diff options
Diffstat (limited to 'arch/x86_64/mm/fault.c')
| -rw-r--r-- | arch/x86_64/mm/fault.c | 50 |
1 files changed, 43 insertions, 7 deletions
diff --git a/arch/x86_64/mm/fault.c b/arch/x86_64/mm/fault.c index 55250593d8c9..5afcf6eb00fa 100644 --- a/arch/x86_64/mm/fault.c +++ b/arch/x86_64/mm/fault.c @@ -5,7 +5,6 @@ * Copyright (C) 2001,2002 Andi Kleen, SuSE Labs. */ -#include <linux/config.h> #include <linux/signal.h> #include <linux/sched.h> #include <linux/kernel.h> @@ -41,6 +40,41 @@ #define PF_RSVD (1<<3) #define PF_INSTR (1<<4) +#ifdef CONFIG_KPROBES +ATOMIC_NOTIFIER_HEAD(notify_page_fault_chain); + +/* Hook to register for page fault notifications */ +int register_page_fault_notifier(struct notifier_block *nb) +{ + vmalloc_sync_all(); + return atomic_notifier_chain_register(¬ify_page_fault_chain, nb); +} + +int unregister_page_fault_notifier(struct notifier_block *nb) +{ + return atomic_notifier_chain_unregister(¬ify_page_fault_chain, nb); +} + +static inline int notify_page_fault(enum die_val val, const char *str, + struct pt_regs *regs, long err, int trap, int sig) +{ + struct die_args args = { + .regs = regs, + .str = str, + .err = err, + .trapnr = trap, + .signr = sig + }; + return atomic_notifier_call_chain(¬ify_page_fault_chain, val, &args); +} +#else +static inline int notify_page_fault(enum die_val val, const char *str, + struct pt_regs *regs, long err, int trap, int sig) +{ + return NOTIFY_DONE; +} +#endif + void bust_spinlocks(int yes) { int loglevel_save = console_loglevel; @@ -160,7 +194,7 @@ void dump_pagetable(unsigned long address) printk("PGD %lx ", pgd_val(*pgd)); if (!pgd_present(*pgd)) goto ret; - pud = __pud_offset_k((pud_t *)pgd_page(*pgd), address); + pud = pud_offset(pgd, address); if (bad_address(pud)) goto bad; printk("PUD %lx ", pud_val(*pud)); if (!pud_present(*pud)) goto ret; @@ -348,7 +382,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, if (vmalloc_fault(address) >= 0) return; } - if (notify_die(DIE_PAGE_FAULT, "page fault", regs, error_code, 14, + if (notify_page_fault(DIE_PAGE_FAULT, "page fault", regs, error_code, 14, SIGSEGV) == NOTIFY_STOP) return; /* @@ -358,7 +392,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, goto bad_area_nosemaphore; } - if (notify_die(DIE_PAGE_FAULT, "page fault", regs, error_code, 14, + if (notify_page_fault(DIE_PAGE_FAULT, "page fault", regs, error_code, 14, SIGSEGV) == NOTIFY_STOP) return; @@ -383,7 +417,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, /* When running in the kernel we expect faults to occur only to * addresses in user space. All other faults represent errors in the * kernel and should generate an OOPS. Unfortunatly, in the case of an - * erroneous fault occuring in a code path which already holds mmap_sem + * erroneous fault occurring in a code path which already holds mmap_sem * we will deadlock attempting to validate the fault against the * address space. Luckily the kernel only validly references user * space from well defined areas of code, which are listed in the @@ -410,8 +444,10 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, if (!(vma->vm_flags & VM_GROWSDOWN)) goto bad_area; if (error_code & 4) { - // XXX: align red zone size with ABI - if (address + 128 < regs->rsp) + /* Allow userspace just enough access below the stack pointer + * to let the 'enter' instruction work. + */ + if (address + 65536 + 32 * sizeof(unsigned long) < regs->rsp) goto bad_area; } if (expand_stack(vma, address)) |