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)){
79 pte = pte_offset_kernel(pmd, page);
80 } while(!pte_present(*pte));
82 *pte = pte_mkyoung(*pte);
83 if(pte_write(*pte)) *pte = pte_mkdirty(*pte);
84 flush_tlb_page(vma, page);
86 up_read(&mm->mmap_sem);
90 * We ran out of memory, or some other thing happened to us that made
91 * us unable to handle the page fault gracefully.
94 if (current->pid == 1) {
95 up_read(&mm->mmap_sem);
97 down_read(&mm->mmap_sem);
103 LIST_HEAD(physmem_remappers);
105 void register_remapper(struct remapper *info)
107 list_add(&info->list, &physmem_remappers);
110 static int check_remapped_addr(unsigned long address, int is_write, int is_user)
112 struct remapper *remapper;
113 struct list_head *ele;
117 fd = phys_mapping(__pa(address), &offset);
121 list_for_each(ele, &physmem_remappers){
122 remapper = list_entry(ele, struct remapper, list);
123 if((*remapper->proc)(fd, address, is_write, offset, is_user))
130 unsigned long segv(unsigned long address, unsigned long ip, int is_write,
131 int is_user, void *sc)
137 if(!is_user && (address >= start_vm) && (address < end_vm)){
138 flush_tlb_kernel_vm();
141 else if(check_remapped_addr(address & PAGE_MASK, is_write, is_user))
143 else if(current->mm == NULL)
144 panic("Segfault with no mm");
145 err = handle_page_fault(address, ip, is_write, is_user, &si.si_code);
147 catcher = current->thread.fault_catcher;
150 else if(catcher != NULL){
151 current->thread.fault_addr = (void *) address;
152 do_longjmp(catcher, 1);
154 else if(current->thread.fault_addr != NULL)
155 panic("fault_addr set but no fault catcher");
156 else if(arch_fixup(ip, sc))
160 panic("Kernel mode fault at addr 0x%lx, ip 0x%lx",
164 si.si_signo = SIGBUS;
166 si.si_code = BUS_ADRERR;
167 si.si_addr = (void *)address;
168 force_sig_info(SIGBUS, &si, current);
170 else if(err == -ENOMEM){
171 printk("VM: killing process %s\n", current->comm);
175 si.si_signo = SIGSEGV;
176 si.si_addr = (void *) address;
177 current->thread.cr2 = address;
178 current->thread.err = is_write;
179 force_sig_info(SIGSEGV, &si, current);
184 void bad_segv(unsigned long address, unsigned long ip, int is_write)
188 si.si_signo = SIGSEGV;
189 si.si_code = SEGV_ACCERR;
190 si.si_addr = (void *) address;
191 current->thread.cr2 = address;
192 current->thread.err = is_write;
193 force_sig_info(SIGSEGV, &si, current);
196 void relay_signal(int sig, union uml_pt_regs *regs)
198 if(arch_handle_signal(sig, regs)) return;
199 if(!UPT_IS_USER(regs))
200 panic("Kernel mode signal %d", sig);
201 force_sig(sig, current);
204 void bus_handler(int sig, union uml_pt_regs *regs)
206 if(current->thread.fault_catcher != NULL)
207 do_longjmp(current->thread.fault_catcher, 1);
208 else relay_signal(sig, regs);
211 void winch(int sig, union uml_pt_regs *regs)
213 do_IRQ(WINCH_IRQ, regs);
220 spinlock_t trap_lock = SPIN_LOCK_UNLOCKED;
222 static int trap_index = 0;
224 int next_trap_index(int limit)
228 spin_lock(&trap_lock);
230 if(++trap_index == limit)
232 spin_unlock(&trap_lock);
237 * Overrides for Emacs so that we follow Linus's tabbing style.
238 * Emacs will notice this stuff at the end of the file and automatically
239 * adjust the settings for this buffer only. This must remain at the end
241 * ---------------------------------------------------------------------------
243 * c-file-style: "linux"