Re: [PATCH v4] ARM: Implement SLS mitigation
From: Russell King - ARM Linux admin <linux@armlinux.org.uk>
Date: 2021-02-21 10:14:41
Also in:
linux-arm-kernel, lkml
On Fri, Feb 19, 2021 at 03:08:13PM -0800, Jian Cai wrote:
quoted hunk ↗ jump to hunk
diff --git a/security/Kconfig.hardening b/security/Kconfig.hardening index 269967c4fc1b..146b75a79d9e 100644 --- a/security/Kconfig.hardening +++ b/security/Kconfig.hardening@@ -121,6 +121,16 @@ choice endchoice +config HARDEN_SLS_ALL + bool "enable SLS vulnerability hardening" + default n
Please get rid of this useless "default n"
+ depends on $(cc-option,-mharden-sls=all) + help + Enables straight-line speculation vulnerability hardening on ARM and ARM64 + architectures. It inserts speculation barrier sequences (SB or DSB+ISB + depending on the target architecture) after RET and BR, and replacing + BLR with BL+BR sequence.
Given that this is in an architecture independent Kconfig file, and it detects support in CC for this feature, why should this help text be written to be specific to a couple of architectures? Will this feature only ever be available on these two architectures? What if someone adds support for another architecture? -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!