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Diffstat (limited to 'arch/um/kernel/trap_kern.c')
-rw-r--r--arch/um/kernel/trap_kern.c251
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:
+ */