diff options
Diffstat (limited to 'arch/um/kernel/trap_kern.c')
| -rw-r--r-- | arch/um/kernel/trap_kern.c | 251 |
1 files changed, 251 insertions, 0 deletions
diff --git a/arch/um/kernel/trap_kern.c b/arch/um/kernel/trap_kern.c new file mode 100644 index 00000000000..47e766e6ba1 --- /dev/null +++ b/arch/um/kernel/trap_kern.c @@ -0,0 +1,251 @@ +/* + * Copyright (C) 2000, 2001 Jeff Dike (jdike@karaya.com) + * Licensed under the GPL + */ + +#include "linux/kernel.h" +#include "asm/errno.h" +#include "linux/sched.h" +#include "linux/mm.h" +#include "linux/spinlock.h" +#include "linux/config.h" +#include "linux/init.h" +#include "linux/ptrace.h" +#include "asm/semaphore.h" +#include "asm/pgtable.h" +#include "asm/pgalloc.h" +#include "asm/tlbflush.h" +#include "asm/a.out.h" +#include "asm/current.h" +#include "asm/irq.h" +#include "user_util.h" +#include "kern_util.h" +#include "kern.h" +#include "chan_kern.h" +#include "mconsole_kern.h" +#include "2_5compat.h" +#include "mem.h" +#include "mem_kern.h" + +int handle_page_fault(unsigned long address, unsigned long ip, + int is_write, int is_user, int *code_out) +{ + struct mm_struct *mm = current->mm; + struct vm_area_struct *vma; + pgd_t *pgd; + pud_t *pud; + pmd_t *pmd; + pte_t *pte; + unsigned long page; + int err = -EFAULT; + + *code_out = SEGV_MAPERR; + down_read(&mm->mmap_sem); + vma = find_vma(mm, address); + if(!vma) + goto out; + else if(vma->vm_start <= address) + goto good_area; + else if(!(vma->vm_flags & VM_GROWSDOWN)) + goto out; + else if(!ARCH_IS_STACKGROW(address)) + goto out; + else if(expand_stack(vma, address)) + goto out; + + good_area: + *code_out = SEGV_ACCERR; + if(is_write && !(vma->vm_flags & VM_WRITE)) + goto out; + page = address & PAGE_MASK; + pgd = pgd_offset(mm, page); + pud = pud_offset(pgd, page); + pmd = pmd_offset(pud, page); + do { + survive: + switch (handle_mm_fault(mm, vma, address, is_write)){ + case VM_FAULT_MINOR: + current->min_flt++; + break; + case VM_FAULT_MAJOR: + current->maj_flt++; + break; + case VM_FAULT_SIGBUS: + err = -EACCES; + goto out; + case VM_FAULT_OOM: + err = -ENOMEM; + goto out_of_memory; + default: + BUG(); + } + pgd = pgd_offset(mm, page); + pud = pud_offset(pgd, page); + pmd = pmd_offset(pud, page); + pte = pte_offset_kernel(pmd, page); + } while(!pte_present(*pte)); + err = 0; + *pte = pte_mkyoung(*pte); + if(pte_write(*pte)) *pte = pte_mkdirty(*pte); + flush_tlb_page(vma, page); + out: + up_read(&mm->mmap_sem); + return(err); + +/* + * 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: + if (current->pid == 1) { + up_read(&mm->mmap_sem); + yield(); + down_read(&mm->mmap_sem); + goto survive; + } + goto out; +} + +LIST_HEAD(physmem_remappers); + +void register_remapper(struct remapper *info) +{ + list_add(&info->list, &physmem_remappers); +} + +static int check_remapped_addr(unsigned long address, int is_write) +{ + struct remapper *remapper; + struct list_head *ele; + __u64 offset; + int fd; + + fd = phys_mapping(__pa(address), &offset); + if(fd == -1) + return(0); + + list_for_each(ele, &physmem_remappers){ + remapper = list_entry(ele, struct remapper, list); + if((*remapper->proc)(fd, address, is_write, offset)) + return(1); + } + + return(0); +} + +unsigned long segv(unsigned long address, unsigned long ip, int is_write, + int is_user, void *sc) +{ + struct siginfo si; + void *catcher; + int err; + + if(!is_user && (address >= start_vm) && (address < end_vm)){ + flush_tlb_kernel_vm(); + return(0); + } + else if(check_remapped_addr(address & PAGE_MASK, is_write)) + return(0); + else if(current->mm == NULL) + panic("Segfault with no mm"); + err = handle_page_fault(address, ip, is_write, is_user, &si.si_code); + + catcher = current->thread.fault_catcher; + if(!err) + return(0); + else if(catcher != NULL){ + current->thread.fault_addr = (void *) address; + do_longjmp(catcher, 1); + } + else if(current->thread.fault_addr != NULL) + panic("fault_addr set but no fault catcher"); + else if(arch_fixup(ip, sc)) + return(0); + + if(!is_user) + panic("Kernel mode fault at addr 0x%lx, ip 0x%lx", + address, ip); + + if(err == -EACCES){ + si.si_signo = SIGBUS; + si.si_errno = 0; + si.si_code = BUS_ADRERR; + si.si_addr = (void *)address; + force_sig_info(SIGBUS, &si, current); + } + else if(err == -ENOMEM){ + printk("VM: killing process %s\n", current->comm); + do_exit(SIGKILL); + } + else { + si.si_signo = SIGSEGV; + si.si_addr = (void *) address; + current->thread.cr2 = address; + current->thread.err = is_write; + force_sig_info(SIGSEGV, &si, current); + } + return(0); +} + +void bad_segv(unsigned long address, unsigned long ip, int is_write) +{ + struct siginfo si; + + si.si_signo = SIGSEGV; + si.si_code = SEGV_ACCERR; + si.si_addr = (void *) address; + current->thread.cr2 = address; + current->thread.err = is_write; + force_sig_info(SIGSEGV, &si, current); +} + +void relay_signal(int sig, union uml_pt_regs *regs) +{ + if(arch_handle_signal(sig, regs)) return; + if(!UPT_IS_USER(regs)) + panic("Kernel mode signal %d", sig); + force_sig(sig, current); +} + +void bus_handler(int sig, union uml_pt_regs *regs) +{ + if(current->thread.fault_catcher != NULL) + do_longjmp(current->thread.fault_catcher, 1); + else relay_signal(sig, regs); +} + +void winch(int sig, union uml_pt_regs *regs) +{ + do_IRQ(WINCH_IRQ, regs); +} + +void trap_init(void) +{ +} + +DEFINE_SPINLOCK(trap_lock); + +static int trap_index = 0; + +int next_trap_index(int limit) +{ + int ret; + + spin_lock(&trap_lock); + ret = trap_index; + if(++trap_index == limit) + trap_index = 0; + spin_unlock(&trap_lock); + return(ret); +} + +/* + * Overrides for Emacs so that we follow Linus's tabbing style. + * Emacs will notice this stuff at the end of the file and automatically + * adjust the settings for this buffer only. This must remain at the end + * of the file. + * --------------------------------------------------------------------------- + * Local variables: + * c-file-style: "linux" + * End: + */ |