diff options
Diffstat (limited to 'arch/s390/mm/fault.c')
| -rw-r--r-- | arch/s390/mm/fault.c | 62 |
1 files changed, 39 insertions, 23 deletions
diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c index a0f9e730f26..fe103e891e7 100644 --- a/arch/s390/mm/fault.c +++ b/arch/s390/mm/fault.c @@ -34,7 +34,7 @@ #include <asm/asm-offsets.h> #include <asm/system.h> #include <asm/pgtable.h> -#include <asm/s390_ext.h> +#include <asm/irq.h> #include <asm/mmu_context.h> #include <asm/compat.h> #include "../kernel/entry.h" @@ -245,9 +245,12 @@ static noinline void do_fault_error(struct pt_regs *regs, long int_code, do_no_context(regs, int_code, trans_exc_code); break; default: /* fault & VM_FAULT_ERROR */ - if (fault & VM_FAULT_OOM) - pagefault_out_of_memory(); - else if (fault & VM_FAULT_SIGBUS) { + if (fault & VM_FAULT_OOM) { + if (!(regs->psw.mask & PSW_MASK_PSTATE)) + do_no_context(regs, int_code, trans_exc_code); + else + pagefault_out_of_memory(); + } else if (fault & VM_FAULT_SIGBUS) { /* Kernel mode? Handle exceptions or die */ if (!(regs->psw.mask & PSW_MASK_PSTATE)) do_no_context(regs, int_code, trans_exc_code); @@ -277,7 +280,8 @@ static inline int do_exception(struct pt_regs *regs, int access, struct mm_struct *mm; struct vm_area_struct *vma; unsigned long address; - int fault, write; + unsigned int flags; + int fault; if (notify_page_fault(regs)) return 0; @@ -296,6 +300,10 @@ static inline int do_exception(struct pt_regs *regs, int access, address = trans_exc_code & __FAIL_ADDR_MASK; perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, 0, regs, address); + flags = FAULT_FLAG_ALLOW_RETRY; + if (access == VM_WRITE || (trans_exc_code & store_indication) == 0x400) + flags |= FAULT_FLAG_WRITE; +retry: down_read(&mm->mmap_sem); fault = VM_FAULT_BADMAP; @@ -325,21 +333,31 @@ static inline int do_exception(struct pt_regs *regs, int access, * make sure we exit gracefully rather than endlessly redo * the fault. */ - write = (access == VM_WRITE || - (trans_exc_code & store_indication) == 0x400) ? - FAULT_FLAG_WRITE : 0; - fault = handle_mm_fault(mm, vma, address, write); + fault = handle_mm_fault(mm, vma, address, flags); if (unlikely(fault & VM_FAULT_ERROR)) goto out_up; - if (fault & VM_FAULT_MAJOR) { - tsk->maj_flt++; - perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, 0, - regs, address); - } else { - tsk->min_flt++; - perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, 0, - regs, address); + /* + * 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. + */ + if (flags & FAULT_FLAG_ALLOW_RETRY) { + if (fault & VM_FAULT_MAJOR) { + tsk->maj_flt++; + perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, 0, + regs, address); + } else { + tsk->min_flt++; + perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, 0, + regs, address); + } + if (fault & VM_FAULT_RETRY) { + /* Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk + * of starvation. */ + flags &= ~FAULT_FLAG_ALLOW_RETRY; + goto retry; + } } /* * The instruction that caused the program check will @@ -429,10 +447,9 @@ int __handle_fault(unsigned long uaddr, unsigned long pgm_int_code, int write) access = write ? VM_WRITE : VM_READ; fault = do_exception(®s, access, uaddr | 2); if (unlikely(fault)) { - if (fault & VM_FAULT_OOM) { - pagefault_out_of_memory(); - fault = 0; - } else if (fault & VM_FAULT_SIGBUS) + if (fault & VM_FAULT_OOM) + return -EFAULT; + else if (fault & VM_FAULT_SIGBUS) do_sigbus(®s, pgm_int_code, uaddr); } return fault ? -EFAULT : 0; @@ -485,7 +502,6 @@ int pfault_init(void) "2:\n" EX_TABLE(0b,1b) : "=d" (rc) : "a" (&refbk), "m" (refbk) : "cc"); - __ctl_set_bit(0, 9); return rc; } @@ -500,7 +516,6 @@ void pfault_fini(void) if (!MACHINE_IS_VM || pfault_disable) return; - __ctl_clear_bit(0,9); asm volatile( " diag %0,0,0x258\n" "0:\n" @@ -615,6 +630,7 @@ static int __init pfault_irq_init(void) rc = pfault_init() == 0 ? 0 : -EOPNOTSUPP; if (rc) goto out_pfault; + service_subclass_irq_register(); hotcpu_notifier(pfault_cpu_notify, 0); return 0; |