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authorRuss Cox <rsc@golang.org>2020-01-17 13:54:30 -0500
committerRuss Cox <rsc@golang.org>2020-03-13 19:05:54 +0000
commitfc8a6336d1ad29acf2c7728ce669df9059169132 (patch)
tree4121580d23be8c08aa0a7b0077254035ecb4473b /src/cmd/internal/obj/arm
parent877ef86bec593cd7e40899ac5446791e65b47839 (diff)
downloadgo-fc8a6336d1ad29acf2c7728ce669df9059169132.tar.xz
cmd/asm, cmd/compile, runtime: add -spectre=ret mode
This commit extends the -spectre flag to cmd/asm and adds a new Spectre mitigation mode "ret", which enables the use of retpolines. Retpolines prevent speculation about the target of an indirect jump or call and are described in more detail here: https://support.google.com/faqs/answer/7625886 Change-Id: I4f2cb982fa94e44d91e49bd98974fd125619c93a Reviewed-on: https://go-review.googlesource.com/c/go/+/222661 Reviewed-by: Keith Randall <khr@golang.org>
Diffstat (limited to 'src/cmd/internal/obj/arm')
-rw-r--r--src/cmd/internal/obj/arm/asm5.go5
1 files changed, 5 insertions, 0 deletions
diff --git a/src/cmd/internal/obj/arm/asm5.go b/src/cmd/internal/obj/arm/asm5.go
index bc55dac878..b398de2dac 100644
--- a/src/cmd/internal/obj/arm/asm5.go
+++ b/src/cmd/internal/obj/arm/asm5.go
@@ -379,6 +379,11 @@ func checkSuffix(c *ctxt5, p *obj.Prog, o *Optab) {
}
func span5(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
+ if ctxt.Retpoline {
+ ctxt.Diag("-spectre=ret not supported on arm")
+ ctxt.Retpoline = false // don't keep printing
+ }
+
var p *obj.Prog
var op *obj.Prog