x86, smap: Add STAC and CLAC instructions to control user space access

[cascardo/linux.git] / arch / x86 / kernel / entry_64.S

diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 69babd8..ce87e3d 100644 (file)
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -56,6 +56,7 @@
 #include <asm/ftrace.h>
 #include <asm/percpu.h>
 #include <asm/asm.h>
+#include <asm/smap.h>
 #include <linux/err.h>
 
 /* Avoid __ASSEMBLER__'ifying <linux/audit.h> just for this.  */
@@ -465,7 +466,8 @@ END(ret_from_fork)
  * System call entry. Up to 6 arguments in registers are supported.
  *
  * SYSCALL does not save anything on the stack and does not change the
- * stack pointer.
+ * stack pointer.  However, it does mask the flags register for us, so
+ * CLD and CLAC are not needed.
  */
 
 /*
@@ -884,6 +886,7 @@ END(interrupt)
         */
        .p2align CONFIG_X86_L1_CACHE_SHIFT
 common_interrupt:
+       ASM_CLAC
        XCPT_FRAME
        addq $-0x80,(%rsp)              /* Adjust vector to [-256,-1] range */
        interrupt do_IRQ
@@ -1023,6 +1026,7 @@ END(common_interrupt)
  */
 .macro apicinterrupt num sym do_sym
 ENTRY(\sym)
+       ASM_CLAC
        INTR_FRAME
        pushq_cfi $~(\num)
 .Lcommon_\sym:
@@ -1077,6 +1081,7 @@ apicinterrupt IRQ_WORK_VECTOR \
  */
 .macro zeroentry sym do_sym
 ENTRY(\sym)
+       ASM_CLAC
        INTR_FRAME
        PARAVIRT_ADJUST_EXCEPTION_FRAME
        pushq_cfi $-1           /* ORIG_RAX: no syscall to restart */
@@ -1094,6 +1099,7 @@ END(\sym)
 
 .macro paranoidzeroentry sym do_sym
 ENTRY(\sym)
+       ASM_CLAC
        INTR_FRAME
        PARAVIRT_ADJUST_EXCEPTION_FRAME
        pushq_cfi $-1           /* ORIG_RAX: no syscall to restart */
@@ -1112,6 +1118,7 @@ END(\sym)
 #define INIT_TSS_IST(x) PER_CPU_VAR(init_tss) + (TSS_ist + ((x) - 1) * 8)
 .macro paranoidzeroentry_ist sym do_sym ist
 ENTRY(\sym)
+       ASM_CLAC
        INTR_FRAME
        PARAVIRT_ADJUST_EXCEPTION_FRAME
        pushq_cfi $-1           /* ORIG_RAX: no syscall to restart */
@@ -1131,6 +1138,7 @@ END(\sym)
 
 .macro errorentry sym do_sym
 ENTRY(\sym)
+       ASM_CLAC
        XCPT_FRAME
        PARAVIRT_ADJUST_EXCEPTION_FRAME
        subq $ORIG_RAX-R15, %rsp
@@ -1149,6 +1157,7 @@ END(\sym)
        /* error code is on the stack already */
 .macro paranoiderrorentry sym do_sym
 ENTRY(\sym)
+       ASM_CLAC
        XCPT_FRAME
        PARAVIRT_ADJUST_EXCEPTION_FRAME
        subq $ORIG_RAX-R15, %rsp