[3/7] AArch64 - add speculation barrier

Message ID 1531154299-28349-4-git-send-email-Richard.Earnshaw@arm.com
State New
Headers show
Series
  • Mitigation against unsafe data speculation (CVE-2017-5753)
Related show

Commit Message

Richard Earnshaw (lists) July 9, 2018, 4:38 p.m.
Similar to Arm, this adds an unconditional speculation barrier for AArch64.

	* config/aarch64.md (unspecv): Add UNSPECV_SPECULAION_BARRIER.
	(speculation_barrier): New insn.
---
 gcc/config/aarch64/aarch64.md | 10 ++++++++++
 1 file changed, 10 insertions(+)

Patch

diff --git a/gcc/config/aarch64/aarch64.md b/gcc/config/aarch64/aarch64.md
index a014a01..c135ada 100644
--- a/gcc/config/aarch64/aarch64.md
+++ b/gcc/config/aarch64/aarch64.md
@@ -205,6 +205,7 @@  (define_c_enum "unspecv" [
     UNSPECV_SET_FPSR		; Represent assign of FPSR content.
     UNSPECV_BLOCKAGE		; Represent a blockage
     UNSPECV_PROBE_STACK_RANGE	; Represent stack range probing.
+    UNSPECV_SPECULATION_BARRIER ; Represent speculation barrier.
   ]
 )
 
@@ -6093,6 +6094,15 @@  (define_expand "set_clobber_cc"
 		   (match_operand 1))
 	      (clobber (reg:CC CC_REGNUM))])])
 
+;; Hard speculation barrier.
+(define_insn "speculation_barrier"
+  [(unspec_volatile [(const_int 0)] UNSPECV_SPECULATION_BARRIER)]
+  ""
+  "isb\;dsb\\tsy"
+  [(set_attr "length" "8")
+   (set_attr "type" "block")]
+)
+
 ;; AdvSIMD Stuff
 (include "aarch64-simd.md")