diff options
Diffstat (limited to 'arch/s390/mm/fault.c')
| -rw-r--r-- | arch/s390/mm/fault.c | 843 |
1 files changed, 500 insertions, 343 deletions
diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c index ed13d429a48..3f3b35403d0 100644 --- a/arch/s390/mm/fault.c +++ b/arch/s390/mm/fault.c @@ -1,8 +1,6 @@ /* - * arch/s390/mm/fault.c - * * S390 version - * Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation + * Copyright IBM Corp. 1999 * Author(s): Hartmut Penner (hp@de.ibm.com) * Ulrich Weigand (uweigand@de.ibm.com) * @@ -10,6 +8,8 @@ * Copyright (C) 1995 Linus Torvalds */ +#include <linux/kernel_stat.h> +#include <linux/perf_event.h> #include <linux/signal.h> #include <linux/sched.h> #include <linux/kernel.h> @@ -19,60 +19,64 @@ #include <linux/ptrace.h> #include <linux/mman.h> #include <linux/mm.h> +#include <linux/compat.h> #include <linux/smp.h> #include <linux/kdebug.h> -#include <linux/smp_lock.h> #include <linux/init.h> #include <linux/console.h> #include <linux/module.h> #include <linux/hardirq.h> #include <linux/kprobes.h> #include <linux/uaccess.h> - -#include <asm/system.h> +#include <linux/hugetlb.h> +#include <asm/asm-offsets.h> #include <asm/pgtable.h> -#include <asm/s390_ext.h> +#include <asm/irq.h> #include <asm/mmu_context.h> +#include <asm/facility.h> +#include "../kernel/entry.h" #ifndef CONFIG_64BIT #define __FAIL_ADDR_MASK 0x7ffff000 -#define __FIXUP_MASK 0x7fffffff #define __SUBCODE_MASK 0x0200 #define __PF_RES_FIELD 0ULL #else /* CONFIG_64BIT */ #define __FAIL_ADDR_MASK -4096L -#define __FIXUP_MASK ~0L #define __SUBCODE_MASK 0x0600 #define __PF_RES_FIELD 0x8000000000000000ULL #endif /* CONFIG_64BIT */ -#ifdef CONFIG_SYSCTL -extern int sysctl_userprocess_debug; -#endif +#define VM_FAULT_BADCONTEXT 0x010000 +#define VM_FAULT_BADMAP 0x020000 +#define VM_FAULT_BADACCESS 0x040000 +#define VM_FAULT_SIGNAL 0x080000 +#define VM_FAULT_PFAULT 0x100000 -extern void die(const char *,struct pt_regs *,long); +static unsigned long store_indication __read_mostly; + +#ifdef CONFIG_64BIT +static int __init fault_init(void) +{ + if (test_facility(75)) + store_indication = 0xc00; + return 0; +} +early_initcall(fault_init); +#endif -#ifdef CONFIG_KPROBES -static inline int notify_page_fault(struct pt_regs *regs, long err) +static inline int notify_page_fault(struct pt_regs *regs) { int ret = 0; /* kprobe_running() needs smp_processor_id() */ - if (!user_mode(regs)) { + if (kprobes_built_in() && !user_mode(regs)) { preempt_disable(); if (kprobe_running() && kprobe_fault_handler(regs, 14)) ret = 1; preempt_enable(); } - return ret; } -#else -static inline int notify_page_fault(struct pt_regs *regs, long err) -{ - return 0; -} -#endif /* @@ -100,76 +104,197 @@ void bust_spinlocks(int yes) /* * Returns the address space associated with the fault. - * Returns 0 for kernel space, 1 for user space and - * 2 for code execution in user space with noexec=on. + * Returns 0 for kernel space and 1 for user space. */ -static inline int check_space(struct task_struct *tsk) +static inline int user_space_fault(struct pt_regs *regs) { + unsigned long trans_exc_code; + /* - * The lowest two bits of S390_lowcore.trans_exc_code - * indicate which paging table was used. + * The lowest two bits of the translation exception + * identification indicate which paging table was used. */ - int desc = S390_lowcore.trans_exc_code & 3; - - if (desc == 3) /* Home Segment Table Descriptor */ - return switch_amode == 0; - if (desc == 2) /* Secondary Segment Table Descriptor */ - return tsk->thread.mm_segment.ar4; -#ifdef CONFIG_S390_SWITCH_AMODE - if (unlikely(desc == 1)) { /* STD determined via access register */ - /* %a0 always indicates primary space. */ - if (S390_lowcore.exc_access_id != 0) { - save_access_regs(tsk->thread.acrs); - /* - * An alet of 0 indicates primary space. - * An alet of 1 indicates secondary space. - * Any other alet values generate an - * alen-translation exception. - */ - if (tsk->thread.acrs[S390_lowcore.exc_access_id]) - return tsk->thread.mm_segment.ar4; - } + trans_exc_code = regs->int_parm_long & 3; + if (trans_exc_code == 3) /* home space -> kernel */ + return 0; + if (user_mode(regs)) + return 1; + if (trans_exc_code == 2) /* secondary space -> set_fs */ + return current->thread.mm_segment.ar4; + if (current->flags & PF_VCPU) + return 1; + return 0; +} + +static int bad_address(void *p) +{ + unsigned long dummy; + + return probe_kernel_address((unsigned long *)p, dummy); +} + +#ifdef CONFIG_64BIT +static void dump_pagetable(unsigned long asce, unsigned long address) +{ + unsigned long *table = __va(asce & PAGE_MASK); + + pr_alert("AS:%016lx ", asce); + switch (asce & _ASCE_TYPE_MASK) { + case _ASCE_TYPE_REGION1: + table = table + ((address >> 53) & 0x7ff); + if (bad_address(table)) + goto bad; + pr_cont("R1:%016lx ", *table); + if (*table & _REGION_ENTRY_INVALID) + goto out; + table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN); + /* fallthrough */ + case _ASCE_TYPE_REGION2: + table = table + ((address >> 42) & 0x7ff); + if (bad_address(table)) + goto bad; + pr_cont("R2:%016lx ", *table); + if (*table & _REGION_ENTRY_INVALID) + goto out; + table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN); + /* fallthrough */ + case _ASCE_TYPE_REGION3: + table = table + ((address >> 31) & 0x7ff); + if (bad_address(table)) + goto bad; + pr_cont("R3:%016lx ", *table); + if (*table & (_REGION_ENTRY_INVALID | _REGION3_ENTRY_LARGE)) + goto out; + table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN); + /* fallthrough */ + case _ASCE_TYPE_SEGMENT: + table = table + ((address >> 20) & 0x7ff); + if (bad_address(table)) + goto bad; + pr_cont(KERN_CONT "S:%016lx ", *table); + if (*table & (_SEGMENT_ENTRY_INVALID | _SEGMENT_ENTRY_LARGE)) + goto out; + table = (unsigned long *)(*table & _SEGMENT_ENTRY_ORIGIN); + } + table = table + ((address >> 12) & 0xff); + if (bad_address(table)) + goto bad; + pr_cont("P:%016lx ", *table); +out: + pr_cont("\n"); + return; +bad: + pr_cont("BAD\n"); +} + +#else /* CONFIG_64BIT */ + +static void dump_pagetable(unsigned long asce, unsigned long address) +{ + unsigned long *table = __va(asce & PAGE_MASK); + + pr_alert("AS:%08lx ", asce); + table = table + ((address >> 20) & 0x7ff); + if (bad_address(table)) + goto bad; + pr_cont("S:%08lx ", *table); + if (*table & _SEGMENT_ENTRY_INVALID) + goto out; + table = (unsigned long *)(*table & _SEGMENT_ENTRY_ORIGIN); + table = table + ((address >> 12) & 0xff); + if (bad_address(table)) + goto bad; + pr_cont("P:%08lx ", *table); +out: + pr_cont("\n"); + return; +bad: + pr_cont("BAD\n"); +} + +#endif /* CONFIG_64BIT */ + +static void dump_fault_info(struct pt_regs *regs) +{ + unsigned long asce; + + pr_alert("Fault in "); + switch (regs->int_parm_long & 3) { + case 3: + pr_cont("home space "); + break; + case 2: + pr_cont("secondary space "); + break; + case 1: + pr_cont("access register "); + break; + case 0: + pr_cont("primary space "); + break; + } + pr_cont("mode while using "); + if (!user_space_fault(regs)) { + asce = S390_lowcore.kernel_asce; + pr_cont("kernel "); + } +#ifdef CONFIG_PGSTE + else if ((current->flags & PF_VCPU) && S390_lowcore.gmap) { + struct gmap *gmap = (struct gmap *)S390_lowcore.gmap; + asce = gmap->asce; + pr_cont("gmap "); } #endif - /* Primary Segment Table Descriptor */ - return switch_amode << s390_noexec; + else { + asce = S390_lowcore.user_asce; + pr_cont("user "); + } + pr_cont("ASCE.\n"); + dump_pagetable(asce, regs->int_parm_long & __FAIL_ADDR_MASK); +} + +static inline void report_user_fault(struct pt_regs *regs, long signr) +{ + if ((task_pid_nr(current) > 1) && !show_unhandled_signals) + return; + if (!unhandled_signal(current, signr)) + return; + if (!printk_ratelimit()) + return; + printk(KERN_ALERT "User process fault: interruption code 0x%X ", + regs->int_code); + print_vma_addr(KERN_CONT "in ", regs->psw.addr & PSW_ADDR_INSN); + printk(KERN_CONT "\n"); + printk(KERN_ALERT "failing address: %016lx TEID: %016lx\n", + regs->int_parm_long & __FAIL_ADDR_MASK, regs->int_parm_long); + dump_fault_info(regs); + show_regs(regs); } /* * Send SIGSEGV to task. This is an external routine * to keep the stack usage of do_page_fault small. */ -static void do_sigsegv(struct pt_regs *regs, unsigned long error_code, - int si_code, unsigned long address) +static noinline void do_sigsegv(struct pt_regs *regs, int si_code) { struct siginfo si; -#if defined(CONFIG_SYSCTL) || defined(CONFIG_PROCESS_DEBUG) -#if defined(CONFIG_SYSCTL) - if (sysctl_userprocess_debug) -#endif - { - printk("User process fault: interruption code 0x%lX\n", - error_code); - printk("failing address: %lX\n", address); - show_regs(regs); - } -#endif + report_user_fault(regs, SIGSEGV); si.si_signo = SIGSEGV; si.si_code = si_code; - si.si_addr = (void __user *) address; + si.si_addr = (void __user *)(regs->int_parm_long & __FAIL_ADDR_MASK); force_sig_info(SIGSEGV, &si, current); } -static void do_no_context(struct pt_regs *regs, unsigned long error_code, - unsigned long address) +static noinline void do_no_context(struct pt_regs *regs) { const struct exception_table_entry *fixup; + unsigned long address; /* Are we prepared to handle this kernel fault? */ - fixup = search_exception_tables(regs->psw.addr & __FIXUP_MASK); + fixup = search_exception_tables(regs->psw.addr & PSW_ADDR_INSN); if (fixup) { - regs->psw.addr = fixup->fixup | PSW_ADDR_AMODE; + regs->psw.addr = extable_fixup(fixup) | PSW_ADDR_AMODE; return; } @@ -177,319 +302,283 @@ static void do_no_context(struct pt_regs *regs, unsigned long error_code, * Oops. The kernel tried to access some bad page. We'll have to * terminate things with extreme prejudice. */ - if (check_space(current) == 0) + address = regs->int_parm_long & __FAIL_ADDR_MASK; + if (!user_space_fault(regs)) printk(KERN_ALERT "Unable to handle kernel pointer dereference" - " at virtual kernel address %p\n", (void *)address); + " in virtual kernel address space\n"); else printk(KERN_ALERT "Unable to handle kernel paging request" - " at virtual user address %p\n", (void *)address); - - die("Oops", regs, error_code); + " in virtual user address space\n"); + printk(KERN_ALERT "failing address: %016lx TEID: %016lx\n", + regs->int_parm_long & __FAIL_ADDR_MASK, regs->int_parm_long); + dump_fault_info(regs); + die(regs, "Oops"); do_exit(SIGKILL); } -static void do_low_address(struct pt_regs *regs, unsigned long error_code) +static noinline void do_low_address(struct pt_regs *regs) { /* Low-address protection hit in kernel mode means NULL pointer write access in kernel mode. */ if (regs->psw.mask & PSW_MASK_PSTATE) { /* Low-address protection hit in user mode 'cannot happen'. */ - die ("Low-address protection", regs, error_code); + die (regs, "Low-address protection"); do_exit(SIGKILL); } - do_no_context(regs, error_code, 0); + do_no_context(regs); } -/* - * We ran out of memory, or some other thing happened to us that made - * us unable to handle the page fault gracefully. - */ -static int do_out_of_memory(struct pt_regs *regs, unsigned long error_code, - unsigned long address) +static noinline void do_sigbus(struct pt_regs *regs) { struct task_struct *tsk = current; - struct mm_struct *mm = tsk->mm; - - up_read(&mm->mmap_sem); - if (is_global_init(tsk)) { - yield(); - down_read(&mm->mmap_sem); - return 1; - } - printk("VM: killing process %s\n", tsk->comm); - if (regs->psw.mask & PSW_MASK_PSTATE) - do_group_exit(SIGKILL); - do_no_context(regs, error_code, address); - return 0; -} - -static void do_sigbus(struct pt_regs *regs, unsigned long error_code, - unsigned long address) -{ - struct task_struct *tsk = current; - struct mm_struct *mm = tsk->mm; + struct siginfo si; - up_read(&mm->mmap_sem); /* * Send a sigbus, regardless of whether we were in kernel * or user mode. */ - tsk->thread.prot_addr = address; - tsk->thread.trap_no = error_code; - force_sig(SIGBUS, tsk); - - /* Kernel mode? Handle exceptions or die */ - if (!(regs->psw.mask & PSW_MASK_PSTATE)) - do_no_context(regs, error_code, address); + si.si_signo = SIGBUS; + si.si_errno = 0; + si.si_code = BUS_ADRERR; + si.si_addr = (void __user *)(regs->int_parm_long & __FAIL_ADDR_MASK); + force_sig_info(SIGBUS, &si, tsk); } -#ifdef CONFIG_S390_EXEC_PROTECT -extern long sys_sigreturn(struct pt_regs *regs); -extern long sys_rt_sigreturn(struct pt_regs *regs); -extern long sys32_sigreturn(struct pt_regs *regs); -extern long sys32_rt_sigreturn(struct pt_regs *regs); - -static int signal_return(struct mm_struct *mm, struct pt_regs *regs, - unsigned long address, unsigned long error_code) +static noinline void do_fault_error(struct pt_regs *regs, int fault) { - u16 instruction; - int rc; -#ifdef CONFIG_COMPAT - int compat; -#endif - - pagefault_disable(); - rc = __get_user(instruction, (u16 __user *) regs->psw.addr); - pagefault_enable(); - if (rc) - return -EFAULT; + int si_code; - up_read(&mm->mmap_sem); - clear_tsk_thread_flag(current, TIF_SINGLE_STEP); -#ifdef CONFIG_COMPAT - compat = test_tsk_thread_flag(current, TIF_31BIT); - if (compat && instruction == 0x0a77) - sys32_sigreturn(regs); - else if (compat && instruction == 0x0aad) - sys32_rt_sigreturn(regs); - else -#endif - if (instruction == 0x0a77) - sys_sigreturn(regs); - else if (instruction == 0x0aad) - sys_rt_sigreturn(regs); - else { - current->thread.prot_addr = address; - current->thread.trap_no = error_code; - do_sigsegv(regs, error_code, SEGV_MAPERR, address); + switch (fault) { + case VM_FAULT_BADACCESS: + case VM_FAULT_BADMAP: + /* Bad memory access. Check if it is kernel or user space. */ + if (user_mode(regs)) { + /* User mode accesses just cause a SIGSEGV */ + si_code = (fault == VM_FAULT_BADMAP) ? + SEGV_MAPERR : SEGV_ACCERR; + do_sigsegv(regs, si_code); + return; + } + case VM_FAULT_BADCONTEXT: + case VM_FAULT_PFAULT: + do_no_context(regs); + break; + case VM_FAULT_SIGNAL: + if (!user_mode(regs)) + do_no_context(regs); + break; + default: /* fault & VM_FAULT_ERROR */ + if (fault & VM_FAULT_OOM) { + if (!user_mode(regs)) + do_no_context(regs); + else + pagefault_out_of_memory(); + } else if (fault & VM_FAULT_SIGBUS) { + /* Kernel mode? Handle exceptions or die */ + if (!user_mode(regs)) + do_no_context(regs); + else + do_sigbus(regs); + } else + BUG(); + break; } - return 0; } -#endif /* CONFIG_S390_EXEC_PROTECT */ /* * This routine handles page faults. It determines the address, * and the problem, and then passes it off to one of the appropriate * routines. * - * error_code: + * interruption code (int_code): * 04 Protection -> Write-Protection (suprression) * 10 Segment translation -> Not present (nullification) * 11 Page translation -> Not present (nullification) * 3b Region third trans. -> Not present (nullification) */ -static inline void -do_exception(struct pt_regs *regs, unsigned long error_code, int write) +static inline int do_exception(struct pt_regs *regs, int access) { +#ifdef CONFIG_PGSTE + struct gmap *gmap; +#endif struct task_struct *tsk; struct mm_struct *mm; struct vm_area_struct *vma; + unsigned long trans_exc_code; unsigned long address; - int space; - int si_code; + unsigned int flags; int fault; - if (notify_page_fault(regs, error_code)) - return; - tsk = current; - mm = tsk->mm; + /* + * The instruction that caused the program check has + * been nullified. Don't signal single step via SIGTRAP. + */ + clear_pt_regs_flag(regs, PIF_PER_TRAP); - /* get the failing address and the affected space */ - address = S390_lowcore.trans_exc_code & __FAIL_ADDR_MASK; - space = check_space(tsk); + if (notify_page_fault(regs)) + return 0; + + mm = tsk->mm; + trans_exc_code = regs->int_parm_long; /* * Verify that the fault happened in user space, that * we are not in an interrupt and that there is a * user context. */ - if (unlikely(space == 0 || in_atomic() || !mm)) - goto no_context; - - /* - * When we get here, the fault happened in the current - * task's user address space, so we can switch on the - * interrupts again and then search the VMAs - */ - local_irq_enable(); - + fault = VM_FAULT_BADCONTEXT; + if (unlikely(!user_space_fault(regs) || in_atomic() || !mm)) + goto out; + + address = trans_exc_code & __FAIL_ADDR_MASK; + perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address); + flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; + if (user_mode(regs)) + flags |= FAULT_FLAG_USER; + if (access == VM_WRITE || (trans_exc_code & store_indication) == 0x400) + flags |= FAULT_FLAG_WRITE; down_read(&mm->mmap_sem); - si_code = SEGV_MAPERR; +#ifdef CONFIG_PGSTE + gmap = (struct gmap *) + ((current->flags & PF_VCPU) ? S390_lowcore.gmap : 0); + if (gmap) { + address = __gmap_fault(address, gmap); + if (address == -EFAULT) { + fault = VM_FAULT_BADMAP; + goto out_up; + } + if (address == -ENOMEM) { + fault = VM_FAULT_OOM; + goto out_up; + } + if (gmap->pfault_enabled) + flags |= FAULT_FLAG_RETRY_NOWAIT; + } +#endif + +retry: + fault = VM_FAULT_BADMAP; vma = find_vma(mm, address); if (!vma) - goto bad_area; - -#ifdef CONFIG_S390_EXEC_PROTECT - if (unlikely((space == 2) && !(vma->vm_flags & VM_EXEC))) - if (!signal_return(mm, regs, address, error_code)) - /* - * signal_return() has done an up_read(&mm->mmap_sem) - * if it returns 0. - */ - return; -#endif + goto out_up; - if (vma->vm_start <= address) - goto good_area; - if (!(vma->vm_flags & VM_GROWSDOWN)) - goto bad_area; - if (expand_stack(vma, address)) - goto bad_area; -/* - * Ok, we have a good vm_area for this memory access, so - * we can handle it.. - */ -good_area: - si_code = SEGV_ACCERR; - if (!write) { - /* page not present, check vm flags */ - if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))) - goto bad_area; - } else { - if (!(vma->vm_flags & VM_WRITE)) - goto bad_area; + if (unlikely(vma->vm_start > address)) { + if (!(vma->vm_flags & VM_GROWSDOWN)) + goto out_up; + if (expand_stack(vma, address)) + goto out_up; } -survive: + /* + * Ok, we have a good vm_area for this memory access, so + * we can handle it.. + */ + fault = VM_FAULT_BADACCESS; + if (unlikely(!(vma->vm_flags & access))) + goto out_up; + + if (is_vm_hugetlb_page(vma)) + address &= HPAGE_MASK; /* * 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, address, write); - if (unlikely(fault & VM_FAULT_ERROR)) { - if (fault & VM_FAULT_OOM) { - if (do_out_of_memory(regs, error_code, address)) - goto survive; - return; - } else if (fault & VM_FAULT_SIGBUS) { - do_sigbus(regs, error_code, address); - return; - } - BUG(); + fault = handle_mm_fault(mm, vma, address, flags); + /* No reason to continue if interrupted by SIGKILL. */ + if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) { + fault = VM_FAULT_SIGNAL; + goto out; } - if (fault & VM_FAULT_MAJOR) - tsk->maj_flt++; - else - tsk->min_flt++; + if (unlikely(fault & VM_FAULT_ERROR)) + goto out_up; - up_read(&mm->mmap_sem); /* - * The instruction that caused the program check will - * be repeated. Don't signal single step via SIGTRAP. + * 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. */ - clear_tsk_thread_flag(tsk, TIF_SINGLE_STEP); - return; - -/* - * Something tried to access memory that isn't in our memory map.. - * Fix it, but check if it's kernel or user first.. - */ -bad_area: - up_read(&mm->mmap_sem); - - /* User mode accesses just cause a SIGSEGV */ - if (regs->psw.mask & PSW_MASK_PSTATE) { - tsk->thread.prot_addr = address; - tsk->thread.trap_no = error_code; - do_sigsegv(regs, error_code, si_code, address); - return; + if (flags & FAULT_FLAG_ALLOW_RETRY) { + if (fault & VM_FAULT_MAJOR) { + tsk->maj_flt++; + perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, + regs, address); + } else { + tsk->min_flt++; + perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, + regs, address); + } + if (fault & VM_FAULT_RETRY) { +#ifdef CONFIG_PGSTE + if (gmap && (flags & FAULT_FLAG_RETRY_NOWAIT)) { + /* FAULT_FLAG_RETRY_NOWAIT has been set, + * mmap_sem has not been released */ + current->thread.gmap_pfault = 1; + fault = VM_FAULT_PFAULT; + goto out_up; + } +#endif + /* Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk + * of starvation. */ + flags &= ~(FAULT_FLAG_ALLOW_RETRY | + FAULT_FLAG_RETRY_NOWAIT); + flags |= FAULT_FLAG_TRIED; + down_read(&mm->mmap_sem); + goto retry; + } } - -no_context: - do_no_context(regs, error_code, address); + fault = 0; +out_up: + up_read(&mm->mmap_sem); +out: + return fault; } -void __kprobes do_protection_exception(struct pt_regs *regs, - unsigned long error_code) +void __kprobes do_protection_exception(struct pt_regs *regs) { - /* Protection exception is supressing, decrement psw address. */ - regs->psw.addr -= (error_code >> 16); + unsigned long trans_exc_code; + int fault; + + trans_exc_code = regs->int_parm_long; + /* + * Protection exceptions are suppressing, decrement psw address. + * The exception to this rule are aborted transactions, for these + * the PSW already points to the correct location. + */ + if (!(regs->int_code & 0x200)) + regs->psw.addr = __rewind_psw(regs->psw, regs->int_code >> 16); /* * Check for low-address protection. This needs to be treated * as a special case because the translation exception code * field is not guaranteed to contain valid data in this case. */ - if (unlikely(!(S390_lowcore.trans_exc_code & 4))) { - do_low_address(regs, error_code); + if (unlikely(!(trans_exc_code & 4))) { + do_low_address(regs); return; } - do_exception(regs, 4, 1); + fault = do_exception(regs, VM_WRITE); + if (unlikely(fault)) + do_fault_error(regs, fault); } -void __kprobes do_dat_exception(struct pt_regs *regs, unsigned long error_code) +void __kprobes do_dat_exception(struct pt_regs *regs) { - do_exception(regs, error_code & 0xff, 0); -} - -#ifdef CONFIG_64BIT -void __kprobes do_asce_exception(struct pt_regs *regs, unsigned long error_code) -{ - struct mm_struct *mm; - struct vm_area_struct *vma; - unsigned long address; - int space; + int access, fault; - mm = current->mm; - address = S390_lowcore.trans_exc_code & __FAIL_ADDR_MASK; - space = check_space(current); - - if (unlikely(space == 0 || in_atomic() || !mm)) - goto no_context; - - local_irq_enable(); - - down_read(&mm->mmap_sem); - vma = find_vma(mm, address); - up_read(&mm->mmap_sem); - - if (vma) { - update_mm(mm, current); - return; - } - - /* User mode accesses just cause a SIGSEGV */ - if (regs->psw.mask & PSW_MASK_PSTATE) { - current->thread.prot_addr = address; - current->thread.trap_no = error_code; - do_sigsegv(regs, error_code, SEGV_MAPERR, address); - return; - } - -no_context: - do_no_context(regs, error_code, address); + access = VM_READ | VM_EXEC | VM_WRITE; + fault = do_exception(regs, access); + if (unlikely(fault)) + do_fault_error(regs, fault); } -#endif #ifdef CONFIG_PFAULT /* * 'pfault' pseudo page faults routines. */ -static ext_int_info_t ext_int_pfault; -static int pfault_disable = 0; +static int pfault_disable; static int __init nopfault(char *str) { @@ -499,25 +588,31 @@ static int __init nopfault(char *str) __setup("nopfault", nopfault); -typedef struct { - __u16 refdiagc; - __u16 reffcode; - __u16 refdwlen; - __u16 refversn; - __u64 refgaddr; - __u64 refselmk; - __u64 refcmpmk; - __u64 reserved; -} __attribute__ ((packed, aligned(8))) pfault_refbk_t; +struct pfault_refbk { + u16 refdiagc; + u16 reffcode; + u16 refdwlen; + u16 refversn; + u64 refgaddr; + u64 refselmk; + u64 refcmpmk; + u64 reserved; +} __attribute__ ((packed, aligned(8))); int pfault_init(void) { - pfault_refbk_t refbk = - { 0x258, 0, 5, 2, __LC_CURRENT, 1ULL << 48, 1ULL << 48, - __PF_RES_FIELD }; + struct pfault_refbk refbk = { + .refdiagc = 0x258, + .reffcode = 0, + .refdwlen = 5, + .refversn = 2, + .refgaddr = __LC_CURRENT_PID, + .refselmk = 1ULL << 48, + .refcmpmk = 1ULL << 48, + .reserved = __PF_RES_FIELD }; int rc; - if (!MACHINE_IS_VM || pfault_disable) + if (pfault_disable) return -1; asm volatile( " diag %1,%0,0x258\n" @@ -526,18 +621,20 @@ int pfault_init(void) "2:\n" EX_TABLE(0b,1b) : "=d" (rc) : "a" (&refbk), "m" (refbk) : "cc"); - __ctl_set_bit(0, 9); return rc; } void pfault_fini(void) { - pfault_refbk_t refbk = - { 0x258, 1, 5, 2, 0ULL, 0ULL, 0ULL, 0ULL }; - - if (!MACHINE_IS_VM || pfault_disable) + struct pfault_refbk refbk = { + .refdiagc = 0x258, + .reffcode = 1, + .refdwlen = 5, + .refversn = 2, + }; + + if (pfault_disable) return; - __ctl_clear_bit(0,9); asm volatile( " diag %0,0,0x258\n" "0:\n" @@ -545,10 +642,15 @@ void pfault_fini(void) : : "a" (&refbk), "m" (refbk) : "cc"); } -static void pfault_interrupt(__u16 error_code) +static DEFINE_SPINLOCK(pfault_lock); +static LIST_HEAD(pfault_list); + +static void pfault_interrupt(struct ext_code ext_code, + unsigned int param32, unsigned long param64) { struct task_struct *tsk; __u16 subcode; + pid_t pid; /* * Get the external interruption subcode & pfault @@ -556,63 +658,118 @@ static void pfault_interrupt(__u16 error_code) * in the 'cpu address' field associated with the * external interrupt. */ - subcode = S390_lowcore.cpu_addr; + subcode = ext_code.subcode; if ((subcode & 0xff00) != __SUBCODE_MASK) return; - - /* - * Get the token (= address of the task structure of the affected task). - */ - tsk = *(struct task_struct **) __LC_PFAULT_INTPARM; - + inc_irq_stat(IRQEXT_PFL); + /* Get the token (= pid of the affected task). */ + pid = sizeof(void *) == 4 ? param32 : param64; + rcu_read_lock(); + tsk = find_task_by_pid_ns(pid, &init_pid_ns); + if (tsk) + get_task_struct(tsk); + rcu_read_unlock(); + if (!tsk) + return; + spin_lock(&pfault_lock); if (subcode & 0x0080) { /* signal bit is set -> a page has been swapped in by VM */ - if (xchg(&tsk->thread.pfault_wait, -1) != 0) { + if (tsk->thread.pfault_wait == 1) { /* Initial interrupt was faster than the completion * interrupt. pfault_wait is valid. Set pfault_wait * back to zero and wake up the process. This can * safely be done because the task is still sleeping * and can't produce new pfaults. */ tsk->thread.pfault_wait = 0; + list_del(&tsk->thread.list); wake_up_process(tsk); put_task_struct(tsk); + } else { + /* Completion interrupt was faster than initial + * interrupt. Set pfault_wait to -1 so the initial + * interrupt doesn't put the task to sleep. + * If the task is not running, ignore the completion + * interrupt since it must be a leftover of a PFAULT + * CANCEL operation which didn't remove all pending + * completion interrupts. */ + if (tsk->state == TASK_RUNNING) + tsk->thread.pfault_wait = -1; } } else { /* signal bit not set -> a real page is missing. */ - get_task_struct(tsk); - set_task_state(tsk, TASK_UNINTERRUPTIBLE); - if (xchg(&tsk->thread.pfault_wait, 1) != 0) { + if (WARN_ON_ONCE(tsk != current)) + goto out; + if (tsk->thread.pfault_wait == 1) { + /* Already on the list with a reference: put to sleep */ + __set_task_state(tsk, TASK_UNINTERRUPTIBLE); + set_tsk_need_resched(tsk); + } else if (tsk->thread.pfault_wait == -1) { /* Completion interrupt was faster than the initial - * interrupt (swapped in a -1 for pfault_wait). Set - * pfault_wait back to zero and exit. This can be - * done safely because tsk is running in kernel - * mode and can't produce new pfaults. */ + * interrupt (pfault_wait == -1). Set pfault_wait + * back to zero and exit. */ tsk->thread.pfault_wait = 0; - set_task_state(tsk, TASK_RUNNING); - put_task_struct(tsk); - } else + } else { + /* Initial interrupt arrived before completion + * interrupt. Let the task sleep. + * An extra task reference is needed since a different + * cpu may set the task state to TASK_RUNNING again + * before the scheduler is reached. */ + get_task_struct(tsk); + tsk->thread.pfault_wait = 1; + list_add(&tsk->thread.list, &pfault_list); + __set_task_state(tsk, TASK_UNINTERRUPTIBLE); set_tsk_need_resched(tsk); + } } +out: + spin_unlock(&pfault_lock); + put_task_struct(tsk); } -void __init pfault_irq_init(void) +static int pfault_cpu_notify(struct notifier_block *self, unsigned long action, + void *hcpu) { - if (!MACHINE_IS_VM) - return; + struct thread_struct *thread, *next; + struct task_struct *tsk; - /* - * Try to get pfault pseudo page faults going. - */ - if (register_early_external_interrupt(0x2603, pfault_interrupt, - &ext_int_pfault) != 0) - panic("Couldn't request external interrupt 0x2603"); + switch (action & ~CPU_TASKS_FROZEN) { + case CPU_DEAD: + spin_lock_irq(&pfault_lock); + list_for_each_entry_safe(thread, next, &pfault_list, list) { + thread->pfault_wait = 0; + list_del(&thread->list); + tsk = container_of(thread, struct task_struct, thread); + wake_up_process(tsk); + put_task_struct(tsk); + } + spin_unlock_irq(&pfault_lock); + break; + default: + break; + } + return NOTIFY_OK; +} - if (pfault_init() == 0) - return; +static int __init pfault_irq_init(void) +{ + int rc; - /* Tough luck, no pfault. */ + rc = register_external_irq(EXT_IRQ_CP_SERVICE, pfault_interrupt); + if (rc) + goto out_extint; + rc = pfault_init() == 0 ? 0 : -EOPNOTSUPP; + if (rc) + goto out_pfault; + irq_subclass_register(IRQ_SUBCLASS_SERVICE_SIGNAL); + hotcpu_notifier(pfault_cpu_notify, 0); + return 0; + +out_pfault: + unregister_external_irq(EXT_IRQ_CP_SERVICE, pfault_interrupt); +out_extint: pfault_disable = 1; - unregister_early_external_interrupt(0x2603, pfault_interrupt, - &ext_int_pfault); + return rc; } -#endif +early_initcall(pfault_irq_init); + +#endif /* CONFIG_PFAULT */ |