diff options
Diffstat (limited to 'arch/x86/kernel/entry_32.S')
| -rw-r--r-- | arch/x86/kernel/entry_32.S | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S index c8b4efad7ebb..2fae6c570fd4 100644 --- a/arch/x86/kernel/entry_32.S +++ b/arch/x86/kernel/entry_32.S @@ -80,6 +80,8 @@ #define nr_syscalls ((syscall_table_size)/4) +#define NMI_MASK 0x04000000 + #ifdef CONFIG_PREEMPT #define preempt_stop(clobbers) DISABLE_INTERRUPTS(clobbers); TRACE_IRQS_OFF #else @@ -321,8 +323,32 @@ END(ret_from_fork) # userspace resumption stub bypassing syscall exit tracing ALIGN RING0_PTREGS_FRAME + ret_from_exception: preempt_stop(CLBR_ANY) + GET_THREAD_INFO(%ebp) + movl PT_EFLAGS(%esp), %eax # mix EFLAGS and CS + movb PT_CS(%esp), %al + andl $(X86_EFLAGS_VM | SEGMENT_RPL_MASK), %eax + cmpl $USER_RPL, %eax + jae resume_userspace # returning to v8086 or userspace + testl $NMI_MASK,TI_preempt_count(%ebp) + jz resume_kernel /* Not nested over NMI ? */ + testw $X86_EFLAGS_TF, PT_EFLAGS(%esp) + jnz resume_kernel /* + * If single-stepping an NMI handler, + * use the normal iret path instead of + * the popf/lret because lret would be + * single-stepped. It should not + * happen : it will reactivate NMIs + * prematurely. + */ + TRACE_IRQS_IRET + RESTORE_REGS + addl $4, %esp # skip orig_eax/error_code + CFI_ADJUST_CFA_OFFSET -4 + INTERRUPT_RETURN_NMI_SAFE + ret_from_intr: GET_THREAD_INFO(%ebp) check_userspace: @@ -906,6 +932,10 @@ ENTRY(native_iret) .previous END(native_iret) +ENTRY(native_nmi_return) + NATIVE_INTERRUPT_RETURN_NMI_SAFE # Should we deal with popf exception ? +END(native_nmi_return) + ENTRY(native_irq_enable_sysexit) sti sysexit |