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author | Paul Mundt <lethal@linux-sh.org> | 2007-11-20 09:01:55 +0100 |
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committer | Paul Mundt <lethal@linux-sh.org> | 2008-01-28 05:18:50 +0100 |
commit | 811d50cb43eb730cc325df0c6913556e25739797 (patch) | |
tree | c62c7ec9d53b4ad3357251bfae0c28f6fb2d773d /arch/sh/mm/fault_32.c | |
parent | sh: Tidy up various clear_page()/copy_page() definitions. (diff) | |
download | linux-811d50cb43eb730cc325df0c6913556e25739797.tar.xz linux-811d50cb43eb730cc325df0c6913556e25739797.zip |
sh: Move in the SH-5 TLB miss.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Diffstat (limited to 'arch/sh/mm/fault_32.c')
-rw-r--r-- | arch/sh/mm/fault_32.c | 303 |
1 files changed, 303 insertions, 0 deletions
diff --git a/arch/sh/mm/fault_32.c b/arch/sh/mm/fault_32.c new file mode 100644 index 000000000000..60d74f793a1d --- /dev/null +++ b/arch/sh/mm/fault_32.c @@ -0,0 +1,303 @@ +/* + * Page fault handler for SH with an MMU. + * + * Copyright (C) 1999 Niibe Yutaka + * Copyright (C) 2003 - 2007 Paul Mundt + * + * Based on linux/arch/i386/mm/fault.c: + * Copyright (C) 1995 Linus Torvalds + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + */ +#include <linux/kernel.h> +#include <linux/mm.h> +#include <linux/hardirq.h> +#include <linux/kprobes.h> +#include <asm/system.h> +#include <asm/mmu_context.h> +#include <asm/tlbflush.h> +#include <asm/kgdb.h> + +/* + * This routine handles page faults. It determines the address, + * and the problem, and then passes it off to one of the appropriate + * routines. + */ +asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, + unsigned long writeaccess, + unsigned long address) +{ + struct task_struct *tsk; + struct mm_struct *mm; + struct vm_area_struct * vma; + int si_code; + int fault; + siginfo_t info; + + trace_hardirqs_on(); + local_irq_enable(); + +#ifdef CONFIG_SH_KGDB + if (kgdb_nofault && kgdb_bus_err_hook) + kgdb_bus_err_hook(); +#endif + + tsk = current; + mm = tsk->mm; + si_code = SEGV_MAPERR; + + if (unlikely(address >= TASK_SIZE)) { + /* + * Synchronize this task's top level page-table + * with the 'reference' page table. + * + * Do _not_ use "tsk" here. We might be inside + * an interrupt in the middle of a task switch.. + */ + int offset = pgd_index(address); + pgd_t *pgd, *pgd_k; + pud_t *pud, *pud_k; + pmd_t *pmd, *pmd_k; + + pgd = get_TTB() + offset; + pgd_k = swapper_pg_dir + offset; + + /* This will never happen with the folded page table. */ + if (!pgd_present(*pgd)) { + if (!pgd_present(*pgd_k)) + goto bad_area_nosemaphore; + set_pgd(pgd, *pgd_k); + return; + } + + pud = pud_offset(pgd, address); + pud_k = pud_offset(pgd_k, address); + if (pud_present(*pud) || !pud_present(*pud_k)) + goto bad_area_nosemaphore; + set_pud(pud, *pud_k); + + pmd = pmd_offset(pud, address); + pmd_k = pmd_offset(pud_k, address); + if (pmd_present(*pmd) || !pmd_present(*pmd_k)) + goto bad_area_nosemaphore; + set_pmd(pmd, *pmd_k); + + return; + } + + /* + * If we're in an interrupt or have no user + * context, we must not take the fault.. + */ + if (in_atomic() || !mm) + goto no_context; + + down_read(&mm->mmap_sem); + + vma = find_vma(mm, address); + if (!vma) + goto bad_area; + if (vma->vm_start <= address) + goto good_area; + if (!(vma->vm_flags & VM_GROWSDOWN)) + goto bad_area; + if (expand_stack(vma, address)) + goto bad_area; +/* + * Ok, we have a good vm_area for this memory access, so + * we can handle it.. + */ +good_area: + si_code = SEGV_ACCERR; + if (writeaccess) { + if (!(vma->vm_flags & VM_WRITE)) + goto bad_area; + } else { + if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))) + goto bad_area; + } + + /* + * If for any reason at all we couldn't handle the fault, + * make sure we exit gracefully rather than endlessly redo + * the fault. + */ +survive: + fault = handle_mm_fault(mm, vma, address, writeaccess); + if (unlikely(fault & VM_FAULT_ERROR)) { + if (fault & VM_FAULT_OOM) + goto out_of_memory; + else if (fault & VM_FAULT_SIGBUS) + goto do_sigbus; + BUG(); + } + if (fault & VM_FAULT_MAJOR) + tsk->maj_flt++; + else + tsk->min_flt++; + + up_read(&mm->mmap_sem); + return; + +/* + * Something tried to access memory that isn't in our memory map.. + * Fix it, but check if it's kernel or user first.. + */ +bad_area: + up_read(&mm->mmap_sem); + +bad_area_nosemaphore: + if (user_mode(regs)) { + info.si_signo = SIGSEGV; + info.si_errno = 0; + info.si_code = si_code; + info.si_addr = (void *) address; + force_sig_info(SIGSEGV, &info, tsk); + return; + } + +no_context: + /* Are we prepared to handle this kernel fault? */ + if (fixup_exception(regs)) + return; + +/* + * Oops. The kernel tried to access some bad page. We'll have to + * terminate things with extreme prejudice. + * + */ + + bust_spinlocks(1); + + if (oops_may_print()) { + __typeof__(pte_val(__pte(0))) page; + + if (address < PAGE_SIZE) + printk(KERN_ALERT "Unable to handle kernel NULL " + "pointer dereference"); + else + printk(KERN_ALERT "Unable to handle kernel paging " + "request"); + printk(" at virtual address %08lx\n", address); + printk(KERN_ALERT "pc = %08lx\n", regs->pc); + page = (unsigned long)get_TTB(); + if (page) { + page = ((__typeof__(page) *)page)[address >> PGDIR_SHIFT]; + printk(KERN_ALERT "*pde = %08lx\n", page); + if (page & _PAGE_PRESENT) { + page &= PAGE_MASK; + address &= 0x003ff000; + page = ((__typeof__(page) *) + __va(page))[address >> + PAGE_SHIFT]; + printk(KERN_ALERT "*pte = %08lx\n", page); + } + } + } + + die("Oops", regs, writeaccess); + bust_spinlocks(0); + do_exit(SIGKILL); + +/* + * We ran out of memory, or some other thing happened to us that made + * us unable to handle the page fault gracefully. + */ +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", tsk->comm); + if (user_mode(regs)) + do_group_exit(SIGKILL); + goto no_context; + +do_sigbus: + up_read(&mm->mmap_sem); + + /* + * Send a sigbus, regardless of whether we were in kernel + * or user mode. + */ + info.si_signo = SIGBUS; + info.si_errno = 0; + info.si_code = BUS_ADRERR; + info.si_addr = (void *)address; + force_sig_info(SIGBUS, &info, tsk); + + /* Kernel mode? Handle exceptions or die */ + if (!user_mode(regs)) + goto no_context; +} + +#ifdef CONFIG_SH_STORE_QUEUES +/* + * This is a special case for the SH-4 store queues, as pages for this + * space still need to be faulted in before it's possible to flush the + * store queue cache for writeout to the remapped region. + */ +#define P3_ADDR_MAX (P4SEG_STORE_QUE + 0x04000000) +#else +#define P3_ADDR_MAX P4SEG +#endif + +/* + * Called with interrupts disabled. + */ +asmlinkage int __kprobes __do_page_fault(struct pt_regs *regs, + unsigned long writeaccess, + unsigned long address) +{ + pgd_t *pgd; + pud_t *pud; + pmd_t *pmd; + pte_t *pte; + pte_t entry; + +#ifdef CONFIG_SH_KGDB + if (kgdb_nofault && kgdb_bus_err_hook) + kgdb_bus_err_hook(); +#endif + + /* + * We don't take page faults for P1, P2, and parts of P4, these + * are always mapped, whether it be due to legacy behaviour in + * 29-bit mode, or due to PMB configuration in 32-bit mode. + */ + if (address >= P3SEG && address < P3_ADDR_MAX) { + pgd = pgd_offset_k(address); + } else { + if (unlikely(address >= TASK_SIZE || !current->mm)) + return 1; + + pgd = pgd_offset(current->mm, address); + } + + pud = pud_offset(pgd, address); + if (pud_none_or_clear_bad(pud)) + return 1; + pmd = pmd_offset(pud, address); + if (pmd_none_or_clear_bad(pmd)) + return 1; + + pte = pte_offset_kernel(pmd, address); + entry = *pte; + if (unlikely(pte_none(entry) || pte_not_present(entry))) + return 1; + if (unlikely(writeaccess && !pte_write(entry))) + return 1; + + if (writeaccess) + entry = pte_mkdirty(entry); + entry = pte_mkyoung(entry); + + set_pte(pte, entry); + update_mmu_cache(NULL, address, entry); + + return 0; +} |