2 * Copyright (C) 2000, 2001 Jeff Dike (jdike@karaya.com)
3 * Licensed under the GPL
6 #include "linux/kernel.h"
8 #include "linux/sched.h"
10 #include "linux/spinlock.h"
11 #include "linux/config.h"
12 #include "linux/init.h"
13 #include "linux/ptrace.h"
14 #include "asm/semaphore.h"
15 #include "asm/pgtable.h"
16 #include "asm/tlbflush.h"
17 #include "asm/a.out.h"
18 #include "asm/current.h"
20 #include "user_util.h"
21 #include "kern_util.h"
23 #include "chan_kern.h"
24 #include "mconsole_kern.h"
25 #include "2_5compat.h"
29 int handle_page_fault(unsigned long address, unsigned long ip,
30 int is_write, int is_user, int *code_out)
32 struct mm_struct *mm = current->mm;
33 struct vm_area_struct *vma;
40 *code_out = SEGV_MAPERR;
41 down_read(&mm->mmap_sem);
42 vma = find_vma(mm, address);
45 else if(vma->vm_start <= address)
47 else if(!(vma->vm_flags & VM_GROWSDOWN))
49 else if(expand_stack(vma, address))
53 *code_out = SEGV_ACCERR;
54 if(is_write && !(vma->vm_flags & VM_WRITE))
56 page = address & PAGE_MASK;
57 if(page == (unsigned long) current_thread + PAGE_SIZE)
58 panic("Kernel stack overflow");
59 pgd = pgd_offset(mm, page);
60 pmd = pmd_offset(pgd, page);
63 switch (handle_mm_fault(mm, vma, address, is_write)){
77 if (current->pid == 1) {
78 up_read(&mm->mmap_sem);
80 down_read(&mm->mmap_sem);
85 pte = pte_offset_kernel(pmd, page);
86 } while(!pte_present(*pte));
88 *pte = pte_mkyoung(*pte);
89 if(pte_write(*pte)) *pte = pte_mkdirty(*pte);
90 flush_tlb_page(vma, page);
92 up_read(&mm->mmap_sem);
96 * We ran out of memory, or some other thing happened to us that made
97 * us unable to handle the page fault gracefully.
100 if (current->pid == 1) {
101 up_read(&mm->mmap_sem);
103 down_read(&mm->mmap_sem);
110 LIST_HEAD(physmem_remappers);
112 void register_remapper(struct remapper *info)
114 list_add(&info->list, &physmem_remappers);
117 static int check_remapped_addr(unsigned long address, int is_write)
119 struct remapper *remapper;
120 struct list_head *ele;
124 fd = phys_mapping(__pa(address), &offset);
128 list_for_each(ele, &physmem_remappers){
129 remapper = list_entry(ele, struct remapper, list);
130 if((*remapper->proc)(fd, address, is_write, offset))
137 unsigned long segv(unsigned long address, unsigned long ip, int is_write,
138 int is_user, void *sc)
144 if(!is_user && (address >= start_vm) && (address < end_vm)){
145 flush_tlb_kernel_vm();
148 else if(check_remapped_addr(address & PAGE_MASK, is_write))
150 else if(current->mm == NULL)
151 panic("Segfault with no mm");
152 err = handle_page_fault(address, ip, is_write, is_user, &si.si_code);
154 catcher = current->thread.fault_catcher;
157 else if(catcher != NULL){
158 current->thread.fault_addr = (void *) address;
159 do_longjmp(catcher, 1);
161 else if(current->thread.fault_addr != NULL)
162 panic("fault_addr set but no fault catcher");
163 else if(arch_fixup(ip, sc))
167 panic("Kernel mode fault at addr 0x%lx, ip 0x%lx",
171 si.si_signo = SIGBUS;
173 si.si_code = BUS_ADRERR;
174 si.si_addr = (void *)address;
175 force_sig_info(SIGBUS, &si, current);
177 else if(err == -ENOMEM){
178 printk("VM: killing process %s\n", current->comm);
182 si.si_signo = SIGSEGV;
183 si.si_addr = (void *) address;
184 current->thread.cr2 = address;
185 current->thread.err = is_write;
186 force_sig_info(SIGSEGV, &si, current);
191 void bad_segv(unsigned long address, unsigned long ip, int is_write)
195 si.si_signo = SIGSEGV;
196 si.si_code = SEGV_ACCERR;
197 si.si_addr = (void *) address;
198 current->thread.cr2 = address;
199 current->thread.err = is_write;
200 force_sig_info(SIGSEGV, &si, current);
203 void relay_signal(int sig, union uml_pt_regs *regs)
205 if(arch_handle_signal(sig, regs)) return;
206 if(!UPT_IS_USER(regs))
207 panic("Kernel mode signal %d", sig);
208 force_sig(sig, current);
211 void bus_handler(int sig, union uml_pt_regs *regs)
213 if(current->thread.fault_catcher != NULL)
214 do_longjmp(current->thread.fault_catcher, 1);
215 else relay_signal(sig, regs);
218 void winch(int sig, union uml_pt_regs *regs)
220 do_IRQ(WINCH_IRQ, regs);
227 spinlock_t trap_lock = SPIN_LOCK_UNLOCKED;
229 static int trap_index = 0;
231 int next_trap_index(int limit)
235 spin_lock(&trap_lock);
237 if(++trap_index == limit)
239 spin_unlock(&trap_lock);
244 * Overrides for Emacs so that we follow Linus's tabbing style.
245 * Emacs will notice this stuff at the end of the file and automatically
246 * adjust the settings for this buffer only. This must remain at the end
248 * ---------------------------------------------------------------------------
250 * c-file-style: "linux"