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authorBen Hutchings <ben@decadent.org.uk>2022-07-23 17:22:47 +0200
committerBorislav Petkov <bp@suse.de>2022-07-23 18:45:11 +0200
commitb648ab487f31bc4c38941bc770ea97fe394304bb (patch)
tree9731e6188db1d88ade89c18f31db30faba007bf9 /arch
parentefc72a665a61fd48c462f5248a9e3dc991398ddd (diff)
x86/speculation: Make all RETbleed mitigations 64-bit only
The mitigations for RETBleed are currently ineffective on x86_32 since entry_32.S does not use the required macros. However, for an x86_32 target, the kconfig symbols for them are still enabled by default and /sys/devices/system/cpu/vulnerabilities/retbleed will wrongly report that mitigations are in place. Make all of these symbols depend on X86_64, and only enable RETHUNK by default on X86_64. Fixes: f43b9876e857 ("x86/retbleed: Add fine grained Kconfig knobs") Signed-off-by: Ben Hutchings <ben@decadent.org.uk> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: <stable@vger.kernel.org> Link: https://lore.kernel.org/r/YtwSR3NNsWp1ohfV@decadent.org.uk
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/Kconfig8
1 files changed, 4 insertions, 4 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index e58798f636d4..1670a3fed263 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2473,7 +2473,7 @@ config RETHUNK
bool "Enable return-thunks"
depends on RETPOLINE && CC_HAS_RETURN_THUNK
select OBJTOOL if HAVE_OBJTOOL
- default y
+ default y if X86_64
help
Compile the kernel with the return-thunks compiler option to guard
against kernel-to-user data leaks by avoiding return speculation.
@@ -2482,21 +2482,21 @@ config RETHUNK
config CPU_UNRET_ENTRY
bool "Enable UNRET on kernel entry"
- depends on CPU_SUP_AMD && RETHUNK
+ depends on CPU_SUP_AMD && RETHUNK && X86_64
default y
help
Compile the kernel with support for the retbleed=unret mitigation.
config CPU_IBPB_ENTRY
bool "Enable IBPB on kernel entry"
- depends on CPU_SUP_AMD
+ depends on CPU_SUP_AMD && X86_64
default y
help
Compile the kernel with support for the retbleed=ibpb mitigation.
config CPU_IBRS_ENTRY
bool "Enable IBRS on kernel entry"
- depends on CPU_SUP_INTEL
+ depends on CPU_SUP_INTEL && X86_64
default y
help
Compile the kernel with support for the spectre_v2=ibrs mitigation.

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