[PATCH] Driver Core: pm diagnostics update, check for errors
[linux-2.6/verdex.git] / arch / um / kernel / trap_kern.c
blob5fca2c61eb980a631fe70d500b18b9422e17e0cf
1 /*
2 * Copyright (C) 2000, 2001 Jeff Dike (jdike@karaya.com)
3 * Licensed under the GPL
4 */
6 #include "linux/kernel.h"
7 #include "asm/errno.h"
8 #include "linux/sched.h"
9 #include "linux/mm.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/pgalloc.h"
17 #include "asm/tlbflush.h"
18 #include "asm/a.out.h"
19 #include "asm/current.h"
20 #include "asm/irq.h"
21 #include "user_util.h"
22 #include "kern_util.h"
23 #include "kern.h"
24 #include "chan_kern.h"
25 #include "mconsole_kern.h"
26 #include "2_5compat.h"
27 #include "mem.h"
28 #include "mem_kern.h"
30 int handle_page_fault(unsigned long address, unsigned long ip,
31 int is_write, int is_user, int *code_out)
33 struct mm_struct *mm = current->mm;
34 struct vm_area_struct *vma;
35 pgd_t *pgd;
36 pud_t *pud;
37 pmd_t *pmd;
38 pte_t *pte;
39 unsigned long page;
40 int err = -EFAULT;
42 *code_out = SEGV_MAPERR;
43 down_read(&mm->mmap_sem);
44 vma = find_vma(mm, address);
45 if(!vma)
46 goto out;
47 else if(vma->vm_start <= address)
48 goto good_area;
49 else if(!(vma->vm_flags & VM_GROWSDOWN))
50 goto out;
51 else if(is_user && !ARCH_IS_STACKGROW(address))
52 goto out;
53 else if(expand_stack(vma, address))
54 goto out;
56 good_area:
57 *code_out = SEGV_ACCERR;
58 if(is_write && !(vma->vm_flags & VM_WRITE))
59 goto out;
60 page = address & PAGE_MASK;
61 pgd = pgd_offset(mm, page);
62 pud = pud_offset(pgd, page);
63 pmd = pmd_offset(pud, page);
64 do {
65 survive:
66 switch (handle_mm_fault(mm, vma, address, is_write)){
67 case VM_FAULT_MINOR:
68 current->min_flt++;
69 break;
70 case VM_FAULT_MAJOR:
71 current->maj_flt++;
72 break;
73 case VM_FAULT_SIGBUS:
74 err = -EACCES;
75 goto out;
76 case VM_FAULT_OOM:
77 err = -ENOMEM;
78 goto out_of_memory;
79 default:
80 BUG();
82 pgd = pgd_offset(mm, page);
83 pud = pud_offset(pgd, page);
84 pmd = pmd_offset(pud, page);
85 pte = pte_offset_kernel(pmd, page);
86 } while(!pte_present(*pte));
87 err = 0;
88 *pte = pte_mkyoung(*pte);
89 if(pte_write(*pte)) *pte = pte_mkdirty(*pte);
90 flush_tlb_page(vma, page);
91 out:
92 up_read(&mm->mmap_sem);
93 return(err);
96 * We ran out of memory, or some other thing happened to us that made
97 * us unable to handle the page fault gracefully.
99 out_of_memory:
100 if (current->pid == 1) {
101 up_read(&mm->mmap_sem);
102 yield();
103 down_read(&mm->mmap_sem);
104 goto survive;
106 goto out;
109 LIST_HEAD(physmem_remappers);
111 void register_remapper(struct remapper *info)
113 list_add(&info->list, &physmem_remappers);
116 static int check_remapped_addr(unsigned long address, int is_write)
118 struct remapper *remapper;
119 struct list_head *ele;
120 __u64 offset;
121 int fd;
123 fd = phys_mapping(__pa(address), &offset);
124 if(fd == -1)
125 return(0);
127 list_for_each(ele, &physmem_remappers){
128 remapper = list_entry(ele, struct remapper, list);
129 if((*remapper->proc)(fd, address, is_write, offset))
130 return(1);
133 return(0);
137 * We give a *copy* of the faultinfo in the regs to segv.
138 * This must be done, since nesting SEGVs could overwrite
139 * the info in the regs. A pointer to the info then would
140 * give us bad data!
142 unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user, void *sc)
144 struct siginfo si;
145 void *catcher;
146 int err;
147 int is_write = FAULT_WRITE(fi);
148 unsigned long address = FAULT_ADDRESS(fi);
150 if(!is_user && (address >= start_vm) && (address < end_vm)){
151 flush_tlb_kernel_vm();
152 return(0);
154 else if(check_remapped_addr(address & PAGE_MASK, is_write))
155 return(0);
156 else if(current->mm == NULL)
157 panic("Segfault with no mm");
158 err = handle_page_fault(address, ip, is_write, is_user, &si.si_code);
160 catcher = current->thread.fault_catcher;
161 if(!err)
162 return(0);
163 else if(catcher != NULL){
164 current->thread.fault_addr = (void *) address;
165 do_longjmp(catcher, 1);
167 else if(current->thread.fault_addr != NULL)
168 panic("fault_addr set but no fault catcher");
169 else if(!is_user && arch_fixup(ip, sc))
170 return(0);
172 if(!is_user)
173 panic("Kernel mode fault at addr 0x%lx, ip 0x%lx",
174 address, ip);
176 if(err == -EACCES){
177 si.si_signo = SIGBUS;
178 si.si_errno = 0;
179 si.si_code = BUS_ADRERR;
180 si.si_addr = (void *)address;
181 current->thread.arch.faultinfo = fi;
182 force_sig_info(SIGBUS, &si, current);
184 else if(err == -ENOMEM){
185 printk("VM: killing process %s\n", current->comm);
186 do_exit(SIGKILL);
188 else {
189 si.si_signo = SIGSEGV;
190 si.si_addr = (void *) address;
191 current->thread.arch.faultinfo = fi;
192 force_sig_info(SIGSEGV, &si, current);
194 return(0);
197 void bad_segv(struct faultinfo fi, unsigned long ip)
199 struct siginfo si;
201 si.si_signo = SIGSEGV;
202 si.si_code = SEGV_ACCERR;
203 si.si_addr = (void *) FAULT_ADDRESS(fi);
204 current->thread.arch.faultinfo = fi;
205 force_sig_info(SIGSEGV, &si, current);
208 void relay_signal(int sig, union uml_pt_regs *regs)
210 if(arch_handle_signal(sig, regs)) return;
211 if(!UPT_IS_USER(regs))
212 panic("Kernel mode signal %d", sig);
213 current->thread.arch.faultinfo = *UPT_FAULTINFO(regs);
214 force_sig(sig, current);
217 void bus_handler(int sig, union uml_pt_regs *regs)
219 if(current->thread.fault_catcher != NULL)
220 do_longjmp(current->thread.fault_catcher, 1);
221 else relay_signal(sig, regs);
224 void winch(int sig, union uml_pt_regs *regs)
226 do_IRQ(WINCH_IRQ, regs);
229 void trap_init(void)
233 DEFINE_SPINLOCK(trap_lock);
235 static int trap_index = 0;
237 int next_trap_index(int limit)
239 int ret;
241 spin_lock(&trap_lock);
242 ret = trap_index;
243 if(++trap_index == limit)
244 trap_index = 0;
245 spin_unlock(&trap_lock);
246 return(ret);
250 * Overrides for Emacs so that we follow Linus's tabbing style.
251 * Emacs will notice this stuff at the end of the file and automatically
252 * adjust the settings for this buffer only. This must remain at the end
253 * of the file.
254 * ---------------------------------------------------------------------------
255 * Local variables:
256 * c-file-style: "linux"
257 * End: