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 000000000000..47e766e6ba10
--- /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:
+ */