diff options
author | Dmitry Torokhov <dtor@insightbb.com> | 2006-08-04 22:50:27 -0400 |
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committer | Dmitry Torokhov <dtor@insightbb.com> | 2006-08-04 22:50:27 -0400 |
commit | d932cb7e630cae3b6b5307b767d296ff1a597c5e (patch) | |
tree | f930d068a12a256fabef0864bcdf8e85f095369e /arch/um/kernel/trap.c | |
parent | 73b59a3b1c09e4bfc678400b77b96134dcfbf112 (diff) | |
parent | f5d635f649607b09b0b4620d25d028fd2b1b7ea5 (diff) |
Merge rsync://rsync.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6 into for-linus
Diffstat (limited to 'arch/um/kernel/trap.c')
-rw-r--r-- | arch/um/kernel/trap.c | 251 |
1 files changed, 251 insertions, 0 deletions
diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c new file mode 100644 index 00000000000..ac70fa5a2e2 --- /dev/null +++ b/arch/um/kernel/trap.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 "sysdep/sigcontext.h" +#include "user_util.h" +#include "kern_util.h" +#include "kern.h" +#include "chan_kern.h" +#include "mconsole_kern.h" +#include "mem.h" +#include "mem_kern.h" +#include "sysdep/sigcontext.h" +#include "sysdep/ptrace.h" +#include "os.h" +#ifdef CONFIG_MODE_SKAS +#include "skas.h" +#endif +#include "os.h" + +/* Note this is constrained to return 0, -EFAULT, -EACCESS, -ENOMEM by segv(). */ +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; + int err = -EFAULT; + + *code_out = SEGV_MAPERR; + + /* If the fault was during atomic operation, don't take the fault, just + * fail. */ + if (in_atomic()) + goto out_nosemaphore; + + 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(is_user && !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; + + /* Don't require VM_READ|VM_EXEC for write faults! */ + if(!is_write && !(vma->vm_flags & (VM_READ | VM_EXEC))) + goto out; + + 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, address); + pud = pud_offset(pgd, address); + pmd = pmd_offset(pud, address); + pte = pte_offset_kernel(pmd, address); + } while(!pte_present(*pte)); + err = 0; + /* The below warning was added in place of + * pte_mkyoung(); if (is_write) pte_mkdirty(); + * If it's triggered, we'd see normally a hang here (a clean pte is + * marked read-only to emulate the dirty bit). + * However, the generic code can mark a PTE writable but clean on a + * concurrent read fault, triggering this harmlessly. So comment it out. + */ +#if 0 + WARN_ON(!pte_young(*pte) || (is_write && !pte_dirty(*pte))); +#endif + flush_tlb_page(vma, address); +out: + up_read(&mm->mmap_sem); +out_nosemaphore: + 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; +} + +void segv_handler(int sig, union uml_pt_regs *regs) +{ + struct faultinfo * fi = UPT_FAULTINFO(regs); + + if(UPT_IS_USER(regs) && !SEGV_IS_FIXABLE(fi)){ + bad_segv(*fi, UPT_IP(regs)); + return; + } + segv(*fi, UPT_IP(regs), UPT_IS_USER(regs), regs); +} + +struct kern_handlers handlinfo_kern = { + .relay_signal = relay_signal, + .winch = winch, + .bus_handler = relay_signal, + .page_fault = segv_handler, + .sigio_handler = sigio_handler, + .timer_handler = timer_handler +}; +/* + * We give a *copy* of the faultinfo in the regs to segv. + * This must be done, since nesting SEGVs could overwrite + * the info in the regs. A pointer to the info then would + * give us bad data! + */ +unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user, void *sc) +{ + struct siginfo si; + void *catcher; + int err; + int is_write = FAULT_WRITE(fi); + unsigned long address = FAULT_ADDRESS(fi); + + if(!is_user && (address >= start_vm) && (address < end_vm)){ + flush_tlb_kernel_vm(); + return(0); + } + else if(current->mm == NULL) + panic("Segfault with no mm"); + + if (SEGV_IS_FIXABLE(&fi) || SEGV_MAYBE_FIXABLE(&fi)) + err = handle_page_fault(address, ip, is_write, is_user, &si.si_code); + else { + err = -EFAULT; + /* A thread accessed NULL, we get a fault, but CR2 is invalid. + * This code is used in __do_copy_from_user() of TT mode. */ + address = 0; + } + + 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(!is_user && 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 __user *)address; + current->thread.arch.faultinfo = fi; + force_sig_info(SIGBUS, &si, current); + } else if (err == -ENOMEM) { + printk("VM: killing process %s\n", current->comm); + do_exit(SIGKILL); + } else { + BUG_ON(err != -EFAULT); + si.si_signo = SIGSEGV; + si.si_addr = (void __user *) address; + current->thread.arch.faultinfo = fi; + force_sig_info(SIGSEGV, &si, current); + } + return(0); +} + +void bad_segv(struct faultinfo fi, unsigned long ip) +{ + struct siginfo si; + + si.si_signo = SIGSEGV; + si.si_code = SEGV_ACCERR; + si.si_addr = (void __user *) FAULT_ADDRESS(fi); + current->thread.arch.faultinfo = fi; + 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); + current->thread.arch.faultinfo = *UPT_FAULTINFO(regs); + 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) +{ +} |