diff options
| -rw-r--r-- | arch/x86_64/kernel/entry.S | 4 | ||||
| -rw-r--r-- | arch/x86_64/kernel/setup64.c | 4 | ||||
| -rw-r--r-- | include/asm-x86_64/system.h | 22 |
3 files changed, 28 insertions, 2 deletions
diff --git a/arch/x86_64/kernel/entry.S b/arch/x86_64/kernel/entry.S index 97583bb9122d..9111d55c3764 100644 --- a/arch/x86_64/kernel/entry.S +++ b/arch/x86_64/kernel/entry.S @@ -136,6 +136,10 @@ /* rdi: prev */ ENTRY(ret_from_fork) CFI_DEFAULT_STACK + push kernel_eflags(%rip) + CFI_ADJUST_CFA_OFFSET 4 + popf # reset kernel eflags + CFI_ADJUST_CFA_OFFSET -4 call schedule_tail GET_THREAD_INFO(%rcx) testl $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT),threadinfo_flags(%rcx) diff --git a/arch/x86_64/kernel/setup64.c b/arch/x86_64/kernel/setup64.c index 70f1bb808a20..07772c80cbff 100644 --- a/arch/x86_64/kernel/setup64.c +++ b/arch/x86_64/kernel/setup64.c @@ -178,6 +178,8 @@ void __cpuinit check_efer(void) } } +unsigned long kernel_eflags; + /* * cpu_init() initializes state that is per-CPU. Some data is already * initialized (naturally) in the bootstrap process, such as the GDT @@ -289,4 +291,6 @@ void __cpuinit cpu_init (void) set_debug(0UL, 7); fpu_init(); + + raw_local_save_flags(kernel_eflags); } diff --git a/include/asm-x86_64/system.h b/include/asm-x86_64/system.h index b7f66034ae7a..7b2c7aa2b06e 100644 --- a/include/asm-x86_64/system.h +++ b/include/asm-x86_64/system.h @@ -20,12 +20,13 @@ #define __RESTORE(reg,offset) "movq (14-" #offset ")*8(%%rsp),%%" #reg "\n\t" /* frame pointer must be last for get_wchan */ -#define SAVE_CONTEXT "pushq %%rbp ; movq %%rsi,%%rbp\n\t" -#define RESTORE_CONTEXT "movq %%rbp,%%rsi ; popq %%rbp\n\t" +#define SAVE_CONTEXT "pushf ; pushq %%rbp ; movq %%rsi,%%rbp\n\t" +#define RESTORE_CONTEXT "movq %%rbp,%%rsi ; popq %%rbp ; popf\t" #define __EXTRA_CLOBBER \ ,"rcx","rbx","rdx","r8","r9","r10","r11","r12","r13","r14","r15" +/* Save restore flags to clear handle leaking NT */ #define switch_to(prev,next,last) \ asm volatile(SAVE_CONTEXT \ "movq %%rsp,%P[threadrsp](%[prev])\n\t" /* save RSP */ \ @@ -157,6 +158,23 @@ struct alt_instr { */ #define clts() __asm__ __volatile__ ("clts") +static inline unsigned long __raw_local_save_flags(void) +{ + unsigned long flags; + + __asm__ __volatile__( + "# __raw_save_flags\n\t" + "pushfq ; popq %q0" + : "=g" (flags) + : /* no input */ + : "memory" + ); + + return flags; +} +#define raw_local_save_flags(flags) \ + do { (flags) = __raw_local_save_flags(); } while (0) + static inline unsigned long read_cr0(void) { unsigned long cr0; |