sh: Tidy up and generalize page fault error paths.
This follows the x86 changes for tidying up the page fault error paths. We'll build on top of this for _32/_64 unification. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This commit is contained in:
Paul Mundt
parent
c4f10e5cd7
commit
dbdb4e9f3f
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@ -10,4 +10,6 @@ enum die_val {
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DIE_SSTEP,
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};
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extern void printk_address(unsigned long address, int reliable);
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#endif /* __ASM_SH_KDEBUG_H */
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@ -2,7 +2,7 @@
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* Page fault handler for SH with an MMU.
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*
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* Copyright (C) 1999 Niibe Yutaka
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* Copyright (C) 2003 - 2009 Paul Mundt
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* Copyright (C) 2003 - 2012 Paul Mundt
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*
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* Based on linux/arch/i386/mm/fault.c:
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* Copyright (C) 1995 Linus Torvalds
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@ -16,6 +16,7 @@
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#include <linux/hardirq.h>
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#include <linux/kprobes.h>
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#include <linux/perf_event.h>
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#include <linux/kdebug.h>
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#include <asm/io_trapped.h>
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#include <asm/mmu_context.h>
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#include <asm/tlbflush.h>
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@ -35,6 +36,20 @@ static inline int notify_page_fault(struct pt_regs *regs, int trap)
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return ret;
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}
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static void
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force_sig_info_fault(int si_signo, int si_code, unsigned long address,
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struct task_struct *tsk)
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{
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siginfo_t info;
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info.si_signo = si_signo;
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info.si_errno = 0;
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info.si_code = si_code;
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info.si_addr = (void __user *)address;
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force_sig_info(si_signo, &info, tsk);
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}
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/*
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* This is useful to dump out the page tables associated with
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* 'addr' in mm 'mm'.
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@ -176,6 +191,185 @@ static noinline int vmalloc_fault(unsigned long address)
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return 0;
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}
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static void
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show_fault_oops(struct pt_regs *regs, unsigned long address)
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{
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if (!oops_may_print())
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return;
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printk(KERN_ALERT "BUG: unable to handle kernel ");
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if (address < PAGE_SIZE)
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printk(KERN_CONT "NULL pointer dereference");
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else
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printk(KERN_CONT "paging request");
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printk(KERN_CONT " at %08lx\n", address);
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printk(KERN_ALERT "PC:");
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printk_address(regs->pc, 1);
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show_pte(NULL, address);
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}
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static noinline void
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no_context(struct pt_regs *regs, unsigned long writeaccess,
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unsigned long address)
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{
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/* Are we prepared to handle this kernel fault? */
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if (fixup_exception(regs))
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return;
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if (handle_trapped_io(regs, address))
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return;
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/*
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* Oops. The kernel tried to access some bad page. We'll have to
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* terminate things with extreme prejudice.
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*/
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bust_spinlocks(1);
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show_fault_oops(regs, address);
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die("Oops", regs, writeaccess);
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bust_spinlocks(0);
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do_exit(SIGKILL);
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}
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static void
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__bad_area_nosemaphore(struct pt_regs *regs, unsigned long writeaccess,
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unsigned long address, int si_code)
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{
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struct task_struct *tsk = current;
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/* User mode accesses just cause a SIGSEGV */
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if (user_mode(regs)) {
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/*
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* It's possible to have interrupts off here:
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*/
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local_irq_enable();
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force_sig_info_fault(SIGSEGV, si_code, address, tsk);
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return;
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}
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no_context(regs, writeaccess, address);
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}
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static noinline void
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bad_area_nosemaphore(struct pt_regs *regs, unsigned long writeaccess,
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unsigned long address)
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{
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__bad_area_nosemaphore(regs, writeaccess, address, SEGV_MAPERR);
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}
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static void
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__bad_area(struct pt_regs *regs, unsigned long writeaccess,
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unsigned long address, int si_code)
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{
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struct mm_struct *mm = current->mm;
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/*
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* Something tried to access memory that isn't in our memory map..
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* Fix it, but check if it's kernel or user first..
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*/
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up_read(&mm->mmap_sem);
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__bad_area_nosemaphore(regs, writeaccess, address, si_code);
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}
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static noinline void
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bad_area(struct pt_regs *regs, unsigned long writeaccess, unsigned long address)
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{
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__bad_area(regs, writeaccess, address, SEGV_MAPERR);
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}
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static noinline void
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bad_area_access_error(struct pt_regs *regs, unsigned long writeaccess,
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unsigned long address)
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{
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__bad_area(regs, writeaccess, address, SEGV_ACCERR);
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}
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static void out_of_memory(void)
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{
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/*
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* We ran out of memory, call the OOM killer, and return the userspace
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* (which will retry the fault, or kill us if we got oom-killed):
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*/
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up_read(¤t->mm->mmap_sem);
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pagefault_out_of_memory();
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}
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static void
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do_sigbus(struct pt_regs *regs, unsigned long writeaccess, unsigned long address)
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{
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struct task_struct *tsk = current;
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struct mm_struct *mm = tsk->mm;
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up_read(&mm->mmap_sem);
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/* Kernel mode? Handle exceptions or die: */
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if (!user_mode(regs))
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no_context(regs, writeaccess, address);
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force_sig_info_fault(SIGBUS, BUS_ADRERR, address, tsk);
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}
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static noinline int
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mm_fault_error(struct pt_regs *regs, unsigned long writeaccess,
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unsigned long address, unsigned int fault)
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{
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/*
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* Pagefault was interrupted by SIGKILL. We have no reason to
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* continue pagefault.
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*/
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if (fatal_signal_pending(current)) {
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if (!(fault & VM_FAULT_RETRY))
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up_read(¤t->mm->mmap_sem);
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if (!user_mode(regs))
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no_context(regs, writeaccess, address);
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return 1;
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}
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if (!(fault & VM_FAULT_ERROR))
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return 0;
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if (fault & VM_FAULT_OOM) {
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/* Kernel mode? Handle exceptions or die: */
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if (!user_mode(regs)) {
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up_read(¤t->mm->mmap_sem);
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no_context(regs, writeaccess, address);
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return 1;
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}
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out_of_memory();
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} else {
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if (fault & VM_FAULT_SIGBUS)
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do_sigbus(regs, writeaccess, address);
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else
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BUG();
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}
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return 1;
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}
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static inline int access_error(int write, struct vm_area_struct *vma)
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{
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if (write) {
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/* write, present and write, not present: */
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if (unlikely(!(vma->vm_flags & VM_WRITE)))
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return 1;
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return 0;
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}
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/* read, not present: */
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if (unlikely(!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))))
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return 1;
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return 0;
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}
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static int fault_in_kernel_space(unsigned long address)
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{
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return address >= TASK_SIZE;
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@ -194,15 +388,12 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
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struct task_struct *tsk;
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struct mm_struct *mm;
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struct vm_area_struct * vma;
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int si_code;
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int fault;
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siginfo_t info;
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unsigned int flags = (FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE |
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(writeaccess ? FAULT_FLAG_WRITE : 0));
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tsk = current;
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mm = tsk->mm;
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si_code = SEGV_MAPERR;
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vec = lookup_exception_vector();
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/*
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@ -220,7 +411,8 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
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if (notify_page_fault(regs, vec))
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return;
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goto bad_area_nosemaphore;
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bad_area_nosemaphore(regs, writeaccess, address);
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return;
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}
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if (unlikely(notify_page_fault(regs, vec)))
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@ -236,34 +428,38 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
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* If we're in an interrupt, have no user context or are running
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* in an atomic region then we must not take the fault:
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*/
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if (in_atomic() || !mm)
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goto no_context;
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if (unlikely(in_atomic() || !mm)) {
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bad_area_nosemaphore(regs, writeaccess, address);
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return;
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}
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retry:
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down_read(&mm->mmap_sem);
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vma = find_vma(mm, address);
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if (!vma)
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goto bad_area;
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if (vma->vm_start <= address)
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if (unlikely(!vma)) {
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bad_area(regs, writeaccess, address);
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return;
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}
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if (likely(vma->vm_start <= address))
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goto good_area;
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if (!(vma->vm_flags & VM_GROWSDOWN))
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goto bad_area;
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if (expand_stack(vma, address))
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goto bad_area;
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if (unlikely(!(vma->vm_flags & VM_GROWSDOWN))) {
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bad_area(regs, writeaccess, address);
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return;
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}
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if (unlikely(expand_stack(vma, address))) {
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bad_area(regs, writeaccess, address);
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return;
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}
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/*
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* Ok, we have a good vm_area for this memory access, so
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* we can handle it..
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*/
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good_area:
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si_code = SEGV_ACCERR;
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if (writeaccess) {
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if (!(vma->vm_flags & VM_WRITE))
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goto bad_area;
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} else {
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if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)))
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goto bad_area;
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if (unlikely(access_error(writeaccess, vma))) {
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bad_area_access_error(regs, writeaccess, address);
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return;
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}
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/*
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@ -273,16 +469,9 @@ good_area:
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*/
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fault = handle_mm_fault(mm, vma, address, flags);
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if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
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return;
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if (unlikely(fault & VM_FAULT_ERROR)) {
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if (fault & VM_FAULT_OOM)
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goto out_of_memory;
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else if (fault & VM_FAULT_SIGBUS)
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goto do_sigbus;
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BUG();
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}
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if (unlikely(fault & (VM_FAULT_RETRY | VM_FAULT_ERROR)))
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if (mm_fault_error(regs, writeaccess, address, fault))
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return;
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if (flags & FAULT_FLAG_ALLOW_RETRY) {
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if (fault & VM_FAULT_MAJOR) {
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@ -307,80 +496,6 @@ good_area:
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}
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up_read(&mm->mmap_sem);
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return;
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/*
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* Something tried to access memory that isn't in our memory map..
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* Fix it, but check if it's kernel or user first..
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*/
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bad_area:
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up_read(&mm->mmap_sem);
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bad_area_nosemaphore:
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if (user_mode(regs)) {
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info.si_signo = SIGSEGV;
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info.si_errno = 0;
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info.si_code = si_code;
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info.si_addr = (void *) address;
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force_sig_info(SIGSEGV, &info, tsk);
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return;
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}
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no_context:
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/* Are we prepared to handle this kernel fault? */
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if (fixup_exception(regs))
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return;
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if (handle_trapped_io(regs, address))
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return;
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/*
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* Oops. The kernel tried to access some bad page. We'll have to
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* terminate things with extreme prejudice.
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*
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*/
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bust_spinlocks(1);
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if (oops_may_print()) {
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printk(KERN_ALERT
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"Unable to handle kernel %s at virtual address %08lx\n",
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(address < PAGE_SIZE) ? "NULL pointer dereference" :
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"paging request", address);
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show_pte(mm, address);
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}
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die("Oops", regs, writeaccess);
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bust_spinlocks(0);
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do_exit(SIGKILL);
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/*
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* We ran out of memory, or some other thing happened to us that made
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* us unable to handle the page fault gracefully.
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*/
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out_of_memory:
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up_read(&mm->mmap_sem);
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if (!user_mode(regs))
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goto no_context;
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pagefault_out_of_memory();
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return;
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do_sigbus:
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up_read(&mm->mmap_sem);
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/*
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* Send a sigbus, regardless of whether we were in kernel
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* or user mode.
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*/
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info.si_signo = SIGBUS;
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info.si_errno = 0;
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info.si_code = BUS_ADRERR;
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info.si_addr = (void *)address;
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force_sig_info(SIGBUS, &info, tsk);
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/* Kernel mode? Handle exceptions or die */
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if (!user_mode(regs))
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goto no_context;
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}
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/*
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