diff options
| -rw-r--r-- | arch/x86/mm/fault.c | 38 |
1 files changed, 25 insertions, 13 deletions
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 7a627ac3a0d2..7e0fa7e24168 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -846,7 +846,7 @@ show_signal_msg(struct pt_regs *regs, unsigned long error_code, */ static bool is_vsyscall_vaddr(unsigned long vaddr) { - return (vaddr & PAGE_MASK) == VSYSCALL_ADDR; + return unlikely((vaddr & PAGE_MASK) == VSYSCALL_ADDR); } static void @@ -872,18 +872,6 @@ __bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code, if (is_errata100(regs, address)) return; -#ifdef CONFIG_X86_64 - /* - * Instruction fetch faults in the vsyscall page might need - * emulation. - */ - if (unlikely((error_code & X86_PF_INSTR) && - is_vsyscall_vaddr(address))) { - if (emulate_vsyscall(regs, address)) - return; - } -#endif - /* * To avoid leaking information about the kernel page table * layout, pretend that user-mode accesses to kernel addresses @@ -1192,6 +1180,14 @@ access_error(unsigned long error_code, struct vm_area_struct *vma) static int fault_in_kernel_space(unsigned long address) { + /* + * On 64-bit systems, the vsyscall page is at an address above + * TASK_SIZE_MAX, but is not considered part of the kernel + * address space. + */ + if (IS_ENABLED(CONFIG_X86_64) && is_vsyscall_vaddr(address)) + return false; + return address >= TASK_SIZE_MAX; } @@ -1359,6 +1355,22 @@ void do_user_addr_fault(struct pt_regs *regs, if (sw_error_code & X86_PF_INSTR) flags |= FAULT_FLAG_INSTRUCTION; +#ifdef CONFIG_X86_64 + /* + * Instruction fetch faults in the vsyscall page might need + * emulation. The vsyscall page is at a high address + * (>PAGE_OFFSET), but is considered to be part of the user + * address space. + * + * The vsyscall page does not have a "real" VMA, so do this + * emulation before we go searching for VMAs. + */ + if ((sw_error_code & X86_PF_INSTR) && is_vsyscall_vaddr(address)) { + if (emulate_vsyscall(regs, address)) + return; + } +#endif + /* * Kernel-mode access to the user address space should only occur * on well-defined single instructions listed in the exception |