) - goto out; - goto retry; + if (!rc) + goto retry; + return 0; } size_t copy_from_user_pt(size_t n, const void __user *from, void *to) @@ -234,8 +175,12 @@ retry: spin_lock(&mm->page_table_lock); do { pte = follow_table(mm, uaddr); - if (!pte || !pte_present(*pte)) + if ((unsigned long) pte < 0x1000) + goto fault; + if (!pte_present(*pte)) { + pte = (pte_t *) 0x11; goto fault; + } pfn = pte_pfn(*pte); offset = uaddr & (PAGE_SIZE-1); @@ -249,9 +194,8 @@ retry: return done + 1; fault: spin_unlock(&mm->page_table_lock); - if (__handle_fault(mm, uaddr, 0)) { + if (__handle_fault(uaddr, (unsigned long) pte, 0)) return 0; - } goto retry; } @@ -284,7 +228,7 @@ static size_t copy_in_user_pt(size_t n, void __user *to, { struct mm_struct *mm = current->mm; unsigned long offset_from, offset_to, offset_max, pfn_from, pfn_to, - uaddr, done, size; + uaddr, done, size, error_code; unsigned long uaddr_from = (unsigned long) from; unsigned long uaddr_to = (unsigned long) to; pte_t *pte_from, *pte_to; @@ -298,17 +242,28 @@ static size_t copy_in_user_pt(size_t n, void __user *to, retry: spin_lock(&mm->page_table_lock); do { + write_user = 0; + uaddr = uaddr_from; pte_from = follow_table(mm, uaddr_from); - if (!pte_from || !pte_present(*pte_from)) { - uaddr = uaddr_from; - write_user = 0; + error_code = (unsigned long) pte_from; + if (error_code < 0x1000) + goto fault; + if (!pte_present(*pte_from)) { + error_code = 0x11; goto fault; } + write_user = 1; + uaddr = uaddr_to; pte_to = follow_table(mm, uaddr_to); - if (!pte_to || !pte_present(*pte_to) || !pte_write(*pte_to)) { - uaddr = uaddr_to; - write_user = 1; + error_code = (unsigned long) pte_to; + if (error_code < 0x1000) + goto fault; + if (!pte_present(*pte_to)) { + error_code = 0x11; + goto fault; + } else if (!pte_write(*pte_to)) { + error_code = 0x04; goto fault; } @@ -329,7 +284,7 @@ retry: return n - done; fault: spin_unlock(&mm->page_table_lock); - if (__handle_fault(mm, uaddr, write_user)) + if (__handle_fault(uaddr, error_code, write_user)) return n - done; goto retry; } diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c index 5a9e9a77dc16..fc102e70d9c2 100644 --- a/arch/s390/mm/fault.c +++ b/arch/s390/mm/fault.c @@ -442,6 +442,29 @@ no_context: } #endif +int __handle_fault(unsigned long uaddr, unsigned long int_code, int write_user) +{ + struct pt_regs regs; + int access, fault; + + regs.psw.mask = psw_kernel_bits; + if (!irqs_disabled()) + regs.psw.mask |= PSW_MASK_IO | PSW_MASK_EXT; + regs.psw.addr = (unsigned long) __builtin_return_address(0); + regs.psw.addr |= PSW_ADDR_AMODE; + uaddr &= PAGE_MASK; + access = write_user ? VM_WRITE : VM_READ; + fault = do_exception(®s, access, uaddr | 2); + if (unlikely(fault)) { + if (fault & VM_FAULT_OOM) { + pagefault_out_of_memory(); + fault = 0; + } else if (fault & VM_FAULT_SIGBUS) + do_sigbus(®s, int_code, uaddr); + } + return fault ? -EFAULT : 0; +} + #ifdef CONFIG_PFAULT /* * 'pfault' pseudo page faults routines. -- 2.20.1