/arch/um/kernel/trap_kern.c
https://bitbucket.org/evzijst/gittest · C · 251 lines · 206 code · 27 blank · 18 comment · 50 complexity · 4f76b16707c31ea9fa59cee994688d3d MD5 · raw file
- /*
- * 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:
- */