* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
-#include <linux/config.h>
#include <linux/module.h>
#include <linux/signal.h>
-#include <linux/ptrace.h>
#include <linux/mm.h>
+#include <linux/hardirq.h>
#include <linux/init.h>
+#include <linux/kprobes.h>
+#include <linux/uaccess.h>
+#include <linux/page-flags.h>
+#include <linux/sched.h>
+#include <linux/highmem.h>
+#include <linux/perf_event.h>
#include <asm/system.h>
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
-#include <asm/uaccess.h>
#include "fault.h"
/*
+ * Fault status register encodings. We steal bit 31 for our own purposes.
+ */
+#define FSR_LNX_PF (1 << 31)
+#define FSR_WRITE (1 << 11)
+#define FSR_FS4 (1 << 10)
+#define FSR_FS3_0 (15)
+
+static inline int fsr_fs(unsigned int fsr)
+{
+ return (fsr & FSR_FS3_0) | (fsr & FSR_FS4) >> 6;
+}
+
+#ifdef CONFIG_MMU
+
+#ifdef CONFIG_KPROBES
+static inline int notify_page_fault(struct pt_regs *regs, unsigned int fsr)
+{
+ int ret = 0;
+
+ if (!user_mode(regs)) {
+ /* kprobe_running() needs smp_processor_id() */
+ preempt_disable();
+ if (kprobe_running() && kprobe_fault_handler(regs, fsr))
+ ret = 1;
+ preempt_enable();
+ }
+
+ return ret;
+}
+#else
+static inline int notify_page_fault(struct pt_regs *regs, unsigned int fsr)
+{
+ return 0;
+}
+#endif
+
+/*
* This is useful to dump out the page tables associated with
* 'addr' in mm 'mm'.
*/
}
pmd = pmd_offset(pgd, addr);
-#if PTRS_PER_PMD != 1
- printk(", *pmd=%08lx", pmd_val(*pmd));
-#endif
+ if (PTRS_PER_PMD != 1)
+ printk(", *pmd=%08lx", pmd_val(*pmd));
if (pmd_none(*pmd))
break;
break;
}
-#ifndef CONFIG_HIGHMEM
/* We must not map this if we have highmem enabled */
+ if (PageHighMem(pfn_to_page(pmd_val(*pmd) >> PAGE_SHIFT)))
+ break;
+
pte = pte_offset_map(pmd, addr);
printk(", *pte=%08lx", pte_val(*pte));
printk(", *ppte=%08lx", pte_val(pte[-PTRS_PER_PTE]));
pte_unmap(pte);
-#endif
} while(0);
printk("\n");
}
+#else /* CONFIG_MMU */
+void show_pte(struct mm_struct *mm, unsigned long addr)
+{ }
+#endif /* CONFIG_MMU */
/*
* Oops. The kernel tried to access some page that wasn't present.
force_sig_info(sig, &si, tsk);
}
-void
-do_bad_area(struct task_struct *tsk, struct mm_struct *mm, unsigned long addr,
- unsigned int fsr, struct pt_regs *regs)
+void do_bad_area(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
{
+ struct task_struct *tsk = current;
+ struct mm_struct *mm = tsk->active_mm;
+
/*
* If we are in kernel mode at this point, we
* have no context to handle this fault with.
__do_kernel_fault(mm, addr, fsr, regs);
}
-#define VM_FAULT_BADMAP (-20)
-#define VM_FAULT_BADACCESS (-21)
+#ifdef CONFIG_MMU
+#define VM_FAULT_BADMAP 0x010000
+#define VM_FAULT_BADACCESS 0x020000
-static int
+/*
+ * Check that the permissions on the VMA allow for the fault which occurred.
+ * If we encountered a write fault, we must have write permission, otherwise
+ * we allow any permission.
+ */
+static inline bool access_error(unsigned int fsr, struct vm_area_struct *vma)
+{
+ unsigned int mask = VM_READ | VM_WRITE | VM_EXEC;
+
+ if (fsr & FSR_WRITE)
+ mask = VM_WRITE;
+ if (fsr & FSR_LNX_PF)
+ mask = VM_EXEC;
+
+ return vma->vm_flags & mask ? false : true;
+}
+
+static int __kprobes
__do_page_fault(struct mm_struct *mm, unsigned long addr, unsigned int fsr,
struct task_struct *tsk)
{
struct vm_area_struct *vma;
- int fault, mask;
+ int fault;
vma = find_vma(mm, addr);
fault = VM_FAULT_BADMAP;
- if (!vma)
+ if (unlikely(!vma))
goto out;
- if (vma->vm_start > addr)
+ if (unlikely(vma->vm_start > addr))
goto check_stack;
/*
* memory access, so we can handle it.
*/
good_area:
- if (fsr & (1 << 11)) /* write? */
- mask = VM_WRITE;
- else
- mask = VM_READ|VM_EXEC;
-
- fault = VM_FAULT_BADACCESS;
- if (!(vma->vm_flags & mask))
+ if (access_error(fsr, vma)) {
+ fault = VM_FAULT_BADACCESS;
goto out;
+ }
/*
- * If for any reason at all we couldn't handle
- * the fault, make sure we exit gracefully rather
- * than endlessly redo the fault.
- */
-survive:
- fault = handle_mm_fault(mm, vma, addr & PAGE_MASK, fsr & (1 << 11));
-
- /*
- * Handle the "normal" cases first - successful and sigbus
+ * If for any reason at all we couldn't handle the fault, make
+ * sure we exit gracefully rather than endlessly redo the fault.
*/
- switch (fault) {
- case VM_FAULT_MAJOR:
- tsk->maj_flt++;
+ fault = handle_mm_fault(mm, vma, addr & PAGE_MASK, (fsr & FSR_WRITE) ? FAULT_FLAG_WRITE : 0);
+ if (unlikely(fault & VM_FAULT_ERROR))
return fault;
- case VM_FAULT_MINOR:
+ if (fault & VM_FAULT_MAJOR)
+ tsk->maj_flt++;
+ else
tsk->min_flt++;
- case VM_FAULT_SIGBUS:
- return fault;
- }
-
- if (tsk->pid != 1)
- goto out;
-
- /*
- * If we are out of memory for pid1, sleep for a while and retry
- */
- up_read(&mm->mmap_sem);
- yield();
- down_read(&mm->mmap_sem);
- goto survive;
+ return fault;
check_stack:
if (vma->vm_flags & VM_GROWSDOWN && !expand_stack(vma, addr))
return fault;
}
-static int
+static int __kprobes
do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
{
struct task_struct *tsk;
struct mm_struct *mm;
int fault, sig, code;
+ if (notify_page_fault(regs, fsr))
+ return 0;
+
tsk = current;
mm = tsk->mm;
* If we're in an interrupt or have no user
* context, we must not take the fault..
*/
- if (in_interrupt() || !mm)
+ if (in_atomic() || !mm)
goto no_context;
- down_read(&mm->mmap_sem);
+ /*
+ * As per x86, we may deadlock here. However, since the kernel only
+ * validly references user space from well defined areas of the code,
+ * we can bug out early if this is from code which shouldn't.
+ */
+ if (!down_read_trylock(&mm->mmap_sem)) {
+ if (!user_mode(regs) && !search_exception_tables(regs->ARM_pc))
+ goto no_context;
+ down_read(&mm->mmap_sem);
+ } else {
+ /*
+ * The above down_read_trylock() might have succeeded in
+ * which case, we'll have missed the might_sleep() from
+ * down_read()
+ */
+ might_sleep();
+#ifdef CONFIG_DEBUG_VM
+ if (!user_mode(regs) &&
+ !search_exception_tables(regs->ARM_pc))
+ goto no_context;
+#endif
+ }
+
fault = __do_page_fault(mm, addr, fsr, tsk);
up_read(&mm->mmap_sem);
+ perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, 0, regs, addr);
+ if (fault & VM_FAULT_MAJOR)
+ perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, 0, regs, addr);
+ else if (fault & VM_FAULT_MINOR)
+ perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, 0, regs, addr);
+
/*
- * Handle the "normal" case first
+ * Handle the "normal" case first - VM_FAULT_MAJOR / VM_FAULT_MINOR
*/
- if (fault > 0)
+ if (likely(!(fault & (VM_FAULT_ERROR | VM_FAULT_BADMAP | VM_FAULT_BADACCESS))))
return 0;
+ if (fault & VM_FAULT_OOM) {
+ /*
+ * We ran out of memory, call the OOM killer, and return to
+ * userspace (which will retry the fault, or kill us if we
+ * got oom-killed)
+ */
+ pagefault_out_of_memory();
+ return 0;
+ }
+
/*
* If we are in kernel mode at this point, we
* have no context to handle this fault with.
if (!user_mode(regs))
goto no_context;
- switch (fault) {
- case VM_FAULT_OOM:
- /*
- * We ran out of memory, or some other thing
- * happened to us that made us unable to handle
- * the page fault gracefully.
- */
- printk("VM: killing process %s\n", tsk->comm);
- do_exit(SIGKILL);
- return 0;
-
- case 0:
+ if (fault & VM_FAULT_SIGBUS) {
/*
* We had some memory, but were unable to
* successfully fix up this page fault.
*/
sig = SIGBUS;
code = BUS_ADRERR;
- break;
-
- default:
+ } else {
/*
* Something tried to access memory that
* isn't in our memory map..
sig = SIGSEGV;
code = fault == VM_FAULT_BADACCESS ?
SEGV_ACCERR : SEGV_MAPERR;
- break;
}
__do_user_fault(tsk, addr, fsr, sig, code, regs);
__do_kernel_fault(mm, addr, fsr, regs);
return 0;
}
+#else /* CONFIG_MMU */
+static int
+do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
+{
+ return 0;
+}
+#endif /* CONFIG_MMU */
/*
* First Level Translation Fault Handler
* interrupt or a critical region, and should only copy the information
* from the master page table, nothing more.
*/
-static int
+#ifdef CONFIG_MMU
+static int __kprobes
do_translation_fault(unsigned long addr, unsigned int fsr,
struct pt_regs *regs)
{
- struct task_struct *tsk;
unsigned int index;
pgd_t *pgd, *pgd_k;
pmd_t *pmd, *pmd_k;
if (addr < TASK_SIZE)
return do_page_fault(addr, fsr, regs);
+ if (user_mode(regs))
+ goto bad_area;
+
index = pgd_index(addr);
/*
return 0;
bad_area:
- tsk = current;
-
- do_bad_area(tsk, tsk->active_mm, addr, fsr, regs);
+ do_bad_area(addr, fsr, regs);
return 0;
}
+#else /* CONFIG_MMU */
+static int
+do_translation_fault(unsigned long addr, unsigned int fsr,
+ struct pt_regs *regs)
+{
+ return 0;
+}
+#endif /* CONFIG_MMU */
/*
* Some section permission faults need to be handled gracefully.
static int
do_sect_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
{
- struct task_struct *tsk = current;
- do_bad_area(tsk, tsk->active_mm, addr, fsr, regs);
+ do_bad_area(addr, fsr, regs);
return 0;
}
static struct fsr_info {
int (*fn)(unsigned long addr, unsigned int fsr, struct pt_regs *regs);
int sig;
+ int code;
const char *name;
} fsr_info[] = {
/*
* The following are the standard ARMv3 and ARMv4 aborts. ARMv5
* defines these to be "precise" aborts.
*/
- { do_bad, SIGSEGV, "vector exception" },
- { do_bad, SIGILL, "alignment exception" },
- { do_bad, SIGKILL, "terminal exception" },
- { do_bad, SIGILL, "alignment exception" },
- { do_bad, SIGBUS, "external abort on linefetch" },
- { do_translation_fault, SIGSEGV, "section translation fault" },
- { do_bad, SIGBUS, "external abort on linefetch" },
- { do_page_fault, SIGSEGV, "page translation fault" },
- { do_bad, SIGBUS, "external abort on non-linefetch" },
- { do_bad, SIGSEGV, "section domain fault" },
- { do_bad, SIGBUS, "external abort on non-linefetch" },
- { do_bad, SIGSEGV, "page domain fault" },
- { do_bad, SIGBUS, "external abort on translation" },
- { do_sect_fault, SIGSEGV, "section permission fault" },
- { do_bad, SIGBUS, "external abort on translation" },
- { do_page_fault, SIGSEGV, "page permission fault" },
+ { do_bad, SIGSEGV, 0, "vector exception" },
+ { do_bad, SIGILL, BUS_ADRALN, "alignment exception" },
+ { do_bad, SIGKILL, 0, "terminal exception" },
+ { do_bad, SIGILL, BUS_ADRALN, "alignment exception" },
+/* Do we need runtime check ? */
+#if __LINUX_ARM_ARCH__ < 6
+ { do_bad, SIGBUS, 0, "external abort on linefetch" },
+#else
+ { do_translation_fault, SIGSEGV, SEGV_MAPERR, "I-cache maintenance fault" },
+#endif
+ { do_translation_fault, SIGSEGV, SEGV_MAPERR, "section translation fault" },
+ { do_bad, SIGBUS, 0, "external abort on linefetch" },
+ { do_page_fault, SIGSEGV, SEGV_MAPERR, "page translation fault" },
+ { do_bad, SIGBUS, 0, "external abort on non-linefetch" },
+ { do_bad, SIGSEGV, SEGV_ACCERR, "section domain fault" },
+ { do_bad, SIGBUS, 0, "external abort on non-linefetch" },
+ { do_bad, SIGSEGV, SEGV_ACCERR, "page domain fault" },
+ { do_bad, SIGBUS, 0, "external abort on translation" },
+ { do_sect_fault, SIGSEGV, SEGV_ACCERR, "section permission fault" },
+ { do_bad, SIGBUS, 0, "external abort on translation" },
+ { do_page_fault, SIGSEGV, SEGV_ACCERR, "page permission fault" },
/*
* The following are "imprecise" aborts, which are signalled by bit
* 10 of the FSR, and may not be recoverable. These are only
* supported if the CPU abort handler supports bit 10.
*/
- { do_bad, SIGBUS, "unknown 16" },
- { do_bad, SIGBUS, "unknown 17" },
- { do_bad, SIGBUS, "unknown 18" },
- { do_bad, SIGBUS, "unknown 19" },
- { do_bad, SIGBUS, "lock abort" }, /* xscale */
- { do_bad, SIGBUS, "unknown 21" },
- { do_bad, SIGBUS, "imprecise external abort" }, /* xscale */
- { do_bad, SIGBUS, "unknown 23" },
- { do_bad, SIGBUS, "dcache parity error" }, /* xscale */
- { do_bad, SIGBUS, "unknown 25" },
- { do_bad, SIGBUS, "unknown 26" },
- { do_bad, SIGBUS, "unknown 27" },
- { do_bad, SIGBUS, "unknown 28" },
- { do_bad, SIGBUS, "unknown 29" },
- { do_bad, SIGBUS, "unknown 30" },
- { do_bad, SIGBUS, "unknown 31" }
+ { do_bad, SIGBUS, 0, "unknown 16" },
+ { do_bad, SIGBUS, 0, "unknown 17" },
+ { do_bad, SIGBUS, 0, "unknown 18" },
+ { do_bad, SIGBUS, 0, "unknown 19" },
+ { do_bad, SIGBUS, 0, "lock abort" }, /* xscale */
+ { do_bad, SIGBUS, 0, "unknown 21" },
+ { do_bad, SIGBUS, BUS_OBJERR, "imprecise external abort" }, /* xscale */
+ { do_bad, SIGBUS, 0, "unknown 23" },
+ { do_bad, SIGBUS, 0, "dcache parity error" }, /* xscale */
+ { do_bad, SIGBUS, 0, "unknown 25" },
+ { do_bad, SIGBUS, 0, "unknown 26" },
+ { do_bad, SIGBUS, 0, "unknown 27" },
+ { do_bad, SIGBUS, 0, "unknown 28" },
+ { do_bad, SIGBUS, 0, "unknown 29" },
+ { do_bad, SIGBUS, 0, "unknown 30" },
+ { do_bad, SIGBUS, 0, "unknown 31" }
};
void __init
/*
* Dispatch a data abort to the relevant handler.
*/
-asmlinkage void
+asmlinkage void __exception
do_DataAbort(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
{
- const struct fsr_info *inf = fsr_info + (fsr & 15) + ((fsr & (1 << 10)) >> 6);
+ const struct fsr_info *inf = fsr_info + fsr_fs(fsr);
+ struct siginfo info;
- if (!inf->fn(addr, fsr, regs))
+ if (!inf->fn(addr, fsr & ~FSR_LNX_PF, regs))
return;
printk(KERN_ALERT "Unhandled fault: %s (0x%03x) at 0x%08lx\n",
inf->name, fsr, addr);
- force_sig(inf->sig, current);
- show_pte(current->mm, addr);
- die_if_kernel("Oops", regs, 0);
+
+ info.si_signo = inf->sig;
+ info.si_errno = 0;
+ info.si_code = inf->code;
+ info.si_addr = (void __user *)addr;
+ arm_notify_die("", regs, &info, fsr, 0);
}
-asmlinkage void
-do_PrefetchAbort(unsigned long addr, struct pt_regs *regs)
+
+static struct fsr_info ifsr_info[] = {
+ { do_bad, SIGBUS, 0, "unknown 0" },
+ { do_bad, SIGBUS, 0, "unknown 1" },
+ { do_bad, SIGBUS, 0, "debug event" },
+ { do_bad, SIGSEGV, SEGV_ACCERR, "section access flag fault" },
+ { do_bad, SIGBUS, 0, "unknown 4" },
+ { do_translation_fault, SIGSEGV, SEGV_MAPERR, "section translation fault" },
+ { do_bad, SIGSEGV, SEGV_ACCERR, "page access flag fault" },
+ { do_page_fault, SIGSEGV, SEGV_MAPERR, "page translation fault" },
+ { do_bad, SIGBUS, 0, "external abort on non-linefetch" },
+ { do_bad, SIGSEGV, SEGV_ACCERR, "section domain fault" },
+ { do_bad, SIGBUS, 0, "unknown 10" },
+ { do_bad, SIGSEGV, SEGV_ACCERR, "page domain fault" },
+ { do_bad, SIGBUS, 0, "external abort on translation" },
+ { do_sect_fault, SIGSEGV, SEGV_ACCERR, "section permission fault" },
+ { do_bad, SIGBUS, 0, "external abort on translation" },
+ { do_page_fault, SIGSEGV, SEGV_ACCERR, "page permission fault" },
+ { do_bad, SIGBUS, 0, "unknown 16" },
+ { do_bad, SIGBUS, 0, "unknown 17" },
+ { do_bad, SIGBUS, 0, "unknown 18" },
+ { do_bad, SIGBUS, 0, "unknown 19" },
+ { do_bad, SIGBUS, 0, "unknown 20" },
+ { do_bad, SIGBUS, 0, "unknown 21" },
+ { do_bad, SIGBUS, 0, "unknown 22" },
+ { do_bad, SIGBUS, 0, "unknown 23" },
+ { do_bad, SIGBUS, 0, "unknown 24" },
+ { do_bad, SIGBUS, 0, "unknown 25" },
+ { do_bad, SIGBUS, 0, "unknown 26" },
+ { do_bad, SIGBUS, 0, "unknown 27" },
+ { do_bad, SIGBUS, 0, "unknown 28" },
+ { do_bad, SIGBUS, 0, "unknown 29" },
+ { do_bad, SIGBUS, 0, "unknown 30" },
+ { do_bad, SIGBUS, 0, "unknown 31" },
+};
+
+asmlinkage void __exception
+do_PrefetchAbort(unsigned long addr, unsigned int ifsr, struct pt_regs *regs)
{
- do_translation_fault(addr, 0, regs);
+ const struct fsr_info *inf = ifsr_info + fsr_fs(ifsr);
+ struct siginfo info;
+
+ if (!inf->fn(addr, ifsr | FSR_LNX_PF, regs))
+ return;
+
+ printk(KERN_ALERT "Unhandled prefetch abort: %s (0x%03x) at 0x%08lx\n",
+ inf->name, ifsr, addr);
+
+ info.si_signo = inf->sig;
+ info.si_errno = 0;
+ info.si_code = inf->code;
+ info.si_addr = (void __user *)addr;
+ arm_notify_die("", regs, &info, ifsr, 0);
}
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff