Update to 3.4-final.
[linux-flexiantxendom0-3.2.10.git] / arch / arm / mm / fault.c
index bc0e1d8..5bb4835 100644 (file)
 #include <linux/highmem.h>
 #include <linux/perf_event.h>
 
-#include <asm/system.h>
+#include <asm/exception.h>
 #include <asm/pgtable.h>
+#include <asm/system_misc.h>
+#include <asm/system_info.h>
 #include <asm/tlbflush.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
@@ -94,7 +83,7 @@ void show_pte(struct mm_struct *mm, unsigned long addr)
 
                pud = pud_offset(pgd, addr);
                if (PTRS_PER_PUD != 1)
-                       printk(", *pud=%08lx", pud_val(*pud));
+                       printk(", *pud=%08llx", (long long)pud_val(*pud));
 
                if (pud_none(*pud))
                        break;
@@ -122,8 +111,10 @@ void show_pte(struct mm_struct *mm, unsigned long addr)
 
                pte = pte_offset_map(pmd, addr);
                printk(", *pte=%08llx", (long long)pte_val(*pte));
+#ifndef CONFIG_ARM_LPAE
                printk(", *ppte=%08llx",
                       (long long)pte_val(pte[PTE_HWTABLE_PTRS]));
+#endif
                pte_unmap(pte);
        } while(0);
 
@@ -174,7 +165,8 @@ __do_user_fault(struct task_struct *tsk, unsigned long addr,
        struct siginfo si;
 
 #ifdef CONFIG_DEBUG_USER
-       if (user_debug & UDBG_SEGV) {
+       if (((user_debug & UDBG_SEGV) && (sig == SIGSEGV)) ||
+           ((user_debug & UDBG_BUS)  && (sig == SIGBUS))) {
                printk(KERN_DEBUG "%s: unhandled page fault (%d) at 0x%08lx, code 0x%03x\n",
                       tsk->comm, sig, addr, fsr);
                show_pte(tsk->mm, addr);
@@ -230,7 +222,7 @@ static inline bool access_error(unsigned int fsr, struct vm_area_struct *vma)
 
 static int __kprobes
 __do_page_fault(struct mm_struct *mm, unsigned long addr, unsigned int fsr,
-               struct task_struct *tsk)
+               unsigned int flags, struct task_struct *tsk)
 {
        struct vm_area_struct *vma;
        int fault;
@@ -252,21 +244,12 @@ good_area:
                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.
-        */
-       fault = handle_mm_fault(mm, vma, addr & PAGE_MASK, (fsr & FSR_WRITE) ? FAULT_FLAG_WRITE : 0);
-       if (unlikely(fault & VM_FAULT_ERROR))
-               return fault;
-       if (fault & VM_FAULT_MAJOR)
-               tsk->maj_flt++;
-       else
-               tsk->min_flt++;
-       return fault;
+       return handle_mm_fault(mm, vma, addr & PAGE_MASK, flags);
 
 check_stack:
-       if (vma->vm_flags & VM_GROWSDOWN && !expand_stack(vma, addr))
+       /* Don't allow expansion below FIRST_USER_ADDRESS */
+       if (vma->vm_flags & VM_GROWSDOWN &&
+           addr >= FIRST_USER_ADDRESS && !expand_stack(vma, addr))
                goto good_area;
 out:
        return fault;
@@ -278,6 +261,9 @@ 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;
+       int write = fsr & FSR_WRITE;
+       unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE |
+                               (write ? FAULT_FLAG_WRITE : 0);
 
        if (notify_page_fault(regs, fsr))
                return 0;
@@ -285,6 +271,10 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
        tsk = current;
        mm  = tsk->mm;
 
+       /* Enable interrupts if they were enabled in the parent context. */
+       if (interrupts_enabled(regs))
+               local_irq_enable();
+
        /*
         * If we're in an interrupt or have no user
         * context, we must not take the fault..
@@ -300,6 +290,7 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
        if (!down_read_trylock(&mm->mmap_sem)) {
                if (!user_mode(regs) && !search_exception_tables(regs->ARM_pc))
                        goto no_context;
+retry:
                down_read(&mm->mmap_sem);
        } else {
                /*
@@ -315,14 +306,41 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
 #endif
        }
 
-       fault = __do_page_fault(mm, addr, fsr, tsk);
-       up_read(&mm->mmap_sem);
+       fault = __do_page_fault(mm, addr, fsr, flags, tsk);
+
+       /* If we need to retry but a fatal signal is pending, handle the
+        * signal first. We do not need to release the mmap_sem because
+        * it would already be released in __lock_page_or_retry in
+        * mm/filemap.c. */
+       if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
+               return 0;
+
+       /*
+        * Major/minor page fault accounting is only done on the
+        * initial attempt. If we go through a retry, it is extremely
+        * likely that the page will be found in page cache at that point.
+        */
+
+       perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, addr);
+       if (!(fault & VM_FAULT_ERROR) && flags & FAULT_FLAG_ALLOW_RETRY) {
+               if (fault & VM_FAULT_MAJOR) {
+                       tsk->maj_flt++;
+                       perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1,
+                                       regs, addr);
+               } else {
+                       tsk->min_flt++;
+                       perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1,
+                                       regs, addr);
+               }
+               if (fault & VM_FAULT_RETRY) {
+                       /* Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk
+                       * of starvation. */
+                       flags &= ~FAULT_FLAG_ALLOW_RETRY;
+                       goto retry;
+               }
+       }
 
-       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);
+       up_read(&mm->mmap_sem);
 
        /*
         * Handle the "normal" case first - VM_FAULT_MAJOR / VM_FAULT_MINOR
@@ -436,6 +454,12 @@ do_translation_fault(unsigned long addr, unsigned int fsr,
        pmd = pmd_offset(pud, addr);
        pmd_k = pmd_offset(pud_k, addr);
 
+#ifdef CONFIG_ARM_LPAE
+       /*
+        * Only one hardware entry per PMD with LPAE.
+        */
+       index = 0;
+#else
        /*
         * On ARM one Linux PGD entry contains two hardware entries (see page
         * tables layout in pgtable.h). We normally guarantee that we always
@@ -445,6 +469,7 @@ do_translation_fault(unsigned long addr, unsigned int fsr,
         * for the first of pair.
         */
        index = (addr >> SECTION_SHIFT) & 1;
+#endif
        if (pmd_none(pmd_k[index]))
                goto bad_area;
 
@@ -484,55 +509,20 @@ do_bad(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
        return 1;
 }
 
-static struct fsr_info {
+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, 0,             "vector exception"                 },
-       { do_bad,               SIGBUS,  BUS_ADRALN,    "alignment exception"              },
-       { do_bad,               SIGKILL, 0,             "terminal exception"               },
-       { do_bad,               SIGBUS,  BUS_ADRALN,    "alignment exception"              },
-       { do_bad,               SIGBUS,  0,             "external abort on linefetch"      },
-       { 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,  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"                       }
 };
 
+/* FSR definition */
+#ifdef CONFIG_ARM_LPAE
+#include "fsr-3level.c"
+#else
+#include "fsr-2level.c"
+#endif
+
 void __init
 hook_fault_code(int nr, int (*fn)(unsigned long, unsigned int, struct pt_regs *),
                int sig, int code, const char *name)
@@ -568,42 +558,6 @@ do_DataAbort(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
        arm_notify_die("", regs, &info, fsr, 0);
 }
 
-
-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"                       },
-};
-
 void __init
 hook_ifault_code(int nr, int (*fn)(unsigned long, unsigned int, struct pt_regs *),
                 int sig, int code, const char *name)
@@ -636,6 +590,7 @@ do_PrefetchAbort(unsigned long addr, unsigned int ifsr, struct pt_regs *regs)
        arm_notify_die("", regs, &info, ifsr, 0);
 }
 
+#ifndef CONFIG_ARM_LPAE
 static int __init exceptions_init(void)
 {
        if (cpu_architecture() >= CPU_ARCH_ARMv6) {
@@ -658,3 +613,4 @@ static int __init exceptions_init(void)
 }
 
 arch_initcall(exceptions_init);
+#endif